Cycling is a good all-round exercise improving both endurance and aerobic capacity. Cycling tones various muscle groups like the calves and thighs, and strengthens the back. An hour of cycling can burn anything between 250 and 700 calories (1046 and 2930 kilojoules) depending on the intensity. It is also an excellent stress reducer.

For those who may be overweight and/or have joint problems which make it difficult for them to do weight-bearing exercise, cycling is a good fitness option.

Possible medical benefits of cycling
Regular cycling at a healthy level has a beneficial effect on many of the body's organs and systems.

The heart and circulatory system
The heart beats faster to pump blood around the body more quickly to supply enough oxygen to the muscles to allow them to do work. At rest the heart normally pumps about 4 litres of blood per minute, but during moderate aerobic activities such as cycling, approximately 20 litres of blood per minute circulate throughout the body. The heart itself is a muscle and when exercised as in cycling it gets bigger and stronger just as your biceps do.

People who take part in regular physical activity have a lowered risk of cardiovascular disease compared with those who don't.

Blood pressure
Regular aerobic activity such as cycling can prevent or delay the development of high blood pressure and in people who already have high blood pressure it can reduce blood pressure.

Cholesterol
Regular aerobic exercise improves levels of 'good' cholesterol (HDL cholesterol) in your blood.

Brain
People who take part in regular exercise tend to have lower body fat and better lipid profiles than others and hence have less arterial disease which is a risk factor for stroke.

Muscles and joints
Exercise improves muscle strength, coordination and balance, which lessens the likelihood of falls in the elderly and improves joint mobility and lubrication. Muscle endurance and tone will result, and prominence of the working muscle groups like the calves and thighs can be noticed. Posture and balance also improves. Gentle cycling may help arthritis sufferers, lessening joint pain and swelling and increasing flexibility.

Skin
One of the skin's major functions is as an excretory organ of the body and during cycling, blood flow to the skin increases to rid the body of heat. This improves the elimination of wastes through sweating.

Lungs
An increase in blood carbon dioxide levels causes breathing to become faster and deeper. This action supplies the oxygen needed by the body. There is also evidence that moderate intensity activities such as biking may reduce the risk of lung cancer. Regular aerobic exercise like cycling also increases your lung capacity.

Gallbladder
Researchers have also reported that biking and other routine physical activities of 30 minutes a day may help women avoid gallstone surgery. People who exercise have more active intestines which, along with the improvement in cholesterol profile which occurs in regular exercisers, may help reduce the risk of gallstones.