The study found a shocking 31 percent increase of the risk of headache and a 28 percent increased risk of migraine for chronic headache sufferers on days that lightning struck within 25 miles (40 kilometers) of their homes. (See lightning pictures.)

Furthermore, new-onset headaches and migraines increased by 24 percent and 23 percent, respectively, according to the study, published January 24 in the headache-focused journal Cephalalgia.

While there have been conflicting studies linking factors such as weather, humidity, and barometric pressure and headaches, the new study is the first to show a correlation between lightning and associated weather phenomena and the squalls in our heads.

How Does Lightning Spark Headaches?

Participants in the study logged their daily headache activity for three to six months, during which any nearby lightning strikes were also recorded. Mathematical models were then applied to rule out other weather factors as the cause of the headaches—and the correlation held true. (Interactive: Make lightning strike.)

The results “suggest that lightning has its own unique effect on headache,” study leader Vincent Martin, a professor of medicine at the University of Cincinnati, said in a statement.

As for how exactly lightning might trigger headaches, Martin said there are a number of possible explanations.

“Electromagnetic waves emitted from lightning could trigger headaches. In addition, lightning produces increases in air pollutants like ozone, and can cause release of fungal spores that might lead to migraine.”

Study co-author Geoffrey Martin—a medical student at the university and Vincent’s son—emphasized in a statement that while the study sheds light on the apparent link between lightning and headaches, “the exact mechanisms through which lightning and/or its associated meteorologic factors trigger headache are unknown.”

Meaning a further brainstorm may be required.