A simple workout that may help keep blood pressure down

New research indicates that exercising only once or twice a week may be enough to preserve some of the blood pressure gains earned through regular physical activity, at least for a short time. People who keep up with three sessions a week, however, may see stronger and longer-lasting effects.

The study, published in BMJ Open Sport & Exercise Medicine, suggests that even one weekly session of isometric exercise may help people hold onto improvements in blood pressure when a more frequent routine is not realistic.

Isometric exercise involves contracting muscles while holding the body still for several minutes. Wall squats, planks and handgrip exercises are common examples.

Previous research has shown that isometric training can reduce blood pressure more effectively than some other forms of exercise, sometimes by amounts similar to or greater than those achieved with certain medications. But scientists have not been certain how often these workouts need to be done to keep those cardiovascular benefits.

How often are wall squats needed?

To find out, researchers recruited 100 adults with an average age of 37.4 years. Their systolic blood pressure ranged from normal to high-normal levels, between 120 and 140 mmHg, and none regularly took part in structured exercise programs.

According to expert guidance, systolic readings between 130 and 139 mmHg are considered high-normal and may call for specific lifestyle advice from healthcare professionals. None of the participants had been diagnosed with hypertension.

To take part, volunteers had to be free of injuries and illness, have no current or past use of blood pressure medication, be nonsmokers and consume no more than 14 units of alcohol a week.

Participants were randomly split into five groups. One group acted as a control, while the other four started the same four-week home exercise program centered on lower-body isometric movements.

Each session involved four wall-squat holds, with two minutes of seated rest between holds. The routine was performed three times a week during the first four weeks.

After that initial phase, the four exercise groups followed different schedules for another four weeks. One group kept exercising three times weekly, another cut back to twice weekly, a third reduced to once weekly, and the final group stopped entirely.

Researchers measured blood pressure, heart rate and other cardiovascular markers at the start of the study and again after four and eight weeks.

Even one session a week helped preserve the gains

After the first four weeks, all four exercise groups showed clear improvements compared with the control group. Systolic blood pressure, which reflects pressure when the heart contracts, fell, as did diastolic blood pressure, which measures pressure when the heart relaxes. Mean arterial pressure, the average pressure throughout the cardiac cycle, also dropped significantly.

Those early results matched earlier studies showing the blood pressure benefits of isometric exercise. But once participants moved to their maintenance schedules, the groups no longer showed statistically significant differences in diastolic blood pressure.

By the end of the eight-week study, participants who exercised once or twice a week still had significant reductions in systolic blood pressure and mean arterial pressure compared with the control group. Neither schedule, however, maintained a statistically significant improvement in diastolic blood pressure.

The strongest results came from the group that continued wall squats three times a week. Their systolic blood pressure dropped by an average of 13.73 mmHg from the start of the study.

By contrast, the twice-weekly group saw an average decrease of 6.95 mmHg, while the once-weekly group recorded a 6.56 mmHg reduction.

Those who stayed with the three-session routine also kept gains in other cardiovascular measures, including total peripheral resistance, which can indicate narrowed blood vessels, and heart rate variability.

What happened when exercise stopped?

The study also showed what occurred when participants stopped exercising completely.

Those who quit wall squats after the first four weeks lost the blood pressure improvements they had previously gained. By the end of the study, their readings were no longer significantly different from those in the control group.

That suggests even a modest amount of regular isometric exercise may be important for holding on to cardiovascular benefits gained during training.

The researchers noted, however, that the maintenance phase lasted only four weeks. Longer studies will be needed to determine whether less frequent training can preserve these benefits over months or years.

"The study demonstrates that while lower frequency isometric exercise training may be sufficient to maintain blood pressure reductions over the short term, higher frequencies are required to preserve these benefits and the associated vascular and cardiac autonomic adaptations," the researchers write.

"The study offers evidence that lower frequency isometric exercise training can help maintain short-term blood pressure reductions, providing a pragmatic option for individuals with limited time or adherence challenges."