Exercising at your max heart rate might leave you drenched in sweat, but it's not something you should do regularly. Spending too much time in the high zone can be a problem. But how do you know if you're pushing the upper limit? Here's what you need to know about exercising in your heart rate zone.
Read more: What Is Your MHR — and How Do You Calculate It?
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Max Heart Rate Defined
Your maximum heart rate is the number of beats per minute of the heart when it's under maximal stress. "This is most commonly calculated using the formula 220 minus your age," says Santa Monica, California-based Shephal Doshi, MD, a cardiac electrophysiologist and director of cardiac electrophysiology and pacing at Providence Saint John's Health Center.
"But as you can imagine, there is significant variability not only by individual but also between the sexes and the type of exercise being performed, like running versus swimming, for example," he says.
While easy to remember, Dr. Doshi and the American Heart Association (AHA) note that this formula is a broad sweep and doesn't consider critical components like:
- Changes to your heart rate as you age.
- Medical conditions that may impact your heart rate.
- Medications that can affect heart rate.
- Your current fitness level.
The gold standard for determining your max heart rate is with a true maximal exercise test, according to a study published in the September-October 2013 issue of the American Journal of Human Biology. A maximal exercise test pushes your body to its physical limit while a doctor — or sometimes an exercise physiologist — monitors your heart rate.
How High Can You Go?
If you're an athlete or serious fitness fanatic, you might like to take your body to the brink to see how it performs. If that's the case, your heart and lungs are likely conditioned to handle this extreme level, even if it's just for a brief period of time. But if you're an average gym-goer, runner or cyclist, you might be wondering how high is too high for you.
According to Dr. Doshi, there is no "single danger zone." How high you take your heart rate during exercise, he says, depends on several variables, including your fitness level and underlying medical problems. "You need to listen to and understand your body when pushing the limits," Dr. Doshi says. And be aware of symptoms such as severe shortness of breath, chest pain, dizziness or severe heart palpitations, which "are all signs that you need to slow down," he adds.
Although you can go over the "theoretical calculated maximal heart rate," Dr. Doshi says it's important to note that this formula generalizes people and doesn't correct if you're an older athlete or an extremely fit person. Thus, Dr. Doshi recommends discussing your needs with your doctor or health care provider. If you're new to exercise or have a medical condition, they can help you determine a safe zone for getting started.
If you want to train at your maximal heart rate, consider consulting an exercise physiologist who can help you find your baseline max heart rate and monitor you while you exercise.
Your Target Heart Rate
Because hanging out in the max zone for too long can be dangerous, you need to find a range that's both safe and intense enough to give you a good workout — that's where your target heart rate zone comes in.
According to the AHA, your target heart rate zone during moderate-intensity exercise is about 50 to 70 percent of your max heart rate. If you want to work at a vigorous level, you bump the range up to 70 to 85 percent of maximum.
Additionally, you can skip the math session and use one of the online calculators to do the calculation for you. The American Council on Exercise has one that calculates your target heart rate range based on whether you're at a beginner, intermediate or advanced fitness level.
The bottom line: It's always important to consult a doctor before starting any new exercise program, especially if it's strenuous. In some cases, a visit to the doctor is especially important before engaging in activities that will raise your heart rate to the top of the recommended cardiovascular zone for your age.
- Shepal Doshi, MD, cardiac electrophysiologist, director, cardiac electrophysiology and pacing, Providence Saint John’s Health Center, Santa Monica, California
- American Journal of Human Biology: “Measured Maximal Heart Rates Compared to Commonly Used Age-Based Prediction Equations in the Heritage Family Study”
- American Heart Association: “Target Heart Rates Chart”
- American Council on Exercise: “Finding Your Target Heart Rate Range”