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Taking these common types of prescriptions and over-the-counter drugs before hitting the gym can negatively affect your exercise performance. The Good Brigade/Getty Images
  • Commonly prescribed and over-the-counter medications may adversely affect exercise performance.
  • Experts share which medications may interact with exercising and how to safely engage in physical activity.
  • The timing of when you take medications is one important factor when it comes to exercising.

So much goes into sticking to a workout routine, from finding the time and place to coming up with exercises you enjoy.

But did you know that part of the preparation should include understanding which prescribed and over-the-counter (OTC) medications can adversely interfere with exercise?

“Before hitting the gym, it’s best to know how the timing of your medications could affect your workout…for some medications, you should work out before taking a dose or wait until the effects of the medication have worn off (usually in 4-6 hours),” Dr. Robert Glatter, ER doctor at Lenox Hill Hospital, told Healthline.

Common OTC and prescription medications can impact stamina, endurance, and overall exercise performance, he said.

However, you can still exercise if you take medications, said HaVy Ngo-Hamilton, PharmD, BuzzRx clinical consultant.

“Knowing that certain medications can have negative effects on your workout routine can be worrisome,” she told Healthline. “However, you should not let this information stop you from exercising or taking medications as prescribed.”

While everyone reacts differently to medications and although there are many factors that could potentially affect workouts, the following medications are ones to keep in mind before hitting the gym.

Simvastatin, atorvastatin, and rosuvastatin are some of the most commonly-prescribed cholesterol medications, said Ngo-Hamilton.

While statins do not consistently reduce performance, endurance, and strength, according to a study in the Journal of Clinical Lipidology, a common side effect of these is muscle pain and soreness. Ngo-Hamilton, said these side effects are what causes many people to stop taking them.

“You should be vigilant and monitor for signs of new muscle pain or muscle cramps the first few weeks you start taking a statin. If you experience any new, unusual muscle soreness, don’t let this discourage you from staying active,” she said.

Muscle pain should get better after a few weeks of taking statin therapy as prescribed.

“Meanwhile, if you experience this side effect, you should modify your workout routine to reduce the pressure on your muscles. For example, instead of resistance training, you should try to do more cardio, stretching, and body conditioning,” said Ngo-Hamilton.

Diuretics are used to treat high blood pressure and heart failure. Because there are different types of diuretics, Ngo-Hamilton said doctors decide the kind of water pill depending on the condition they are prescribed for.

Thiazide, loop diuretics, and potassium-sparing diuretics are commonly prescribed. While these help the body remove fluid and reduce pressure on blood vessels, they can increase the risk of dehydration.

“While on a diuretic, you should watch for signs of dehydration, such as dizziness or lightheadedness, especially when you first start on a water pill,” said Ngo-Hamilton. “Drinking plenty of water before and after your workout, then throughout the day, is the best way to prevent this side effect while working out.”

Beta-blockers, calcium channel blockers, ACE inhibitors, and angiotensin receptor blockers (ARBs) are commonly-prescribed blood pressure medications.

“If you take a blood pressure medication, watch for signs of low blood pressure that can happen post-workout, such as dizziness or feeling like you are going to faint,” said Ngo-Hamilton.

Since people are often on both blood pressure medication and a diuretic, which can also lower blood pressure, she said it’s important to stay well-hydrated to prevent falls and injury.

“[And] be careful when you change positions from sitting or laying down to standing up. A drastic drop in blood pressure can happen with changing position, causing lightheadedness,” Ngo-Hamilton said.

Additionally, she noted that beta-blockers, such as metoprolol, atenolol, and carvedilol carry extra precautions for diabetic patients because, in addition to lowering blood pressure, beta blockers can also mask the signs and symptoms of low blood sugar.

“Low blood sugar presents with shakiness, sweating, and feeling anxious,” said Ngo-Hamilton.

Sweating is the only symptom that beta blockers do not mask.

“Since sweating is normal with exercising, an episode of low blood sugar during a workout session can easily be missed or ignored, leading to serious health consequences,” she said.

Sedating medications can cause sleepiness, drowsiness, and grogginess, which can reduce your energy levels or stamina to exercise.

“People also can feel sluggish and uncoordinated with certain allergy and sleep medicines,” said Ngo-Hamilton. “[Accidents] and falls can happen due to impaired coordination and slowed reaction. Keep in mind that using the treadmill, StairMaster, or elliptical while on these medications can be dangerous.”

Below are some of the most common medications that can have sedating effects:

  • Sleeping pills: Benadryl (diphenhydramine), Unisom (doxylamine), Ambien (zolpidem), Lunesta (eszopiclone)
  • Anti-anxiety medicines: Atarax (hydroxyzine); Ativan (lorazepam); Xanax (alprazolam)
  • Antihistamine allergy medicines: Allegra (fexofenadine), Zyrtec (cetirizine), and Benadryl (diphenhydramine)
  • Opioid pain medications: Percocet (oxycodone-acetaminophen), OxyContin (oxycodone); Norco (hydrocodone/acetaminophen)
  • Muscle relaxers: Flexeril (cyclobenzaprine), Soma (carisoprodol)

Stimulants, particularly medications to treat ADHD, such as Adderall and Ritalin can increase heart rate and rate of breathing, “so it’s advisable to take them after workouts, as opposed to before exercising,” said Glatter.

However, he added that a meta-analysis concluded that ADHD prescription medications had a positive effect on athletic performance.

Stimulants are also often prescribed to treat narcolepsy.

“[Stimulants] may mask exercise-induced fatigue, making it more difficult to know when you’ve reached your limit. Stimulants may also cause hand tremors and make you feel irritable and anxious,” said Ngo-Hamilton.

Maintaining an awareness of how you feel while working out is the best way to know if medication is affecting the quality and intensity of your exercise program, said Glatter.

He said pay attention to symptoms such as lightheadedness, fatigue, elevated heart rate, difficulty catching your breath, dizziness, muscle cramping, and excessive sweating.

“For example, high intensity interval training (HIIT) could be impacted in people taking beta blockers for high blood pressure, since the ability to increase your heart rate is limited by the medication itself. Likewise, long-distance running and even strength training could be impaired if you take beta blockers. It’s important to listen to your body, and pay attention to changes in heart rate, or feelings of fatigue, dizziness,” he said.

Ask your doctor for advice about navigating physical activity while taking medications.

“Based on your health history, if you take certain medications with side effects that may affect your workout routine, such as muscle pain, dehydration, or drowsiness, your doctor and pharmacist can give you tips on how to reduce them,” said Ngo-Hamilton.

Asking your doctor about the timing of when to take medications in relation to when you exercise is also important for safety.

“The intensity and type of exercise you are doing are important factors in determining the optimal time to take your medications,” said Glatter.