How To Tell If Your Heart Rate Is Too High During HIIT

The operative word in the term "high-intensity interval training," or HIIT, is intense. Whether you're doing your HIIT workout as part of a group fitness class, virtually through a program like Peloton digital, or are following a routine alone, you know that sweating, grunting, and shortness of breath are partly what you've signed up for. Pushing yourself to the max for a short interval of time, then recovering before going back for some more, is what makes HIIT an effective way to burn a ton of calories in a short period of time.

"The greater the intensity of the intervals, the greater the demand for the oxygen needed for you to recover," DeBlair Tate, a certified fitness coach, explained to Well + Good. Tate added that your body will continue to burn calories up to two days after you've concluded your sweat session! But there is too much of a good thing. "Some people go to bootcamps five times a week, and your sympathetic nervous system is under so much stress by doing that, just as it is in your day to day life ... it's not sustainable and it's not conducive to optimal health and fitness," Hannah Almond, Head of Yoga at UK boutique fitness chain BLOK, told INSIDER. So how can you tell if you're pushing yourself too far? The simple answer: check your pulse, and make sure your heart rate isn't too high.

There's a pretty straightforward math equation to figuring out how high your heart rate should get when you're doing HIIT. In an interview with The List, celebrity fitness trainer Jillian Michaels shared the formula that most fitness trainers rely upon. "You want to push yourself during the work period of the interval so that you are peaking at 90 to 100 percent of your maximum heart rate, or MHR," she explained. "You can get this number by simply subtracting your age from 220. So for example, a 35 year old's MHR would be 220 minus 35. That would be an MHR of 185 beats per minute." If you're that 35 year-old, and your heart rate is 200 instead of 185, yeah...you need to pull it back a notch.

And if you vomit or faint, or feel acute pain, particularly in your chest, stop immediately, urged Dr. Aaron Baggish, associate director of the Cardiovascular Performance Program at Massachusetts General Hospital. "Don't push through the exercise, which may cause damage to your heart or muscles, but do call your doctor and get your symptoms checked out," Baggish told Harvard Health.