If you have elevated blood pressure that you are trying to control with lifestyle modifications, such as diet and physical activity—or even if you take medication for hypertension—you might consider adding isometric handgrip exercise to the mix. A review paper from the American Heart Association (AHA), published in Hypertension in April, concluded that this alternative therapy can produce “significant reductions” in blood pressure. The exercise, which simply involves squeezing a device, is “isometric” because you keep your muscles contracted without moving your hand.
Squeezing out results
The AHA reported on a number of promising studies. One, published in the Journal of Hypertension in 2010, pooled data from three trials and found that people who did at least four weeks of handgrip training reduced their blood pressure by about 10 percent, compared to a control group. These are impressive results—even better than the reductions from aerobic exercise seen in some studies. Benefits have been observed in both men and women, young and older people, and people with prehypertension and hypertension, with the largest reductions generally seen in those with the highest blood pressure levels.
On the other hand, the studies have mostly been small and short and have used different devices and protocols (for instance, one hand or both). Not surprisingly, results vary among users. Larger and longer studies are needed, especially in people with hypertension.
How isometric exercise may help reduce blood pressure continues to elude investigators, but some recent evidence suggests it may increase the ability of blood vessels to dilate; it may also improve control of the autonomic nervous system and decrease oxidative stress.
High-tech versus low-tech
The Zona Plus ($400 or $600) is a computerized handgrip device sold to “improve cardiovascular health.” Much of the research on it has been done at McMaster University in Canada, with studies showing blood pressure reductions ranging from 5 to 19 points systolic (the top number on a blood pressure reading), on average (and more modest reductions for diastolic). The recommended routine is to squeeze the device at 30 percent of your maximum strength for two minutes with one hand, rest for a minute, then do the same with your other hand; then repeat the steps. It takes just 12 minutes a day, including the rest periods, and you’re supposed to do this at least five times a week (though the protocol in most studies was three times a week). The device calculates your proper grip strength and keeps track of the time.
You could also experiment with a basic, inexpensive spring-loaded handgrip device, but you’d have to estimate what a moderately intense squeeze is and time it yourself. (Gripping too tightly for too long can result in a temporary spike in blood pressure.) A 2008 study, also from McMaster, found that older people with normal blood pressure who used a $2 spring handgrip trainer three times a week for eight weeks had significant drops in systolic and diastolic blood pressure (10 and 3 points, respectively), with no changes in the control group.
If you have hypertension, there’s no harm in trying handgrip exercise as an adjunct therapy—in addition to aerobic exercise. It may also help if you have prehypertension. If you are on blood pressure medication and do the exercises regularly, it’s possible you may be able to lower the dose—but only under medical supervision.
If you opt to go low-tech instead of buying the Zona Plus, researchers have suggested that men buy a moderate-resistance handgrip, women the lowest resistance; squeezing the device about halfway should be moderate intensity. Another option is to use a rubber, foam or tennis ball, though, again, you’d have to guess-timate what a moderate-intensity squeeze is and be vigilant in maintaining the grip.
An optimal protocol has not been established, but the AHA recommends a routine similar to Zona Plus instructions, done at least three times a week. It can take several weeks to see results, and you must continue the exercises to maintain any benefits. Because isometric handgrip exercise has not been studied in very-high-risk people, anyone with severe uncontrolled hypertension (over 180/110) should not do it.