One of the many mysteries of men, such as their preoccupation with girls' heinies and the presence of much energy in their groinal area so early in the morning, is the phenomenon of dozing off right after sex. A lot of women are baffled as to why this happens, but rest assured, girls - it's not that the guy you slept with found you boring or fat. Men are just biologically programmed that way.

Author Melinda Wenner of Scienceline, a project of New York University's Science, Health and Environmental Reporting Program names factors that make men doze off post-coitus. First, and very obviously, is that sex usually happens at night in bed. Next, a study of their brains found out that in order for men to reach orgasm, they must let go of all anxiety and fear, which is kind of relaxing and thus leads to sleep.

The chemicals released by the brain during a man's climax also promote sleepiness after intercourse. During ejaculation, the brain releases the chemicals norepinephrine, serotonin, oxytocin, vasopressin, nitric oxide (NO), and the hormone prolactin. Prolactin is linked to the feeling of sexual satisfaction. Studies reveal that the hormone is linked to sleep. Releasing prolactin during orgasm causes men to feel sleepy, albeit satisfied.

For some unknown reason, though, prolactin levels are higher in men after sexual intercourse than after masturbation. So relax. He may basically ignore you after doing the deed, but that doesn't mean that he doesn't like you. Men cannot live on porn alone.