How Long Does it Take to Lose Running Fitness?

Amanda Loudin, RunHaven.com, March 2015

We runners, when laid off of our favorite activity, tend to get a little upset. Scratch that. We tend to freak out.

The biggest fear — other than taking out the nearest healthy runner who waxes on about a spectacular run — is how quickly and how much running fitness we’ll lose when away from the sport. I’m here to tell you that the news isn’t all that bad.

First off, the good news is that up to five days away from the sport won’t hurt your running fitness at all, according to legendary coach Jack Daniels. So if you’re down with the flu, taking a few days off to prevent an injury or just plain old busy — fear not.

If you do get injured and need to stay away from running for six weeks or so, however, two things come into play: how long you’ve been running and how fit you were when the injury occurred. So a veteran runner with years of running fitness under his or her belt is going to fare a bit better than someone brand new to the sport.

A study by Edward Coyle in the Journal of Applied Physiology looked at the effects of detraining over a 12-week period. The results show that there’s a pretty steep initial drop-off in fitness: VO2 max dropped by 7 percent in just 12 days. After that, however, the declines were smaller, with the final VO2 max decrease topping out at 18 percent. When the researchers took a look at capillary density in the muscles, there wasn’t any detected loss, which is definitely good news.

The thing to keep in mind, here, however, is that these are studies of people who remained inactive while training. Use it or lose it, in other words. If, on the other hand, you can stay active via cross training, your losses will be much smaller.

If you choose a regimen of vigorous aqua jogging, for instance, you can expect to maintain your fitness for up to six weeks. Other types of activities that keep your aerobic and anaerobic systems in shape, such as cycling, rowing or swimming, will also keep the losses small and the return faster.

Bottom line: don’t freak out if you are down and out. With the right approach, you WILL get your run back.