response: There also hasn't been any evidence of any serious bad effects.
original_response: That seems to be the case.  It also looks like evidence has shown that there's no adverse effects from trying to counteract the effects of CFS, which is good.
history: I have quite a lot of energy, but I know some people just aren't as lucky. Is their a medical condition for being constantly tired? There is a condition called chronic fatigue syndrome in which people have long-term fatigue in a way that limits daily activity. That must be awful. I wonder what causes it. Depression perhaps? I don't think the cause is fully understood.  It could be genetic, could be biological, or it could be psychological. Well, I guess the medical profession had better get to the bottom of it. It must be destroying people's lives! I wouldn't know, but there is some evidence that cognitive behavioral therapy combined with increasing activity can help. That makes sense. If a person exercises it often brings ones energy levels up.
knowledge: In a systematic review of exercise therapy, no evidence of serious adverse effects was found; however data was insufficient to form a conclusion.