Interval Training improves Blood Vessel Function in hypertensive men

Rockville, Md.— Researchers have found that men with high blood pressure may have reduced blood vessel dilation in the legs and that a form of high-intensity interval exercise training improves blood vessel function in this population. The study is published ahead of print in the American Journal of Physiology-Cell Physiology.

Essential hypertension—a type of high blood pressure that occurs without a known cause—is associated with an impaired ability of the blood vessels to dilate (also called vasodilation or vascular responsiveness). Relaxation of the smooth muscle cells play a role in vascular responsiveness. During exercise, cells in the blood vessels called endothelial cells release chemicals that aid in smooth muscle cell relaxation. Research has shown that exercise can be beneficial for blood pressure regulation. Studies have also found that people with hypertension have reduced vascular responsiveness in their arms, but little is known about the relationship between hypertension, exercise and vasodilation in the legs.

A research team from Denmark compared sedentary men with essential hypertension (average age: 59) to an age-matched control group without high blood pressure. Before the exercise training, the research team assessed the vasodilation response in the men's legs. They first infused sodium nitroprusside—a medication used to lower blood pressure by promoting vasodilation—into the femoral artery in the thigh. Afterward, the volunteers received an infusion of acetylcholine, a compound found in the nervous system that naturally dilates blood vessels.

The volunteers participated in supervised cycling sessions two to three times a week for six weeks. The sessions consisted of 10-20-30 training, where the volunteers cycled in one-minute intervals:

The first 30 seconds was at 30% maximal intensity,

followed by 20 seconds at 50% intensity, and

the final 10 seconds at 100% effort.

Each exercise session—lasting less than 20 minutes—consisted of five consecutive intervals followed by a three-minute recovery and another five-minute interval set. Heart rate was determined continuously during each session and blood pressure and blood flow to the legs were measured before and after the training period.

After the six weeks of training, the hypertension group showed marked improvements in blood pressure as well as vascular responsiveness in the legs. "These findings provide the first line of evidence in humans, that smooth muscle cell vasodilator responsiveness is reduced in the lower limbs of hypertensive men, and that an improved endothelial function can compensate for this impairment," the authors wrote. "Based on the present findings, the 10-20-30 training may be considered an attractive and simple exercise modality for men with essential hypertension."

For more details click on the link: https://doi.org/10.1152/ajpcell.00047.2020