The Two Best Ways To Build Endurance As Fast As Possible (Without Destroying Your Body) – Part 2

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Welcome to Part 2 of Chapter 2 in Beyond Training: Mastering Endurance Health & Life.

In part 1 of this chapter, you learned about the concept of polarized training, and the fact that most elite endurance athletes spend approximately 80% of their time training aerobically, 20% of their time performing high-intensity interval training, and (unlike most recreational athletes) very little time performing junk miles in the “no man's land” intensity zone of training kind of hard, but not quite hard enough.

As I highlighted in part 1, the problem with the method of polarized training is that it takes lots and lots of time. If you're going to keep nearly all of your training aerobic and relatively low intensity, you must be willing to potentially neglect family, work, friends and other hobbies – and instead devote your precious time to exercise for long periods of time at an easy pace.

And while there is nothing inherently wrong with spending lots of time training (especially if that's what you love to do) there are other methods that you can use to achieve similar fitness adaptations with significantly fewer hours (6).

So in this section, you're going to discover exactly what those alternative training methods are…and how you can be what I call an “ancestral athlete” (similar to an ancient hunter-gatherer, a persistence hunter or a primal warrior).


How Your Body Builds Endurance

Before we delve into how to build endurance without putting in dozens of hours of training each week, it’s going to be important for you to understand how your body actually builds endurance, and what the primary determinants of cardiovascular and endurance performance actually are.

Your cardiovascular performance is based on three primary variables:

1) Heart rate (how many times your heart beats per minute)

2) Stroke volume (the amount of blood pumped per heartbeat)

3) Heart contractility (the forcefulness of each actual contraction of your heart muscle)

As each of these variables increase, the amount of blood flow and oxygen supply to your exercising muscles also increases.

So at first glance, it would seem that the heart is the primary thing you need to worry about when it comes to endurance training, and aerobic training has certainly been proven as one of the best ways to improve the variables above (18). But there are important determinants of endurance success that go above and beyond simply your heart.

For example, when your muscles contract, they propel the flow of blood traveling through your veins and back to heart, which increases the amount of blood filling your heart (this is called a preload). This preload actually enhances the heart's stroke volume during exercise, making adequate contraction and strength of your skeletal muscle a major determinant of your endurance performance (12).

That's not all. Tiny powerhouses in your cells called mitochondria use oxygen to manufacture high levels of ATP energy via the breakdown of carbohydrates or fat. So if you increase your mitochondrial density, more energy becomes available to your working muscles, which allows you to produce higher amounts of force for longer periods of time.

In addition, your actual VO2max (the maximum amount of oxygen you can deliver to your muscles in a given amount of time) is a result of two variables:

1) how much blood your heart can send to your muscles (a combination of the heart rate, stroke volume and heart contractility you already learned about)

2) how much of the oxygen sent to your muscles is actually extracted from the blood and used by the muscles before the blood heads back to your heart.

The second variable above depends on oxygen delivery to active muscle fibres, and this is influenced by everything from blood flow distribution to capillary density to arterial oxygen content to local enzymatic adaptations to the number and density of mitochondria (18).

So the important question is this:

If you want to optimize your heart capacity while at the same time increasing the number and the density of your mitochondria, raising your VO2 max, and strengthening your skeletal muscles for higher force production and better venous return to your heart, is there anything comparable to or superior to long, slow aerobic training?

The answer is an unequivocal yes, and this is where HIIT enters the picture. 


HIIT Your Mitochondria

HIIT is the acronym for High Intensity Interval Training. Don't shudder too hard – it's not as bad as it sounds. I'll explain in just a bit what HIIT involves and how you can intelligently implement HIIT into an endurance training protocol without hurting yourself, but first I'll show you the proven power of how HIIT can influence the components of endurance success described above (9).

Let's begin with your mitochondria.

For years, exercise scientists have been convinced that the only way to increase mitochondrial density is with aerobic endurance training, but recent studies have proven otherwise.

Not only is an increase in the size and number of mitochondria is a proven adaptation to HIIT (8), but the mitochondrial benefit of HIIT goes way beyond just size and number. For example, all of your mitochondria contain oxidative enzymes, such as citrate synthase, malate dehydrogenase, and succinate dehydrogenase. These oxidative enzymes lead to improved metabolic function of your skeletal muscle – particularly by causing more effective fat and carbohydrate breakdown for fuel and also be accelerating energy formation from ATP.

So more oxidative enzymes means you have a higher capacity for going longer and harder.

And it turns out that an initial study (16) on the effect of HIIT training on oxidative enzymes demonstrated massive increases in skeletal muscle oxidative enzymes in subjects engaging in 7 weeks of intense cycling sprints, in which subjects performed four to ten 30-second maximal cycling sprints followed by 4-minute recovery intervals, on just three days per week.

But what about HIIT vs. aerobic cardio?

Another 6-week training study (5) compared the increase in oxidative enzymes that resulted from either:

1) four to six 30-second maximal effort cycling sprints, followed by 4.5-minute recovery bouts and performed 3 days per week (this is classic HIIT training)…


2) 40–60 minutes of steady cycling at 65% VO2 max (an easy aerobic intensity) 5 days per week.

The levels of oxidative enzymes in the mitochondria among subjects who performed the HIIT program were significantly higher – even though these folks were training at just a fraction of the volume of the aerobic group.

How could this favorable endurance adaptation happen with such short exercise periods?

It turns out that the increased mitochondrial density and oxidative enzyme activity from HIIT is caused by a completely different message-signaling pathways than traditional endurance training.

In this alternative pathway, a “master switch” is activated that promotes the favorable endurance adaption. This master switch is known as PGC-1α (pronounce this as “pee-gee-see-one-alpha” if you want to impress your friends), which stands for “peroxisome proliferator-activated receptor-g coactivator-1α”. PGC-1α causes that favorable increase in mitochodnrial density and oxidative enzyme activity, but can be activated by two completely separate signaling pathways – the calcium–calmodulin kinase (CaMK) pathway or the adenosine monophosphate kinase (AMPK) pathway (15).

Continuous, voluminous endurance training seems to activate the master PGC-1α switch via the former pathway, while intense interval training activates it via the latter pathway (see image below, courtesy of

Conveniently, this increase in oxidative enzymes can actually change your metabolism, causing you to shift into higher fat oxidation during exercise. This may seem a bit ironic, since you found out in the zones and intensity chapter that high-intensity interval training certainly burns a higher percentage of carbohydrate as a fuel while you're doing the actual intervals. But multiple studies ( 22. 27) have proven that after just a few weeks of HIIT, your fat burning becomes significantly higher and your carbohydrate burning becomes significantly lower.

So with HIIT you become a metabolically efficient, fat-burning machine in far less time than it takes to accomplish this same effect through long aerobic sessions (10).

But these benefits go above and beyond what you burn during your actual workout session. For example, many endurance athletes are also interested in weight loss (although we affectionately call it “improving our power-to-weight ratio” rather than “burning some fat off our ass”).

The good news for those of us who want this improved power-to-weight ratio is that in addition to shifting your body into higher fat oxidation during exercise, HIIT also increases your postexercise oxygen consumption (EPOC). After a hard, interval-based workout, your oxygen consumption (and thus the total amount of calories you burn after the  actual workout) remains elevated as your working muscle cells restore physiological and metabolic factors in your cells to their pre-exercise levels.

