What Your Blood Pressure Should Be
"Oh, no. I don't have high blood pressure," declared Ron after I informed him that his pressure of 138/78 was on the high side. "Lots of times I take it and it's lower than that, like 120 or 130."
Ron admitted that his primary care physician had told him for years that his blood pressure had been "borderline," occasionally as high as the 145/85 range. But other times it was lower, and Ron's reluctance to accept it led to a stalemate.
Unconvinced, I had Ron undergo some simple testing. A heart ultrasound revealed several concerning findings: an overly muscular heart muscle (left ventricular hypertrophy), an enlarged left atrium (a risk for rhythm disorders like atrial fibrillation), and an enlarged aorta, the main artery of the body emerging from the heart (a risk factor for stroke and eventual aneurysm). Ron's blood sugar was modestly elevated, 112 mg/dl (pre-diabetes is 110 mg/dl or greater), and his creatinine (a measure of kidney function), was mildly increased at 1.4 mg/dl, signifying early kidney damage, likely from high blood pressure.
In other words, there was nothing "borderline" about Ron's blood pressure. If organs like the heart and kidneys show evidence of low-grade damage, it is much more than borderline-it is well-established.
Yes, occasional blood pressures were indeed borderline, but the net long-term effects were clearly significantly and measurably negative.
What is high blood pressure?
Blood pressure is the driving force within the arteries of the body, literally the hydraulic pressure that drives blood flow to all organs.
We require pressure sufficient to feed organs adequately and meet their varied needs, including under conditions of increased demand (e.g., walking on a treadmill, digesting dinner, sexual activity, etc.).
What we do not want is pressure so high that it scratches, scrapes, and gouges the fine lining along the length of arteries. Repeated injury leads to scarring, thickening, and, eventually, atherosclerosis.
At what point does blood pressure wreak damage and result in long-term increased likelihood of death and cardiovascular complications? A systolic pressure of 150? How about 140?
Many people are shocked to learn that measurable complications of blood pressure begin as low as 115. The large National Health and Education Survey, funded by the National Institutes of Health (not a drug company), showed that systolic (top number) pressures of 115 or above are sufficient to generate damage to arteries and other organs such that, over several years, increased death and disease can be measured (Prospective Studies Collaboration 2002). Every increment in blood pressure of 20/10 doubles the risk of cardiovascular disease.
The most recent national guidelines for blood pressure issued by the National Health, Lung, and Blood Institute recommend maintaining systolic blood pressure <120, diastolic <80 (<120/80), a substantial change from the previous cut-off of 140/90. The new guidelines also provide for a category called "pre-hypertension," meaning blood pressures of 120-139 systolic, 80-89 diastolic, that justify lifestyle modification for improvement (JNC-VII 2003).
The (Pfizer sponsored) Camelot Study conducted by Dr. Steve Nissen of the Cleveland Clinic has fueled the argument that blood pressure should be lower. In this study of nearly 2000 participants (all of whom had coronary heart disease), reducing blood pressures from the "normal" range of 129/78 down to 124/76 led to 31% (relative) reduction in heart attack, death, and hospitalization. It also resulted in less plaque atherosclerotic growth when patients' arteries were examined with intracoronary ultrasound (Nissen SE et al 2004). It's irresistible to wonder what would have happened had blood pressures been lowered to 100, and perhaps future clinical trials will answer this question for us.
Why is high blood pressure such a large problem?
Take a look down the aisles of your grocery store and you'll see why 47 million adults in the U.S., or 1 of every 4, have the combination of features dubbed the "metabolic syndrome."
Many media reports obsess about the increasingly sedentary lifestyle of Americans and blame the obesity and diabetes epidemic on too much TV and video games. But this clearly is only part of the problem. A big problem--in fact, I believe, the number one principal source of the problem--is modern diet. (You ever wonder why, if lack of physical activity is the cause for obesity, then why are construction workers, laborers, and baseball players--all lead physically active lives, no less active than their predecessors--all fatter than they used to be? It's diet.)
Ninety percent of products lining supermarket shelves are highly processed foods, rich in hydrogenated fats, sugar or sugar-equivalents, and depleted of fiber.
Combined with inactivity, sleep deprivation, and stress, and a constellation of phenomena results, including abdominal obesity, low HDL cholesterol, high triglycerides, increased blood sugar, and high blood pressure, a collection of features known as the "metabolic syndrome."
High blood pressure and metabolic syndrome commonly go hand-in-hand. If you have hypertension, there's a 50:50 chance that you have at least some of the characteristics of the metabolic syndrome, particularly resistance to insulin that precedes development of full-blown diabetes. In fact, the association is so strong that hypertension should be regarded as a significant risk factor for future diabetes, with a 200-300% increased risk of diabetes.
If metabolic syndrome drives your blood pressure, it is also wonderfully responsive to change in food choices, along with increased physical activity and weight loss. There are also fun and unexpected ways to reduce blood pressure, while minimizing or eliminating the need for prescription medication.
(Not all blood pressure, however, is related to development of the metabolic syndrome, or represents a combination of causes, including genetic causes.
Genetic causes are more likely to require prescription medication.)