No matter what your modality of choice is, all fitness enthusiasts have one thing in common: We’re all trying to make the most out of our workouts. And whether that means spending 45 minutes on a spin bike or an hour and a half on a yoga mat, according to a cardiologist, one of the top methods for maximizing any exercise routine is by paying attention to your heart rate.

“The best way to monitor your workout performance is to wear a heart-rate monitor that tells you when you reach your max predicted heart rate,” says Jennifer Haythe, MD, a board-certified cardiologist (and avid marathon runner!) based in New York. (Obviously, if you have any kind of conditions, you should check with your doc before adding anything new to your fitness regimen.) To find this number during your own heart-rate training workouts, subtract your age from 220; so, for a 30-year-old woman, that would be 190 BPM or (beats per minute).

To figure out where your heart rate should fall during a workout, you’ll want to take your fitness level into account. “For those with lower levels of physical fitness, the goal is to achieve 50 to 70 percent of your max predicted heart rate, and for highly trained athletes, the goal is to hit 90 percent.” So when that same 30-year-old woman works out, she’d want her heart rate to be between 145 and 181 BPM, depending on her fitness level. The only place where this rule doesn’t apply? During HIIT workouts, where you’ll be spiking your heart rate to high levels during your working intervals, then allowing it to partially drop while you’re resting in between sets.

Aside from aiming to hit your target number when you’re heart-rate training, you’ll also want to pay attention to what happens afterward. “Watch how long it takes for your heart rate to return to baseline after completing an aerobic activity,” says Dr. Haythe. “It should drop by about 20 beats within the first minute of stopping exercise, though the longer you exercise at peak heart rate, the longer it will take for your heart rate to return to normal.”

Keeping tabs on your heart rate can help you maintain awareness of how hard you’re going in a given workout, which will ultimately help you hit your goals in a more targeted way. If your goal is to improve your cardiovascular fitness and spike your energy systems, aim to stay between 60 and 70 percent of your maximum predicted heart rate, and if you want to up your endurance level, aim to hit 70 to 90 percent.

So forget watching the minutes or miles on the machine tick by: All you really need to ensure you’re getting the most out of your workout is an eagle eye on your heart rate.

Want to practice heart rate training for yourself? Try this treadmill endurance workout. 

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