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Many people who start practicing handstands or headstands report discomfort in their head, ranging from a mild sense of fullness to "my head is going to explode." The standard response in online communities is something like this: The sensation is caused by blood rushing to your head, it's harmless, and it will go away with practice. This oft-cited blog post is a good example.

They seem to be claiming that with exposure, the body becomes more effective at regulating changes in bloodflow that result from being inverted. If this is true, do we know what the regulatory mechanism is and how it improves?

  • Too broad. You're asking for a textbook in the title and three long answers in the body. If you can edit your question to just one of the three you asked it will probably be okay. – Carey Gregory Feb 17 at 6:35
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    Okay, I have edited the question. – octern Feb 17 at 9:30
  • Thank you. You can always ask the other two as separate questions. – Carey Gregory Feb 18 at 0:14
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What happens during inversion?

  • increase in blood pressure

  • Oxygen uptake increase

  • Heart rate decreased significantly

  • The double product, the frequency of breaths, and tidal volume were not significantly changed

What happens post exercise ?

nonsignificant changes in heart rate, systolic blood pressure, and double product from the pre-inversion baseline standing position. 

What are chronic changes

No physiologic adaptations occurred in any of the inverted positions as a result of inversion training. 

Mechanism for maintenance of Blood pressure?

There is baroreceptor at aorta and carotid sinus. These receptors have a baroreflex mechanism that helps maintain normal pressure on the brain and other vital organs.

As the acute adaptation and resetting are correlated using a graphic analysis, we hypothesize that the baroreceptors can recognize a new pressure level within minutes. The inherent ability incurs downward and upward adaptation as well as resetting at lower and higher holding pressure, respectively.link

It is important to note that baroreceptors adapt to sustained changes in arterial pressure. For example, if arterial pressure suddenly falls when a person stands, the baroreceptor firing rate will decrease; however, after a period of time, the firing returns to near normal levels as the receptors adapt to the lower pressure. CV physiology

Adaptation of carotid and aortic baroreceptors

the longest measure time for an almost complete adaptation of mechanoreceptors is about 2 days, which is the adaptation time for many carotid and aortic baroreceptors; however some physiologist believes that these specialised baroreceptors never fully adapt.

[excerpt from Guyton And Hall textbook of medical physiology]-

excerpt from Guyton And Hall

So, as people practice this handstand posture, slowly the receptors may start to adapt or they might never adapt

Hence, in short, we can say that the body's mechanism either remained the same or adapted a little in long term, while the short term regulation of blood pressure remained the same.

Cerebral blood flow

With the regulation of BP in mind, we can think further about the regulation of cerebral blood flow.

cerebral blood flow is autoregulated extremely well between the arterial pressure limits of 60 mm Hg and 140 mm Hg; further, the cerebral blood flow autoregulation occurs even when the mean arterial pressure Rises to as high as 160 - 180 mm as in case of hypertensive

[Ref. Guyton and Hall Physiology]- 7]

  • Welcome to MedicalSciences.SE. We work differently to most SE sites, where we have a strict policy that all answers should be backed up with reliable references so that the answer can be independently verified, regardless of the reader's background. See this list of reliable sources. If you still have trouble with this, feel free to visit the help center or Medical Sciences Meta. Unreferenced claims can lead to answers being deleted. – Chris Rogers Feb 17 at 11:34
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    Okay Chris I understand, I'll add references – Physicsapproval Feb 17 at 11:46
  • Good answer. I'd just note, adaptation of the baroreceptors, which you spend a good deal of space on, would be the opposite of the adaptation the OP seems to be asking about. A baroreceptor that adapts to a higher pressure during an inversion, would allow higher blood pressure in the cerebral vessels, making it less effective at regulating changes, rather than more. I'd suggest leaving the paragraphs on baroreceptor adaptation out of this answer, since it's directed at a different question. – De Novo supports GoFundMonica Feb 17 at 19:08
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    I'd also suggest converting your image of text to a block quote. Text in images can't be found in a search, and increase the page load time. – De Novo supports GoFundMonica Feb 17 at 19:10
  • @DeNovo The images appear to be photos from a textbook. Although they could be converted to text using an OCR service, which are available free on the web, that's not something most people would be familiar with. The underlining and notes on the first photo will also make OCR problematic. If OP wants to do as you recommend, I suggest onlineocr.net (just because I've used it and it works, no personal connection). – Carey Gregory Feb 18 at 0:11

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