Jan. 11, 2024 – What you already know: Physical activity helps ease high blood pressure.
What you may not know: Researchers have found that one type of exercise – and one single exercise in particular – helps lower blood pressure especially well.
A 2023 review of 270 prior studies including nearly 16,000 people found that a program of isometric exercise reduced systolic blood pressure (the top number) by 8.24 mm Hg (or milligrams of mercury, a measure doctors use for blood pressure), and diastolic blood pressure by 2.5 mm Hg.
Isometric exercise brought bigger blood pressure benefits than aerobic exercise (a blood pressure drop of 4.49 points and 2.53 points), resistance training (down 4.55 and 3.04 points), and interval training (a decrease of 4.08 and 2.5 points).
“We, along with other research groups around the world, have clearly demonstrated the efficacy of isometric exercise to lower resting blood pressure in people with blood pressures ranging from normal through to hypertensive,” said study co-author Jim Wiles, PhD, director of clinical exercise science research at Canterbury Christ Church University in England.
Why Are Isometric Exercises So Good for BP?
You perform an isometric exercise when you flex your muscles to hold a position. (When you move, those are called isotonic muscle contractions.)
“A lot of people actually do isometric exercise and don’t realize it, for example, when you go to a yoga class,” said Neil Smart, PhD, a professor of exercise and sports science at the University of New England in Australia.
Imagine squeezing a tennis ball for 30 seconds. When you hold an isometric pose, your straining muscles constrict the surrounding blood vessels. Partially pinching off blood flow this way while flexing causes a buildup of anaerobic metabolites (substances that inhibit the flow of oxygen).
“The body doesn’t like them,” Smart said. “As soon as you stop squeezing, blood flow will be normalized and then enhanced in an attempt to clear up this mess that’s been created in the forearm.”
“Enhanced” means this: The rush of red blood cells creates stress along blood vessel walls, triggering the release of nitric oxide, a compound that causes blood vessels to dilate. Blood pressure eases.
“Even though it’s only a localized activity, there seems to be a whole-body effect in terms of blood pressure,” Smart said.
Research has only looked at three exercises: Leg extensions (performed with weight on a leg extension machine), hand grip squeeze, and wall squats. It’s possible other isometric exercises may offer benefits – they just haven’t been studied specifically for blood pressure.
Wall squats in particular seem effective. When 24 middle-aged men with high-normal blood pressure performed isometric wall squats three times a week for a year, their systolic blood pressure decreased by 8.5 points, and their diastolic blood pressure decreased by 7.3 points, according to a 2022 study in the Journal of Hypertension.
“How the repetition of this acute response translates into chronic blood pressure changes is not well understood, but it is linked to potential changes in local vascular function, autonomic vascular function and possibly structural vascular adaptations,” said study author Jamie O’Driscoll, PhD, a researcher at Canterbury Christ Church University in England
Those changes may include your body adapting to the workout by releasing more nitric oxide each time, causing a greater blood vessel expansion.
Of course, lifting heavy weights, running, and every other physical activity flexes your muscles and puts a brief squeeze on your blood vessels. But a 2-minute isometric hold, repeated in succession, seems to be the key to triggering the vasodilating effect.
An Addition, Not a Substitution
If you have blood pressure issues, don’t pack up your running shoes or stop lifting weights.
“No one should replace aerobic exercise with isometric,” said Philip Millar, PhD, an associate professor of physiology at the University of Guelph in Canada. “For example, isometric training does not appear to change cholesterol levels, a known cardiometabolic benefit of aerobic exercise.”
Think of isometric exercises as something to add to your regular physical activity. And that’s easy, since you can do them a tiny space, without leaving the house, and you don’t need gym equipment or a lot of extra time.
That’s especially important for people who can't get around well, particularly older people or those with obesity who find walking for 30 minutes to be too difficult. And people who can’t afford a gym membership, travel often, or simply lead busy modern lives can always squeeze in some isometric exercises.
“If someone isn’t able to work out normally, because of physical limitations, then it’s worth trying,” said Linda Pescatello, PhD, a professor of kinesiology at the University of Connecticut. She published a recent paper calling for more research before physical activity guidelines are universally updated to include isometric training.
People with diagnosed hypertension should talk to their doctor before taking on a new exercise routine. But if you’re ready to try isometric exercise, perform one of these moves three times per week, with at least a day of rest in between.
Isometric Hand Grip
The key thing to remember here is don’t go all out each time. Holding an isometric muscle flex with more than 50% effort can cause your blood pressure to spike, Smart said.
Tennis balls work well – and you’ll have to estimate your gripping effort – or to be more precise, you can pick up inexpensive hand grip dynamometers online for less than $30. (Professional models cost several hundred dollars.) You’ll need two, so you can grip both at the same time.
“There’s evidence to suggest that if you try alternating hands, you might actually dilute the effect,” Smart said.
If you use dynamometers, first find your maximum hand grip pull. With your forearms resting on a table, squeeze the dynamometer in each hand as hard as you can, noting the peak force. (It will be in either kilograms or pounds.) Then calculate 30% of that number to find your target. So if your hardest squeeze is 100 pounds (a typical pull for middle-aged men; women pull closer to 55 pounds), then your target on the dynamometer will be 30 pounds.
To perform one rep, hold the dynamometers (or tennis balls) with your forearms resting on a table or armrests, and elbows bent at 90 degrees. Squeeze until you hit 30% of your max grip, and hold for 2 minutes, or until you reach fatigue.
“Most people can’t do it the first time,” Smart said.
Rest for 2 minutes, then repeat three more times for a total of four reps.
Wall Squat (or Wall Sit)
Stand with your back to the wall, your feet shoulder-width apart, and your heels about 12 inches away from the wall. Using your hands to steady yourself, bend your knees and slide down the wall until you’re in a sitting position. Adjust your feet so that your knees are directly over your ankles. Keep your shoulders and butt against the wall for the entire movement, and keep your feet flat on the floor.
Hold the position for as long as you can, up to 2 minutes, then rise and rest for 2 minutes. Repeat three more times for a total of four reps.
If the exercise feels too hard, squat shallower until you feel enough of a burn. You’ll improve over time.
Plank
Caveat: The plank hasn’t yet been studied to find out if it lowers blood pressure, but researchers included in previous studies suspect that, once examined, planks could help with blood pressure. Beyond that speculation, planking is a straightforward, challenging, low-impact exercise worth trying.
Get down in a pushup position and balance yourself on your toes with your forearms on the floor. Engage your core and glute muscles and hold that position while keeping your entire body in a straight line. (If your butt dips, for example, you’ve lost form and should stop.)
Hold for as long as you can, up to 2 minutes. (Don’t worry if you fall short; even 30 seconds can be challenging.) Repeat for four total reps.
Important tip for all isometric exercise: Don’t forget to breathe. “We see that, especially when people are planking, they try to hold their breath,” said Véronique Cornelissen, PhD, a professor of kinesiology at Katholieke Universiteit Leuven in Belgium. “You can cause bigger fluctuations in blood pressure that may cause, for instance, arrhythmia.”
Try breathing in for two counts, and out for two counts as you perform each exercise.
