Overtraining
Overtraining is chronic exhaustion caused by too much training and too little recovery – an overly large calorie deficit makes it worse.
Ausführlich erklärt
Overtraining happens when, over weeks, you pile on more load than your body can process – training, everyday stress, lack of sleep and an overly large calorie deficit all count. Your performance drops even though you're doing more, and recovery takes weeks to months.
Sports physicians distinguish between stages (joint consensus statement of the European and American sports medicine societies ECSS and ACSM, Meeusen et al., 2013): after a hard week you're simply tired – that's normal, and you recover within days. With “overreaching”, the tiredness lasts one to two weeks. True overtraining syndrome is rare but serious: exhaustion that doesn't go away even after several weeks of rest.
Warning signs you can notice yourself: your morning resting heart rate stays five to ten beats above normal; you sleep badly even though you're exhausted; your mood and motivation to train take a nosedive; you constantly catch colds; your performance drops despite training; in women, periods may stop. One or two of these signs don't yet mean overtraining – but several over two weeks are a clear reason to ease off and get checked by a doctor.
When losing weight, one particular case is common: if you train a lot and eat too little at the same time, you slip into relative energy deficiency – experts call it RED-S (“Relative Energy Deficiency in Sport”, IOC consensus 2014/2018). The body then cuts back on bones, hormones, the immune system and mood. A deficit of no more than 300 to 500 kilocalories a day, enough protein and rest days protect against this. If you notice that exercise and eating are becoming compulsive, seek help – a good first contact is the eating disorders helpline of the German Federal Institute for Public Health (BIÖG, formerly BZgA) on 0221 892031.
In teenagers, there's also the growth spurt, which itself needs a lot of energy; training volumes at sports clubs should be agreed with coaches and paediatricians. The simplest prevention for everyone: an easy week after every hard one, at least one training-free day a week, and treating sleep as part of training.