by Dr. Patti Britton
1. hey are tired to begin with, and sex helps them relax and let go -- figuratively and literally.
2. The hormones men and women produce at orgasm can lead to the desire to lay back in the afterglow, and that sense of physical peace often leads to sleep.
3. The ejaculatory release for men, and the inherent letting down of bodily tension, makes men physically tired.
4. Most people (again, men and women) hold their breath during sex, breathe shallowly or don't focus on breathing. I'll bet the ranch that he's not breathing deeply. That gives him oxygen deprivation, which causes sleepiness. And, it could (rare, though) persist into the next day.
Subject: 4 Reasons Why Men Sleep after Sex 
Fri Dec 05, 2008 8:05 pm