Sleeping is actually a very energy-consuming thing. When people sleep, various systems in the body will do a lot of work to deal with toxins and restore body functions. Generally, a nap of 20 to 30 minutes is enough, and an hour is too long. Remember to eat something after getting up and supplement some vitamin B and vitamin C. The food is preferably fruit. If you exercise in a closed gym without ventilation around, people will feel tired.