Strength training is a well-established way to boost the capabilities of the body's many muscle groups, and the same may well be true of those that facilitate breathing. A new study has provided the strongest evidence yet that a daily practice designed to strengthen breathing muscles can lower blood pressure and improve vascular health, just as effectively or perhaps even more so than aerobic exercise.
The research was carried out at the University of Colorado (UC) Boulder and centers on a type of breathing exercise known as High-Resistance Inspiratory Muscle Strength Training (IMST). This first emerged in the 1980s as a therapy for critically ill patients with respiratory disease, and tasks subjects with inhaling harshly through a handheld device that offers resistance by sucking air in the opposite direction.
Traditionally, these types of therapies strengthen the diaphragm and other breathing muscles through daily, low-resistance sessions lasting 30 minutes apiece. But the UC Boulder scientists have been investigating how high-resistance sessions of much shorter duration could also prove beneficial.
“There are a lot of lifestyle strategies we know can help people maintain cardiovascular health as they age," says lead author Daniel Craighead. "But the reality is, they take a lot of time and effort and can be expensive and hard for some people to access. IMST can be done in five minutes in your own home while you watch TV.”
To explore these possibilities, the scientists conducted a study involving 36 adults between the ages of 50 to 79, who had above normal systolic blood pressure but were otherwise healthy. The participants were made to perform 30 inhalations per day with an IMST device, six days a week, over a six-week period. Half of the participants were put on a high resistance regime, the other half on a lower resistance. None of the subjects knew which group they were placed in.
Assessing the subjects after six weeks showed a sharp decline in systolic blood pressure among the high-resistance group, amounting to a nine-point decline on average. The scientists say this exceeds the type of decline you'd expect from walking 30 minutes a day, five days a week, and is equal to the decline you could expect from some drug treatments to lower blood pressure.
Notably, these benefits persisted well after the conclusion of the regime, with assessments six weeks afterwards showing that most of the improvements in blood pressure levels had been maintained. Additionally, the regime led to a 45-percent improvement in vascular endothelial function, which is the arteries' ability to expand when stimulated. It also drove up levels of nitric oxide, a key molecule in preventing plaque buildup. Markers of inflammation and oxidative stress were also significantly lowered.
“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,” says senior author Doug Seals. “That’s noteworthy.”
The scientists also see the IMST practice as a potentially helpful one for postmenopausal women, with previous research showing that the vascular health of those not taking supplemental estrogen doesn't see the same benefits from aerobic exercise as men. More generally, they see the technique not as a replacement for aerobic exercise, but as a useful option for folks who don't have access to gym facilities, walking trails or have ailments that restrict their activities.
The researchers are in the process of drawing up a follow-up study involving around 100 people, which will pit a 12-week IMST regime head-to-head with an aerobic exercise program to tease out the effects even further.
The research was published in the Journal of the American Heart Association, while the video below provides an overview of the work.
Source: University of Colorado Boulder
