Medically reviewed in April 2021
High blood pressure can be a silent killer. You may not feel it, but it could be wreaking havoc on your heart, your veins and even your kidneys and eyes. The Centers for Disease Control and Prevention (CDC) says that about 70 million Americans have high blood pressure, while the American Heart Association (AHA) estimates 80 million.
Only about half of people with high blood pressure—also known as hypertension—have it under control, according to the CDC. We asked Gregory L. Miller, MD, FACC, a cardiologist with Mercy Health Saint Mary’s in Grand Rapids, Michigan why hypertension is so dangerous and why more people aren’t actively trying to lower their blood pressure.
Silent killer
One reason so many people have uncontrolled hypertension is because they simply don’t know their blood pressure is elevated. “Hypertension isn’t something that’s symptomatic,” says Dr. Miller. “People aren’t alarmed. They’re feeling fine, so they’re not going to seek medical care.”
For people who know they have high blood pressure and still aren’t controlling it, Miller suggests they might have poor access to medical care. “A lot of people use emergency rooms or urgent care when they need it. They might have high blood pressure then, but it’s not necessarily representative of their normal blood pressure,” he says.
He also believes some doctors don’t treat blood pressure aggressively enough. “A lot of times we’re faulted for not trying hard enough to reach target blood pressure numbers,” he says. “We’ll say, ‘We’ve got it under 160/90 and that’s good enough,’ or, ‘The patient is elderly and I don’t want to push too hard.’”
What’s normal?
A blood pressure reading has two elements: systolic, the top number, and diastolic, the bottom number. A normal blood pressure level is under 120/80; between 120 and 129 and under 80 is considered elevated; anything over 130 on the top or 80 on the bottom is hypertension.
These are pretty solid guidelines, says Miller, but he also notes that blood pressure changes frequently. Blood pressure is usually highest in the morning when there are more catecholamines—chemicals like adrenaline—in the blood.
There’s also day-to-day variation based on a number of factors like diet, hydration and weather. There’s even a phenomenon called “white coat hypertension” where people have higher blood pressure in a doctor’s office, possibly due to stress or anxiety around seeing a doctor.
Complications of hypertension
High blood pressure can damage arteries, which can lead to plaque build-up and atherosclerosis. Atherosclerosis is a major risk factor in heart attacks, strokes, heart failure and angina.
But high blood pressure doesn’t end with the heart and the blood vessels. It can also cause kidney damage. “High blood pressure is a big cause and one of the few treatable causes of kidney damage,” Miller says. Kidney damage from high blood pressure is called hypertensive nephropathy. “Everything—coronary artery disease, heart failure—gets worse from renal insufficiency,” says Miller.
Hypertension can damage the blood vessels in your eyes, called hypertensive retinopathy, potentially leading to double vision, headaches and even vision loss. High blood pressure also puts you at risk for damage to eye nerves and blockages in the blood vessels that deliver blood to the eyes.
Risk factors and treatment
Treatment usually starts with diet, exercise and losing weight. “We’ve seen a number of people who have successfully lost weight and their blood pressure gets much better,” says Miller. “And we ask people to limit sodium, which increases water retention and blood pressure.” However, diet and exercise alone might not be enough—Miller says they make a significant but fairly small difference of between 10 to 20 percent. “Most people need medication,” he says.
Medicinal treatment usually consists of one or more medications such as beta blockers, ACE inhibitors and diuretics, in conjunction with regular exercise, a healthy diet and limiting sodium to no more than 2,300 mg per day.
Risk factors for high blood pressure include:
- Age - About 65 percent of Americans over 60 have hypertension
- Race - African Americans are at a greater risk for high blood pressure than Hispanics and Caucasians
- Gender - Men have a higher risk of hypertension before age 55. After age 55, women have a higher risk
- Family history
