Detraining: What Happens When You Stop Exercising?
Many things can get in the way of your fitness routine. Getting injured, taking a break to focus on something else, or simply losing interest. The question is:
How soon and to what degree will you get out of shape if you stop working out?
Good to know:
If you plan a break, consider reducing your training instead of skipping it – it will help you retain your form! Tips on how to do this can be found at the end of the article.
The so-called detraining effect can result in the partial or complete reversal of all benefits you got from your regular workouts. The response is individual and highly dependent on your current form and training history.
However, most people notice a difference between a shorter (4 weeks or less) and longer (more than 4 weeks) break.
Short break (≤ 4 weeks) from training
According to research, many physiological changes start to take place even after a short break.
- Endurance goes first
- Highly-trained athletes notice a bigger drop than recreational runners
For recreational runners, training history will make a difference. If you were only training for a couple of months before your short break, you probably won’t notice any changes. However, if you have a year or more of training behind you, you might notice your times getting slower.
Example: If you could run a 5k in 22 minutes, after 2 weeks you might need 1 minute more.
Did you know?
The most commonly used measure of an individual’s fitness level is the maximum oxygen uptake, VO2max. It shows how efficiently your body can use oxygen during exercise. It is the first thing to decrease when you stop exercising, ranging from 4-14%.(2)
Endurance athletes might notice up to 25% shorter “time to exhaustion”, which affects their performance significantly.
Muscle, strength, flexibility
You probably won’t notice a decrease in muscle strength. In general, it’s easy to get your numbers back up fast after a short break. However, some may see a drop in power after a short break, especially highly-trained athletes.
A drop in muscle glycogen could make your muscles appear smaller, due to less water retention.(3) It can also make you feel fatigued faster once you get back to training. No need to worry, this effect will reverse quickly once you are back on track.
A decrease in flexibility might be felt in the hips, trunk, and spine. In other words, that pose you practiced during yoga classes will probably be harder when you come back after 3 weeks of no training.
Long break (4+ weeks) from training
Research shows that a long break from a training routine has significant effects on your body.(4)
- Endurance might reverse to the pre-trained state
- Muscle mass decreases, but it does not turn into fat
The VO2max will continue decreasing, even up to 20%. At this point, you might be at risk of losing all your cardio gains, because the functioning of your whole cardiorespiratory system is slowly returning to its pre-trained state.
Example: If a 5K now takes you 22 minutes, you might now need 25 minutes or longer.
Muscle & fat
The loss of lean muscle mass starts happening slowly. Physiologically, this resembles the normal aging process. When it comes to strength, research is not clear. It seems that the rate at which you lose strength depends on how many years or months of training you had, the type of training, and your age.
Example: In one study published in Medicine & Science in Sports & Exercise, 9 weeks of strength training increased leg strength in previously untrained young men from 80 to 100 kg on a knee extension machine. 12 weeks later their strength remained almost the same. 7 months later it dropped to 90 kg.
Did you know?
“Muscle memory” helps well-trained individuals regain their strength faster after a longer training break. A key part of muscle memory is the neural adaptations that happen as you spend time learning a skill and getting stronger.(5)
Even though muscle mass decreases, it does not “turn into fat”. A longer break might, however, reverse the positive effects previous exercise had on your fat metabolism. It’s difficult to distinguish what affects your fat metabolism more: training, calorie deficit, or a combination of both. So, whether you will gain fat or not during your break depends on your metabolism as well as nutrition habits.
Is there anything you can do to keep the negative effects to a minimum?
If you are aware that you won’t be able to return to your regular training routine soon, don’t despair. You can try some of the following tips to keep your detraining effects to a minimum:
- Focus on intensity: You can maintain a lot of your fitness by reducing your workouts up to 50% (frequency and duration) and cranking up the intensity – try interval runs!
- Cross-training: If you are injured, ask your doctor which activity is safest for you. Often swimming is a good alternative. This works especially well in preserving fitness for recreational athletes. It is important to find cross-training activities that match the specific demands of the particular sport.
- Eat enough protein: Making sure that you eat enough protein will help you at least slow down the process of losing muscle mass during times when you are not able to do your regular workouts.
Training an uninjured limb can make the injured limb stay fitter and stronger! This so-called “cross-transfer” effect is sometimes used in post-surgery rehabilitation.(6)