To improve your endurance, otherwise known as cardiovascular fitness or exercise tolerance, exercise must use oxygen or be "aerobic."

Important Points: It must use the large muscles of the arms or legs. It must feel like moderate work, with faster breathing and more heartbeats each minute.* (see last page) It must occur regularly at least three times each week. It must be continuous for 20 minutes, not including warm-up and cool-down. Endurance Exercise Choose an exercise that is convenient and enjoyable, and start now. A good 6-week starter program of aerobic exercise is described here that will work for dancing, walking, biking, swimming, stepping, or whatever you choose. Remember to warm up and cool down, and don't increase your level more than once each week to allow the body to adapt to your new level of activity.

Weeks 1 and 2
Exercise continuously for 15 minutes three times each week, not focusing on distance or speed. Simply work on getting your time in while maintaining a steady pace and breathing deeply.

Week 3
Exercise for 20 minutes, three times this week. The exercise should feel like mild work, making you breathe deeply and feel warm. After 10 minutes, check your pulse if you can.

It should be at about 60 percent of your predicted maximum heart rate.* Speed up or slow down if necessary to keep your heart rate at this level.

Week 4
Exercise for 25 minutes, three times this week. The exercise should feel like moderate work and make you feel warm. You should be able to carry on a conversation without becoming more than slightly short of breath. Slow down if you cannot. Aim for 60-70 percent of your maximum predicted heart rate.*

Week 5
Exercise for 30 minutes, three times this week. The exercise should feel like moderate work, as described previously. Aerobic activity begins to burn fat and cholesterol after 20 minutes.

Week 6
Exercise for 35 minutes, three times this week. The exercise should feel like moderately heavy work, and you can aim for 70-75 percent of your maximum predicted heart rate if it feels good. If one of your goals of exercise is weight loss, 5 days of aerobic exercise for 35 minutes or more is recommended. After 6 weeks, you can either gradually increase exercise time to 45 or 60 minutes or increase the pace within the 35-minute time frame.

* A target heart range is a guide for some people to check the effect of endurance exercise. It is 60-80 percent of the predicted (average, usual) maximum heart rate of people in a certain age group. You can use a chart to find a target heart range for your age group, unless you are taking heart or blood pressure medication or have other health problems. Remember, the best guide is how you feel!

To determine your heartbeats per minute, you will have to find and count your pulse. Stop exercise briefly, and quickly follow these instructions. It will take some practice!

To find your heart rate (beats/minute):

- Immediately after exercising, place the tip of your third finger lightly over the blood vessel in your neck located to the left or right of your Adam's apple, or place it on your wrist just below the base of your thumb.

- Count the beats you feel for 10 seconds.

- Multiply the number of beats by 6 to determine beats per minute.

- If your pulse is below your target heart range, exercise a little harder next time. If you are above your target heart range, exercise a little less vigorously.

Activity	Calories Burned Per Hour
Bicycling 6 mph Bicycling 12 mph Jogging 5.5 mph Jogging 7 mph Jumping rope Running in place Running 10 mph Skiing (cross-country) Swimming 25 yds/min Swimming 50 yds/min Tennis (singles) Walking 2 mph Walking 4 mph	240 410 740 920 750 650 1,280 700 275 500 400 240 440

Source: American Heart Association