Weather impacts about half of people who get migraines, a growing issue in the face of climate change, experts say.
Migraine Canada, a registered non-profit, estimates that about 12 per cent of Canadians (4.5 million) live with migraine headaches. Around 2 per cent are considered to have chronic migraines, meaning they experience 15 or more headache days per month.
A migraine is defined by the U.S.-based National Institute of Neurological Disorders and Stroke as a
There are a number of factors that can trigger migraines, including stress, overexertion, loud noises and low blood sugar.
Another common trigger is a change in weather, something some an experts say is happening more often due to climate change.
HOW CLIMATE CHANGE IS LINKED
What happens for those people is that a low- or high-pressure system, sometimes associated with approaching storms, changes the atmospheric pressure.
It's this change in pressure that causes migraines for some.
High- and low-pressure systems move across Canada because of the jet stream, according to Toronto-based climate and public health expert Jeffrey Brook.
There is research to suggest the heating climate is impacting the jet stream, changing how often the atmospheric pressure shifts.
"We do know that pressure extremes seem to be happening more," Brook, an assistant professor at the Dalla Lana School of Public Health at the University of Toronto, said in an interview with CTVNews.ca.
"Some climatologists think that because of the changeability, the jet stream can get into patterns where all of a sudden, things don't move as much, so the area of high pressure stays for longer.
An Alberta-based migraine expert summarized the trend as follows.
"We can assume that if we have more extreme weather with more pressure variations and storms coming in, it's likely to make things rougher for migrators who are sensitive," said Werner Becker, a professor of neurology at the University of Calgary.
Migraine Canada also cites .
Climate change is believed by scientists to be linked to an increase in pollen during allergy seasons, which for some people can also mean a higher chance of migraines.
WHAT ELSE CAUSES MIGRAINES?
The "dam theory" is one way experts look at triggers for migraines, Becker told CTVNews.ca in an interview. According to this theory, some migraines only emerge with the presence of more than one trigger.
The conditions outside might not be enough but, when combined with another factor, can lead to a migraine.
"Let's say you're weather sensitive, but it doesn't quite trigger a migraine," Becker said. "But you're getting pretty stressed out or you're short of sleep, or you're skipping a meal. That's another thing to put you over."
Some people who experience headaches will never have a migraine, which can be due to their genes, Becker said.
"For a regular migraine, it's much more complicated," he said. "There are many, many genes that seem to be able to just increase your migraine tendency a little bit."
Migraine "attacks," Becker said, have different severities, but they are "more than just a headache."
WHAT CAN CANADIANS DO?
There are a number of preventative measures people can take to reduce their chances of getting migraines, Becker said.
"Make lifestyle adjustments," he said. "Regular sleep, regular meals, try to learn to manage stress or manage it and also avoid other triggers."
Processed meats, some cheeses and red wine are some triggers that could impact a person's migraines, he said.
A number of medications are also available in Canada to help treat symptoms of migraines, but relying on painkillers is not ideal, Becker said.
"If your attacks are frequent and if you take (painkillers) too often…you can get into a medication overuse headache," he said.
Some specific medications can reduce migraine frequency and are taken by injection every few months.
Becker said that many people suffer through migraines without help, but seeking health-care advice can make a difference.
"People that have frequent migraines, one a week or more, they really shouldn't just sit down and take it," Becker said. "There are some new treatments available now…Don't just get into taking the acute medications, like painkillers, every day."
