Atenolol is a beta blocker. All beta blockers slow down your heart rate. The slower rate happens at rest and also when you exercise.
In general, when your pulse speeds up, it’s an excellent way to tell how hard you are exercising. To get the most from aerobic exercise, you want to have your heart rate in a moderate intensity zone for at least 30 minutes most days of the week.
Moderate intensity means exercising at a heart rate that is 60% to 75% of your maximum heart rate. An easy formula to find your maximum heart rate: 220 minus your age. So if you are 60 years old, your maximum heart rate is 160. Moderate intensity exercise for you will be a pulse of 96 to 120 beats per minute.
But this formula does not work for people who take a beta blocker. And there is no standard way to correct the formula. Instead, you can use your breathing. If you are breathing very hard and not able to talk during exercise, you are at high intensity. With moderate intensity, you should be able to talk but with pauses to catch your breath.
You can take your beta blocker and still get the same benefits of exercise. The training effect does not depend on a faster heartbeat. In fact, even though the beta blocker will keep your heart rate low, you’ll be able to burn body fat, lower your cholesterol and blood sugar. You will make your muscles and bones stronger with regular exercise. You’ll also improve your heart’s efficiency and endurance.
At first, taking the beta blocker might make you feel a bit sluggish during exercise. But over time, you should get back to the same sense of fulfillment from working out.