Wearable fitness trackers are becoming increasingly popular, putting heart rate monitoring at your fingertips. But what is the best way to use this information? Monitoring your heart rate can give you insight about your health status and help you improve your physical fitness, according to cardiologist and Club Red Clinical Ambassador Brandy Patterson, MD, and UVA Exercise Physiology Research Lab Manager Lisa Farr.
Resting Heart Rate
Your resting heart rate, the number of times your heart beats each minute while at rest, can be used as a measure of physical fitness. “People who are physically fit usually have a lower resting heart rate,” Patterson says. “Marathon runners can have resting heart rates in the 50s or 60s.”
A resting heart rate of 60 to 80 beats per minute (bpm) is considered normal. However, it’s important to remember that heart rate varies constantly throughout the day. “It changes from minute to minute,” Patterson says. If your heart rate is 90 bpm after walking to your chair from the restroom, there’s no need to panic.
“A resting heart rate above 100 bpm is considered tachycardia, or abnormally fast,” Patterson says. “If it’s between 90 and 100 constantly, I do start to get concerned.” If you notice your heart rate is consistently high, it may be time for a conversation with your doctor.
Maximum Heart Rate
Monitoring your heart rate during exercise can help you improve your physical fitness. “Having numbers to shoot for can help people stay safe and also make sure they’re working hard enough to accomplish their goals,” says Farr.
Begin by determining your maximum heart rate, the number of times your heart can beat in one minute during maximal physical exertion. While measuring your exact maximum heart rate requires testing in an exercise sports lab, a simple formula will get you close to the precise number. Just subtract your age from 220 to get within 10 to 12 beats of your maximum.
Exercise and Heart Rate
The American Heart Association (AHA) recommends adults get 150 minutes of moderate-intensity exercise or 75 minutes of vigorous exercise each week. You can use your heart rate to gauge how hard you’re exercising. The AHA defines moderate-intensity exercise as between 50 and 70 percent of your maximum heart rate and vigorous exercise as between 70 and 85 percent.
To calculate the zones, multiply your maximum heart rate by 0.5, 0.7 and 0.85. For example, if you’re 40 years old your maximum heart rate is 180 (220-40=180). Therefore:
- Fifty percent: 180 x 0.5=90
- Seventy percent: 180 x 0.7=126
- Eighty-five percent: 180 x 0.85=153
Moderate-intensity exercise for you means your heart rate is between 90 and 126 bmp. Vigorous exercise raises your heart rate to 126 to 153 bpm.
If you take certain medications for your heart, such as beta-blockers and anti-arrhythmia drugs, these ranges may not be useful to you. The medicine may keep your heart rate from increasing as much compared to someone not taking the medicine.
If you take one of these medications, you can use the talk-sing test to gauge your intensity, according to the American College of Sports Medicine. At moderate intensity, you should be able to talk, but not sing. As you move into vigorous activity, it becomes harder to talk.
The Myth: ‘Fat-Burning Zone’
When you look up heart rate zones online, you’ll undoubtedly find references to the “fat-burning zone.” Many sources label moderate exercise that raises your heart rate to about 50 to 70 percent of your maximum the “fat-burn zone” and that which raises it to 70 to 85 percent the “cardio zone.”
That information simply isn’t correct. “They might say if you want to burn fat, you need to be here and if you want to improve cardiovascular fitness, be here,” Farr says. “They’re actually telling people they need to consciously exercise less hard to burn more fat. That is plain not true.”
Start Slow, But Challenge Yourself
If you’re new to exercise or starting again after a long break, it’s best to begin slowly and work your way up to prevent injury. “I sometimes see people who aren’t used to exercising, so any time they break a sweat they feel like they’re working too hard and that’s probably not true.” Farr says. “That said, a beginning exerciser should be cautious and build up a base because a huge reason people drop out of exercise programs is because they begin too ambitiously and injure themselves.”
Farr suggests using the first several weeks to ease into a new routine. “When someone begins an exercise program, key goals are to develop the habit, to learn how to set exercise equipment or to just generally feel more comfortable with exercise, and to make sure you don’t do something to halt your progress, like get injured,” she says. “A few weeks in, you can begin to worry more about the intensity of what you are doing.”
For those who have been exercising longer, using heart rate to guide intensity can be useful. “The more physically conditioned you are, the harder it is to get your heart rate up,” Patterson says.
Farr stresses the importance of “not becoming complacent.” “People have a tendency to want to do the same exercise on the same machine at the same level every day,” she says. “It’s definitely beneficial to change it up — try different exercises, have some sessions be longer and easier and others shorter and harder.”
There is a limit to how much is gained by increasing the intensity of your exercise, Farr and Patterson say. It’s best not to raise your heart rate above 85 percent of your maximum for your entire or most of your workout. “Anything over that doesn’t give you more fat- or calorie-burning ability or increase your cardiovascular fitness,” Patterson says.
Because heart rate calculations are an estimate of how hard you are working, it’s important to also note how you feel. “It’s critical to know what things are not normal to feel,” she says. “Those include chest pain or pressure, dizziness or lightheadedness, palpitations or a heart rate that feels irregular or becoming very short of breath in a way that’s alarming to you.”
Before you begin a new fitness routine, be sure to speak with your doctor. Looking for a primary care physician? Go to uvahealth.com to find a doctor near you.