Temperatures are starting to rise, with some parts of the US facing a record-setting early heat wave this week. But while you’re probably focused on staying cool, there’s one more thing that should be on your radar: a higher-than-usual risk of migraine headaches.
That’s the major takeaway from new research published in the journal Neurology: The study uncovered three lesser-known factors that can trigger migraine—and these triggers can crop up even more in the late spring and summer.
If you’re one of the 12% of Americans who deals with these headaches, this is information to keep in your back pocket. Here’s what the study found, plus how doctors who treat patients with migraine recommend protecting yourself.
The study followed people with migraines for a decade.
For the study, researchers followed 7,032 people living in Israel for about a decade who suffered from migraines. During the study period, researchers looked at participants’ daily exposure to air pollution, along with tracking weather conditions. They also looked at how often and when people visited the hospital or their primary care doctor with a migraine. That data was compared to the levels of pollution and weather conditions on that particular day, along with seven days before that.
During the study period, 2,215 people (or 32%) had at least one visit to the hospital or a clinic with a migraine. The researchers also found that 47% of participants in the study bought triptan medications at one point or another—fast-acting prescription medications that are designed to stop a migraine—with most using at least two tablets a month.
Ultimately, the researchers discovered a link between three weather-related factors and migraine: air pollution, temperature (including UV exposure), and humidity. First, they found a correlation between higher levels of air pollution and the most number of visits to a hospital or clinic for a migraine. They also found that the day with the least visits to the hospital or clinic also had lower-than-average pollution levels. People with short-term exposure to high levels of nitrogen dioxide (a common pollutant from traffic exhaust) were 41% more likely to go to the hospital or clinic for migraine than people who weren’t exposed to high levels of the gas.
The study also showed that people who were exposed to high levels of UV rays from the sun on a given day were 23% more likely to visit a healthcare provider for migraine symptoms than those who weren’t. High temperatures and low humidity appear to be linked to more migraine headaches, likely because they amplify the effect of nitrogen dioxide, the researchers said.
With climate change intensifying how often we deal with heat waves and pollution, it’s important to consider these risk factors when it comes to migraine, the researchers wrote.
Why do these factors raise the risk of migraine?
It’s important to note that the study didn’t prove that air pollution, heat, and lower humidity levels cause migraines—it just found a link between them. But doctors say there’s likely something here.
Air pollution can spark neuroinflammation (the immune system’s inflammatory response in the brain and spinal cord), which is a risk factor for migraine, Sana Ghafoor, MD, neurologist at Tufts Medical Center, tells SELF. This may cause a release of pain chemicals like calcitonin gene-related peptide (CGRP) and substance P that can lead to a migraine, Dr. Ghafoor says.
Air pollution may be particularly problematic for people with allergies who also struggle with migraines, Clifford Segil, DO, a neurologist at Providence Saint John’s Health Center in Santa Monica, California, tells SELF. The body may see air pollution as an allergen and mount an immune response, which can spark a migraine in people who are sensitive to this trigger, he explains.
Then, there’s the fact that heat can impact blood vessels and nerves. “When people heat up, nerves and blood vessels in tight locations can become irritated, as the diameter of a blood vessel or nerves increases with heat,” Dr. Segil says. That, too, can trigger a migraine. You’re also more susceptible to getting dehydrated when it’s hot out, Dr. Ghafoor says: “If you’re overheated and dehydrated, those can also trigger migraines.”
Dr. Segil points out that high humidity common in the spring and summer (and not just that related to air pollution) can trigger migraines too. High humidity causes you to sweat and lose water, which can decrease the amount of blood in your blood vessels (if you don’t replace it), Dr. Segil says. “This decreases the diameter of blood vessels and can cause headaches, just like an increased blood vessel diameter,” he says.
Dr. Ghafoor says she often sees more patients have migraine headaches when high humidity strikes. “Even with small [atmospheric] pressure changes, it can activate nerve endings and sinuses, which can lead to the release of pain chemicals,” she says.
Of course, you have more than these three triggers to worry about.
These are some of the most common migraine triggers, according to the US National Library of Medicine:
- Stress
- Anxiety
- Hormonal changes in women
- Bright or flashing lights
- Loud noises
- Strong smells
- Medicines
- Too much or not enough sleep
- Sudden changes in weather or environment
- Too much physical activity
- Tobacco
- Caffeine or caffeine withdrawal
- Skipping meals
- Medication overuse
These foods and ingredients can also trigger migraines, per the US National Library of Medicine:
- Alcohol
- Chocolate
- Aged cheeses
- MSG
- Some fruits and nuts
- Fermented or pickled goods
- Yeast
- Cured or processed meats
What’s the takeaway?
Migraine triggers are personal, making it important to do what you can to figure out yours and then try to avoid them as best as possible. (Dr. Ghafoor recommends keeping a headache diary to try to narrow things down.) But factors like air pollution, heat, and humidity can be tough to avoid.
If levels of air pollution are high in your area, Dr. Segil recommends wearing a face mask like an N95 when you need to be outdoors. Keeping your windows shut and running an air purifier can also help tamp down on pollution indoors. If you’d like, you can track pollution levels throughout the day and try to stay inside during peak times, Dr. Ghafoor says.
When heat and humidity strikes, Dr. Ghafoor recommends doing what you can to stay well hydrated. “Make sure that it’s not just water, but electrolytes too,” she says. “All of that is a very important part of lifestyle management for patients who have migraine.”
Ultimately, doing your best to try to figure out your triggers (and avoid them) can go a long way toward helping to keep you more comfortable on a regular basis. “Knowing and identifying migraine triggers is very important,” Dr. Ghafoor says. “It’s empowering the patient to understand their disease.”
Related:
- 19 Possible Causes of Random Dizzy Spells—and When to Worry
- Is Botox for Migraine Pain Worth It? We Asked 8 People for Their Honest Reviews
- Why Do Strong Fragrances Make Me Feel Like Crap?
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