Hello. Thanks for writing to HCM. I read your question and understand it. I try my best to solve your problem. You had done more intense cardio workout , so it is possible to get throbbing headache after workout. You should keep in mind that if you want to increase your workout than gradually day by day you can increase , never try to do hard workout on a single day. When you do heavy workout your heart try to push more blood to peripheral muscle and tissue. And thats why you feel symptom. My advise to you that please take deep breathing for sometime when you feel headache and take some rest . If you symptom persist than consult a good physician. I hope that my answer will help you a lot. Thanks and Regrads. Dr Vijay