Is exercising with high blood pressure dangerous

UT Southwestern Medical Center researchers have identified one reason people with hypertension experience an even greater increase in their blood pressure when they exercise, and they've learned how to prevent the rise.

A study in a March issue of the Journal of Physiology reported that hypertensive people who exercise undergo decreased blood flow and oxygen in muscles. The scientists also identified a specific type of blood pressure medication that minimizes this effect.

"While there are many hypertension medications effective at lowering blood pressure at rest, very few are effective during exercise," said Dr. Wanpen Vongpatanasin, associate professor of internal medicine at UT Southwestern and lead author of the study. "People with high blood pressure need to exercise not only to help their blood pressure, but also their overall cardiovascular health."

Dr. Vongpatanasin said that some people with high blood pressure stop exercising out of fear of heart attack or stroke, and that sometimes physicians counsel those patients to limit activity because of those concerns.

While it's been known that blood pressure increases during exercise in people with hypertension, a mechanism behind the action and a way to block it in humans hadn't been identified previously.

Dr. Vongpatanasin and colleagues had 13 participants with mild hypertension and 13 with normal blood pressure perform hand grip exercises under regular conditions, followed by activity under conditions that affect a part of the nervous system that controls blood pressure.

They found increased nerve activity in hypertensive participants during exercise but not in those with normal blood pressure. Blood flow and oxygen levels in the arm muscles also fell more rapidly in the hypertensive group.

"In normal people, the body can increase blood flow to the working muscle despite increase in nerve activity, which tends to cause blood vessels to constrict," Dr. Vongpatanasin said. "Hypertensive patients have increased nerves and impaired ability to maintain muscle blood flow adequately."

Researchers then treated study participants with two types of blood pressure medications. An angiotensin receptor blocker, which prevents the hormone angiotensin from increasing blood pressure, increased blood flow during exercise. A diuretic that reduces blood pressure by stimulating sodium loss did not.

"Since nerve increases weren't reduced during treatment, we believe the angiotensin receptor blocker works directly on blood vessels to improve blood flow," Dr. Vongpatanasin said.

The next step, she said, will be to see if other hormones associated with angiotensin are involved in similar responses.

Other UT Southwestern researchers involved in the study were Zhongyun Wang, research associate in internal medicine; Debbie Arbique, advanced practice nurse in internal medicine; Dr. Gary Arbique, associate professor of radiology; Beverley Adams Huet, assistant professor of clinical sciences; and Dr. Jere Mitchell, clinical professor of internal medicine and physiology. Researchers from Cedars-Sinai Medical Center also participated.

The study was funded by the National Institutes of Health, the National Institute of Diabetes and Digestive and Kidney Diseases' George M. O'Brien Kidney Research Core Center at UT Southwestern and a Clinical and Translational Sciences Award from the National Center for Research Resources.

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Materials provided by UT Southwestern Medical Center. Note: Content may be edited for style and length.

Although hypertension is the most common and costly cardiovascular disease risk factor, it is highly preventable by positive changes in your lifestyle. Exercise is usually the initial lifestyle therapy recommended to prevent, treat, and control hypertension. Regular light exercise can make a difference to your blood pressure, and consequently prevent cardiovascular diseases. For hypertensive individuals, knowing how to exercise safely is crucial to prevent unnecessary complications.

Know your FITT prescription

The prescription of exercise as a management of a disease is usually based on the respective FITT formulation. FITT is an acronym that implies how often (Frequency), how hard (Intensity), how long (Time) and what kind (Type) of exercise should you comply. Generally, hypertensive individuals should be involved in moderate-intensity aerobic exercise or moderate-intensity dynamic resistance exercise. Aerobic exercise includes walking, jogging, running, stair climbing, cycling, and swimming. Dynamic resistance training is a resistance exercise that involves joint movement. This includes functional bodyweight exercise or using equipment like machine weights, free weights, and resistance bands. Most professional committees/organizations recommend exercising on most, preferably all days, of the week at least 30 minutes per day. The American Heart Association recommended an average of 40 minutes of moderate- to vigorous-intensity aerobic activity 3 or 4 times per week to lower high blood pressure.

Start slowly

Whatever exercise you opt for, remember to start slowly and add up the intensity when you’ve raised your fitness level. If you are planning to join a gym class, start by attending a beginner’s level class. Always remember to warm up before you exercise to prevent injury and cool down afterwards. Build up the intensity of your workouts little by little.

Monitor your progress and measure your blood pressure regularly

Monitor your progress and take regular blood pressure readings using a home blood pressure monitor. This can help you determine whether your fitness regime is helping to reduce your hypertension or not. Monitor your blood pressure before exercising and at least one hour afterwards.

Listen to your body

Stop exercising if you experience any chest pain or tightness, dizziness, excessive fatigue, or severe shortness of breath. Seek medical help immediately if necessary. Make sure you consult your doctor before starting an exercise program, especially if you are not physically fit and active previously.

Inform others of your condition

High blood pressure can be unpredictable, and even light-to-moderate exercise can cause an increase in blood pressure. Wearing a medical ID bracelet or informing your exercise partner on your condition can protect you in case something happens during a workout.

Avoid strenuous strength-related activities

You should try to avoid any exercise that is very intensive for short periods of time, such as sprinting or weightlifting. These activities will raise your blood pressure rapidly, and place an unwanted strain on your heart and blood vessels. Other activities that you should avoid include squash, skydiving and scuba diving unless you are a trained professional with well-controlled hypertension.

Don’t accumulate your regime

If you don’t have enough time to do a 30-minute exercise session per day, consider breaking it into 10-minute workout whenever you can. This would be better than accumulating your exercise regime into one session, as sudden bursts of activity could be risky to your health. It can also put you at risk of certain musculoskeletal injuries such as sprained ankle, wrist sprain or dislocation and muscle tear.

References:

Linda S. Pescatello et al., ‘Exercise for Hypertension: A Prescription Update Integrating Existing Recommendations with Emerging Research’, Current Hypertension Reports 17, no. 11 (2015), https://doi.org/10.1007/s11906-015-0600-y

https://www.healthxchange.sg/high-blood-pressure/living-well-high-blood-pressure/exercise-right-lower-high-blood-pressure

https://www.hopepaige.com/information/how-to-exercise-safely-with-high-blood-pressure

https://www.express.co.uk/life-style/health/927262/high-blood-pressure-symptoms-lower-exercise

https://www.resperate.com/blog/hypertension/treatments/lifestyle/hypertension-gym-exercises-dos-donts

https://www.webmd.com/fitness-exercise/guide/workout-injuries-prevention-and-treatment#1

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