Overheating/dehydration/hunger. Any of these, or any combination will do it for me. Elimination of these, and the headache dissapears immediately. When I am not paying attention, the headache is kind of an alarm, to wake me up and take notice.
I only get headaches when I am dehydrated, so I’d check that if you can. Weigh yourself before and after, and keep in mind you can carry 1/2-1lb of water in your clothes already sweated out. I’ve found when I thought I was drinking enough water…after 7-10 miles I might lose 3 or 4 lb of sweat. Very possibly your salt/potassium balance is off too, but my major problem is always water.
I have a friend going through this right now. He had a MRI and they can find nothing. He eats and drinks well, just comes on from time to time. Usually a hard effort does it, but not all the time. Does this sound familiar?
What about getting headaches from the aerobars? In a race scenario, sometimes I tend to be pulling and straining my neck a lot harder than while training.
That is it pretty much. Hard effort is relative, though. I raced ‘harder’ a couple weeks ago and really did not get the headache. Yesterday was a hard effort, but not nearly as hard as some other races, but still got a good one.
I’m completely with you on that one. I always get a headache after a long exertion. I think it is either dehydration (most likely culprit) but then again, I would get some altitude sickness as a child so maybe the 6 - 7 hours of exertion kept me in a slightly low oxygen state and I got a headache. It always goes away after sleeping though for me.
Hyponatremia can indeed be serious, but it much less common than dehydration. I’m guessing Foolish Tri Guy isn’t drinking distilled water during his races.