Headaches during sex are likely more common than reported, according to a recent study.

Researchers from Loyola University found that about 1 percent of adults report they have experienced headaches associated with sexual activity, and that such headaches can be severe. However, the actual incidence might be higher, researchers said.

"Many people who experience headaches during sexual activity are too embarrassed to tell their physicians, and doctors often don't ask," Dr. Jose Biller, researcher and chair of Loyola's Department of Neurology, and is certified in Headache Medicine by the United Council for Neurologic Subspecialties, said in a statement.

People have long joked about spouses avoiding sex by claiming to have a headache. But sex headaches are not a laughing matter, Biller said.

Headaches in general usually are caused by disorders such as migraines or tension-type headaches. But headaches also can be secondary to other conditions, and some of these conditions can be life-threatening.

"Headaches associated with sexual activity can be extremely painful and scary," Biller said. "They also can be very frustrating, both to the individual suffering the headache and to the partner."

In their study, Biller and colleagues said men are three to four times more likely to get headaches associated with sexual activity than women. Depending on the type of headache, certain medications can help relieve the pain or even prevent headache.

Researchers said the vast majority of headaches associated with sexual activity are benign. But in a small percentage of cases, these headaches can be due to a serious underlying condition, such as a hemorrhage, brain aneurysm, stroke, cervical artery dissection or subdural hematoma.

"So we recommend that patients undergo a thorough neurological evaluation to rule out secondary causes, which can be life-threatening," Biller said. "This is especially important when the headache is a first occurrence."

Researchers said individuals can reduce their risk of sex headaches by exercising, avoiding excessive alcohol intake, keeping a healthy weight and counseling.