The wall sit, a simple body weight exercise that can be done virtually anywhere, isn't just for building strength. It can help your cardiovascular health, too.

A recent study in the British Journal of Sports Medicine suggests that isometric exercises, such as wall sits (also known as wall squats), can help reduce blood pressure even more effectively than other forms of exercise, including aerobic activity, weight training or high-intensity interval workouts.

The research is good news for people who struggle to meet physical activity guidelines that recommend at least 150 minutes of weekly moderate-intensity exercise, such as brisk walking or bicycling. The new analysis found that about eight minutes of isometric exercise, three times a week, can lead to a meaningful reduction in blood pressure.

This means holding a wall sit for two minutes, resting for two minutes and repeating that four times. A single session, including rest, will take only 14 minutes.

On average, a regular isometric routine of wall sits lowered systolic blood pressure (the top number) by 10 mmHg and diastolic pressure by 5 mmHg, according to the research.

The study's authors say the findings support development of new exercise guidelines that go beyond recommending aerobic exercise for the prevention and treatment of hypertension.

"Our main message is that actually engaging in exercise is fantastic and any exercise might reduce your blood pressure," said Jamie O'Driscoll, the senior author of the study. "But if you're an individual who is currently exercising to the guidelines and you're still having a bit of difficulty reducing that blood pressure and you want to avoid going on medication, perhaps isometrics is an additional mode to complement the exercise you're already doing."

An isometric exercise refers to a static contraction in which the length of the muscle does not change, said Jamie Edwards, the first author of the study and a PhD researcher at Canterbury Christ Church University.

"Any kind of an exercise that is holding tension in any position which doesn't involve dynamic movement is generally isometric exercise," he said.

The research reviewed 270 randomized controlled trials that collectively studied 15,827 participants. The researchers looked at the blood pressure effects of three isometric exercises: squeezing a handgrip dynamometer, extending your legs against a fixed resistance and squatting with your back flat against the wall. (While planks are a popular example of isometric exercises, they were not included in the study.)

The researchers found that, overall, isometric exercise training was the most effective exercise for lowering systolic and diastolic blood pressures.

"From a clinician standpoint, these are very promising findings," said Laura Richardson, a registered clinical exercise physiologist at the University of Michigan who was not involved in the study. "Being able to use isometric exercise as a therapeutic tool for those with hypertension is wonderful. I really think it's a great way to get more individuals involved in being active."

Isometric exercises effectively lower blood pressure because contracting a muscle and holding the position temporarily reduces blood flow to that muscle, O'Driscoll said. When you release that contraction, blood flow through the muscle tissue increases. This produces important signals that prompt blood vessels to relax more and creates less resistance to blood flow, which ultimately reduces blood pressure, O'Driscoll said.

How to do a wall sit

To do a wall sit, find a wall that you can lean against. Take a couple of steps forward. Keep your feet hip width apart and slide your back down the wall until your knees are at about a 90-degree angle, as if you're sitting in a chair, Richardson said.

The lower you squat, the more intense the workout. Be careful of how much you bend your knees in the beginning. Work your way down to 90 degrees. If you can't get there, Richardson recommends sliding down based on your knee flexibility and holding steady until you feel lower-body muscle fatigue.

Isometric exercises such as wall sits engage a lot of muscles, help build strength and are helpful for improving balance and range of motion, Richardson said.

"Primarily, you're going to be using a lot of your leg muscles: your quadriceps, your glutes, your calves," said Richardson, who is also a clinical associate professor at the University of Michigan School of Kinesiology. "If your back is flat against the wall, it's going to help engage the abdominal muscles."