When Rachael Fisher first started suffering from migraines at age 25, she thought for sure stress was the cause. She worked for a demanding boss whose loud outbursts tended to give Rachael headaches so severe she would vomit—a classic migraine symptom.

But Fisher soon noticed that the migraines were occurring even when she wasn’t under stress. She felt panic because she couldn’t control the episodes and she was desperate for an end to the pain. So she started keeping a diary about her migraines and the results were eye-opening.

“I didn’t realize how much my menstrual cycle was a trigger until I started keeping the diary,” Fisher, now 32, of Clifton, NJ, says. “I found that the two weeks after my menstrual cycle are ‘good weeks.’ I feel more energized and I know it’s okay for me to have a drink with friends, even though alcohol can be a trigger. During the bad weeks, I won’t even attempt a sip.”

What Causes a Migraine?
The migraine brain seems to be hyperexcitable—nerve cells in the brain fire too easily and start the attack. Excited brain cells prompt the release of chemicals that cause the painful swelling of blood vessels in the brain. Migraine triggers can be internal or external. Internal triggers include the menstrual cycle, stress and getting too little or too much sleep. External triggers include weather and seasonal changes, flickering or bright lights, some foods, certain odors, excessive noise and skipping meals.

Some people with migraines have no triggers at all, while others have many. And triggers are very individualized. What sparks a headache in one migraineur may not affect another. For that reason, a migraine diary is one of the most important diagnostic tools a neurologist has in helping a patient gain control over her headaches.

How a migraine diary can help
“The diary helps empower patients to take an active role in their headache care. Identifying triggers allows patients the opportunity to avoid them,” says Brian Grosberg, M.D., director of the Inpatient Headache Program at the Montefiore Headache Center in New York City. “It certainly helps the physician, too, by identifying ways to improve both the prevention and acute treatments of someone’s headaches.”

In the diary, your doctor will likely ask you to note when your headaches began, their frequency, how long they last and how severe they are. You’ll also indicate the circumstances surrounding your headaches, such as the start and end of your menstrual cycle and if you came into contact with any common migraine triggers.

Other factors to note include the weather (especially extreme changes from hot to cold) high humidity or changes in barometric pressure. “I have a migraine patient who says she can predict the rain better than the weatherman,” says Dr. Grosberg.

Also make note of events outside of your normal routine, like a particularly stressful experience, jet lag, traveling to a city at a high altitude or a night out at a loud, smoky nightclub.

Gain Control Over Your Headaches
Once you identify your triggers, don’t fear them. Instead, be empowered by them. “Migraineurs may feel really worried, that if they do X, Y or Z then that’s going to set off a migraine,” says Kevin McKay, Ph.D., psychologist with the Headache Management Program at The Miriam Hospital’s Centers for Behavioral and Preventive Medicine in Providence, RI. “But armed with the knowledge of your triggers, you can limit exposure to them, and adapt when necessary.”