I’ve heard recently from several runners who were complaining about splitting headaches after their runs. It’s no coincidence that they’re all getting post-run headaches this time of year.

Headaches during or after running are fairly common, especially when running in warmer weather. They could be attributed to one or more of these factors:

Dehydration: Headaches can be a symptom of dehydration, so make sure you’re drinking enough before, during and after your runs. A basic rule of thumb is to drink 6-8 ounces every 20 minutes during your run. But use your thirst as your guide—if you’re feeling thirsty, you should drink.

Sunlight: Bright sunlight can be a headache trigger for some people. To help prevent headaches (and protect your skin and eyes at the same time), wear a hat with a brim and running sunglasses when running during the day.

Exercise headaches: If the headache pain is on both sides of your head during or after a run, it may be an exercise headache. Exercise headaches occur more frequently when running in hot weather or high altitudes, and among those who have a personal or family history of migraines.

The exact cause of exercise headaches is unknown, but they are usually harmless and can be treated with over-the-counter pain medication. You may be able to prevent them if you avoid running during the hottest part of the day. If you start getting exercise headaches along with any of the following symptoms, talk to your doctor: Headache lasting longer than a day, loss of consciousness, rigid neck, double vision, vomiting, headache on only one side of the head, or the first episode of exercise headache occurring after age 40.

---
By Christine Luff, About.com Guide to Running / Jogging