The Stages of Detraining and How Long Running Fitness Lasts

Molly Hurford
by Molly Hurford
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The Stages of Detraining and How Long Running Fitness Lasts

There are many reasons runners have to take a break from running. Whether it’s an injury or accident, work or family obligations, life happens. Just remember: You’re not the only one — and your comeback might not be as difficult as you’ve feared.

Significant detraining takes longer than a lot of athletes think, and it doesn’t take that much training to prevent it.

The good news: If you’ve been training regularly for a while, you have more time than you think. “Significant detraining takes longer than a lot of athletes think, and it doesn’t take that much training to prevent it,” says Jim Rutberg, author of “The Time-Crunched Cyclist” and former coach with CTS. “There’s also a matter of perspective. When life or injury gets in the way, you might lose some fitness but it’s more important to avoid losing all fitness. Don’t give up, just go slower.”

The bad news: There’s no cut-and-dry answer to how long you can take off of running and still maintain fitness. The answer, as with most questions around endurance training, seems to be “it depends.” Between the five coaches interviewed on this topic, there was a wide range of “max time off before you lose fitness.” Some said after 14 days of no running, there would be an aerobic decline, while some pointed to a five-week rule.


Dr. Michael Ross, sports medicine physician and director of Rothman Institute’s Performance Lab, pointed to professional cyclist Miguel Indurain, who was tested a decade after retiring from professional sport and saw almost no depreciation in his VO2 max or threshold power. All of the coaches agreed here: If you’re in crazy good shape, you’re less likely to see your fitness plummet after a few weeks off. But if you just started a running regimen a month ago and take a few weeks off, you’re probably going to be back to square one when you start back.


If you know you have to back off your training — to stay home with a newborn, for a scheduled surgery or a hectic project at work — Dr. Ross recommends hitting the gym for strength training. The more lean muscle you have, the better your body will react to time off, he says — and studies have shown that while aerobic fitness may take a hit after a few weeks away from running, your muscles will be slower to fade. (Also, the more lean muscle you have, the better your metabolism will react to time off.)


The brain — nervous system — seems to gain and lose adaptation the fastest, says running coach Kyle Boorsma. “This is why elite athletes often feel ‘so out of shape’ after only a week off even though, at a metabolic level, likely most things are unchanged. Changes in things like mitochondria will take weeks to months to occur.” So while you might be feeling slow, that might be all it is: a feeling. Don’t fret over a few missed days, it’s probably all in your head.


Dr. Ross says that depending on what level of fitness you’re hoping to maintain, you can afford up to six weeks off — you may not set any PRs on your first runs back, but you’ll be able to regain fitness quickly. After eight weeks off, he says, you’re in the danger zone of losing fitness and having a much harder time making a comeback, so don’t expect the bounce-back to be immediate.  



If it’s time that’s your problem, versus an injury forcing your hand, you can maintain more fitness than you’d expect by just doing a couple short, hard workouts when possible. “The good news for athletes is that other studies have shown fitness can be maintained for fairly lengthy periods if reduced volume is combined with increased intensity,” says Matt Fitzgerald, author of “80/20 Running.”

If you can lose fitness, you can get it back.


“Re-adjust your mindset so you’re not frustrated by every run or ride being slower than you think you should be going,” adds Rutberg. “You’re doing what you can do, maintaining the fitness you realistically can based on other priorities. Don’t beat yourself up about it, enjoy the fact you’re doing what you are doing. If you can lose fitness, you can get it back.”


Whether you’re time-crunched, injured or there’s some other reason you need to take a break from training, it might be a good idea to chat with a coach when you’re about to take a break, says CTS coach Tracy Drews. He or she can help you come up with a plan that works with your lifestyle and/or recovery to make sure that when you want to come back to running, you’ll have the smoothest return possible.

About the Author

Molly Hurford
Molly Hurford

Molly is an outdoor adventurer and professional nomad obsessed with all things running, nutrition, cycling and movement-related. When not outside, she’s writing and podcasting about being outside, training and health. You can follow along with her adventures on Instagram at @mollyjhurford.


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