system
Given the following post, respond as if you're commenting on Reddit:
human
How is high blood pressure bad for you but exercise isn't bad for your cardiovascular system (like blood vessels)?

I understand that exercise will increase the strength of your heart muscle (I think?) making it more efficient.

But as far as the blood pumping through the veins, how is that any different than if someone's blood pressure was just high? I've read that high blood pressure can weaken/damage the inner lining of blood vessels increasing the risk of a stroke later on in life, and I don't see how that would be any different with exercise.
gpt
Because it is a constant stress on the walls of your arteries and your heart vs just a temporary one.  Your heart has to work harder to pump the same amount of volume into a smaller space, which is one cause of high blood pressure.  If it does this all the time, eventually it's going to tire itself.  And no, it's not constant exercise for it because it never has a chance to lower its workload so as to regenerate muscle.  

High blood pressure can also lead to things like aneurysms (burst of a blood vessel in the brain), a heart attack (destruction of blood vessels on the heart, such as the coronary artery), hemorrhaging (blood vessels bursting in your body), or congestive heart failure (the load the heart has to pump against [your blood pressure] is so great that it simply cannot overcome the resistance to get blood into your aorta, and you die).  

Another thing is that high blood pressure can shut down your kidneys by the same method (destruction of blood vessels) and since your kidneys rely on blood flow to work (and filter the blood properly), you get build up of all sorts of nasty stuff in your blood. 

During exercise, your blood pressure is just temporarily elevated, which your body is more than capable of handling.  With high blood pressure, your blood pressure is elevated all the time, which your body can only handle to a certain extent.