Physical activity is any activity that involves major muscle groups, including routine daily activities such as shopping or climbing stairs. Exercise includes any activity done with a goal of improving or maintaining physical fitness.

Physical fitness can be described as the ability to carry out daily tasks without getting very tired, having enough energy to pursue leisure and recreational activities, and reacting to physical challenges when they arise.

There are three main types of exercise:

  1. Aerobic exercise
  2. Resistance training
  3. Stretching exercise
Aerobic exercise

Aerobic exercise involves walking, running, or swimming, which increases the flow of blood through the heart. Aerobic means “with oxygen” and refers to working at a level where the large muscles get adequate oxygen from the blood to sustain prolonged activity. Even small movements that happen throughout a person’s normal activities can burn 100 to 800 calories/day.

Resistance training

Resistance training is exercise designed to increase muscle strength and includes lifting weights. This kind of exercise is sometimes called anaerobic, meaning “without oxygen.”

In contrast to aerobic exercise, the muscles do not get enough oxygen to sustain anaerobic exercise for prolonged periods of time. As an example, anaerobic exercise might involve lifting a heavy weight a number of times, after which the involved muscles are deprived of oxygen and are too fatigued to continue that level of exertion.

Stretching exercise 

Stretching exercises are movements designed to improve flexibility and prevent injury. Improving flexibility allows joints to move over a wider range of motion. Good range of motion in all joints helps to maintain musculoskeletal function, balance, and agility.


Apart from improving overall physical fitness, exercise has numerous health benefits:

  1. The risk of dying is decreased in those who exercise regularly. As an example, one study found that men who engaged in moderately vigorous sports had a 23 percent lower risk of death than men who were less active. Exercise also helps to lower the risk of death in men with coronary artery disease.
  2. Exercise is an essential component of weight management programs. Exercise burns calories and may help to burn calories even while not exercising. Dieting can lead to loss of muscle, but exercise can help maintain muscle mass while dieting.
  3. Exercise improves blood sugar control in people with diabetes and can help prevent or delay the onset of type 2 diabetes.
  4. Aerobic exercise helps decrease blood pressure; this effect may be even greater in people with high blood pressure.
  5. Exercise often improves the blood fats (lipid profile) by decreasing triglyceride levels and raising high-density lipoprotein (good cholesterol) levels.
  6. Most people report a reduction in stress after they exercise. Research has shown that exercise is associated with reduced tension, anxiety, and depression.
  7. Weightbearing exercise (exercise which uses the body’s weight to work against gravity, including walking or running) helps to prevent osteoporosis and reduces the incidence of fractures.
  8. Exercise training can improve circulation and exercise tolerance for people who have angina (chest pain from a reduced blood supply to the heart). After exercise training, a person may be able to exercise longer or at a greater intensity.
  9. Some evidence suggests that exercise can provide protection against breast and prostate cancer, delay or prevent dementia, and decrease the risk of gallstone disease.
  10. Exercise can help with quitting smoking

Most people do not need any special testing before starting to exercise, but it is best to check with your health care provider before starting a new routine or type of exercise. People with diabetes or multiple risk factors for heart disease may need an exercise test before starting an exercise program.

If you do not normally get much exercise, start by exercising for a few minutes at a low intensity (for example, walking). As physical fitness improves, you can slowly begin to exercise harder, more frequently, or for a longer time, with a goal of getting at least 30 minutes of exercise on five days each week.

Exercise does not need to be continuous to produce health benefits; it can be broken up into three or four 10-minute sessions per day. Moderate-intensity exercise should be performed on most days of the week. However, exercising only one or two days per week is better than not exercising at all.The greatest health benefits are seen in those who change from a sedentary lifestyle to being moderately active. Moderate exercise can be integrated into your daily routine with activities such as brisk walking (at three to four miles per hour), yard work, or dancing. A simple way to start exercising is to walk. Start by walking a comfortable distance; establish a personal baseline by walking at a speed and for a length of time that is easily tolerated. Doing too much too fast may result in discomfort, disappointment, or disability from muscle pulls and strains. Try to increase your baseline distance by 10 percent each week. Measure out the distance in a neighborhood, walking trail, or shopping mall.

