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Too Many Rest Days? How to Stop Aerobic Detraining

Updated: Jun 3, 2020

Gyms of all shapes and sizes have been shut-down for the past few months due to a government-imposed quarantine caused by the COVID-19 pandemic. For the regular gym-goers, this has made it much harder to maintain adequate levels of activity to keep all those hard-earned gains. (Not talking to you, Bob, with your full home set-up... but please can we borrow one squat rack?)

Because we work so hard to make improvements in our physical fitness whether it be weightlifting, running, cycling, Crossfit, bodybuilding- or even goat yoga- we’re going to take a look at how and why we lose our gains from inactivity, also called detraining or deconditioning, as well as what we can do to stop or at least minimize this phenomenon.

What is aerobic exercise and why is it different from other kinds of workouts?

This article is going to focus primarily on aerobic exercise deconditioning, and Friday's part 2 will touch on declines in strength and muscle. While there is some overlap between them, there are important distinctions in underlying physiology. Generally speaking, and regardless of what kind of physical activity one partakes in, maintaining even a slightly elevated fitness level is energy costly; this increases in a linear fashion.

Another way to think about it is to compare a Ferrari and a Camry: our body would rather be the energy-efficient Camry than the gas-guzzling Ferrari. Maintaining an increased aerobic capacity is typically less energy demanding than maintaining the necessary muscle mass and physiological adaptations required for strength. This leads to a slightly slower detraining effect for aerobic fitness. (Don't go back to your Netflix binges just yet, though!)

In combination with the decrease in energy demand, our daily lives tend to lend to a greater degree of carryover from normal everyday tasks. Activities such as walking or cycling to and from work, doing yard work, and any other activity which elevates our heart rate above baseline for a prolonged period which results in a slower rate of aerobic detraining. According to the American College of Sports Medicine (ACSM), as little as two weeks can lead to significant declines in aerobic fitness. The rate of detraining is dependent upon many factors including but not limited to:

  • level of fitness at the time of cessation

  • age

  • underlying medical issues

  • genetics

  • nutrition

Fitness level and genetics are two of the greatest determining factors here. Stopping exercise for anywhere from 2-8 months will likely lead to a loss in most or even all fitness gains. Those who are more highly trained will decondition at a much slower rate. As the adage goes, it’s a marathon, not a sprint. (And don’t worry, we’ll talk more about the underlying physiology behind this process in future posts for those of you who like to jump down the rabbit hole. #science)

Give me back those gains: how to stop deconditioning

Now that we’ve established how quickly and easily we can lose those hard-earned gains, let's talk about how to slow this process down... and potentially even stop it. First and foremost, a baseline needs to be established to continue to provide an adequate stimulus to maintain current levels of fitness. Which is just one more reason to track your exercise and nutrition (not that we needed any more). Because we’re only trying to slow/stop the detraining process, not make more gains, we don’t need what’s called an overload stimulus.

OK FREEZE. What is an overload stimulus? As defined by the International Sports Science Association, you must increase the intensity, duration, type, or time of a workout progressively to see further adaptations. So what does that mean? You have to work harder consistently for a long time. As you get better at any particular physical activity and it becomes easier, you have to keep making it harder. For instance: you start curling 50 pounds 5 times. After 3 months, you’re still doing that; but now that it’s easier, you should be adding another rep or two.

Now that we’ve all just strained our brain a little bit, it’s time to get back on track. That overload stimulus we just learned about isn’t needed to maintain our gains, just to make more gains. If you want to keep all of those sexy beach muscles (for when we’re finally able to go to the beach) or run in the Boston Marathon next year, establish a baseline.

Pro Tip: Establish a baseline. Write down everything you’ve been doing, and continue to try your very best to keep it up.

Right now, this most likely means improvising. Time to flex those creative muscles. 😉 Here are some easy ideas:

  • Instead of bench press, try push-ups.

  • If you’re already a push-up pro, try having your kid sit on your back.

  • Do so many reps your arms fall off. (Or maybe try some safer Challenges.)

  • If you like to run intervals on the treadmill but don’t have access to one, try using telephone poles as a guide to dictate your intervals. (They’re typically spaced apart pretty evenly, so they work well for a subjective measure of distance.)

You can also talk to one of CAC’s phenomenal trainers, who are all exceptionally qualified and more than happy to help. We’re here for you.

Don’t forget to stop by Friday, 6/5, for Detraining Part 2 so you can learn more about the effects of detraining on strength, muscle, and other primarily anaerobic physical activities.

A woman stretching with the blog title overlaid.
Pin this pic so you can avoid detraining!

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Amanda Stone
Amanda Stone
Jun 04, 2020

I used to do the telephone poles as a kid! My mom loved running so I'd be like I'll run to that pole... and then we walk 😂


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