As temperatures break records across the U.S., so will cases of migraines. That’s the latest from a recent study by the University of Cincinnati College of Medicine researchers.

With global temperatures more than 2 degrees warmer than the 20th century average, last year was Earth’s hottest on record. And May 2024 was a record-breaking month, marking the 12th consecutive month of record high temperatures.

According to Dr. Vincent Martin, director of the Headache and Facial Pain Center at University of Cincinnati’s Gardner Neuroscience Institute, and lead author of the study, “Weather change is one of the most common trigger factors for migraine.”

The study, produced by Teva Pharmaceuticals USA, tested the efficacy of a new preventive treatment for headaches caused by rising temperatures by cross- referencing regional weather data with 71,030 daily diary records of 6,060 migraine patients. Researchers discovered a 6% increase in headache occurrences for every 10 degrees the temperature rose.

“What we found was that increases in temperature were a significant factor in migraine occurrence across all regions of the United States,” Martin said.

Migraines affect at least 39 million Americans, according to the American Migraine Foundation. The World Health Organization reports that headache disorders as a whole affect 3.1 billion people around the world as of 2021.

Migraines are characterized by severe throbbing pain caused by the activation of nerve fibers within the wall of brain blood vessels. Left untreated, the National Institute of Neurological Disorders and Stroke said attacks can last several hours or even days.

Those with the condition often experience sensitivity to light, noise and odors, as well as nausea and vomiting. Among the many migraine triggers, which range from hangovers to skipping meals, the institute said a sudden change in weather is a common culprit.

“Hippocrates, the father of medicine, believed that weather and medicine were intimately linked,” said former Department of Agriculture chief meteorologist and study co-author Al Peterlin.