The Effect of Strenuous Exercise on the Heart

Target Heart Rate

Your heart lets you know when you’re working it too hard. Too many beats per minute and you should slow down, suggests the American Heart Association. But if you don’t get your heart pumping fast enough, you’ll minimize the positive effects of your activity. Aim for a heart rate between 50 percent and 85 percent of your resting heart rate, which is how fast your heart beats when you’re not doing anything. The average resting heart rate is 60 to 80 beats every minute. Subtract your age from 220 to figure out the fastest your heart can safely beat.

Strenuous Exercise

Long jogs, back-to-back basketball games, sprints and heavy weight lifting count as strenuous exercise, since periods of intense activity will get and keep your heart pumping well above your target heart rate. If your target rate is too high, you may be straining your heart, says the American Heart Association, so slow down. “We don’t want people to overexercise,” Gerald Fletcher, cardiologist and professor in the Mayo Clinic College of Medicine in Jacksonville, Florida, said in an interview with the American Heart Association. “If you’re not able to carry on a conversation [while exercising], that may be a bit too much.”

Heart Arrhythmias

Certain episodes, including strenuous exercise, can cause your heart to beat faster or slower than normal or literally skip beats, according to the American Heart Association. The harder you work, the harder your heart has to work, which can increase blood flow and flood your system with stress hormones. Your heart rate should return to normal after your workout ends, and you may not feel any different. But if your heart rate feels funny, especially after an intense workout, call your doctor immediately, the association recommends.

The Hockey Heart Study

A 2002 study out of Nova Scotia, Canada, measured how strenuous hockey affected the hearts of 113 men who had normal heart rates at the outset. Results showed “cardiac responses that might be dangerous to players’ health,” according to the study. These responses included heart rates in excess of target and maximum heart rates and poor post-exercise heart rate recovery -- meaning study participants’ hearts continued working too hard after the exercise ended. Some participants also had nonsustained ventricular tachycardia, a type of arrhythmia.