Wjen I push myself on a brisk walk, at the end of the walk I have what feels like a migraine. It is on one side of the bridge of the nose and around that eye socket. It takes from 50 minutes to 1.5 hour and eventually goes away. I have had cluster headaches in the past, but this does not pierce to the center of the brian like they did. It is around one eye. If I walk slower and don t elevate my heart rate it doesn t seem to happen. I am drinking a lot, before and during the walks so I don t think it s dehydration, but it is possible. What is causing the headache. I need to lay down and shut out any light when I get back from the walk and it is very painful.