So-called “exercise hypertension,” an abnormally high increase in blood pressure that healthy people experience during exercise, is a risk factor for permanent and severe high blood pressure at rest.
A study shows that this impaired ability of the endothelial cells, which control the relaxation of large blood vessels, is a potential cause of exercise hypertension. Knowing this indicates a cellular goal for preventative therapies when 90 percent of adults are at risk for developing high blood pressure.
Typically during exercise, blood pressure rises to push the flow of oxygen-rich blood throughout the body. In some individuals, instead of reaching a systolic (upper number) blood pressure of around 200 mmHg at maximum exercise, they increase by 250 mmHg or higher.
Researchers evaluated 38 men and 44 women aged 55 to 75 who had untreated mild hypertension but were otherwise healthy. Their resting blood pressure ranged from 130 to 159 mmHg systolic (upper number) and 85 to 99 mmHg diastolic (lower).
Researchers examined blood vessel stiffness – a marker of early heart disease – using ultrasound to measure how fast blood traveled from the arteries in the subjects’ necks to their legs with each heartbeat. They compared these measurements with blood pressure measurements taken at rest and while participants went to maximum effort on a treadmill. Because rigid blood vessels do not absorb any pressure behind the bloodstream, the faster the blood moves, the more stringent the vessel is.
In their analysis, the researchers found that higher blood pressure in response to exercise was associated with a poorer expansion of blood vessels in the arm after the cuff test, suggesting that endothelial cells failed to expand enough to handle the extra blood flow. There was no association between stiffness in the blood vessel walls or resting blood pressure with increased blood pressure during exercise.
Impaired endothelial function is not only related to high blood pressure. It is also associated with aging, menopause, high cholesterol, smoking, and diabetes and can be a standard process for developing heart disease among all these risk factors.
It is too early to recommend that people take exercise tests to measure blood pressure. If it is estimated as part of a medical evaluation or during a workout, one should be careful about exercise blood pressure. It may be a warning that resting blood pressure may also increase.