Once you feel comfortable doing low-intensity exercise regularly, consider aerobics for greater, faster weight loss. “Aerobic” means “with extra oxygen.” Aerobic exercise is fairly strenuous, but it should not feel exhausting.
Aerobic benefits–weight loss and improved fitness–are possible only when the heart rate is in its age-specific “target range.” A rate below your personal target range doesn’t move enough oxygen into your heart and muscles, and a rate above the target range taxes you beyond prudent limits and leaves you exhausted.
To find your individual target range, first, take your pulse while resting. Press your fingertips (not your thumb) on either side of your neck right below your jaw. Count the number of beats for 15 seconds. Multiply by four to get your heart rate per minute.
Target heart rate is 60 to 80 percent of the maximum heart rate per minute for your age. To calculate your own personal maximum heart rate, take 220 minus your age. (For a 45-year-old woman, 220-45=175.) Then after warming up, try to maintain your pulse at 60 to 80 percent of that number. (For the 45-year-old woman, 175 x .6 = 105 beats per minute, and 175 x .8 = 140 beats/minute.)
For best aerobic conditioning, keep your heart rate within your target range for about 20 minutes three times a week.