Fatigue and Rest Scientists have made an interesting experiment about fatigue. When a muscle in the body e home from school they want to run out to play... not to lie down and rest. The reason is that if only a certain part of the body is tried the best way to make that part feel fresh again is to make other parts of the body active! We can actually rest by means of activity. Of course, if you are totally exhausted, the best thing to do is to go to sleep!