I've noticed it starts whenever I go too long without exercise. It goes away after being consistent with my program, though, so I am not too worried. But if any of you are experiencing the same thing for the first time or it is far worse than before, please, have yourselves checked by a doctor as this could be a sign of something serious. Anyway, the most common cause of exercise induced headaches is just over exertion. But there can be several other causes, like when you already suffer from migraine, then the exercise can cause a trigger. If you ever experience exercise induced headaches, here are some tips to prevent it: 1. Make sure you are warming up before starting your exercise program and cooling down after. Do some light exercises and stretching to gradually increase your heart rate. Do some 5 to 10 minutes of light jogging and some 10 to 15 minutes of dynamic stretching exercises to avoid muscle stiffness. 2. Start Slowly. If it's your first time running, meaning you have not run at all since you were a kid, then do some brisk walking for a few days. Once your body is used to it, then you may want to do some light jogging for a few minutes interspersed with walking. In any exercise program, it is always important for you to start slow. This not only avoids the headaches, but it also avoids serious injuries. 3. Stay Well Hydrated. Drink! Drink! Drink! Try to bring a small bottle of water whenever you do your brisk walks. Run in places where there are stores you can stop over and buy drinks. 4. Avoid exercises that involves too much stooping. 5. Try taking some Ibuprofen (Advil) before starting your exercises. 6. Try gentler exercises. Try exercises that have lower impact but with more stretching. Try Yoga or swimming. 7. Taper off slowly: If you're already involved in intense exercise, don't stop suddenly. If you know you're going to be taking some time off, slow down the exercise, don't quit cold turkey. If you still experience exercise induced headaches after trying these tips, please, go see a doctor as it may be something serious. It is always a good thing to have yourselves checked before starting any exercise programs.