In a review article of studies on HIIT, (14) found that significantly higher EPOC values with HIIT training compared to continuous aerobic training – which translates into higher and longer calorie burning long after your workout is over.

Month after month, this “bonus” calorie burn can significantly add up.


HIIT Your VO2 Max

Next, let's see what HIIT can do to your VO2 max, your body’s upper limit for consuming, distributing and using oxygen for energy production.

In one study (9) 4 repetitions of 4-minute runs at 90%–95% of heart rate maximum, followed by 3 minutes of active recovery, performed 3 days per week for 8 weeks resulted in a 10% greater improvement in stroke volume compared to long, slow distance training 3 days per week for 8 weeks. Remember that stroke volume is one of the key components of your body's ability to deliver maximum oxygen to working muscles.

Another study (24) showed that that high-intensity intervals performed at 90%–95% of VO2 max increased left-ventricle heart mass by 12% and cardiac contractility by 13% – and these are two other significant determinants of cardiovascular capacity and oxygen delivery during exercise.

Daussin et al. (6) measured the increase in VO2max among subjects who performed 8 weeks of either  HIIT program or a continuous aerobic endurance exercise program. As you'd probably expect by  now, the increase in VO2max was significantly higher in the HIIT program (15%) compared to the continuous aerobic endurance group (9%).

Since improving cardiovascular function and increasing VO2max are two major ways to help patients with cardiovascular disease, even cardiac rehab facilities are catching on to the idea of HIIT training, and are beginning to include this style of training for heart disease patients. Even though traditional low-intensity, aerobic exercise can definitely improve heart disease risk factors, these same cardiovascular capacity improvements from interval training happen in shorter time, with fewer sessions (1).


HIIT Your Skeletal Muscle

And how about your skeletal muscle?

As you learned earlier, when your muscles contract, they propel blood back to heart, which increases the amount of blood filling your heart and the heart's subsequent stroke volume. Within just 1-2 days of HIIT training, tiny blood vessel changes begin to take place in your skeletal muscle that improve the flow of oxygen in and out of the muscle and better “match” oxygen delivery to oxygen utilization (17). These microvascular adaptations are accompanied by an actual increase in the strength of the skeletal muscle fibers themselves, which allows for even more forceful pumping potential.

In addition to improving force and contractility of skeletal muscle, HIIT also significantly lowers insulin resistance and results in a number of skeletal muscle adaptations that cause enhanced muscular fat oxidation and improved glucose tolerance (4) – yet another method by which HIIT can turn you into a fat-burning machine.

There are skeletal muscle benefits of HIIT which I've personally discovered that go above and beyond what you may find in research studies. For example, when I've exposed my body to “pain cave” style workout sessions (such as 45 minutes of hard cycling intervals), I'm not only able to dig mentally deeper, but also less likely to experience protective muscles spasms, or cramps.

This makes sense, since Tim Noakes, among other exercise scientists, has suggested that much of the cramping that endurance athletes experience during a race may in fact be due to the fact that people are calling upon their bodies to do something during a race that their bodies simply haven't been exposed to during training. For example, if your quadriceps muscles have rarely been exposed to 350 watts of power on the bicycle, and you call on them to produce that amount of power when you attempt to pass someone or surge during a race, they may simply respond by rebelling and going a protective spasm.

As your quads curl up into a thumb-sucking fetal position, you can throw back all the salt capsules you want, but it's not going to help if it has nothing to do with your hydration status and everything to do with how you actually trained.


The Problem With High-Intensity Interval Training

So it would seem that HIIT is the ultimate solution for people who have limited time to train and can't engage in the hours necessary for the polarized training approach.

But are there any problems with HIIT?

You bet.

First, there are benefits which you derive from long endurance training sessions that you simply can't touch with HIIT. For example,  researchers at the University of Western Ontario had 20 (untrained) volunteers perform six weeks of training, three times a week (18). One group ran steadily at an easy, aerobic intensity of 65% VO2max, starting with 30 minute runs and building up to 60 minutes, while the other group did 30 second sprints with four minute recoveries, starting with four repetitions and building up to six.

As expected from what we already know about HIIT, the sprint group increased their parameters of endurance performance as much or more than the easy, aerobic group. Both groups increased VO2max by around 12%, both groups increased their 2K time trial running performance by around 5% and both groups lost fat (although the HIIT group lost twice as much fat!).

But when researchers measured maximal cardiac output (Qmax), which is a measurement of the largest amount of blood your heart can pump in a given amount of time, the aerobic group increased their Qmax by 9.5%, while the sprinters didn’t experience any increase in Qmax.

So what this study tells us is that if you want to get the most bang for your buck from your endurance training by not only maximizing your much blood your muscles can utilize (with HIIT) but also by maximizing how much blood your heart can send to your muscles (with aerobic training), then you must include some semblance of long, steady workouts in your training program. In other words, HIIT works more effectively on your peripheral muscle fitness while endurance training works more effectively on your central, cardiovascular fitness.


Should You Do Crossfit?

Next, the HIIT approach is overdone by many people.

These training enthusiasts get exposed to the same kind of evidence you've just seen, but take things to an entirely unhealthy level. While I'll be one of the first to endorse HIIT as an ideal, time-effective way to build a big endurance engine, there is a definite limit to how much of this type of training you can do before it begins to cripple you – beating up your joints with excessive high impact and loading, depleting your hormones as you “sprint from a lion” every day, and leaving you mentally frayed from having to repeatedly dip into the training pain cave.

In the same way that “black hole” training can leave you exhausted, “skinny-fat” or overtrained, too much time spent top-end training can have a similar effect. And when it comes to HIIT, more is definitely not better.

Take Crossfit, for example.

CrossFit is an extreme exercise program designed to improve core strength and functional fitness through the use of strategies such as Olympic weightlifting, kettlebells, gymnastics rings, pull-up bars, and a wide variety of body weight moves and calisthenics. A typical workout may include running, rowing, rope climbs, jumping up onto and off of boxes, flipping tractor tires, carrying heavy operational gear, or bouncing medicine balls against the floor or wall. Typically, these workouts are done in a group setting with an instructor, and a great deal of emphasis is placed on beating those around you, outperforming your peers, and pushing yourself to failure.

Examples of daily CrossFit workouts include routines such as:

Three rounds for time of:
Run 800 meters with a 45 pound barbell
15 foot Rope climb, 3 ascents
135 pound Thruster, 12 reps

Complete as many rounds as possible in 20 minutes of:
10 Pull-ups
75 pound dumbbell Deadlift, 5 reps
135 pound Push-press, 8 reps

Five rounds for time of:
135 pound Deadlift, 9 reps
135 pound Hang power snatch, 6 reps
135 pound Overhead squat, 3 reps

Crossfit Endurance is a hybrid method of Crossfit training designed specifically for endurance athletes, and according to the Crossfit Endurance website, they have triathletes work up to a weekly schedule that includes “4 days of Crossfit training, 3 strength-training days and 2 days each of sport-specific training for swimming, biking and running.” (here's a sample 12 Week Crossfit Endurance program from Competitor magazine). As you can see, the “WOD's” (Workout Of The Day) in Crossfit Endurance programs are basically very similar to regular Crossfit, but with extra swimming, cycling and running HIIT thrown in.

