We know that exercise is good for us, even in moderate amounts. But for people with chronic health conditions, who take prescription medications, exercise is also key to symptom management and health enhancement. However, medicines can negatively impact exercise too; here are five.

Exercise ameliorates insulin sensitivity in those with diabetes. Physical activity also decreases the risk of cardiovascular disease progression and death from heart disease in hypertensive individuals. Importantly, even high-intensity interval training is generally safe and effective for those with chronic illnesses, according to the Mayo Clinic.

However, chronic health conditions often go hand in hand with the need to take one or more medications—and when combined with exercise, some of these drugs can cause serious and potentially dangerous health risks. Fortunately, there are work-arounds to ensure that exercise is safe.

Here’s a look at five common medications that can negatively impact exercise.

ACE inhibitors

Lisinopril, captopril, enalapril, and other ACE inhibitors decrease the activity of the renin-angiotensin-aldosterone system, and block the conversion of angiotensin I to angiotensin II. Angiotensin II causes vasoconstriction of blood vessels, and blocking it relaxes blood vessels, thus dropping blood pressure.

Consequently, people on ACE inhibitors have lower blood pressure values—both at rest and during exercise. Blood pressure, however, naturally drops after exercise for up to 9 hours—specifically, systolic blood pressure can decrease by 10-20 mm Hg. This phenomenon, called post-exercise hypotension (PEH), is particularly pronounced among those with high blood pressure, according to the authors of a review published in the Journal of Human Hypertension.

“PEH has been well documented in humans with both borderline hypertension and hypertension,” they wrote. “However, its occurrence in normotensive humans is inconsistent. Although we have found that PEH can be detected in normotensive individuals, it was found to be much less consistent and of lesser magnitude than in hypertensive individuals. This may be due to other compensatory mechanisms, such as the baroreflex, that are activated in normotensive subjects, and prevent the degree of PEH from affecting orthostatic tolerance.”

The risk is that PEH, in combination with hypotension secondary to ACE inhibitors, can lead to dizziness and syncope. Thus, modifications are a good idea in exercisers taking these medications, according to a review published by the American College of Exercise (ACE).

“It is critical that clients who take ACE inhibitors consistently adhere to a gradual cool-down after each and every exercise session,” the review author wrote. “One of the classic benefits of a cool-down is enhanced venous return and the prevention of blood pooling in the skeletal muscle. A gradual cool-down of five to 10 minutes of light aerobic activity permits the body to return to homeostasis and prevents excessive reductions in blood pressure.”

Beta-blockers

Beta-blockers are used to treat hypertension and heart disease. Atenolol, metoprolol, and other beta-blockers bind to epinephrine receptors in the heart, thus lowering resting/exercise heart rate and blood pressure. These effects blunt increases in heart rate and blood pressure, which serve as a proxy for exercise intensity and workload. Moreover, beta-blockers can lead to glucose intolerance in those with diabetes by masking hypoglycemia symptoms. 

For individuals taking beta-blockers, instead of target heart rate, an alternative method of monitoring exercise intensity could be the “ratings of perceived exertion” (RPE) scale—a subjective observation of how someone feels when they are working out, based on factors like increased heart rate, faster breathing, or muscle fatigue. 

Additionally, to avoid dangerous dips in blood sugar levels when beginning an exercise regimen, it’s a good idea to check levels with a glucometer while exercising (ie, before, midway, and at the end of the session). 

Diuretics

Also used to treat hypertension, hydrochlorothiazide and other diuretics decrease plasma volume by increasing urine output, thus lowering blood pressure. As with those taking ACE inhibitors, patients taking diuretics exhibit lower resting and exercise blood pressures.

Because patients taking diuretics can also be taking ACE inhibitors, hypotension is an even greater concern once PEH sets in. Gradual cool-down is necessary, and it may be a good idea to weigh daily to monitor changes in water weight due to diuretic administration.

Sulfonylureas

Sulfonylureas are a class of drugs used in the management of type 2 diabetes. Glipizide and glyburide promote the secretion of insulin, and can thus interfere with exercise. The transporter protein GLUT-4 responds to exercise and insulin. Concurrent stimulation by exercise and insulin can lead to hypoglycemia. Thus, especially when initiating an exercise regimen, anybody taking sulfonylureas should have their blood glucose tested before, while, and after exercising to determine whether drops in blood sugar are within acceptable levels.

Statins

Although uncommon, statins can lead to exertional rhabdomyolysis, which impacts kidney function. This repercussion is more likely in exercisers who are deconditioned, those performing high-intensity resistance training, and those exercising in hot/humid environments. Signs and symptoms include dark-colored urine, muscle pain, and fatigue.

To curb the risk for exertional rhabdomyolysis, both aerobic and resistance training should begin at a low intensity and progress slowly. Additionally, exercisers should remain adequately hydrated, and outdoor exercise should also be done during cooler times of the day.

This story is contributed by Naveed Saleh and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.