its a bit more complicated than this, but here goes.. pretty much any aas is a sympathetic stimulator.. what that means is: we have two basic modes of operation, the parasympathetic (feed/breed) which is a relaxing state our body desires, its physiological effects are low heart rate and bp, good blood flow to the gut, etc.. we have another system known as sympathetic which is desgined to kick in only in times of stress (fight or flight). for example, caffiene is known as a pretty potent sympahetic stimulator, it "revs"you up, you become a bit edgy, heart rate and bp go up, your body puts more blood to the muscles in preperation to run from that tiger or fight it,..that test high we all have is our body being much more sympathetically wired than it is designed. we are in a more or less un-natural 10 week state of flight of fight. the headaches you wake up with, the night sweats, the quicker than normal temper, all goes back to that concept. its our bodies way of dealing, and sleep/rest is SO IMPORTANT but its also hard for our poor nervous system to hop out of the sympathetic mode with all these hormones kicking around. so although you may go to bed at 11 and set the alarm for 7, i am willing to bet you often wake up at 5-6 even though you WANT to get 8 hours. its temporary thankfully, give a few weeks post cycle and things should calm down.