Now don't get me wrong: Crossfit can definitely get you fit, and has indeed been proven to increase your VOmax. As a matter of fact, a very recent study (Smith, et al.) found that 10 weeks of Crossfit based high intensity power training significantly increased maximal aerobic fitness (VO2 max) and body composition.

Granted, a whopping 16% of the total recruited subjects had to drop out of the Crossfit study, citing overuse or injury for failing to complete the program and finish follow up testing – despite the fact this study included significant skill work for the improvement of the Olympic lifts and gymnastic exercises performed in Crossfit. While peer-reviewed evidence of injury rates in these type of high intensity training programs is sparse, there are emerging reports of increased rates of musculoskeletal injury and metabolic derangement from these kind of programs (2).

I've done many Crossfit workouts, and have  my own personal suspicions about why this injury and overtraining potential might be the case with Crossfit, or any program that throws too much high-intensity interval training into the mix – especially combined with hard weight training sets.

First, Olympic weightlifting, and many of the other moves performed in a workout such as Crossfit, require a great deal of attention to proper technique, and should ideally be performed with low repetitions (under 8), good form, and not necessarily in the presence of physical exhaustion that distracts you from good form. This is simply not the case in many triathletes or endurance athletes who are combining high repetition snatches or heavy clean-and-jerks with sprinting, tire flips and rowing – especially for those individuals who are new to such a program and are simply jumping in and replicating or attempting to beat what their peers are doing during the workout.

Next, having a set number of reps that you must complete “for time” (i.e. as many rounds of row, push-press and pull-ups as you can do in 20 minutes), forces many type-A endurance athletes to push themselves harder than they might normally go without necessarily listening to the body's natural warning signs to slow down or stop. This can often result in “forcing” the body through a particular motion even if the supporting muscular is fatigued. When you're subjecting your joints to the strain of hammering in and out of an exhausted, poorly performed overhead press or a swinging, ballistic pull-up, it should come as no surprise when the shoulders begin to grind and hurt during the next day's swim workout.

Next, the majority of HIIT studies that show HIIT to be efficacious, without high injury drop-out rates, are using HIIT very infrequently, with small and potent doses spread sparingly through the week –  in contrast to the frequent, often daily CrossFit style exposure to intense intervals combined with heavy weight training. For example, when I was at the 2010 USA Triathlon Art & Science of Triathlon Coaching Symposium, a HIIT researcher named Stephen McGregor introduced a HIIT training routine that has been shown in research to lead to incredibly significant increases in power output, peak power and VO2 max. It goes like this:

-Start @ 4 x 30 seconds maximum sprints, with two to four minutes rest after each sprint, just three times per week.

-Gradually increase this to 10 x 30 second sprints with 2.5 minutes rest, again just three times per week

-Do this for for 7 weeks, for a total of 6.5-15 minutes of actual HIIT per week.

But instead of this minimalist, high-quality approach, many people who are implementing HIIT into their training routines, (including CrossFitters) are easily doing twice the volume described above – not just in a week, but in a single day!

Finally, your time in the gym should primarily be spent getting strong and developing clean and functional movement patterns that  enhance balance, symmetry and stability – and not building your muscular and cardiovascular endurance, or trying to compete for time or points while simultaneously pushing through soreness and fatigue. This is a concept that I write about extensively in my book Weight Training for Triathlon: The Ultimate Guidebook.  With the high amounts of metabolic conditioning that any endurance athlete experiences while swimming, bicycling or running, it can become very easy to pile on excessive metabolic stress when more of this same conditioning is experienced in a gym setting. The way I like to think about it is this: use the gym for strength, and work on your endurance elsewhere.

So ultimately (and I write about this more extensively in this article on How To Combine Crossfit With Endurance Training), here’s the problem with Crossfit.

If the highly anaerobic and power/strength demanding Crossfit workouts are performed in a typical carbohydrate depleted state by a triathlete or endurance athlete who is engaging in heavy bouts of aerobic training simultaneous to Crossfit involvement, the result is poor form and increased risk of injury during the actual Crossfit routine combined with sacrificed biomechanics and hormonal imblances from Crossfit-induced soreness/fatigue during any subsequent aerobic swim, bike or run sessions.

In other words, aerobic athletes and triathletes cannot have their Crossfit cake and eat it too, and I guarantee that if you’re doing a “proper” Crossfit program and combining it with a “proper” triathlon or endurance training program, there is absolutely no chance that you are giving your testosterone:cortisol ratio or inflammatory response to exercise an adequate time to recover, which results in lowering of your immune system, excessive loading of soft tissue and joints, and increased risk of overtraining syndrome.

And while perhaps it is simply a consequence of the type of self-quantified Crossfitters who are going out of the way to test their own blood markers, as a wellness practitioner for WellnessFX, I see the biomarker values of many, many Crossfitters each week – and they tend to be some of the most hormonally depleted and beat up folks for whom I consult. And if you don't want this type of hormonal mileiu to result in the kind of adrenal fatigue you'll see in the graph below (courtesy my first piece of advice is typically to back off Crossfit and add in more recovery sessions, easy swims, yoga, sleep, rest and calorie intake.

So can you do a program such as Crossfit right, and avoid the kind of adrenal fatigue you see in graph above? 


There are fantastic Crossfit coaches who design workouts and training routines with a specific strategy designed to allow for proper rest and recovery combined with good attention to form, without the pressure on participants to completely bury themselves on five, six or seven days of the week as some kind of badge of honor. There is actual attention paid to elements such as tissue quality, mobility, technical proficiency, proper progression of workouts and proper movement patterns. A very good book if you want to do Crossfit the right way is written by Brian Mackenzie and is called “Power, Speed, Endurance“.

But in many cases, Crossfit also serves as a perfect example of how HIIT training can be overdone if you're not careful. 


How To Do Polarized Training the Right Way

Now you know that if you have lots of time on your hands, you can build endurance effectively by performing 80% of your training in a very easy, aerobic zone and 20% of of your training in a very hard, anaerobic zone. This is called polarized training, and the biggest mistake most people make with this approach is not doing the easy 80% easy enough and not doing the hard 20% hard enough.

So how can you do polarized training the right way?

I'm not great at math, so let's use a simple weekly training volume number to work with – say, 20 hours. Begin by allocating 16 hours (80% of these 20 hours) to easy, aerobic training. If you want to know how to find out what your aerobic training heart rate zone is, then go back and read Chapter 1 or use the easy two steps of Phil Maffetone “180-age” formula below (from

1. Subtract your age from 180.

2. Modify this number by selecting among the following categories the one that best matches your fitness and health profile:

 a. If you have or are recovering from a major illness (heart disease, any operation or hospital stay, etc.) or are on any regular medication, subtract an additional 10.

 b. If you are injured, have regressed in training or competition, get more than two colds or bouts of flu per year, have allergies or asthma, or if you have been inconsistent or are just getting back into training, subtract an additional 5.

 c. If you have been training consistently (at least four times weekly) for up to two years without any of the problems just mentioned, keep the number (180–age) the same.

 d. If you have been training for more than two years without any of the problems listed above, and have made progress in competition without injury, add 5.

