Losing Running Fitness: How Long Does It Take to Get Out of Shape
When you feel like you are at the top of your game – or, trying desperately to get there – taking any amount of time away from training can seem debilitating. The more you run, the more you feel as though you must continue to run, lest you will lose all of the benefits of the previous months, or even years, of training.
Fortunately, science has shown us that fitness is not quite as fragile as athletes sometimes mistakenly believe, but there certainly is credence to the notion that even a week off can result in feeling slightly out of shape. Reviewed here is everything you need to know about losing fitness.
The most common measurement of running fitness is VO2 max, which is essentially a quantification of the body’s ability to consume oxygen. The greater your individual VO2 max, the better you will perform in endurance activities. This number is not static, however, and changes as you gain, and lose, endurance. Even more, it can be generally correlated with your running times. For instance, a 4:00:00 marathon runner has a VO2 max around 37.87 ml/kg/min, while a 3:00:00 marathoner has one of 53.48 ml/kg/min. The ability for researchers to provide an exact number relative to fitness has been instrumental in studying the effects of “detraining,” or, losing fitness.
Fortunately, taking time away from activity is not as detrimental as some athletes may lead themselves to believe. In the initial 10 days off from running, VO2 max decreases are negligible1. By studying nine highly trained endurance athletes for four weeks and allowing them one hour of exercise per week, as opposed to six to ten hours, minimal detraining effects were observed. After two weeks, VO2 max drops 6 – 7%, while the most crucial period appears to be after nine and eleven weeks, with a 19%2 and 25%3 drop, respectively. Therefore, as a general rule of thumb, a runner could speculate that for every week of training lost, 2-3% VO2 max reduction is observed. To put this reduction in simpler terms, you can subtract 12 – 18 seconds per ten minutes of running time. For instance, after three weeks of inactivity, a 30:00 5k runner could expect to run the same distance roughly 36 – 54 seconds slower.
However, there are a number of factors to take into consideration. If you take time (i.e. two weeks) off after a marathon, you will not necessarily feel the same detraining effects as someone who rests for two weeks in the middle of a heavy training cycle. The marathoner will have already experienced a slight amount of detraining thanks to the taper, and this is often to blame for the exclamation after a post-marathon break of, how did I get so out of shape!? While VO2 max is an important and easily measured factor, another determination that runners should make when considering fitness loss is skeletal and muscular fitness.
Structural fitness is the combination of muscular strength, injury-preventing capabilities and how quickly your body and brain can communicate when undertaking tasks, such as getting off the starting line at the sound of a gun or navigating a technical trail. Unfortunately, this type of fitness is less straight forward than testing VO2 max, but it is still an important consideration.
After 10 – 14 days4 of not running, your body will lose some of its muscular coordination and strength. This will lead you to feeling “awkward” when you start running again and you will perhaps feel off balance. You will also lose important injury-preventing mitochondria5 that were built during your long runs and strength training activities. An athlete will lose half of his or her mitochondrial stores in 12 days of detraining, which will take 36 days to rebuild. In addition, blood volume will decrease within the body, which will hamper an athlete’s ability to efficiently shuttle oxygen and nutrients to the muscles.
On the other hand, how much of feeling out of shape is purely mental? For many athletes, even a one or two-day layoff from training can lead to feelings of inadequacy or low confidence. The connection between a strong mind and a strong body is well-known, and it should be no surprise that approaching time off with a negative attitude can affect the way a person feels when he or she returns to running. For many, the difference between rebuilding fitness effectively and delaying the process hinges on whether you have the proper frame of mind.
How Long Does it Take for Fitness to Return?
For many, returning to peak fitness is entirely individual. Hal Higdon, running guru, often notes that a general rule of thumb is to expect fitness return to occur in twice the amount of time as was taken off. Other physiologists agree with this statement, such as Dr. Edward Coyle, a renowned physiologist from the University of Texas at Austin. Keep in mind, however, that each time you improve your fitness, you will detrain to a higher level than before. For instance, if you took a two-week break after running a PR of 20:00 in the 5k last year and followed the same routine after a PR of 19:30 in the 5k this year, you would have a higher starting point after the two-week break following the faster PR.
Importance of Consistent Training
Overall, training consistency is most important. The effects mentioned in the above studies all assumed that the athlete taking the time off was a well-trained individual who had trained for at least four to six months. Fitness is also a double-edged sword. For instance, an elite athlete will lose his or her edge at an initial greater rate than a recreational athlete, yet the elite athlete will never detrain his or her body to the point of reaching the athletic abilities of a sedentary individual. For a person who has only been involved in a running program for two to three months and then takes two to three months off, he or she can expect to start at square one upon returning to running, while a veteran runner of 20 years will experience a less dramatic fall.
Importance of Taking the Time off When You Need It
While there is truth to the statement that a runner will lose fitness when taking time off, it is still important to realize the relativity of the statement. If in the middle of marathon training and a small injury comes up, it is absolutely better to take one to two days off when the problem first arises, as opposed to letting the problem fester and result in a two to three-week layoff.
1. E. F. Coyle, M. K. Hemmert, A. R. Coggan. Effects of detraining on cardiovascular responses to exercise: role of blood volume, Journal of Applied Physiology Jan 1986, 60 (1) 95-99; DOI: Link
2. Ready AE, Quinney HA. Alterations in anaerobic threshold as the result of endurance training and detraining. Med Sci Sports Exerc. 1982;14:292–6. Link
3. Nichols JF, Robinson D, Douglass D, Anthony J. Retraining of a competitive master athlete following traumatic injury: a case study. Med Sci Sports Exerc. 2000 Jun;32(6):1037–1042. Link
4. Costill DL, Fink WJ, Hargreaves M, King DS, Thomas R, Fielding R. Metabolic characteristics of skeletal muscle during detraining from competitive swimming. Med Sci Sport Exer. 1985;17(3):339–43. Link
5. Joyner MJ, Coyle EF. Endurance exercise performance: the physiology of champions. The Journal of Physiology. 2008;586(Pt 1):35-44. doi:10.1113/jphysiol.2007.143834. Link