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I was reading about Postural Orthostatic Tachycardia Syndrome (POTS) & I was wondering if for regular healthy people, does pulse rate increase when going from lying down to standing up?

Not asking for diagnostic criteria for POTS - I know that it's an increase of 30 to 40 on getting up.

My question is not about that but about how a healthy body behaves on getting up

  1. Does Pulse Rate increase on going from supine to standing up position?
  2. How long does it take it to go up?
  3. Does it come down without sitting or lying down or are standing pulse rates always higher than sitting & lying down pulse rate?

I found answers to the first question which don't agree with each other.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3361090/

When humans stand up, approximately 500 ml of blood descends from the thorax into the abdominal cavity and limbs. A normal autonomic nervous system responds with immediate peripheral vasoconstriction, increase in heart rate of 10–20 beats per minute (bpm), and minimal change in blood pressure

https://www.ncbi.nlm.nih.gov/books/NBK402/

These changes in blood pressure may be accompanied by a physiologic increase in heart rate of 10 beats per minute or less

The first says it increases 10 to 20 bpm. The 2nd says it's less than 10.

Other than that, it doesn't say how long it remains raised? Does it come down after a short time or does it remain raised till you lie down again?

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    Have you tried experimenting on yourself? That would be very easy to do and it would help meet this site's requirement that questions demonstrate some degree of prior research.
    – Carey Gregory
    Aug 23, 2023 at 14:23
  • @CareyGregory - I did but how do I know if my readings are the same of the average readings or not? May be, my increase is much below average or much above average inspite of the fact that it's not clinically a problem. I can add it to the question if needed but then it becomes a personal question which is it not what is intended. I am not trying to diagnose myself because I don't think I have any problem.
    – user93353
    Aug 23, 2023 at 19:31
  • Regardless of where you fall on the bell curve, it would show you what happens when you stand. The relative changes should be the same for any "normal" person. The other alternative is you do some more research on the question and show us what you found. Questions here must show evidence of having made some effort to find the answer yourself.
    – Carey Gregory
    Aug 23, 2023 at 20:08
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    @CareyGregory I have added some more info I had found.
    – user93353
    Aug 23, 2023 at 20:23

1 Answer 1

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Postural changes in heart rate

I found an old study examining postural changes in blood pressure in 43 healthy people: Borst et al. American Journal of Physiology, 1982. Mechanisms of initial heart rate response to postural change.

The authors’ results reveal the following:

Standing evokes an immediate, large… increase of heart rate of about 20 seconds duration.

The heart rate does indeed rise with standing.

The immediate heart rate increase with active standing is due to the exercise reflex and results in a first peak about 3 seconds after standing briskly.

The first peak of heart rate is about three seconds after standing.

The secondary, more gradual heart rate increase after 5 seconds of standing and the subsequent rapid decrease of heart rate between about 12 and 20 seconds corresponds through the baroreceptor reflex with a striking fall, recovery, and sometimes overshoot of arterial pressure.

The pattern of heart rate change is not a simple rise and fall, but rather it is biphasic.

Heart rate gradually falls towards baseline levels.

Regarding mechanisms, the authors state the following:

Central command, muscle receptors, high-pressure receptors, low-pressure receptors, and the plasma catecholamine level are probably all involved in the initial heart rate response to standing.


Further exploration

Blood pressure (BP) depends on severs factors including total peripheral resistance (TPR) and cardiac output (CO). CO in turn depends on the stroke volume (SV; volume pumped with each cardiac cycle) and heart rate (HR).

The relationship is shown below:

BP = CO x TPR

Which is the same as:

BP = HR x SV x TPR

Heart rate increases in order to maintain adequate blood pressure for the perfusion of the brain (reduced cerebral perfusion might cause lightheadedness or collapse.

Heart rate is able to respond quickly, but as it falls again, other slower-responding mechanisms can also contribute to maintaining blood pressure, such as total peripheral resistance.

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