Once you have determined the proper intensity for your unique body, most of your polarized sessions (16 hours) should be performed at a long, easy, aerobic intensity, with another 4 hours per week being allocated to HITT.

For example, if you're a triathlete, 4 hours of HIIT allows you enough time to perform one or two intense interval training sessions each week for the swim, bike and run. This might be two 30 minute swim workouts comprised of 25-200 meter repeats, a 1.5-2 hour bike workout with 8-10 short steep hard hill climbs and full recovery after each climb, one track intervals running workout one hill repeats running workout. If you simply cannot physically perform your HIIT sessions above your lactic acid threshold (or a relatively anaerobic state) then you're probably doing your aerobic sessions too hard.

Now of course, this is all painting with a fairly broad brush. There is actually an entire branch of exercise training and science devoted to the concept of “periodization“, which dictates splitting your build-up to an event or race into periods of the year that have a specific training focus. In a traditional periodization model based on polarized training, you may end up training closer to 90/10 during the off-season and 70/30 as you build-up to a race. Or from an ever longer term periodization perspective, an athlete on a 4 year Olympics development plan may be skewed towards a higher percentage of aerobic training early in the process, and as the years progress towards the Olympics, gradually include more and more race-intensity paced intervals.

But this book is about how the average, everyday athlete can train for endurance while tackling the the delicate balance between health and performance, and part of that is keeping things relatively simple. If you were to graph your training intensity for any given year, you'd come out very close to 80/20.

If this whole polarized training thing sounds like a lot of potentially exhausting time spent exercising, you're right: it definitely is. So how on earth do professional endurance athletes pull off this type of approach, for as many as 25-35 hours a week, without being completely crushed by the stress? Mark Sisson gives an excellent perspective on this conundrum in his book “The Primal Connection” – in which he describes how a major factor at play in the success of a pro endurance athlete is the absence of significant work stress, deadlines, office obligations, etc. in the life of someone who is able to devote most of their time to training.

Here's how Mark puts it in a section of his book in which he describes his experiences coaching a team of world-ranked professional triathletes, and comparing their lives to that of the amateur triathlete:

“The typical amatueur triathlete was a type-A overachiever with a demanding career and a busy family life. Fitting in the requisite workouts was a constant juggling act between work and family obligations. The word “squeeze” was used repeatedly to describe scheduling efforts, starting with the morning alarm and an abrupt commencement of the day's first workout. Pacing seemed to be an obsession, not just for tracking workout speed, but minding the clock at all times in order to remain “on time” for every item on the packed daily agenda. The popular “quick lunchtime swim workout” referred more to the peripherals than the lap times – rushing out of the office, a presto change-o in the locke room, a one-minute post-workout shower, and then bursting back into the office an hour later with water beads still dripping from hair onto collar.

In contrast, the professional athletes – whose job was to simply race fast – lived lives centered around their workouts with minimal interference from real-life distractions or social obligations. While the pros conducted their workouts aggressively, the pace of their lives was leisurely  Lunch time swim? Sure, but instead of toweling off, jerking the tie back into place and rushing out to the parking lot, the post-swim routine the pros consisted of lingering in the poolside spa for nearly as long as the workout, shooting the breeze, stretching tight muscles, and generally decompressing from the intense effort in the wate.r Eventually, the pack moved from the spa into an easy lunch involving more shooting of the breeze. Eventually, they remounted their bikes for a couple more hours of pedaling, then took an afternoon nap, followed by a late-day run, followed by a stretching/icing session, followed by a quiet evening of television, reading or lingering over a huge meal. As I spent more time in their world, I learned that the competitive advantage enjoyed by these professionals went beyond their impressive workouts. Embracing life both with purpose and at a more leisurely pace produces extraordinary results…”

In a nutshell, stress is stress – not matter whether it's from exercise or from lifestyle, and the more stress you're placing on yourself from your lifestyle, the less stress you'll be able to place on yourself from exercise.


How To Do HIIT the Right Way

And what if you don't have time to do polarized training, you don't want to waste your time with junk miles, but you also don't want to damage your body with excessive HIIT?

What I'm about to explain to you is exactly how I personally train for endurance, and is very similar to the method that I use with most of my clients and athletes.

I call this “Ancestral Athlete” approach, and here is why.

If you take a glance at our modern sedentary lifestyles, combined with our post-industrial diets, we have pushed ourselves far from above and beyond what our bodies are conditioned to expect. Use your imagination for a moment to picture the typical post-industrial day of sitting in an office surrounding by electromagnetic frequencies, deadlines, stress and fake food.

Now contrast this “death by sitting” day with the more natural life our ancestors lived – which involved relatively high amounts of low intensity physical activity – time spent hunting, gathering, farming or gardening. These low intensity (but hardly sedentary) days were combined with sudden bursts of high energy, such as when it became necessary to run from a lion, move a heavy rock or log, or engage in hand-to-hand combat. And it was very rare to spend several hours a week simply training mindlessly at a threshold pace, since this would be a great way to deplete energy stores and beat up the body with no practical benefits.

Think of it this way: until the recent industrial era, life was a constant physical challenge. We didn't have refrigerators, preservatives, microwaves, fast food or pizza delivery to help us put dinner on the table. Rather than jetting to the grocery store with a credit card, we'd wander on the plains with a weapon, or go out to gather grasses, grains, fruits and vegetables – and we'd expend extra energy properly preparing those natural foods. And while there were certainly drawbacks to this seemingly crude or uncomfortable mode of existence, the benefits for physical fitness and endurance-building were potent.

An ancestral approach to training is based around the theory that we are naturally designed to perform high amounts of low level physical activity combined with an occasional very high intensity burst – and when it comes to the delicate trade-off between health and performance this allows for building endurance without inflicting significant physical and metabolic damage.

Living and training in this ancestral manner means respecting our ancestors and thinking critically about how the environmental and training stresses we place on our bodies affects our health positive or negative ways. You may want to check out or listen to my interview with Art De Vany if you want to learn more about how the ancestral concept applies to not only to training, but also to life in general.

Of course, I'm all about the in-the-trenches application of these philosophies. After all, you can dream about hunter-gatherers all day long, but it doesn't help if you're still heading out the door everyday at lunch to pound the pavement for an hour.

So let's see what the Ancestral Athlete approach would look like, using an Ironman triathlon training routine as an example.

A sample week of training (very similar to the training approach in my “Triathlon Dominator” and “Tri-Ripped” triathlon training programs) should be based around one mid to long aerobic session per week for swimming, cycling and running. This session should be devoted to a high amount of time spent in Zone 2, with focused Zone 3, race-pace intervals. For Ironman, this could be a 2-3 hour focused interval training session on the bike, a 60-90 minute high-quality run and a 45-60 minute swim that incorporates longer 400-1000m intervals.

