# Is it possible to regulate blood pressure through purely mechanical means? **URL:** \ **Category:** Factual Questions\ **Created:** [January 15, 2013, 1:28pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277 "2013-01-15T13:28:02Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [January 15, 2013, 1:28pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/1 "2013-01-15T13:28:02Z")
Instead of popping ACE inhibitors and “healthy lifestyle choices”, what if I just wore a check valve? ---
**Author:** ![kp\_72110](https://avatars.discourse-cdn.com/v4/letter/k/e68b1a/32.png) [@kp\_72110](https://boards.straightdope.com/u/kp_72110)\ **Post date:** [January 16, 2013, 2:12am UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/2 "2013-01-16T02:12:52Z")
I doubt it. Would bleeding yourself with leeches be any different? Seems that’s what a check valve would do, let off pressure by expelling blood. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [January 16, 2013, 2:47am UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/3 "2013-01-16T02:47:25Z")
> [@kp\_72110](#): > > I doubt it. Would bleeding yourself with leeches be any different? Seems that’s what a check valve would do, let off pressure by expelling blood. GMTA! I asked my doctor exactly this, some years ago after numerous meds had worked poorly. What next? Regular weekly leechings? ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [January 16, 2013, 3:19am UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/4 "2013-01-16T03:19:58Z")
What if it weren’t a check valve that released blood permanantly, but cycled it through a low pressure bladder? ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [January 16, 2013, 9:42am UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/5 "2013-01-16T09:42:46Z")
I thought that _in general_ high blood pressure wasn’t a result of too much blood, but of what I guess you could call internal mechanical control problems, which is why one of the ways the meds control BP is by relaxing the constriction of the walls of the blood vessels and slowing down the heart beat. Though I do remember there is a condition where you have too many red blood cells, or I think that is what I remember USP leeches being used for in the 80s. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [January 16, 2013, 11:20am UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/6 "2013-01-16T11:20:41Z")
> [@aruvqan](#): > > I thought that _in general_ high blood pressure wasn’t a result of too much blood, but of what I guess you could call internal mechanical control problems, which is why one of the ways the meds control BP is by relaxing the constriction of the walls of the blood vessels and slowing down the heart beat. Though I do remember there is a condition where you have too many red blood cells, or I think that is what I remember USP leeches being used for in the 80s. Indeed. High blood pressure can be treated, if not come about by, at least three different mechanisms: 1. increased blood volume (the only one that a check valve might influence) 2. excessive constriction of the blood vessels (thereby increasing the pressure within them) 3. excessively forceful beat (i.e. [systolic](http://en.wikipedia.org/wiki/Systole_(medicine)) “pump” of the heart) [Diuretics](http://en.wikipedia.org/wiki/Diuretic) work on #1 above (as do, indirectly, [beta-blockers](http://en.wikipedia.org/wiki/Beta_blocker)). [ACE-inhibitors](http://en.wikipedia.org/wiki/ACE_inhibitor), [ARBs](http://en.wikipedia.org/wiki/Angiotensin_II_receptor_antagonist) (angiotensin receptor blockers), [calcium channel blockers](http://en.wikipedia.org/wiki/Calcium_channel_blocker), [alpha blockers](http://en.wikipedia.org/wiki/Alpha_blocker), and direct [vasodilators](http://www.mayoclinic.com/health/high-blood-pressure-medication/HI00057) work on #2 [Beta-blockers](http://en.wikipedia.org/wiki/Beta_blocker) act on #3 (as do some [calcium channel blockers](http://en.wikipedia.org/wiki/Calcium_channel_blocker) to a minor extent) In any case, having a system with three arms allows for precise, minute-to-minute regulation of BP. At least as important, different tissue beds respond and are regulated differently from each other, thus allowing for dynamic (re)distribution of blood flow depending on the need and problem confronting the organism, e.g. blood loss, “fight of flight” ---
**Author:** ![Anny\_Middon](https://avatars.discourse-cdn.com/v4/letter/a/bc79bd/32.png) [@Anny\_Middon](https://boards.straightdope.com/u/Anny_Middon)\ **Post date:** [January 16, 2013, 5:54pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/7 "2013-01-16T17:54:46Z")
I have hypertension that has not been controlled very well by drugs. My doctor suspects I have obstructive sleep apnea. (I had a sleep study a week ago; still awaiting results.) If apnea is causing my high blood pressure, then treating the apnea with a CPAP machine will lower my blood pressure. ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [January 16, 2013, 6:12pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/8 "2013-01-16T18:12:40Z")
