I know why your heartrate goes up during exercise but the left ventricle can only be filled so much.
Does pulsing blood at a faster rate necessarily lead to a greater BP?
Unless the blood vessels increase in diameter a sufficient amount, then you will need to push harder to get more blood through.
It is a similar situation when people try to increase the water flow from their shower heads. You can either increase the pipe diameter to the shower (or remove the flow restrictor in the showerhead) or increase the supply pressure.
It makes obvious sense that more blood needs more space but . . .
I am imagining a bulge of liquid moving along a rubber hose. A distance away is a second bulge. This represents an artery under resting condition. with each bulge being a heart contraction.
During exercise, due to restrictions in the size of the left ventricle, I am imagining that these bulges are not larger in size but more frequent along the hose. The hose is not stretching any larger overall, but there are more nodes of stretch.
Is this incorrect?
Yeah, that’s probably not the best way to think about the circulatory system. Remember that there aren’t any ‘bulges’ of blood moving through your arteries, the pressure from each heartbeat gets transmitted more-or-less instantly throughout your bloodstream. That’s why there’s only a small delay in the pulses between, say, your carotid and your radial artery (this is easy to do, use one hand to feel the pulse on your neck, and use the other to check that hand’s radial artery).
A better analogy might be a bellow-like pump forcing water through a loop of garden hose that dumps back into the reservoir the pump feeds off of. There’s a small hole in the far end of the loop, and the pressure of the pump is forcing a stream out water to leak out.
Now, if you want to get MORE water out of that hole you have, as you mentioned, two options. Either make the hole bigger (vasodilate) or push on the bellows faster/harder (increased heart contraction/rate). Generally, your body will do both, but you can only make your blood vessels so big. So, mostly, we pump the bellows more.
It’s worth mentioning that this will only increase your systolic blood pressure, which are the bulges you’re envisioning. The underlying friction inside your garden hose, however, doesn’t change much, and neither does your diastolic pressure.
So my heart can pump harder? (not just faster?)
Yeah.
When exercising, your heart beats harder, faster, better, stronger.
Can you provide a cite for this?
While I assume the Tubes were paraphrasing the Olympic Motto and the Bionic Man intro, what he says is an inevitable outcome of the Frank-Starling law.
My Physiology Prof used to paraphrase the Frank-Starling law as “what goes in has to come out”. Basically, if you put blood into the heart at the atria, it *must *come out from the ventricles in the same cycle. During exercise, more blood enters the atrium on each beat, so more blood has to leave. The way the heart does that is to contract the ventricles harder, forcing out more blood at each beat.
Of course because more blood is being forced out on each contraction, the blood pressure also goes up.
I am assuming you don’t want a cite for the fact that the heart beats faster during exercise.
My mom’s physical therapist noted that when she comes back to her retirement home apt. from the dining room, her b.p. is elevated a bit. I suppose it is because she was sitting for almost an hour and then got up to walk. Same thing happens when she goes to the doc’s office, but there is also a ramp to go up and I think she is a bit stressed about being in any such office anyway. All kinds of things can raise one’s b.p.
Mine is low normally, but it shot into the stratosphere a couple years ago when I was in agony from biliary colic, a condition caused by gallstones getting stuck in a duct.