You need to clearly ask your cardiologist if this is something to be concerned about. I can't give you medical advice. However,a significant decrease in blood pressure is perfectly normal in many people - and can be more dramatic in people with hypertension. In fact, what's NOT normal is for blood pressure to not go down (as it doesn't in about 20 percent of hypertensive patients). Your drop in blood pressure is not down to a dangerous level at all. Again, take what I'm telling you, if you wish, and ask your doctor specifically if this is correct or not for you (I am basing what I'm writing on published research, by the way, but never take what your ead on line - talk to your doctor as you seem so worried). First of all , make sure you take your blood pressure pre- exercise while sitting and breathing comfortably for a while. Make sure you are not dehydrated prior to exercising. Understand that blood pressure dropping somewhat after exercise is 100 percent NORMAL whether people have hypertension or not. It will sometimes remain lower for hours. Keep a record of your blood pressure immediately after exercise in take it again a 15 minutes, half an hour. Share this with your doctor. Lower blood pressure after exercise is one reason that consistent exercise is one of the best ways to lower elevated blood pressure and why, along with weight loss as needed, it can help people get off medication as your body adjusts to exercise. Why does it drop? There is vasodilation when you exercise and also exercise also typically reduces levels of catecholamines - hormones made by your adrenal glands that can boost blood pressure (that's why stress boosts hypertension and one reason exercise can lower it; it's also one reason doctors will suggest exercise to boost mood and relieve anxiety by calming excess "stress hormones" and their symptoms). There is a complicated process through many factors influence baroreceptors which adjust the body's blood pressure according to what you are doing - the changes are mediated by the autonomic nervous system. Exercise can help normalize that system.. For example, if a person is on bedrest for months, their body typically will not automatically adjust to standing up - blood pressure my drop and they may feel faint and have to slowly get back in shape and the body adjusts.. this may not be a good example but consider that the more your exercise the more your muscles and heart function may improve and normalize - and that goes for blood pressure. Again, talk to your doctor and keep up the good work exercising!.