Five minutes to lower blood pressure

A new CU Boulder study shows that a five-minute exercise per day, which is described as “strength training for your breathing muscles,” lowers blood pressure, improves vascular health, and can be done daily.

The Journal of the American Heart Association published the strongest evidence yet to show that the time-efficient High-Resistance Inspiratory Muscle Strength Training, (IMST), could be a key component in protecting aging adults from the nation’s most deadly killer, cardiovascular disease.

Only 65% of Americans over 50 have high blood pressure, which puts them at higher risk for heart attack and stroke. However, less than 40% of Americans meet the recommended aerobic exercise guidelines.

There are many lifestyle strategies that can be used to maintain good cardiovascular health, according to experts. However, these strategies can be time-consuming and expensive, and may not be accessible to everyone, says Daniel Craighead, assistant researcher in the Department of Integrative Physiology. IMST can easily be completed in just five minutes while you are watching TV, he said.

IMST was developed in 1980 to aid patients with severe respiratory diseases. It involves exhaling through a device that provides resistance. Imagine sucking through a tube that pulls back.

Initial recommendations for patients with breathing disorders were to use a 30-minute per-day regimen at low resistance. Craighead and his colleagues have been examining whether a shorter protocol, which involves 30 inhalations per day at high resistance and six days per week, could reap benefits for cardiovascular, cognitive, and athletic performance.

They recruited 36 healthy adults between the ages of 50 and 79 who had normal systolic blood pressure (120mg mercury or more). Half of the participants did High-Resistance IMTST for six weeks, while half followed a placebo protocol where resistance was lower.

Six weeks later, the IMST group saw their systolic (the highest) blood pressure drop nine points. This is a decrease that generally surpasses that achieved by walking 30 mins per day, five days a semaine. This decline is also comparable to some blood pressure-lowering medication regimens.

Six weeks after quitting IMST, most improvement was maintained by the IMST group.

Craighead said they found it to be more efficient than traditional exercise programs and may have longer-lasting benefits.

Also, the treatment group saw a 45% increase in vascular endothelial functions, which is the ability of arteries to expand upon stimulation. There was also a significant rise in levels nitric dioxide, a key molecule for dilation and prevention of plaque buildup. As we age, our levels of nitric oxide naturally decrease.

After IMST, markers of inflammation and oxidative stresses, which can increase heart attack risk, were markedly lower.

Surprisingly, 95% of sessions were completed by those in the IMST Group.

Doug Seals, a Distinguished Professor in Integrative Physiology, said that he had discovered a new form of therapy that lowers blood pressure without using pharmacological compounds. He also claims that it has a higher adherence rate than aerobic exercise. This is noteworthy.

This practice could be especially helpful for women who are postmenopausal.

Seals’ previous research showed that women postmenopausal who don’t take supplemental estrogen do not reap the same benefits from aerobic exercise as men when it comes to vascular function. The new study found that IMST improved it in these women just as much as in men.

Craighead stated that aerobic exercise will not improve postmenopausal women’s cardiovascular health. They need to change their lifestyle to do so. This could be it.

Some preliminary results show that MST may also improve brain function and physical fit. Other studies have also shown that MST can improve sports performance.

Craighead said that marathon runners experience fatigued respiratory muscles, which can cause them to take blood from their skeletal muscles. He uses IMST for his marathon training. The idea is that your legs will not get fatigued if you increase the endurance of your respiratory muscles.

Seals stated that they aren’t sure how a move to strengthen breathing muscles can lower blood pressure. However, they believe it causes the cells in blood vessels to produce more Nitric Ox, which allows them to relax.

Seals was recently awarded $4 million by the National Institutes of Health to conduct a larger follow up study of approximately 100 people. This will compare a 12-week IMST protocol with an aerobic exercise program.

The research group is currently developing a smartphone app that will allow people to perform the protocol at home with already-commercially available devices.

Anyone considering IMST should first consult their doctor. They said that IMST has been remarkably safe so far.

