For most of my life my blood pressure has been on the low side of normal. Considering that fat people are told that this is desirable, I was never cautioned by a doctor that I might want my blood pressure at the higher end. But several things caused me to wonder whether this conventional wisdom was valid.
When I was in college and stressed, I assumed that stress translated to hypertension and took a physical education class based on the ideas of Hans Selye using breathing to lower my blood pressure, which it did. I realized that I always felt worse after class, dragging myself home and feeling sleepy for hours.
As a budding herbalist I learned that European doctors often diagnose and treat low blood pressure whereas US physicians rarely do. I find no difference in official guidelines today where 90/60 is the accepted lower level except for trained athletes in both locales. Unless one is in shock, fainting or frequently dizzy there is no official concern about low or borderline low blood pressure. Still American doctors are more concerned about hypertension than hypotension.
Wikipedia lists low blood pressure symptoms, many of which are related to causes rather than effects of hypotension:
- chest pain
- shortness of breath
- irregular heartbeat
- fever higher than 38.3 °C (101 °F)
- stiff neck
- severe upper back pain
- cough with phlegm
- prolonged diarrhea or vomiting
- dyspepsia (indigestion)
- dysuria (painful urination)
- adverse effect of medications
- acute, life-threatening allergic reaction
- loss of consciousness
- profound fatigue
- temporary blurring or loss of vision
- connective tissue disorder Ehlers-Danlos Syndrome
- Black tarry stools
When I was doing my EMT training on oxygen therapy it occurred to me that many of the symptoms I felt were symptoms associated with oxygen hunger. Was it possible that with my borderline low blood pressure, blood wasn’t delivering enough oxygen to my brain? After all blood needed to get through the contracted muscles and herniated discs in my neck. This was reinforced by my experience in acupuncture class where walking briskly around the block during break kept me more alert than going across the street for hot coffee.
I propose that borderline low blood pressure which is currently classified as “asymptomatic” often leads to low brain oxygen, brain fog, cold and tingling extremities, and what we call in Chinese medicine yang deficiency. It probably interferes in the desire to exercise, the levels of possible exercise and the benefits of exercising. Chances are that it is a factor in at least some patterns of obesity.
Look for low capillary refill when you press on a fingernail. pulse oxymeter readings below 95%, cold hands and feet, brain fog, and poor memory.
Then there is the common sense issue. Obesity adds miles of blood vessels. For every ten pounds of fat gained, your heart has to pump blood through an additional 35 miles of blood vessels, and ten pounds of muscle has about 65 miles. So it makes sense that some degree of elevated blood pressure might be needed to push nutrient and oxygenated blood through them. Shouldn’t a 250 pound person have more pressure than a 150 pound person to get through an extra 550 miles of blood vessels?
Note I am not suggesting that the extra burden of pumping through blood vessels isn’t hard on the heart or kidneys. The negative cardiovascular effects of hypertension are well known. What is less understood is the adverse effects of low blood circulation on the brain with lowered delivery of oxygen and other blood-borne nutrients. In the obese, elevated blood pressure may be the body’s way of compensating for oxygenating extra mileage.
There is currently a special standard based on age but very little addressing constitution. According to JAMA’s 2014 evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee:
There is strong evidence to support treating hypertensive persons aged 60 years or older to a BP goal of less than 150/90 mm Hg and hypertensive persons 30 through 59 years of age to a diastolic goal of less than 90 mm Hg; however, there is insufficient evidence in hypertensive persons younger than 60 years for a systolic goal, or in those younger than 30 years for a diastolic goal, so the panel recommends a BP of less than 140/90 mm Hg for those groups based on expert opinion.
Still two persons of the same age might have different optimal blood pressures. One who demonstrates what Chinese medicine calls Heat- inflammation, red skin, rapid pulse and a scarlet tongue probably needs blood pressure controlled more vigorously than one who demonstrates Cold signs like cold extremities, a slow pulse, a pale tongue and pale skin.
I also need to point out that too-small blood-pressure cuffs in an increasingly obese population will tend to overdiagnose hypertension and will engender treatment when not needed. IOW ask for a large cuff if you are heavy or you may make things worse.
This doesn’t mean that anything goes. You don’t want to stroke out. I am talking about expanding the marginal limits of what is acceptable in blood pressure standards at both ends. In other words blood pressure should be high enough to circulate blood trough the tissue, and when it gets higher, an individualized consideration of how high is acceptable should be undertaken.