What an interesting question. My first response was “NOPE” in that the blood is in a closed circuit. There is no air pressure pushing on the “survace” of blood. There is an effect of the air pressure on dissolved gases in the blood (via lungs) as most scuba divers are aware.
Then I thought, “What about the sphygmomanometer (sp?)?” The mercury tube type that one sees in a Dr.'s office has a vacuum above the mercury in the tube thus is not affected by air pressure. Same with the dial types. The “zero” pressure in the top of the tube (one reference) is compared to the other pressure in the cuff. Mathematically, the 130 in the 130 over 70 bp is actually 130 in the cuff - 0 in the reference tube.
Then I thought, “What are the units for the sphygmomanometer?” I figure they must be in mm Hg. If this is the case, we can compare that to the average pressure at sea level (760 mm Hg). If you took your bp at sea level on a 760 day and then on a 750 day, would your bp measured be “off” by 10 mm Hg?
First, we should look at the “average” fluctuation in air pressure. Here in The States, if air pressure deviates from standard by more than 3/4 of an inch, we’re in the middle of a big storm. This would equate to roughly 18 mm Hg. Not a big deal when compared to 760 mm Hg as standard. However, 18 may be a big deal when compared to systolic pressure of 130. Now, the question becomes, “should we be concerned?”
Then I thought, what does the systolic and diastolic pressure actually mean? Well, it’s the pressure required to collapse the vein partially and then completely. The resulting pressures in terms of the blood are the pressures that the blood must exert to begin opening a crushed vein and to completely open the crushed vein. These pressures are exerted by the squeezing of the cuff, above and beyond the ambient pressure. This means that the ambient pressure is subtracted out of both measures.
Whew… In short, I dont’ think it has any effect.
[disclaimer]If it does, it’s certainly teeny.[/disclaimer]
I’ll jot off an email to doctor relatives and ask them, just to be sure.
Se non e vero, e ben trovato.
with heartfelt wishes,
Spritle