National Headache Foundation survey of some 170 headache patients, 46% reported having had sex-related headaches

The survey, conducted on the National Headache Foundation's web site during December, included 182 people, mainly women aged 21 and older.

Nearly all participants -- 96% -- reported getting headaches from any cause. The same percentage said they're sexually active.

When asked if sex has ever triggered a headache, 54% said no and 46% said yes. Sex-related headaches most often occurred after sex, the survey shows.

Among people reporting sex-related headaches, about 40% said they've cut back on their sexual activity because of their sex-related headaches, and only 12% said they've talked to a doctor about their sex-associated headaches.

That doesn't mean that sex is their only headache trigger. Among people who reported sex-related headaches, 42% reported having had no more than six of those headaches.

Not everyone got headaches from sex. In fact, 20% of participants noted sex eases their headaches and 6% report having sex more often for the headache relief.

If you're a migraine sufferer, sex may be the last thing on your mind -- especially when painful migraine symptoms force you to seek solitude in a dark, quiet room. Yet new findings suggest that sex may be linked to migraines and headache relief.

According to a study published in the journal Headache, young adult migraine sufferers (men and women) reported having 20% more sexual desire than other adults who had headaches (but not migraine headaches).

This study found that migraine headaches and sexual desire are at least partially affected by serotonin, a neurotransmitter in the body that has a "feel good," calming effect. With migraine headaches, there are lower levels of serotonin, yet serotonin is released in abundance during sexual activity that leads to orgasm.

How Is Serotonin Linked to Migraine Sufferers?

Serotonin has been shown to have a major effect on mood and emotion. In the body, serotonin neurons are connected to many physiological functions including sleep, wakefulness, eating, sexual activity, impulsivity -- even memory and learning.

Along with migraine headaches, low levels of serotonin in the brain are associated with clinical depression, sleep, and pain disorders such as fibromyalgia, says pain specialist Harris H. McIlwain, MD, a Tampa-based rheumatologist and author of the book Diet For A Pain-Free Life.

In addition, when estrogen levels plummet for women before menstruation, levels of serotonin also change. As a matter of fact, serotonin deficiency is related to premenstrual syndrome (PMS), menstrual cramps, increased pain, and eating disorders -- all common problems in women.

Doctors often prescribe antidepressants to raise levels of serotonin, McIlwain tells WebMD, while triptans, a newer class of drugs that treat migraine headaches, work by imitating serotonin and stimulating receptors in the brain.

What Causes Migraine Headaches?

Experts are not completely sure what causes migraine headaches. According to Howard S. Smith, MD, director of pain medicine, Albany Medical Center and professor of anesthesiology at Albany Medical Center, migraines appear to be the result of a complex cyclic contact between the cranial blood vessels and the trigeminal nerve.

In his book The Women's Guide to Ending Pain, Smith explains that with a migraine, some "triggers" such as food, stress, fatigue, or poor sleep, activate neurons that are in charge of releasing a selection of neuropeptides -- substance P and neurokinin A.

Substance P helps nervous system cells send messages to each other about painful stimuli. It's thought that when substance P levels are elevated in the body, they may produce higher levels of pain. The release of these chemicals causes an increase in blood flow to the brain. The distended blood vessels and inflammatory response stimulate the trigeminal nerve to send out impulses back to the brain for processing, resulting in a migraine headache.

How Can Sex Help Migraine Sufferers?

Occasionally orgasm can relieve migraine headaches, says Randolph W. Evans, MD, clinical professor of neurology at Baylor College of Medicine.

Although the mechanism is not known, Evans tells WebMD that orgasm is a complex neurophysiological-endocrinological event that could relieve migraine headache in two ways:

• Stimulation of the posterior vagina and sexualactivity may activate inhibitory pain-modulating circuits. Theories are that this is a physiologic reflex related to the birth process to produce pain relief when the cervix and pelvis are stretched. 
• Endorphin release that occurs after sexual arousal andorgasm may relieve or reduce migraine headaches. Endorphins are morphine-like pain relief hormones made by the brain; they are associated with a happy, positive feeling and can keep pain messages from reaching the brain.

These mechanisms might be responsible for the "temporary" relief of pain -- but not for permanent and total relief. Experts believe there is another factor related to sexual orgasm that suppresses migraine headache pain or suppresses the migraine process.

Alternately, a few studies have found that about 5% to 10% of migraine sufferers report sexual activity is a migraine headache trigger (equally for men and women), while other studies show that physical exercise can also trigger migraine headaches.