Most people exercise to improve their fitness. Occasionally, you may find yourself unable to train for a few days, weeks, and even months due to injuries, illness, or other commitments. We all know that regular training, combined with sufficient recovery, makes you stronger and fitter. The opposite is also true, if you stop training, your fitness will gradually decline.
You don’t need to panic if you have to skip one workout because you have to study, or have to work overtime. Missing a training session can actually be beneficial because it helps your body to recover from previous training sessions. Recovery is crucial for becoming stronger and fitter from the training you performed. Without adequate recovery, your body cannot adapt to the training stimulus.
When you don’t train for an extended period your fitness decreases
Detraining should not be confused with the recovery process following a single training session or a training period and it occurs after recovery is complete. When detraining starts is dependent on the intensity and volume of your previous training sessions. If you are fully recovered and do not introduce a new training stimulus, detraining starts and your fitness decreases.
How quickly will your fitness decrease?
After three to five days of inactivity, the first signs of detraining gradually become noticeable. Around the fifth day of inactivity, the blood volume decreases, making it harder to transport oxygen from your lungs to your muscles. This is also why your heart rate is higher at a given intensity. The distribution of oxygen through your body becomes less efficient, so your heart has to beat faster to deliver enough oxygen-rich blood to your muscles.
After several days without training, lactate metabolism is also negatively affected. In trained athletes, lactate levels will be higher at the same absolute intensity, which means that the lactate threshold is reduced. If you have not trained for five days your glycogen stores will also decrease to normal levels.
What happens in your body when you can't train for a longer period?
After about ten days without training, your VO2max decreases. This decrease continues after you stop exercising for a period of 6-8 weeks. Although VO2max decreases, trained athletes will remain a higher VO2max compared to inactive people.
Your muscles are also affected when you're not able to train for a longer period of time. After two to three weeks without training, the number of mitochondria (energy factories) in your muscles decreases. Although in the first few weeks there are no changes in the proportion of fast and slow-twitch muscle fibres, the amount of slow-twitch muscle fibres will decrease after eight weeks.
All this suggests that your muscles will be less able to produce energy for high-intensity exercise. After a period of detraining, you can rebuild your fitness.
Adjust your diet if you cannot train for a few days
If you can't train you also use less energy. To prevent weight gain you should make sure that your energy intake isn't higher than your energy expenditure, therefore you should eat less on days you're not training. After a few days without training your body will rely more on carbohydrates than fat during exercise. If you have not trained for a long time, about two weeks, changes take place that favour fat tissue storage.
Despite the decline in fitness, a rest period after the season remains essential
A period of rest after the season is very important for an athlete. At least two to three weeks without exercise helps your body to completely recover, minor injuries will heal, and you will feel mentally refreshed. You will start the new season fit, injury-free, and with a lot of motivation. To prevent that your fitness completely drops, you can participate in other sports during this rest period.
