Everyone knows that regular physical activity can strengthen your muscles and improve your endurance. But your heart, a muscle, can also benefit from physical activity. In fact, exercise helps protect against heart disease and reduces symptoms in people who already have heart disease.
Regular physical activity can lower triglycerides and help raise HDL cholesterol. When it results in weight loss, physical activity can also play a key role in managing the metabolic syndrome and reducing LDL cholesterol. Moreover, it reduces the risk of other chronic diseases, such as type 2 diabetes and high blood pressure -- risk factors for coronary heart disease -- as well as osteoporosis and some cancers. Physical activity is an integral part of an overall healthy lifestyle, including a balanced diet and not smoking, that can lower your risk of heart disease.
Exercise benefits the body in a number of ways. Most importantly, it improves aerobic capacity (the body's ability to take in and use oxygen during exercise), and it increases muscular strength. Both aerobic exercise and resistance training promote physical fitness and benefit your heart and overall health.
To learn more about these and other types of exercise, see the next page.
Types of Exercise
There are several different types of exercise that benefit the body. First, aerobic exercise, which uses large muscle groups, forces the heart and lungs to work harder to meet the muscles' demand for oxygen. These activities involve regular, repeated activity performed at a pace intense enough to quicken your breathing and get your heart pumping faster than usual. Over time, the heart and other muscles become more efficient at using oxygen and can work harder and longer using less energy. Ultimately, this improves cardiovascular fitness, resulting in a decreased resting heart rate and decreased blood pressure. This also makes routine daily activities, such as running around after a busy toddler or bringing groceries in from the car, easier and less fatiguing. Examples of aerobic exercise include brisk walking, jogging, swimming, cycling, and cross-country skiing.
Second, resistance training, such as lifting weights, develops muscular strength and size. The weights involved are usually handheld or built into exercise equipment, but a similar effect can be achieved by stretching large rubber bands or even lifting objects such as heavy books. Resistance training performed two to three times a week can improve muscular strength and endurance. To build muscle strength, select 8 to 10 different strength-building exercises that use the major muscles, and perform 8 to 15 repetitions of each exercise for each isolated muscle.
Just as the different foods groups are important to eating a balanced diet, different forms of exercise are important to a balanced program of physical activity and are vital to weight control. Aerobic exercise appears to benefit the heart the most, improving aerobic capacity and significantly burning calories, which aids weight loss. But resistance training increases lean body mass, which improves strength and balance, making it easier to perform aerobic exercises. Resistance training also speeds up metabolism. Stretching and flexibility exercises improve range of motion, making it easier to move muscles and joints, preventing injury while performing aerobic activities and resistance training.
Regular exercise brings not only physical, but also mental benefits. See the next page to learn the effects of exercise on body and mind.
Effects of Exercise
Physical activity also helps prevent the loss of lean muscle tissue that may occur when dieting. In addition, studies have indicated that people who participate in regular physical activity tend to have a lower body mass and adopt healthier lifestyle habits, including quitting smoking and choosing healthier foods.
And not to be overlooked, exercise can help alleviate stress and contribute to a positive attitude. Many people report that a regular program of physical activity brings an improvement in self-esteem and self-image along with an improvement in physical appearance. An increase in strength can even contribute to greater general mobility and make it easier to handle basic, everyday tasks. It's never too late to get moving. But if you haven't been active in a while or if you've had a heart attack, talk with your doctor about becoming physically active. If you experience any warning signs, including dizziness, shortness of breath, cold sweat, or pain or pressure in your upper body, stop the activity, and seek medical attention immediately.
For an exercise program to be effective, you need to exercise within the range of your target heart rate. To find out how to determine your target heart rate and track your exercise, see the next page.
Tracking Your Fitness
You don't have to be a marathon runner to gain the benefits of physical activity, but it does help if you're tracking your fitness. If you're not particularly active now, make it your goal to add moderate amounts of activity to your day. Start slowly and work your way up to include at least 30 minutes of physical activity on most days of the week. An easy way to assess whether your heart and lungs are becoming more fit as you become more active is to check your heart rate while engaging in physical activity. According to the National Heart, Lung, and Blood Institute, you should stay within your target heart rate range while exercising.
Your heart rate is the number of times your heart beats at any given minute. Your target heart rate range includes the minimum and maximum your heart should beat per minute to improve your level of fitness. To calculate your target heart rate range, first you must estimate your maximum heart rate. A general method of determining your maximum heart rate is to subtract your age from 220; your target heart rate range, then, is 50 to 75 percent of your maximum heart rate. (For example, if you are 55 years old, subtract 55 from 220, which equals 165; this is your maximum heart rate. Multiply 165 by 50 percent, or 0.50, which equals approximately 83, to determine the minimum beats per minute of the target heart rate range. Multiply 165 by 75 percent, or 0.75, which equals approximately 124, to determine the maximum beats per minute of the target heart rate range. The target heart rate range is 83 to 124 beats per minute.) It is advisable to stay within your target heart rate range while exercising. Unless you're in excellent shape, exceeding this range can be too strenuous, while activity below this range may not be enough to benefit your heart and lungs.
To find out if you're exercising within your target heart rate range, take your pulse during and immediately after completing your activity. Place the tips of your first two fingers on the inside of your wrist, right below the base of your thumb. When you feel your pulse, check the second hand on a clock or on your watch, and then count your pulse for ten seconds and multiply the count by six. Adjust the intensity of your activity so you stay within your target heart rate range.
To learn more about fitness and exercise, check out the links on the next page.
ABOUT THE AUTHOR
Adrienne Forman, M.S., R.D., is a consultant and freelance writer, specializing in nutrition and health communications. She is the editor of Shape Up America! newsletter, an online publication, and has been a contributing editor of Environmental Nutrition newsletter for the past 14 years. Adrienne is a former Senior Nutritionist at Weight Watchers International, where she was instrumental in creating multiple weight-loss programs, including their popular Points® program.