And here is the important key of the Ancestral Athlete approach: the remainder of your aerobic, physically active training should be accomplished by simply staying as active as possible throughout the day. You'll learn many “biohacks” later in this book (such as treadmill workstations, cold thermogenesis, electrical stimulation, suspension trainers, etc.) that allow you to implement this concept more easily and naturally into your every day life, but examples include:

Standing and walking as much as possible (I stand 6-8 hours per day while working, and often conduct phone calls and consults while walking)…

-Never sitting for longer than an hour at a time without standing and doing 50-100 jumping jacks, 5 doorway pull-ups, 20 push-ups or squats or some other calisthenic movement…

-Spending as much time as possible outdoors in the fresh air, sunshine, experiencing both hot and cold temperature fluctuations, and avoiding carrying your phone, electronics and other electrical devices…

-Lifting something heavy everyday (I usually flip a tire a few times, or load up a barbell in the garage)…

-Commuting whenever possible, whether on a mountain bike, by foot, or even by learning new modes of movement such as Parkour, MovNat or Fitness Exploring… 

-Beginning every day with cold showers to spark the metabolism, followed by deep breathing and stretching…

-Learning how to breathe, stand and move properly so that your aerobic metabolism stays elevated throughout the day…

Once these long session are programmed into your week on the days that create the least lifestyle stress for you (typically the weekend for the average, everyday athlete), and light physical activity is naturally worked into your life, you can then inject brief bouts of high quality intense workouts and structured weight training sessions throughout week – but only performed if you feel completely rested and ready to do them with perfect form. 

Using these concepts, an Ironman triathlon training week would look like this:

-Monday: 30 minutes easy bicycling skills & drills, 20 minutes easy swim drills.

-Tuesday: 20 minutes heavy barbell lifts, 30 minutes run HIIT workout.

-Wednesday: 30 minutes bicycling HIIT workout, 30 minutes swim HIIT workout.

-Thursday: 20 minutes heavy barbells lifts, 30 minutes easy run drills.

-Friday: 60 minutes injury prevention and core training, yoga, or an easy swim.

-Saturday: 2.5 hours of 20 minutes on, 5 minutes off cycling intervals at race-pace, 3x1000m swim at race-pace

-Sunday: 60-90 minutes of 9 minutes on, 3 minutes off running intervals at race-pace.

It's important to understand that this “train less” approach will only work if your body is primed for optimal health, which you're going to learn exactly how to accomplish in future chapters.

And although this brief description of an Ancestral Athlete training week may seem like it merely scratches the surface of what a typical training protocol would look like, don't worry…

…in later chapters of Beyond Training (click here for full description of everything you'll learn in this book), I'll be teaching you every biohack, healthy living component, recovery protocol, nutrition blueprint, and every strategy you need to ensure that you're able to proceed in training and beyond training with zero guesswork.


Sidebar Note: “Am I Too Old For HIIT”?

One concern repeatedly expressed to me by older athletes is the fear of tearing a muscle, getting a sprain or strain, or developing a stress fracture from the high intensities experienced during a HIIT training session.

It's true that it can certainly get a bit more difficult to jump, sprint, and move just as powerfully as you may have been able to do in your younger years. There are a few reasons why:

1) Your metabolism decreases with age, by about 10% from your 30’s to your 60’s, and a further 10% from your 60’s forward. This means you main gain fat more easily.

2)  Your maximum oxygen consumption decreases by significantly each decade from 25 to 65 years of age, and then decelerates even more quickly – which means intense cardiovascular efforts can be very difficult.

3) You grow less responsive to energy stimulating hormones called catecholamines (like epinephrine), and as a result, you maximum heart rate decreases, which also can decrease the intensity of hard efforts.

4)  The total amount of blood your heart pumps per beat and the ability of your muscles to extract oxygen from that blood decrease, which can affect your cardiovascular capacity.

5) Your muscle strength peaks around 25 years old, plateaus through 35 or 40 years old, and then begins to decline quickly, with 25% loss of peak strength by the time you’re 65. This is due to a loss in the number of muscle fibers.

6)  Your tendon, ligament, and joint elasticity is decreased as “cross-linkages” form between soft tissue fibers in these areas.  This can cause a loss of 2-4 inches of lower-back and hip flexibility.

7)  Your bone density decreases as the calcium content of bones gets lower and the matrix inside the bone begins to deteriorate, which can lead to increased risk of osteoporosis or fractures, especially in women.

But don't get depressed and let this information convince you that you shouldn't go near heavy weights or a track. Instead, the HIIT approach for an aging athlete can have a dramatic anti-aging effect on many of the variables listed above.

For example, hard running intervals that involve heavy breathing and burning muscles can help to boost a slowing metabolism, slow the rate of VO2 max decline, improve venous return back to the heart, and put your body through a greater flexibility enhancing mobility than a slow jog. When performed in moderation, the impact from hard running also has a potent bone-building effect.

For both bone density and staving off the loss of muscle that occurs with aging, loading of the bones and joints along the long vertical axis is very effective, and can be achieved with potent strength exercises that will be discussed later in this book, such as squats, overhead presses, chest presses, or lunges. These same strength exercises can build new neurons as you challenge your body and mind to move through movements that can be more complex than simply spinning on a bicycle.

A study done by Ana Pereira at the University of Tras-os-Montes explains that a high-speed, power-based weight training program in older individuals can increase functional capacity of the upper and lower body extremity muscles much more efficiently compared to a program that only includes slow and controlled weight training.

And both high intensity intervals and weight training can cause a catecholamine and hormonal response that keeps your maximum heart rate elevated and maintains your body in a relatively anabolic state compared to pure, low intensity cardio.

In other words, by exposing your body to the hormone rush, mental stimulation and thrill of lifting heavy stuff or sprinting, you actually stay young.

Or, in the words of 83 year old Ironman world record holder Lew Hollander:

“Go Anaerobic Every Day.” 


Questions or feedback about the two best ways to build endurance as fast as possible? Extra material you'd like to see added to this chapter of the book? Thoughts about what works well for you? Leave your comments below!


Links To Previous Chapters of “Beyond Training: Mastering Endurance, Health & Life”

Part 1 – Introduction

-Part 1 – Preface: Are Endurance Sports Unhealthy?

-Part 1 – Chapter 1: How I Went From Overtraining And Eating Bags Of 39 Cent Hamburgers To Detoxing My Body And Doing Sub-10 Hour Ironman Triathlons With Less Than 10 Hours Of Training Per Week.

-Part 1 – Chapter 2: A Tale Of Two Triathletes – Can Endurance Exercise Make You Age Faster?

Part 2 – Training

-Part 2 – Chapter 1: Everything You Need To Know About How Heart Rate Zones Work

-Part 2 – Chapter 2: The Two Best Ways To Build Endurance As Fast As Possible (Without Destroying Your Body) – Part 1

-Part 2 – Chapter 2: The Two Best Ways To Build Endurance As Fast As Possible (Without Destroying Your Body) – Part 2

Also…for those of you who like to look ahead, the rest of Part 2 is going to include:

-Training, Food and Supplement Protocols for Testing, Tracking & Enhancing Endurance, Strength, Speed, Power, Balance, Range of Motion 

-Underground Training Tactics, including EMS, Cold Thermo, Overspeed, Isometrics/Superslow, etc.


