Thought I would pop back on and leave this real quick since over the last couple of days, the subject of insomnia has come up.  Not for anyone in particular, but it's just something that has helped me out over the years.  Now I'm really gone. 
Nature’s cycle of human sleep to restore and rebuild the body is between the hours of 10:00pm-6:00am, when most healthy ppl can reach the ideal Delta state of sleep (1/2-4 hz brain waves).  (The human skin repairs are from 11pm-2am)  Now for daytime sleepers, sleep is not as deep b/c their brain wave state is usually just a REM sleep (a high Theta brain wave state of 4-8hz).
Also, when NOT sleeping in the dark, the brain’s pineal gland can be depleted of the body’s own natural melatonin (a hormone), and when that happens insomnia can be a problem.  And BTW, sleeping in a room with a TV on, the light from it does cancel out and can even deplete the natural melatonin supplied by the pineal gland.  
Supplementation with melatonin pills can help.