Fatigue evolved to protect us from overexertion and injury.

疲劳是为了保护我们免于过度劳累和受伤而进化的身体机制。

This can also be a by-product of tension due to overexertion of the muscles.

这也可能是由于过度使用肌肉导致的紧张的副作用。

" I'm afraid that would come under the heading of 'overexertion'" , said Madam Pomfrey, pushing him firmly back onto the bed and raising her wand in a threatening manner.

“这恐怕属于‘用力过度’，”庞弗雷夫人坚决地把他推回床上，威胁他举起魔杖。