1. Bartels, M.N., Bourne, G.W., & Dwyer, J.H. 2010. High-intensity exercise for patients in cardiac rehabilitation after myocardial infarction. Physical Medicine and Rehabilitation, 2 (2), 151-55.
2. Bergeron, MF, Nindl, BC, Deuster, PA, Baumgartner, N, Kane, SF, Kraemer, WJ, Sexauer, LR, Thompson, WR, and O’Connor, FG. Consortium for Health and Military Performance and American College of Sports Medicine consensus paper on extreme conditioning programs in military personnel. Curr Sports Med Rep 10: 383-389, 2011.
3. Billat, L.V. 2001. Interval training for performance: A scientific and empirical practice. Special recommendations for middle- and long-distance running. Part I: aerobic interval training. Sports Medicine, 31(1), 13-31.
4. Boutcher, 2011. High-Intensity Intermittent Exercise and Fat Loss. Journal of Obesity. 10.1155/2011/868305
5. Burgomaster, K.A., et al. 2008. Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. Journal of Physiology, 586 (1), 151-60.
6. Daussin, F.N., et al. 2008. Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects.American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 295, R264-72.
7. de Oliveira, E.P., & Burini, R.C. 2009. The impact of physical exercise on the gastrointestinal tract. Current Opinion in Clinical Nutrition and Metabolic Care, 12 (5), 533-38.
8. Gibala, M. 2009. Molecular responses to high-intensity interval exercise. Applied Physiology, Nutrition, and Metabolism, 34 (3), 428-32.
9. Helgerud, J., et al. 2007. Aerobic high-intensity intervals improve VO2max more than moderate training. Medicine and Science in Sports and Exercise, 39 (4), 665-71.
10. Horowitz, J.F., & Klein, S. 2000. Lipid metabolism during endurance exercise. American Journal of Clinical Nutrition, 72 (2 Suppl.), 558S-63S.
11. Joyner, M.J. 1991. Modeling: Optimal marathon performance on the basis of physiological factors. Journal of Applied Physiology, 70 (2), 683-87.
12. Joyner, M.J., & Coyle, E.F. 2008. Endurance exercise performance: The physiology of champions. Journal of Physiology, 586 (1), 35-44.
13. Kubukeli, Z.N., Noakes, T.D., & Dennis, S.C. 2002. Training techniques to improve endurance exercise performances. Sports Medicine, 32 (8), 489-509.
14. LaForgia, J., Withers, R.T., & Gore, C.J. 2006. Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. Journal of Sports Science, 24 (12), 1247-64.
15. Laursen, P.B. 2010. Training for intense exercise performance: High-intensity or high-volume training? Scandinavian Journal of Medicine and Science in Sports, 20 (Suppl. 2), 1-10.
16. MacDougall, J.D., et al. 1998. Muscle performance and enzymatic adaptations to sprint interval training. Journal of Applied Physiology, 84 (6), 2138-42.
17. McKay BR, Paterson DH, Kowalchuk JM. (2009). Effect of short-term high-intensity interval training vs. continuous training on O2 uptake kinetics, muscle deoxygenation, and exercise performance. Journal of Applied Physiology. 107(1):128-38
18. MacPherson RE, Hazell TJ, Olver TD, Paterson DH, Lemon PW., 2011. Run sprint interval training improves aerobic performance but not maximal cardiac output. Medicine and Science in Sports & Exercise. 43(1):115-22.
19. Musa, D.I., et al. 2009. The effect of a high-intensity interval training program on high-density lipoprotein cholesterol in young men. Journal of Strength and Conditioning Research, 23 (2), 587-92.
20. Pauls, C., & Kravitz, L. 2010. Barefoot running: An exciting new training dimension to consider for certain clients. IDEA Fitness Journal, 7 (4), 18-20.
21. Pavlik, G., et al. 2010. The athlete’s heart Part I (Review). Acta Physiologica Hungarica, 97 (4), 337-53.
22. Perry, C.G., et al. 2008. High-intensity aerobic interval training increases fat and carbohydrate metabolic capacities in human skeletal muscle. Applied Physiology, Nutrition, and Metabolism, 33 (6), 1112-23.
23. Seiler, S., & Hetlelid, K.J. 2005. The impact of rest duration on work intensity and RPE during interval training. Medicine & Science in Sports & Exercise, 37 (9), 1601-1607.
24. Slørdahl, S.A., et al. 2004. Atrioventricular plane displacement in untrained and trained females. Medicine & Science in Sports & Exercise, 36 (11), 1871-75.
25. Smith MM, Sommer AJ, Starkoff BE, Devor ST., 2013). Crossfit-based high intensity power training improves maximal aerobic fitness and body composition. Journal of Strength and Conditioning Research, Feb 22.
26. Tabata, I., et al. 1996. Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Medicine & Science in Sports & Exercise, 28 (10), 1327-30.
27. Talanian, J.L., et al. 2007. Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women. Journal of Applied Physiology, 102 (4), 1439-47.
28. Wisløff, U., Ellingsen, Ø., & Kemi, O. J. 2009. High-intensity interval training to maximize cardiac benefits of exercise training? Exercise Sport Science Review, 37 (3), 139-46.

Ask Ben a Podcast Question

63 thoughts on “The Two Best Ways To Build Endurance As Fast As Possible (Without Destroying Your Body) – Part 2

  1. Adam says:

    Great read.

    I’m wondering, is there anything out there comparing Tabata style HIIT workouts to traditional HIIT workouts? Which would you consider to be more advantageous for all the factors mentioned in this article? For instance, would a 20sec on/10sec off, or 30 sec on/30 sec off, type of Tabata style HIIT Workout for x number of rounds produce better results than a 30 sec on/2-5 min off traditional HIIT workout for the same number of rounds?



  2. SteveToGo says:

    Hi Ben,

    I am racing the head of the charles (15-18min rowing race) mid October. Work and family commitments mean that i havent been able to do my training consistently and I am only going slower. I only seem to be able to exercise 3x per week. What do you recommend?

    1. Structured HITT

      For more: This is exactly the type of question myself, my team of coaches and the community in my Inner Circle can help to answer for you.

      The Inner Circle is a collective of people who are pursuing the same goals you are – trying to live a healthy, happy, adventurous, fulfilling and limitless life in a modern world. In the Inner Circle, we all help each other with questions, ideas, motivation, suggestions and much more!

      Here is where you access that community:

      If you prefer a more direct, customized approach, I'd be happy to help you via a personal one-on-one consult. Just go to and then choose a 20 or 60-minute consult, whichever you'd prefer. I can schedule ASAP after you get that. Additionally, if I'm "out of your price range" (yes, yes, I know I can be a spendy guy to access) I have a team of coaches I've personally trained who can help you here:…

      I hope that helps, and I look forward to getting you everything you need!

  3. Jason says:

    Hi Ben. This article is confusing. In part 1 you alluded to the fact that there is an alternative way to polarized training to increase endurance. In part 2 you introduce HIIT training as that alternative but immediately say that polarized training involves 80% slow and 20% HIIT training. If polarized training already includes HIIT training what is the point of part 2. Are you just saying you don’t really need the 80% slow training to get most of the benefits?

    1. I understand that this can be confusing but the basic idea is that if you are a professional athlete wanting to get the most ideal results possible than polarized training is the way to go because it includes the best of both worlds but it takes copious amounts of time. For most people it is much better to go with high intensity interval training because it is a much more efficient way to train

  4. Captain Hobo says:

    In the time it would take me to read that article I could just run enough to become fit

  5. Marianne says:

    Good Job….In terms of muscle endurance, increase your reps to about 12 to 15.

