Jets linebacker Lorenzo Mauldin (55) wears special contact lenses and a helmet shade to prevent migraines.

By ZACH SCHONBRUN

FWhen he woke last Sunday morning, Jeremy Kerley sensed trouble already coming on. Fitful sleep is often his trigger, he said. The migraine eventually hit him like an anvil late in last week’s game against the Giants.

His eyes grew blurry and he felt what he described as a “sharp, shooting, throbbing pain.” He wanted to sit down. He wanted to lie down. He knew he needed to leave the field.

Kerley, the Jets’ punt returner, departed to the locker room and did not return. As the Jets came from behind to beat the Giants in overtime, he was receiving intravenous fluids and oxygen to help relieve the anguish from a struggle that has afflicted him since high school.

For Kerley, migraines are the silent menace that constantly lurks. They ambush him almost once a month, even though he rarely talks about it. He knew his grandfather got them; only recently, he discovered that his dad did, too. He just never knows when they will affect him.

Though Kerley is one of approximately 38 million Americans who suffer from them, migraines are not something that is openly discussed in N.F.L. locker rooms. They are far more common in women, and often minimized as simply a headache, a stigma that Kerley acknowledged could make it difficult to pull himself out of a game.

But those who do struggle with migraines — which the Migraine Research Foundation considers a neurological disease, like epilepsy — understand the plight. When Kerley felt a severe headache coming on last season after a game at Minnesota, his teammate Percy Harvin patted him on the back.

“I know how you feel,” Harvin said quietly. He has struggled with migraines throughout his career.

Kerley did the same thing earlier this season, after linebacker Lorenzo Mauldin revealed that he had had migraines since adolescence. Kerley gave him recommendations about nutritional supplements that he found helpful, like fish oil and magnesium. Mauldin also now takes prescription medication to both relieve and prevent severe headaches.

He said that light could often trigger his migraine episodes, so Mauldin wears special contact lenses and a protective shade on his helmet.

“It hurts because it’s pulsating and you can’t really stop it,” Mauldin said. “With a bruise or something, you can put alcohol or peroxide over it and it’ll be fine. Or if you’ve hurt a muscle, you can ice it. But you can’t put ice over a migraine.”

In September, a migraine forced Ohio State quarterback Cardale Jones to the emergency room, something that is not uncommon, said Dr. Melissa Leber, the director of emergency department sports medicine at the Icahn School of Medicine at Mount Sinai. She typically treats patients intravenously. But that often cannot relieve the crippling symptoms right away.

“Some people can’t even get out of bed,” Leber said. “Others can function just while not feeling well. It really runs the gamut for how debilitating it can be.”

Migraines are thought to be related to the brain’s trigeminal nerve, which can grow hypersensitive and cause pain signals to fire throughout the brain, typically concentrated around the eyes or temples. Though migraines are strongly hereditary, showing up in people who have had no sports history, they are often clinically similar to post-traumatic headaches, like the headaches that arise after a concussion, according to Dr. Tad Seifert, a neurologist at Norton Healthcare in Louisville, Ky.

During the summer, Seifert led a study of 74 high school football players in the Louisville area and found that 33.8 percent of them suffered from migraines, a rate twice that of the normal population. The rate rose to 37.5 percent in players who reported having sustained a concussion once in their lives, and 40.7 percent in those who reported multiple concussions.

“The elephant in the room is whether there is some influence of contact sports and the development of frequent or chronic headache later in life,” Seifert said. “And if so, how much?”

Seifert, who also chairs an N.C.A.A. task force on headaches, said that he expected to publish a similar report involving 834 Division I athletes in the spring. Though he would not go into detail about the results, he said that it looked to be “very similar to what we’ve found in this sample of high school players.” Mauldin, it should be noted, sustained a concussion earlier this season.

There is no cure for migraines, and sufferers often go the rest of their lives “controlling” the issue, Seifert said, comparing it to those dealing with high blood pressure or diabetes. What concerns him, though, are the studies that have shown that people with migraines are more susceptible to concussions, and when they do sustain one, it takes them longer to recover.

“We know that the migraine brain is just wired differently,” Seifert said. “And we know that it’s a brain that is hypersensitive to external injury. And those pain receptors that are in overdrive — it takes that much longer to calm down and return to baseline.”

In the time it takes for the receptors to settle, though, the pain can bring a linebacker to his knees.

“When they pop up out of nowhere, you start to feel a sensation like in between the middle of your forehead,” Mauldin said. “But it’s in the back of your head as well. It’s like somebody’s punching you in the side of the head.”

Kerley said he had yet to receive a migraine disease diagnosis, but he thinks it could be related to difficulties he regularly has with sleeping, being someone who has sleep apnea. When he feels a headache coming on, he has a nasal spray that he said often cured his symptoms within a half-hour. But last Sunday, it was too late.

“If you don’t catch it while it’s early, it could get pretty bad,” Kerley said. “Mine got there.”