One problem with just bleeding off excess blood (I know, not really excess, unless it is fluid retention) is that your body will quickly replace the plasma but will take a while to replenish blood cells, so you’d have to ensure that mostly plasma was let out (or just water, since plasma contains substances that your body needs too). ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [January 16, 2013, 7:05pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/9 "2013-01-16T19:05:49Z")
> [@Michael63129](#): > > One problem with just bleeding off excess blood (I know, not really excess, unless it is fluid retention) is that your body will quickly replace the plasma but will take a while to replenish blood cells, so you’d have to ensure that mostly plasma was let out (or just water, since plasma contains substances that your body needs too). Yes, what we really need is some type of filter system that removes only the parts of the blood that raise blood pressure. Maybe a wearable dialysis system. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [January 16, 2013, 7:19pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/10 "2013-01-16T19:19:43Z")
You can control blood pressure via a mechanical check valve about as well as you can fly an airplane with a bungee on the control yoke. In other words, not very well or for very long without going into a downward spiral. The body regulatory functions are highly complex feedback loops that don’t take well to clumsy attempts as spoofing or fiddling with them (hence why most blood pressure medication also works poorly and/or has adverse side effects). Stranger ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [January 16, 2013, 8:23pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/11 "2013-01-16T20:23:22Z")
Emergency medical crews used to use Military/Medical Anti-Shock Trousers (MAST), basically an inflatable pair of pants that would squeeze blood out of the relatively less urgent lower body, raising the blood pressure in the body core. This qualifies, I think, as “regulating blood pressure through mechanical means”. They are no longer in fashion, probably because (a) they didn’t work all that well, and (b) there are a whole lot more IV-trained EMS people out there. ---
**Author:** ![Cheshire\_Human](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@Cheshire\_Human](https://boards.straightdope.com/u/Cheshire_Human)\ **Post date:** [January 17, 2013, 5:59pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/12 "2013-01-17T17:59:49Z")
Attach yourself to a heart-lung machine, then stop the heart and lungs. You then control it with a dial on the machine. Probably a bit extreme a solution. ---
**Author:** ![SpoilerVirgin](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@SpoilerVirgin](https://boards.straightdope.com/u/SpoilerVirgin)\ **Post date:** [January 17, 2013, 8:37pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/13 "2013-01-17T20:37:38Z")
> [@aruvqan](#): > > Though I do remember there is a condition where you have too many red blood cells, or I think that is what I remember USP leeches being used for in the 80s. [Polycythemia](http://en.wikipedia.org/wiki/Polycythemia). One of my best friends has it and needs to be bled regularly, although they do it with syringes rather than leeches. ---
**Author:** ![sidecar\_jon](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@sidecar\_jon](https://boards.straightdope.com/u/sidecar_jon)\ **Post date:** [January 17, 2013, 9:33pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/14 "2013-01-17T21:33:30Z")
this magician seem to be able to control his pulse through physical means! [![](https://img.youtube.com/vi/hpRdzHy3C2k/hqdefault.jpg "23 of 50 Greatest Magic Tricks - The Human Body Pulse Trick") ](https://www.youtube.com/watch?v=hpRdzHy3C2k) Wonder what it does to BP though ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [January 17, 2013, 9:51pm UTC](https://boards.straightdope.com/t/is-it-possible-to-regulate-blood-pressure-through-purely-mechanical-means/647277/15 "2013-01-17T21:51:49Z")
> [@sidecar\_jon](#): > > this magician seem to be able to control his pulse through physical means! > [http://www.youtube.com/watch?v=hpRdzHy3C2k](http://www.youtube.com/watch?v=hpRdzHy3C2k) > > Wonder what it does to BP though All he’s doing is [preventing blood from flowing through his arm](http://www.csiro.au/helix/sciencemail/activities/TrickPulse.html); his heart rate stays the same. Blood pressure may increase a bit as blocking blood flow through the arm increases overall resistance to blood flow, just as the voltage across a parallel circuit fed with constant current will increase if you remove a resistor (at least temporarily, since I’m sure having an amputation causes the body to compensate).