After reaching 45 to 60 minutes per day, you can increase the intensity of exercise by walking a greater distance in the same time. The goal is to develop a habit of regular physical activity at a level that is comfortable.


An exercise program should include aerobic exercise, resistance training, and stretching.

Warm up

Exercise sessions should begin with a 5- to 10-minute period of warm-up. Start with some low-level aerobic exercises (walking, stationary cycling, calisthenics) and then do stretches and flexibility movements. The warm-up period allows for a gradual increase in the heart rate and may reduce the risk of injuries.


It is a good idea to mix up aerobic exercise, strength training, and stretching so as to keep the workout fun and interesting.

Aerobic exercise

Walking is an excellent aerobic activity. Cycling, rowing, stair machine climbing, and other endurance-type activities are also great. Swimming and water aerobics are excellent for people with arthritis. Low-impact activities are recommended because they are less likely to result in physical injury. Running on a street is a higher-impact activity because of the stresses on the feet and legs as they strike the ground with each step.

The exercises should be enjoyable and simple to carry out to encourage a long-term commitment. It may be best to vary the exercises you do each week (such as swim on three of the days and walk on three of the days) to decrease repetitive strain to your muscles and other tissues.

There is no age specific heart rate recommendation; a specific heart rate is not necessary to achieve health benefits. If you are breathless, fatigued, and sweating, you have worked hard enough. During moderate-intensity exercise, you should be able to carry on a conversation.

The 2018 Physical Activity Guidelines recommend 150 to 300 minutes a week of moderate-intensity, or 75 to 150 minutes a week of vigorous-intensity (or an equivalent combination) aerobic activity. This recommendation is in addition to routine, light-intensity activities of daily living (eg, cooking, casual walking, shopping, etc).

Resistance training

Resistance training can be done with weights, machines, or exercise bands. However, you can do resistance exercises even if you do not have access to a gym or special equipment; for example, you can strengthen your muscles by lifting household objects or doing exercises like pushups in your home. It should be performed at least twice a week with at least 48 hours of rest between sessions. Resistance training is commonly described in terms of “sets” of “repetitions.”

  1. A repetition is a single completed back and forth motion of a resistance exercise, such as bending and extending the arm at the elbow while holding a weight (or other heavy object) in the hand.
  2. A set is a number of repetitions done without resting.

Most experts recommend at least one set of exercises, including 8 to 12 repetitions, for each of the major muscle groups.

Begin with minimal resistance (light weights, resistive bands, or something like a can of food or bottle of water) to allow the muscles and other tissues to adapt. Examples of exercises for the upper body are shown in a figure.

It is important to use proper technique. If you belong to a health club or gym you might ask a trainer to observe technique. Be sure to breathe normally while lifting weights. Do not hold the breath; instead, exhale with exertion. Do not perform resistance training if you are in pain or have swelling anywhere.


Stretching and flexibility exercises should include every major joint (hip, back, shoulder, knee, upper trunk, neck). It is best not to stretch “cold” muscles, so engage in a few minutes of low-intensity aerobic exercise first. Movement into a stretch should be slow, and the stretch itself should be held for approximately 10 to 30 seconds. Do not bounce while beginning or performing a stretch.

Stretching exercises are shown in a figure. Each exercise should be performed several times. Stretch and yoga classes are also a good way to remain flexible. The stretch should not cause pain but only mild discomfort. 

Cool Down

Cool-down exercises should be done for approximately five minutes at the end of an exercise session. Similar to the warm-up period, cool-down may include low-level aerobic exercise (such as slow walking), calisthenics, and stretching. This allows the body to clear acid that has built up in the muscles and allows more blood back into the circulation because less is sent to the muscles. This helps to prevent muscle cramps and sudden drops in blood pressure that can cause lightheadedness.

  1. Remember to drink fluids during and after exercise. Thirst is a good indicator that more fluids are needed.
  2. Do not exercise outdoors if the temperature is too hot or too cold.
  3. In cooler weather, it is better to wear layers of clothes while exercising outdoors. A layer of clothing can be removed if needed.
  4. Wear supportive, well-fitting running or walking shoes. Replace shoes when signs of deterioration develop (eg, cracking, separation of shoe from the sole, imprint of the foot in the insole). The amount of time exercise shoes will last depends upon a number of factors, including how often and where the shoes are worn.