Today exercise is promoted heavily for health benefits in particular reducing the risk of cardiovascular disease and weight control. As numerous individuals reported improvement in general well being, several research projects started in the 1980s to assess the potential benefits of physical activity on the stress, anxiety and depression.

There are two types of exercise. Aerobic and anaerobic. Aerobic exercise uses the basic principle of breaking down glucose in the muscles in the presence of oxygen to release energy and produces carbon dioxide and water. Aerobic exercise includes walking, swimming, jogging, cycling etc. Anaerobic exercise uses energy produced without oxygen and an example of anaerobic exercise is weight lifting.

Several studies have been done to assess whether exercise reduces stress. The overall opinion is that exercise reduces stress. Here are some.

Roth and Holmes-1985: highly fit but highly stressed college students had less depression than highly stress, low fitness students.

Roth and Holmes 1987: College students, highly stressed, who were in an exercise program had greater decrease of depression than others who had no exercise or had only relaxation therapy.

Overton, Joyner and Lipton 1988: Exercise reduces resting blood pressure.

Not only does exercise improve the physical response to stress, it improves mood states such as anxiety and depression. Moses et al 1989 found improvement in tension and anxiety and confusion after 12 weeks of exercise and at a further 3 month follow up, there was improvement of coping ability.

Depression and other mood disorders develop as a result of depletion of certain neurotransmitters such as serotonin and noradrenaline and antidepressant medications that enhance the level of these chemical improve depression. Exercise also increase the blood level of these chemical and explains to some extent the mood enhancing effect of exercise.

Another hypothesis is that exercise increases the level of endorphins, a chemical that improves anxiety level. There is, however, little support for this.

What types of exercise? Exercise that involve repetitive, rhythmic movements of large muscle groups such as arms and legs are recommended. The criteria for aerobic exercise is met when the heart rate is increased to a certain level. There are two training Protocols. These are the Bruce Protocol that varies treadmill speed and grade and the Balke Protocol where the speed is constant but the grade varies.

There is growing evidence that exercise reduces stress. It may also reduce anxiety and decrease depression.

Aerobic exercise requires a significant time commitment, so make a plan. It should be convenient. You should know what specific exercise you will be doing. If you find it boring, then involve others or use distractions.

Remember that there are certain risks from exercise. First check with your doctor before you start and make sure the doctor is aware of the level of exercise you are planning to do. There are potential side effects of exercise. I am not a kiljoy but you should be aware of them. Orthopaedic injury is common. Cardiac event can occur. Existing medical conditions such as Asthma or Diabetes can become worse.

Even if you are not convinced that exercise reduces stress, lets be honest. Generally it is good for you.

Dr. Phil Hariram.