Having sex isn't all health and orgasms. For some, it's downright hell …

1. Orgasm Overload

As the old adage goes, you can never have too much of a good thing — unless that good thing is achieving multiple orgasms. Doctors warn that the female body can go into an automatic nervous system overload following the overstimulation of the vaginal, clitoral or even rectal areas at one time. The dilated blood vessels allow the body to release too many neurochemicals that cause dizziness, lightheadedness and nausea. 

2. Orgasm Flu

Somewhere, Darwin is turning over in his grave. According to researchers, there’s a small percentage of men who are surprisingly allergic to their own baby batter. After climaxing, they immediately suffer flu-like symptoms — runny nose, fever and stiff joints — that can last for up to two weeks, rendering them virtually handicapped to masturbation and sexual intercourse. 

3. Headaches

Don’t worry, your girlfriend isn’t trying to avoid intimacy, she might be one of the 1 in 100 people who suffer from sex headaches brought on by sexual intercourse — especially orgasms. As blood vessels dilate and constrict with increased excitement, pressure causes pre-climax aching in the neck or head. More common sex headaches occur post-climax. Another possible headache cause might include the moment both people realize the condom fell off.

4. Amnesia

For most of us, we’re stuck living with the regret of that double-bagger one-night stand who haunts our memories. But for some, it’s not a problem. They suffer from a sudden and temporary memory-loss condition called “transient global amnesia.” Doctors aren’t sure what causes the memory loss, but it happens after random sexual experiences — a person can’t recall what happened in the last 24 hours.

5. Depression

Sex isn’t always rainbows and roses, no matter how great you think your sexual prowess may be. Researchers at Ohio State found that more than 1/3 of people who engage in casual sex see an increase in negative thoughts if they’ve experienced those thoughts before. In women, the hormonal changes may be to blame for this fluctuation in negative feelings that can increase during sexual experiences.