You're brilliant at your intervals, getting your heart rate up into the training zone, and having the best workout you've had in a long time. Then, out of nowhere, your head starts pounding. What's going on?
Up to 25% of active people say they periodically experience throbbing head pain, sometimes with nausea, when they exercise hard, especially in hot weather or indoor environments that are warm.
Many forms of intense exercise certainly can cause headaches, even in people who don't usually experience regular headaches. Last year, the International Headache Society listed "primary exercise headaches" among one of its main headache triggers.
According to Dr Rashmi Halker Singh, assistant professor of neurology at the Mayo Clinic in Arizona, "primary exercise headaches develop during or after sustained exertion. Exercise headaches usually hit when you're working out intensely and your normal heart rate doubles. They occur more frequently in people who also suffer from migraines, but can also happen because of other causes, including dehydration."
Generally, these headaches can arrive during or after exercise and last up to 48 hours. Medical professionals are not quite sure exactly what causes these headaches, although some studies suggest that changes in blood flow to the brain during prolonged exercise might play a role.
As someone who has suffered from migraines most of my life, I was not surprised when I experienced my first exercise headache halfway through a half marathon several years ago. The race conditions were hot and humid and I had not adequately hydrated prior to the starting line.
By the time I realised what was going on, it was too late. The hydration and fuel I was feeding my body at mile eight, was not enough to combat the nagging ache in my head. While this headache was painful and annoying, I quickly realised that what I was feeling was not a migraine, rather a headache produced by the intensity of the exercise, environmental conditions, and lack of proper fuel.
If you're finding that you are experiencing exercise headaches while working out, it's probably a good idea to get checked by your doctor to rule out a serious underlying medical problem. For those who are not dealing with an underlying medical condition, Dr Halker recommends using common sense for your exercise sessions by eating and drinking before workouts to avoid low blood sugar or dehydration and consider slowing down, at least temporarily.
Remember, these headaches are associated with high levels of sustained exertion, so if you find that you are being plagued with these pains, try switching out your higher-intensity workouts in favour of lower-intensity activities for a while.
Sara Lindburg has a B.S. in Exercise Science and an M.Ed. in Counselling. A 41-year-old wife, mother, and full-time secondary school counsellor, she combines 20-plus years' experience in the fitness and counselling fields and she has found her passion in inspiring other women to be the best version of themselves on her Facebook page, FitMom. Her inspiration for writing comes from her 6-year-old son, Cooper, and 8-year-old daughter, Hanna. Follow Sara on twitter.