lose fitness

How Long Before You Lose Your Fitness Level?

There can be all sorts of reasons why a runner might have a break away from running: recovering from an injury, illness, burnout, vacation, or just life.

Just how much is your fitness impacted if you have some time away from running? It is a common question.

Some runners even give up altogether on their goal if their training gets sidetracked for a week or two thinking all is lost while others have an inability to take a scheduled rest day in fear of losing the gains that have been made.

All runners have some level of fear about taking a day or few off from training with the belief that weeks or months of hard work will immediately be negated.

I too still battle this irrational fear from time to time. It’s time to put some facts to those fears and put them to rest.

The fact is, without scheduled rest time for recovery, you are continuing to wear your body down and not giving it a chance to recover, rebuild and become stronger.

But the question is, what are the exact effects to your performance when taking time away from running?

When we examine the impact of taking time away from running we have to consider two things: the effects of time away from running on your aerobic capacity and loss of muscle mass that you have developed through your training.

Aerobic Capacity

VO2 max is one of the best measurements available as a measure of a runners’ fitness level. VO2 max is the maximum capacity of an individual’s body to transport and use oxygen during exercise, and is a measurement of the physical fitness of the individual.

The good news for most runners is they tend to sweat the small stuff. In the case of missing a workout or two it may seem like the end of the world but the reality is studies have shown there is little reduction in VO2 max (your fitness level) within the first week away from running.

For you marathon runners that worry about your taper period – take a deep breath and relax.

You are simply reducing your training volume, not your running altogether.

Those that have been running for a longer period of time and have a well established running base will lose their aerobic fitness gains much slower than a runner that has not developed a base or been running for very long. In both cases, there is no immediate fitness loss.

Muscle Development

Just like your aerobic capacity there is negligible loss in your muscle development and tone within the first week away from running.

After a week there begins to be minimal losses in muscle power but the good news is you can quickly regain these losses when you resume running.

You can even speed the muscle rebuilding process with speed workouts such as fartlek training.


You won’t lose your aerobic capacity or muscle power as long as your time away from running is less than two weeks.

Any minimal losses can quickly be regained. Remember it is always best to err on the side of caution and take a rest day or cross-train if your body is giving you signals that you are on the verge of injury.

There are times when a week or two away from running is actually beneficial, such as after a strenuous marathon performance.

Coming back to running too soon after such an event puts you at a very high risk for injury if your body has not fully recovered.

If you are away for more than two weeks, you’ll have a bit of work to do in order to get back to where you left off but all of your work is still not lost.

Your mind will remember how fast you were able to run previously, but your body will not perform quite at the same level.

The impact to your overall readiness for your goal race will be based on when your extended break occurs in your training.

Breaks of more than 2 weeks at the beginning of a 16-18 week training plan early on will be less detrimental than those that occur during peak training weeks closer to your goal race.

Take those scheduled rest days, don’t give up on your goals with a week or two away for whatever reason.

Your shoes will be waiting for you and your body will quickly recover to where you left off.