Exercise for Fitness

"Walking is good for you, but to be really fit don't I have to get all sweaty like from jogging?" Some exercises are good for endurance and other exercises help you lose weight and something else prevents heart disease, and still something else prevents bone loss. "What do I REALLY need to do?" Your doctor or physiotherapist has likely heard all these questions. When it comes to the benefits of exercise, increasing cardiorespiratory fitness (heart and lung capacity and endurance) is often emphasized more than improving overall health and preventing disease. Thus, many people think of exercise only as strenuous physical activity such as running or cross country skiing.

The truth is, to improve cardiorespiratory fitness you usually need to raise your heart rate to between 70% and 90% of its maximum value for 20  or more minutes. Such exercise will feel somewhat hard to very hard.

But, you can attain many other health benefits with a lesser amount or intensity of exercise. Less strenuous exercise can help you improve overall health and may reduce the risk of medical problems like osteoporosis, diabetes, and heart disease.

Fortunately, almost any exercise, even activities like housework, can help improve health. Mild to moderate intensity exercise like walking or gardening can help you lower cholesterol, lower blood pressure, lose weight, have more energy, sleep better, and feel better about yourself. Moderate exercise can also help your heart pump more blood more effectively.

To improve your overall health, exercise for a total of 30 minutes or more a day at least 3 days a week. The options for mild to moderate exercise are almost limitless: walking, biking, swimming, hiking, roller skating, low impact aerobics, tennis, golf, canoing, etc.

Remember, that even brief bouts of exercise, if repeated, can be effective. Three 10 minute bouts of exercise give almost the same health and fitness benefits as one 30 minute workout.

Less strenuous exercise can also help make bones stronger, improve the body's handling of blood sugar, lower the risk of heart disease, and prolong life. Those who rarely exercise need not be discouraged: inactive people who increase their activity level can benefit even more than people who already exercise.

Osteoporosis, which involves the gradual weakening of bone, commonly occurs in older adults, especially women over 50. With osteoporosis, even minor falls can cause broken bones, especially in the hip and wrist. In the United States alone, osteoporosis leads to an estimated 1.5 million bone fractures each year. Fortunately, simple weight bearing exercise like walking can help to maintain and enhance bone density.

Diabetes causes high levels of sugar in the blood. Blood sugar is usually regulated through the hormone insulin, which your body produces. Normally, insulin helps sugar get from the bloodstream into muscle cells, where it is used for energy. Diabetes is caused by either a lack of insulin (type 1) or a resistance to insulin (type 2) . By age 70, about one person in four is at risk of developing type 2 diabetes, the type more likely to develop in adults.

Many authorities now suggest that insulin resistance can be attributed at least in part to weight gain, physical inactivity, or both. Studies have also shown that exercise has an insulin-like effect in people who have diabetes, apparently helping more blood sugar get into muscle cells. Consequently, regular physical activity is commonly recommended for preventing and treating diabetes.

Exercise also has a favourable effect on many of the risk factors associated with heart disease. Even mild aerobic exercise programs which involve continual use of large muscles like those in the legs can result in a moderate loss of body fat. Aerobic exercise can also help lower blood pressure in people who have moderately high blood pressure, blood cholesterol, and triglycerides, and low density lipoprotein (LDL)  cholesterol. Aerobic exercise can also increase high density lipoprotein (HDL); However, for optimal improvement in blood fats, regular aerobic exercise must be combined with a diet low in calories, saturated fat and cholesterol.

Finally, numerous studies show that low fitness is associated with a shorter life span. One landmark study found that physical fitness markedly decreased the risk of death from cancer and heart disease. The least fit people in the study had substantially higher death rates than the most fit. However, the people who progressed from the lowest fitness level to the next category had the biggest decrease in risk. These and other findings indicate that even small increases in fitness can have a major impact on longevity.

The health benefits of moderate exercise are many, but raising your workout intensity has the added benefit of giving you more stamina for all your activities.

To understand the importance of good cardiorespiratory fitness, you need to appreciate the fact that sustained physical exertion requires oxygen. After age 20, your capacity to take in and use oxygen decreases by about 1% a year. This capacity to use oxygen is commonly referred to as aerobic capacity or maximal oxygen consumption and is a key gauge of a person's cardiorespiratory fitness level.

An endurance exercise program generally leads to a 20% increase in aerobic capacity, which translates to a 20 year rejuvenation. In other words an inactive 65 year old who initiates a vigorous exercise program can achieve the same  cardiorespiratory fitness he had two decades earlier as a 45 year old.

How does increased aerobic capacity help you perform your daily activities? First, any given task requires a certain amount of oxygen. An unfit woman, for example, may use nearly her entire aerobic capacity to accomplish a simple activity like gardening. Although a fit woman may consume a similar amount of oxygen for gardening, because her aerobic capacity is higher, she will have more energy to tap and be less tired.

Walking is undoubtedly the most accessible and underrated exercise to improve cardiorespiratory fitness. In one study of inactive adults over age 50, 83% of men and 91% of women achieved 70% of their maximal heart rate simply by walking a mile briskly. These findings clearly show that most middle aged and older adults can improve their fitness by regular walking, especially if they are currently inactive.

As with less strenuous exercise, workout choices for increasing cardiorespiratory fitness are many and include running, in-line skating, and aerobics classes. Choose an activity from the exercises mentioned earlier and perform it at a greater intensity. Also, you can try increasing the length of each exercise session, try working out four or five times a week, or both.

An expert panel commissioned by the Centres for Disease Control and Prevention and the American College of Sports Medicine reviewed the extensive body of research on the health benefits of regular physical activity. The recommendations of the panel were expressed in a concise public health message that read: "Every US adult should accumulate 30 minutes or more of moderate intensity physical activity on most, preferably all days of the week".

Whether you're interested in improving overall health, increasing cardiorespiratory fitness, or both, it's good advice. Remember: this information is not intended to substitute for medical advice. Consult a physician prior to starting any exercise program.

Remember, this information is not intended as a substitute for medical advice. Consult your family physician prior to starting any new exercise program.

Reference
Pate RR, Pratt M, Blair SN, et al: Physical activity and public health: a recommendation from the Centres for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273(5):402-407.