  6. Jo Share says:

    Thanks Ben – great article. I came across it while researching acute respiratory adaptations to exercise for my Sports Science degree and its spot on. As an endurance athlete myself will definitely be incorporating more HIIT to my training!

  7. Rama says:

    Ben I love this article and how you speak about balancing going long with HIIT. One of the things you really didn’t seam to touch was the mental training factor. I don’t know how someone who never goes long in training will be able to handle the mental battle on a long race as well as also developing a proper pacing strategy.

    1. Mental training can be practiced in the long run sessions. They still exist, there is just far fewer of them!

  8. Henric says:

    Great article !

    I can only spend 8-12 hours for training per week. I do 1-2 strength sessions (all Bodyweight exercises), 1-2 Sufferfest videos (45-60min) and long aerobic sessions of cycling and running (2-5 hours) on the weekend, length depending on how close to the races I am. Swimming is kept to a minimum of 1-2 session (1x 30-40min, 1x60min). In addition to your article, I think it is very, very important to develop a good body feeling and not just simply following a (of course necessary) plan. If you feel exhausted and tired, one or two days of extra recovery can make all the difference.

  9. Marius says:

    The HIIT studies usually last 6-8 weeks. Do you see improvement dooing HIIT Beyond that? Isn’t well established that improvements you get after those 6-8 weeks are minimal. So what to do the remaining 44 weeks of the year?

    1. Yep, I do HIIT almost every week of the year for total fitness maintenance.

  10. Max S says:

    If my only goal is increasing cardiac output, what % of heart rate should I train in? Are there any things other than long endurance runs that I can do to help with cardiac output? I’ve heard oxygen deprivation training helps strengthen lung muscles, which should be correlated with cardiac output, right?

    1. I go into each of the different modes of cardio and their effect here:…

    2. And yes, O2 dep training, diapraghmatic breathwork, hypoxic, all that can help with cardiac output, but nothing beats intense intervals in 2-5 minute period of time for that.

  11. Graham Finlayson says:

    Hi Ben,

    First of all, brilliant article, I love reading your article.

    Please Please, can you help with this question.

    I am trying incorporate runs into my workouts, I want to weight train, play football twice per week and do the above, but need recovery days. So ideally 2 runs, 2 football, 2 gym sessions and 1 recovery/foam rolling day.

    My cardio post weight sessions and runs I am trying to keep at 146 zone so try and improve my base running. I am currently around 1.5 stone overweight and poor fitness, so the footballing sessions are really challenging( I used to play at a semi pro level) so I can build up to this standard. Just need some advice trying to fit it in. I don’t plan on doing marathons, but swim a lot after my workouts.

    thanks Ben.

  12. Mal says:

    Ben, I like reading your website and the scientific studies adds value to the info you publish. However, things like “Ben’s Encoder” dont help your cause mate!

  13. Daniel says:

    Hi Ben. Wow I’m blown away by these articles , really eye opening and amazing, keep up the great work! Pondering for some advice: I’m a 15 year old boy who sails at national level. Sailing requires endurance (6 hour days) operating with medium intensity (around 50 mins of 140-170bpm). Quads are contracted isometrically, so blood flow is restricted, causing lots of lactic acid build up. Could you recommend some kind of programme focussing on cardio endurance for someone like me? Cheers :)

    1. Book some time with me here… and we'll get you sorted out!

  14. onebodyd4l says:

    Hi Ben – really like the articles. I'm all for looking at long term health when designing training programs. For doing the polarized training, what is the minimum number of hours for this to be effective? Also have I understood correctly that for minimalist program that the aerobic sessions are more like prolonged interval sessions going in and out of Z3/Z4?

    1. For some expert polarized training info you should check out… and yes, the minimalist replacement for aerobic sessions is often a "progression workout" that starts in z2 and increases after a time or distance interval.

  15. Adam says:

    I understand how you could periodize when using polarized training: MAF in Base, Speed in Build, etc. If I'm using short HIIT training techniques how would Build differ from Base and Peak? -Adam

    1. You mean for your cardio sessions? The HIIT just gets more specific. You start using bricks more if triathlete, doing more hills if hilly course, doing more longer race specific zone 3 intervals (vs very few in base), etc.

      1. Adam says:

        Yes cardio, and thanks that makes sense.

        So my typical work day gives me 30 minutes during lunch, and I started using the HIIT run workout you mentioned: roughly 4 x 30 with 4 minute rest in between and slightly increasing the rest pace as well as the sprint pace every week. I'm really loving this workout, and I definitely feel like I'm getting more bang for my buck in such a short time slot. Is this considered a Base workout, and I should keep progressing into Build by getting closer and closer to running the whole session at my goal race pace? ( same idea for cycling and swimming ). Thanks much, Adam

        1. As you get into build, you'd add more repeats with shorter rest. Build just means more intensity and more volume!

          1. Adam says:

            Gotcha. Thanks so much for helping me get higher quality workouts in a crunched schedule!

  16. Jay says:

    Another awesome post! There’s more information about endurance in one place than I could find. Great! Need this for the summer training. Thank you for your site!


  17. Tim says:

    Thanks for the great information…very interesting. Is it recommended that your aerobic base workouts and your HIIT workouts be seperate from one another. Can you get the same results if you combine zone 2 and zone 4+ into each of your daily workouts? For example, if I bike 3 times per week and run 3 times per week, and each workout (regardless of distance), contains 80% zone 2 and 20% zone 4+ would I receive the same benefits?

    1. Tough to say on this because there's no research. You'd need to use yourself as an “n=1” experiment for this!

  18. Eric says:

    I just moved to a new office and, based on your recommendation, created a standing desk. Getting all sorts of comments and looks, but looking forward to the benefits for ultrarunning and health in general.

  19. @chickpea_22 says:

    Great stuff Ben. How would you apply this concept to marathon training? Currently I do hill repeats, mile repeats and a long run of 2-3 hours each once a week. Twice a week I hit the gym and do supersets. I also do some flexibility, balance and mobility work throughout the week. Thanks.

    1. I'd recommend you do 2 strength sessions, 1 HIIT session, 1 Hill session and 1 longer structured interval run per week, along with 1-2 “cross training” session (sports, elliptical, water running, etc), along with the mobility work you're already doing! I plan on including a marathon training plan along with the book when it is published!Ben

  20. Richard Jones says:

    Regarding McGregor's HIIT routine, when you say rest between 30 second sprints, what exactly do you mean? Stop moving? Walk? Jog? And by sprint do you mean our maximum effort that we can maintain for 30 seconds? Or do you mean literally sprint (which I would understand as 100% effort, which I may or may not be able to maintain for 30 seconds). Thanks.

    1. Easy walk or just standing there. Jogging is usually not enough for full recovery. And this is max sustainable pace for 30 seconds!

  21. Jack says:

    Enjoying this very much! Love having one place to learn about what's happening in the frontier of health and fitness!
    Two questions:

    1. Seems there is some debate over the value of drills in minimalist training (and in general). As they are in the sample schedule and Triathlon Dominator and Tri-Ripped, it's clear they are important parts of your plans. For those of us who might be confused about the matter, would you clear it up?

