What is the relationship between physical activity and the risk of lung cancer?

The studies generally suggest that with increased physical activity the risk of lung cancer, which can reach up to 20 percent is reduced. An analysis of many existing studies found evidence that higher levels of physical activity protect against lung cancer, but was unable to fully control the effects of smoking or respiratory disease in estimating the magnitude of the potential benefit. The relationship between physical activity and the risk of lung cancer is less clear for women than for men.

Source: National Cancer Institute