yes strenuous exercise is a major trigger for me. I am an amateur cyclist, I cycle about 4 to 5 days a week, distances between 30 and 80 miles a ride. The last 3 attacks I have had have all come from strenuous rides in the heat or being dehydrated due to running out of water. and then have put me in the 8 week cluster cycle. I have not had an attack for three years as I am on the D3 regime and became over confident and then rode very hard on a hilly course on aug 10th and bang, back again. Now in week 4 of the cycle, busting weekly with Vit M and last week with vitamin L, wake up nightly with the right eye pain and coffee aborts it, after the vitamin L , I have now had 2 nights of undisturbed sleep, hoping I am reaching the end of the cycle. I am also taking Quercetin, Tumeric, Vitamin C to battle histamine which also seems to have helped.