    2. How would this weekly schedule be adapted for shorter distances (sprint to 70.3?

    Thanks and love

    1. Jack says:

      Thanks and love what you're doing!

    2. Jack,Drills are designed for economy and efficiency, but if you do them right, you work on fitness at the same time. People get injured from hypo mobility (i.e. stuck SI joint or lack of big toe mobility – two biggies) and you're out doing A/B/C track drills, leg swings, and some core and hip alignment as part of your workout, you nip much of that in the bud. In terms of adapting to shorter schedules, that's what something like is created for – although the main difference is that the weekend workouts you see in the samples above are significantly shortened…

      1. Andrew says:

        How would a tabata workout fit into this schedule, if at all.

  22. Ben, very intriguing series you've got going. I have to say, it's right up my alley, too. I'm working on my PhD full time, have our 3rd child on the way and want to run my first 1/2 IM in Sept, so my training time is limited. I'm interested to see how the training progresses. For instance, you give a sample IM workout week, but what is the progression of those workouts as you move through the training season? Thanks again for all the great tips.

    1. Hi Jack! The finished book will include instructions on how to access a plan that will come along with the book which lays out how this stuff is supposed to look throughout the year, but for now the best examples would be in my current training plans at and

  23. "your time in the gym should primarily be spent getting strong and developing clean and functional movement patterns that enhance balance, symmetry and stability"…. that's what crossfit does. stop showing your ignorance. anyone can abuse or misuse any training protocol including yours. you make many straw-man arguments that are more anecdotal than empirical. stick to selling magic bracelets.

    1. James says:

      Man you need a hug. Many, many people do injure themselves in crossfit. ask any PT. It doesn’t mean it’s bad – but there is something about the mentality that people over do it more than usual.

  24. Robert Wadhams says:

    This is really fantastic stuff Ben… I am going to have to read this a few times to absorb it. Lots of really good information, just far to easy to pass things over on the first read.

    One question though.. I have had a situation where I had a running injury (IT band) that kept me from running for several months. During that time I did a fair amount of strength training but was totally incapable of running. I did recover about a month from my targeted half marathon, went out for a few runs and did just fine in the race. my overall time really didn't suffer too much after a 5 month layoff. My question is that is it possible to sustain a reasonable amount of cardio endurance by strength training?

    Thank you.

    1. Reasonable, yes, Robert. But for added speed and a maintenance or slight increase of VO2Max, it's even better to include aqua jogging, elliptical, isometrics, etc. I talk about this at <a href="http://www.BulletproofKnee.com<br />Cheers,Ben

  25. James says:

    While the HIIT may be a subset of the 80% aerobic benefit, it is a big stress to body. Is it safe to add 3 HIIT on top of the 2 quality sessions (threshold, intervals, reps) each week. Just sounds like recipe for injury.

  26. Rodrigo Lamego says:

    Great article Ben. For me in particular it was very usefull. In january I’ve joined a Crossfit program in a gym close to my house. However, there were not a single week I didnt get hurt in one way or another due to the current stress involved in endurance training. I sincerely wanted to combine both thecrossfit program and the ironman training, but I was feeling exausted and done . So I quit. Now I have incorporated some of the weight training, core and other exercises to my daily routine, right before the aerobic train of the day. It has been great! And I’m feeling stronger and with more energy. For me this is the correct way. Thanks for the advise, most of my doubts are gone!

  27. Olivier says:

    This is great work … really enjoyed going through it. This is likely to spark some changes in my training routine.

    1. Richard says:

      Great stuff. I am trying to work out what it looks like on a practical basis. I am training for 3 events all in the same week in August. A 5k run a 100m sprint and a 2k row (erg). Am I better looking at 30 second or 4 minute HIT reps. I also thought 1 slow row and a slow run. do I do weights on HIT days or LSD days? For your info I am 48 years old and fairly well trained trying to eat low carb also.

  28. Sonia says:

    Hi Ben,

    Good article.

    Although I understand that you may (and I should think ‘must’ given that you’re commenting on it) have personally experienced a crossfit box where they emphasized peer competition, I wanted to say that this is not the general culture that I have experienced. I’ve been to several boxes in Australia (where I live) as well as some in London, San Fran and Portland. In none if these did I feel that I was pushed to compete with those around me. I was always encouraged to compete against me..or my previous best effort.

    I just wanted to put that out there. Crossfit is a sport and there is a competitive element to it (as there can be in just about any sport) where people can compete against other athletes. But this is just one aspect to it. Crossfit was the first ‘gym’ experience I had where I was part of a super encouraging and lovely community of people.

    As for injury, absolutely, it’s a sport. People get injured doing yoga, football, dancing, tennis, running, cycling. I don’t think you can hang it all specifically on crossfit. Like all sports, choose your coach wisely!

    I hope your readers will go and experience their local crossfit box to judge for themselves.

    Thank you for all the great stuff you write!

    1. Julia says:

      I have to agree. I bought the crossfit endurance book, and the crossfit WODs are pretty different then what you might find at any random box, in the sense that they are shorter (less than ten minutes) on days you do strength, they include a lot fewer olympic lifts that might lead to injury, etc. I find the program a very balanced way to strength train and do HITT, with some crossfit WODs thrown in here and there if you’re up to it.

      Also, injury happens when people don’t listen to their bodies. That happens in any sport. There’s lots of ways to modify the crossfit endurance program to suit your recovery needs, and beginners who can’t manage the volume are encouraged to prioritize the strength and triathlon workouts and drop the crossfit WODs.

  29. Campbell Maffett says:

    Interesting concept and approach…I'll be interested to hear how it turns out for an IM.

    What is the structure of a HIT session for swim, bike and run, specifically, do you include warm-up/down in the time, and does it also include interval recovery? I come from a "traditional" approach, so am grappling with how the session details look in comparison to what you are proposing.

    Also, is a HIT approach just for people who are time poor, or if you have sufficient time then to maximise overall volume then to go with an 80-20 (or 90-10, or 70-30) approach? If HIT is so good, then why aren't top athletes doing it??

    Thanks, and keep up the good work.

    1. Campbell, this is the training approach I've used to consistently go under 10 hours in Ironman. I've had many, many athletes use this approach in my training programs too. In terms of specific structure of a HIIT session, that is something that will be detailed in a "sample plan" that will come along with the actual book when it comes out. If you have sufficient time, the 80/20 approach is an option and more "pleasant" for some people as you're not having to go "to the pain cave" so much. For making the significant jump from, say, a 9.5 hour Ironman to an 8 hour Ironman it's definitely the way to go, which is why pro athletes use it. Your engine just isn't big enough to go 8 hours on HIIT Training.

  30. Dennis says:

    Great stuff, another fantastic read. Do you count the "race pace" (iron man) zone 3 intervals as part of the 20% HIT, or since they are not really HIIT or easy aerobic do they fall outside of the 80/20 framework? Thanks!

    1. 80/20 is for Polarized training, Dennis…not HIIT training! Hopefully that makes sense. Meaning you don't have to do your long aerobic sessions as all Zone 2 if you're doing HIIT.

  31. Joe says:

    Excellent sfuff Ben. Keep up the good thorough work.

    1. Thanks Joe. Glad you made it through the whole thing. ;)

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