Your target heart rate during exercise depends on your age and the intensity of the activity. Here are some guidelines from various sources:

• American Heart Association: Target heart rate during moderate-intensity activities is about 50-70% of maximum heart rate, while during vigorous physical activity it’s about 70-85% of maximum. The figures are averages, so use them as a general guide.

• CDC: For moderate-intensity physical activity, your target heart rate should be between 64% and 76% of your maximum heart rate. For vigorous-intensity physical activity, your target heart rate should be between 77% and 93% of your maximum heart rate. To estimate your maximum age-related heart rate, subtract your age from 220.

• Mayo Clinic: Your target heart rate zone for vigorous exercise is 148 to 162 beats per minute, rounded to whole numbers. For moderate exercise, aim for a target heart rate of 50% to 70% of your maximum heart rate.

• Allina Health: The target heart rate is based on 60 to 80 percent of a maximum heart rate. To figure your target heart rate, subtract your age from 220. If you are just starting an exercise routine, you may want to start out at 60 to 70 percent of your target heart rate. As you become more fit, you may want to progress to 70 to 80 percent of your target heart rate.

• Johns Hopkins Medicine: Target heart rate is generally expressed as a percentage (usually between 50 percent and 85 percent) of your maximum safe heart rate. The maximum rate is based on your age, as subtracted from 220. Therefore, the target heart rate that a 50-year-old would want to aim for during exercise is 85 to 145 beats per minute.

To measure your heart rate during exercise, you can use a heart rate monitor or take your pulse manually. To take your pulse manually, find your pulse (inside your wrist, on the thumb side, is a good place) and count the number of beats in a minute. Alternatively, you can take your pulse for 30 seconds and double it.