Weight loss experts say it's best to exercise aerobically at least three times a week at 60 to 80 percent of your target heart rate. Here is an easy 5 step method for calculating your target heart rate from Robert Hackman, Ph.D., University of Oregon, who specializes in the study of exercise and dieting.
1. Measure your pulse rate for one minute before you get out of bed in the morning to determine your resting heart rate.
2. Subtract your age from 220 for your maximum heart rate.
3. Subtract your resting heart rate from your maximum heart rate for your adjusted heart rate.
4. Multiply your adjusted heart rate by 0.6 to 0.8 to get your exercise addition.
5. Add your resting heart rate and your exercise addition for your target heart rate. This is the heart rate you should aim for as you exercise.
Source: Delicious! Magazine - January/February 1993