Exercise is defined as physical activity that is performed to maintain fitness and health. Combined with proper nutrition, moderate-intensity exercise is an important element in the effort to maintain a healthy lifestyle. In addition to promoting general well-being, regular physical activity has proven effective in preventing and controlling many medical conditions, including:

• Cardiovascular disease
• Obesity
• Diabetes
• Osteoporosis
• Depression
• Chronic low back pain
• Constipation
• General fatigue or low sex drive
• Low sex drive (libido)
• Hemorrhoids

The effect of not exercising has been compared to the effect of smoking a pack of cigarettes per day. A combination of lack of exercise and poor diet accounts for about 14 percent of all deaths every year (second only to smoking), including deaths from coronary artery disease, colon cancer and type 2 diabetes according to a 1990 study by the National Center for Health Statistics. Studies have shown that the benefits of an exercise regime begin to accrue rapidly, even when people begin with just one exercise session a week. To fully experience the healthy benefits of exercise, many physicians recommend that people get between 30 and 60 minutes of exercise, four to six times a week.

Nearly all the benefits of exercise fall into one of the following six categories:

• Cardiovascular fitness. Helps the heart, lungs and blood to use oxygen. Higher levels of fitness improve stamina and endurance. This will also promote a lower heart rate over time.
  
  
• Muscular strength. The ability to use a muscle to exert force during activity. People who improve their muscle strength will more easily be able to lift greater amounts of weight with less chance of injury.
  
  
• Muscular endurance. The ability of the muscle to exert force over longer periods of time. People who improve their muscular endurance will be able to lift a heavy object for longer periods of time.
  
  
• Flexibility. Ability to easily move a joint through its full range of motion. People who improve their flexibility can bend and stretch more easily.
  
  
• Body composition. Ratio of lean muscle to fat tissue. People who are fit will have a healthy ratio of lean muscle to fat tissue.
  
  
• Mental health. The ability to cope with life’s trials and stresses. Regular exercise improves self-esteem, reduces stress and depression, and increases alertness. It provides opportunities for social interaction and teaches numerous life lessons, such as perseverance, and setting and achieving goals. Some studies have suggested that exercise may also imporve cognitive function in some patients.

Exercise can also help with sexual dysfunction. Controlling blood pressure, glucose and weight with exercise reduces the odds of sexual problems. Kegel exercises, clenching exercises that strengthen the pelvic floor muscles, can improve sexual response and help prevent urinary incontinence in women and men.

Research has shown that it is never too early or too late to start enjoying the benefits of exercise. When children are fit at an early age, they are likely to remain active and physically fit throughout their lives. People who are physically active during their young adulthood (aged 18 to 30) appear to enjoy lower heart disease risk factors during middle age, including obesity and diabetes. Exercise also helps people maintain their flexibility, strength and endurance as they get older

In older adults, the importance of exercise is often overlooked, especially for those in the older age range who may feel they are too old to exercise safely. However, research has shown that people can benefit from regular exercise past the age of 90. Not only can exercise prevent or ease the symptoms of many of the diseases and conditions which accompany old age, it can also improve quality of life by allowing older adults to stay stronger and more independent for longer.

Any physical activity that raises the heart rate and increases breathing, such as walking or household chores, helps to improve the strength and health of the lungs, the heart and the circulatory system. Also, stretching regularly can help combat the effects of aging and inactivity, both of which cause the muscles, tendons and ligaments to shorten, reducing flexibility. Furthermore, stretching exercises can alleviate symptoms of stress, carpal tunnel syndrome and arthritis. Strength training – exercising with small weights or resistance bands – is believed to help reverse the muscle loss that comes with old age. For older adults, regular exercise makes it easier to perform everyday tasks and meet life’s physical challenges.

For women, exercise can have added benefit. Exercise can improve some common causes of menstrual discomfort such as cramps, bloating and headaches. Also, for menopausal women, exercising just once a week could significantly reduce the risk of early death. This is because exercise can lower high cholesterol, which is one of the effects of the decrease in estrogen following menopause. Exercise is also important in the prevention of osteoporosis.

Exercise has also been shown to improve quality and duration of sleep. Exercise tires the body out, making it easier to fall asleep and achieve deeper sleep stages for longer durations of time. However, it is important not to exercise too close to bedtime because exercise releases energy and raises the body temperature, both of which can make it difficult for some people to fall asleep.

Additionally, it is thought that exercise aids digestion by helping digested foods move through the intestine. This can reduce the risk of constipation. Also, because exercise decreases stress, it could be beneficial for those suffering from irritable bowl syndrome (IBS) and other disorders that are triggered by stress.