4 Surprising Reasons to Do Cardio While You’re Weight Training

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If you were to go with me to a weight training session at the gym, you'd often see me darting off to the bicycle, treadmill or elliptical trainer in between weight lifting sets – and sometimes just throwing in a round of jumping jacks.

This isn't because I have some rare form of exercise attention deficit hyperactivity disorder. It's instead because there are multiple benefits to injecting strategically timed cardio sessions into your weight training routine – AKA “cardio with weights”.

Here are four surprising reasons to do cardio while you're weight training (and a bonus video at the end):

Reason #1: Removal of Lactic Acid:

Multiple studies have shown that you can complete more reps, produce greater force, and experience far less lactic acid accumulation when you use the strategy of doing easy aerobics during your recovery between weight lifting sets, rather than just watching TV or reading a magazine.

Here's why:

In most weight lifting scenarios, you are primarily utilizing an energy system in your body called anaerobic glycolysis. This is the process via which your body breaks down sugars into useable fuel for a forceful muscle contraction. But use of glycolysis results in significant accumulation of lactic acid. Too much lactic acid in a muscle decreases force production capability.

This is where easy aerobic exercise between your weight lifting sets comes in handy.

Light aerobic exercise, such as cycling, jogging, or even jumping jacks, can increase blood flow, which could increase the amount of oxygen that is available to either convert lactic acid to pyruvate (which can then be used as fuel) or to convert lactic acid to sugar in the liver, via a process called gluconeogenesis.

Reason #2: Hormonal Release:

When you lift weights, you get a release of growth-related hormones that help your muscles to grow or get stronger. These hormones include growth hormones, insulin-like growth factor, testosterone, and epinephrine. Depending on the type of weight training that you do these hormones can stay very significantly elevated for up to 30 minutes after you finish your exercise session (for example, higher-volume bodybuilding-style training results in a higher release of these hormones than short, explosive lifting).

But weight training isn't the only form of exercise that causes a significant hormonal release. Brief and hard bicycling bouts in particular have been shown to cause a very similar amplification of growth hormones.

So why not get the best of both worlds and combine the last reason with this reason?

You can do your weight training set, then do a brief and intense 30-60 second bicycling bout, recover with easy aerobic cycling until you're breathing easily (indicating lactic acid has been significantly buffered), then go back to the next weight training set.

Reason #3: Maintain Ideal Muscle Temperature

Your muscle's force production capability are enhanced when your muscle is at specific temperatures. When you keep a muscle warm, you slightly decrease the muscle stiffness. While it may seem that a more “stiff” muscle would be capable of producing higher force, a slightly less stiff muscle can actually increase the responsiveness of the muscle's tendons and the mechanical force production capabilities.

So while something like static stretching is not a good idea between, for example, a set of squats (it is too much stretching for your hamstrings and too much reduction in force production capability), riding the bike can keep your muscle just warm enough to allow for optimum muscle contraction.

Reason #4: Improved Nerve Speed

When you feel tired or exhausted towards the end of a weight lifting set, it is not just failure of your muscles that you are experiencing, but also a fatigue of your nervous system – as you lose the neural ability to recruit units of muscle and the firing frequency of your neurons.. But your nervous system not only operates at peak speed at specific ideal muscle temperatures described above, but it also recovers faster than your muscles do.

This means that if you're just sitting around between your weight training sets, you're allowing your nervous system to “cool-down” more than it actually needs to, and to an extent that may hinder your strength for the next set. By doing some type of aerobic activity, or by using the strategy above to combine a hard cycling bout with easy cycling recovery, you can keep your muscle temperatures high enough to ensure ideal neuromuscular activity for your next set.

So whether you want to remove lactic acid, enhance hormonal release, maintain your muscle's ideal temperature or improve your neuromuscular capability, you've now got some good reasons to do something other than just sit there after you finish a bench press, squat, deadliest or some other weight training exercise. Mix it up with cardio and you'll get better results.

Here's that video I promised, which shows me demonstrating what I just explained:

If you like information like this, you should get my new book Weight Training for Triathlon – The Ultimate Guide. No other triathlon book to date has been so well designed, so easy to use, and so committed to weight training.

This book was designed specifically for triathletes to increase strength, speed, endurance, and stamina. This guide will have you shaving off time in all three events by using the most advanced and efficient exercises available. Get it here.

Questions, comments or feedback? Leave them below.

Weight Training Book by Ben Greenfield


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12 thoughts on “4 Surprising Reasons to Do Cardio While You’re Weight Training

  1. I?m amazed, I must say. Seldom do I come across a

    blog that?s both equally educative and interesting, and let me tell you,

    you’ve hit the nail on the head. The problem is something that too few people are speaking intelligently about.

    I’m very happy that I came across this during my hunt

    for something regarding this.

  2. Jerry says:

    Great idea and I plan to start it this coming week.

    I do moderate weight bodybuilding splits training 4-5 days weekly.Can this concept be used by me without any overtraining issues?

    Also, my in between set cardio will consist of working kicks, punches, blocks so that I can also maintain Martial Arts technique while lifting.

    For that 30-60 second period I’ll execute techniques as fast as possible.

    I guess my main concern is not over taxing my CNS.

    The total cardio component per workout will average 20-30 minutes.

    Thanks for your input.

    1. It's really hard to say without knowing more about you. Feel free to book a consult at https://bengreenfieldfitness.com/coaching. and make sure to check this article out as well! https://greenfieldfitnesssystems.com/article-arch…

  3. John says:

    Thanks in advance for response.

    Can I do shadow boxing for 2 minutes inbetween

    sets of weights and stlll benefit?

    Is a 2 or 3 day full body workout of 45 minutes best?

    On rest days I will be strecthing for 20 minute sessions.

    Thanks again!

    1. Yes, that would be fine John, and multiple weekly fully body workouts tends to work best!

  4. George H says:

    Is this the best way to train for a race like the Warrior Dash or other obstacle mud races, or is there something different we should do?

    1. Listen to podcast #187!

  5. Anton says:

    The post was a little confusing. I understand about the cardio injected into workoutirs but when was the problem.
    First it was said to do cardio between "sets" then was mentioned to be done when finishing "a" bench press, squat, deadlift. Which is it? Also if doing 30-60 seconds intense cardio then recovery till breathing normal seems redundant if you are only taking a 2 or less minute rest between sets AND reps. What's the happy medium?

    1. Doing bench press, squat or deadlift (or anything else) would be consider a "set". So you'd do cardio after each set…

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