Most women use an outdated exercise target heart rate formula that might be OK for guys, but is too high for females, according to researchers at Northwestern Medicine. Using the old “220 – Age” formula might not be that bad for men, but it can cause women to raise their heart rate much more than they need to during exercise.
The study of more than 5,000 women found that females hit their aerobic heart rate earlier than the old formula indicated. Trying to hit the old heart rate range can lead to fatigue and shortened workouts if women try to keep maintain pace during their exercise sessions.
Using the correct formula to find your maximum heart rate, then performing some simple math, you can get — and stay — into the right exercise zone for you.
Calculate Your Maximum Heart Rate
Step #1 – Multiply your age by .88 to get your approximate maximum heart rate
Step #2 – Subtract that number from 206
Calculate Your Workout Target Heart Rate
Step #3 – Multiply that number by .50 to .65 for beginner (fat-burning) exercise
Step #4 – Multiply by .65 to .80 for intermediate (cardio) exercise
Step #5 – Multiply by .80 to .90 for high intensity interval training (HIIT) exercise
Exercise Target Heart Rate Example
Jane is 35 years old. To calculate her target heart rate ranges for different types of workouts, she’d use the following calculations:
35 X .88 = 31
206 – 31 = 175
Fat-burning workout heart rate = 175 X .50 and .65, or between 88 and 114 beats per minute
Cardio workout heart rate = 175 X .65 and .80, or between 114 and 140 beats per minute
HIIT workout heart rate = 175 X .50 and .65, or between 140 and 158 beats per minute
Monitor Your Monitor!
If you use a wristwatch-type heart rate monitor when you exercise, or regularly use a piece of exercise equipment with a built-in monitor, adjust your workouts to use a smaller percentage of your monitor’s readout, or use the beats-per-minute setting instead.
For example, many commercial heart rate monitors ask you to enter your age, which the monitor then uses to calculate your maximum heart rate using the 220-age formula. Women should exercise about 5 percent lower than what a typical monitor suggests. For example, if Jane wanted to stay between 70 and 80 percent of her personal maximum heart rate during her workout, she’d use her monitor to stay between approximately 65 and 75 percent of what the monitor says is her maximum heart rate. While a 5 percent difference might not seem like much, remember, that’s using 5 percent more of your maximum effort for 30 minutes or longer.
Another, more accurate, way to use a heart rate monitor is to use the beat-per-minute function instead of percentage-of-maximum-heart-rate readout. This lets the monitor use just your heart rate to give you information, rather your pulse and a math formula. Jane’s target exercise heart rate would be 123 to 140 beats per minute. Instead of seeing 74% or 78% on her monitor during her workout, Jane would see 130 or 137.
Check with your doctor or personal trainer before you begin any exercise program. Review your target heart rate range for the type of exercise you plan on doing. Depending on your condition, you might need to work at the lower end of your target heart rate range while you build cardio stamina and endurance, or at the higher end if you’re in very good shape.