High blood pressure is known as the “silent killer” because it often comes with no symptoms and puts people at a higher risk of heart disease.
Exercise can lower blood pressure without medication, so experts have been urging doctors to prescribe it for people with hypertension, which is defined at or above 130/80 mmHg.
But what kind of exercise is best?
A recent review of studies suggests it’s isometric exercise, particularly the wall squat.
Unlike walking or running, which is all about movement, isometric exercise involves contracting muscles and holding that position for a few minutes without moving. It’s static, but very intense. Think of a plank.
The paper, published in the British Journal of Sports Medicine, found all types of physical activity — including aerobic exercise, resistance training and high-intensity interval training — were “significantly effective” in reducing resting blood pressure.
But isometric exercise was the most effective. It reduced systolic blood pressure (the upper number of the reading) by 8 points and diastolic blood pressure (the lower number) by 4 points, the authors write.
The findings are based on a systematic review and meta-analysis of 270 randomized controlled trials that involved more than 15,000 participants and looked at the effects of various modes of exercise on resting blood pressure.
It’s not clear why isometric exercises are so effective, but it appears to be linked to the unique physiological response to a static muscle contraction, says Jamie Edwards, the lead study author.
“When holding this contraction, the local blood vessels in the surrounding area become mechanically compressed by the contracting muscles,” Edwards, a researcher and instructor at Canterbury Christ Church University in England, tells TODAY.com.
“On release of this contraction — for example, when you stand up from a squatting position — there is a reactive rush of blood flow to the vessels, which causes the release of molecules that (widen) your vessels.”
How to do a wall squat:
The wall squat was the most effective individual exercise in the isometric category, Edwards and his colleagues found.
It’s simple, but incredibly intense. Stephanie Mansour, a certified personal trainer, instructs people to lean against a wall with feet hip-width apart and slide down into a squat. Feet should be far enough from the wall so that the knee joints can form a 90-degree angle, with thighs parallel to the floor.
Edwards suggested doing four wall squats lasting 2 minutes each, separated by rest intervals of 1 to 4 minutes. This should be done three times per week. Keep breathing normally throughout an isometric contraction, he advises.
It’s likely that repeating this pattern over several weeks results in sustained reductions in blood pressure, Edwards notes.
Cardiologist’s take
Dr. Luke Laffin, co-director of the Center for Blood Pressure Disorders at the Cleveland Clinic, says there’s no question people need to exercise to manage their blood pressure.
But the ultimate goal is to reduce the risk for strokes and heart attacks, and study after study has shown aerobic physical activity — like walking, cycling or running — is better than isometric exercise when it comes to lowering cardiovascular risk, he notes.
“Aerobic exercise training should be promoted above all else,” Laffin tells TODAY.com.
He recommends at least 150 minutes of moderate intensity aerobic physical activity per week, split most any way people want. Studies show “weekend warriors” who squeeze all their exercise into two days get similar health benefits as people who do more frequent shorter workouts.
Moderate intensity activity means you can carry on a conversation while you’re doing it, Laffin says.
Different types of exercise can offer different benefits, so a combination of cardio, resistance training and high-intensity interval training can be best, with isometric exercise considered complimentary to those workouts, both Laffin and Edwards say.
Who should avoid isometric exercise?
People with aortic aneurysms or history of aortic dissection should avoid it, Laffin says. Women make up most cases of spontaneous coronary artery dissection — a tear or a bleed within the layers of a heart artery wall.
Isometric exercise produces a sudden acute load on the aorta, which can lead to further damage, Laffin warns.
How long does it take to lower blood pressure with exercise?
Exercise has been associated with “immediate significant reductions” in systolic blood pressure (the upper number of the reading), which can last for almost 24 hours, studies have found. This is known as post-exercise hypotension.
The body releases nitric oxide, which causes blood vessels to open wider for improved blood flow, Laffin says.
A sustained change would take about three months of regular exercise, Bethany Barone Gibbs, a vascular researcher who studies the prevention and treatment of cardiometabolic disease, previously told TODAY.com.