Working out just five minutes daily via a practice described as “strength training for your breathing muscles” lowers blood pressure and improves some measures of vascular health as well as, or even more than, aerobic exercise or medication, new CU Boulder research shows.

The study, published June 29 in the Journal of the American Heart Association, provides the strongest evidence yet that the ultra-time-efficient maneuver known as High-Resistance Inspiratory Muscle Strength Training (IMST) could play a key role in helping aging adults fend off cardiovascular disease – the nation’s leading killer.

In the United States alone, 65% of adults over age 50 have above-normal blood pressure – putting them at greater risk of heart attack or stroke. Yet fewer than 40% meet recommended aerobic exercise guidelines.

Developed in the 1980s as a way to help critically ill respiratory disease patients strengthen their diaphragm and other inspiratory (breathing) muscles, IMST involves inhaling vigorously through a hand-held device which provides resistance. Imagine sucking hard through a tube that sucks back.

Initially, when prescribing it for breathing disorders, doctors recommended a 30-minute-per-day regimen at low resistance. But in recent years, Craighead and colleagues have been testing whether a more time-efficient protocol–30 inhalations per day at high resistance, six days per week–could also reap cardiovascular, cognitive and sports performance improvements.

For the new study, they recruited 36 otherwise healthy adults ages 50 to 79 with above normal systolic blood pressure (120 millimeters of mercury or higher). Half did High-Resistance IMST for six weeks and half did a placebo protocol in which the resistance was much lower.

After six weeks, the IMST group saw their systolic blood pressure (the top number) dip nine points on average, a reduction which generally exceeds that achieved by walking 30 minutes a day five days a week. That decline is also equal to the effects of some blood pressure-lowering drug regimens.

Even six weeks after they quit doing IMST, the IMST group maintained most of that improvement.

“We found that not only is it more time-efficient than traditional exercise programs, the benefits may be longer lasting,” Craighead said.

The treatment group also saw a 45% improvement in vascular endothelial function, or the ability for arteries to expand upon stimulation, and a significant increase in levels of nitric oxide, a molecule key for dilating arteries and preventing plaque buildup. Nitric oxide levels naturally decline with age.

Markers of inflammation and oxidative stress, which can also boost heart attack risk, were significantly lower after people did IMST.

And, remarkably, those in the IMST group completed 95% of the sessions.

“We have identified a novel form of therapy that lowers blood pressure without giving people pharmacological compounds and with much higher adherence than aerobic exercise,” said senior author Doug Seals, a Distinguished Professor of Integrative Physiology. “That’s noteworthy.”

The practice may be particularly helpful for postmenopausal women.

In previous research, Seals’ lab showed that postmenopausal women who are not taking supplemental estrogen don’t reap as much benefit from aerobic exercise programs as men do when it comes to vascular endothelial function. IMST, the new study showed, improved it just as much in these women as in men.

“If aerobic exercise won’t improve this key measure of cardiovascular health for postmenopausal women, they need another lifestyle intervention that will,” said Craighead. “This could be it.”

Preliminary results suggest MST also improved some measures of brain function and physical fitness. And previous studies from other researchers have shown it can be useful for improving sports performance.

“If you’re running a marathon, your respiratory muscles get tired and begin to steal blood from your skeletal muscles,” said Craighead, who uses IMST in his own marathon training. “The idea is that if you build up endurance of those respiratory muscles, that won’t happen and your legs won’t get as fatigued.”

Seals said they’re uncertain exactly how a maneuver to strengthen breathing muscles ends up lowering blood pressure, but they suspect it prompts the cells lining blood vessels to produce more nitric oxide, enabling them to relax.

The National Institutes of Health recently awarded Seals $4 million to launch a larger follow-up study of about 100 people, comparing a 12-week IMST protocol head-to-head with an aerobic exercise program.

Meanwhile, the research group is developing a smartphone app to enable people to do the protocol at home using already commercially available devices.

Those considering IMST should consult with their doctor first. But thus far, IMST has proven remarkably safe, they said.

“It’s easy to do, it doesn’t take long, and we think it has a lot of potential to help a lot of people,” said Craighead.


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