Men who exercise hard are less likely to die from cancer, according to a Finnish study.

"Physical activity has been associated with a reduced risk of cancer in some population studies," Dr. Sudhir Kurl, of the University of Kuopio, and colleagues note in the British Journal of Sports Medicine. But the amount and intensity of physical activity needed to reduce premature death is based on only a few studies.

To investigate further, the researchers assessed 2560 men from eastern Finland with no history of cancer at the beginning of the study. During an average follow up of 16.7 years, total of 181 men died of cancer.

The researchers measured physical activity in metabolic units (METs or metabolic equivalents of oxygen consumption). METs are a measure of energy expenditure.

The men were 53 years old, on average, at follow-up. Their average intensity of leisure-time physical activity was 4.5 METs and average duration of physical activity was 462 minutes per week. However, 27 percent of the men exercised for less than 30 minutes per day.

The researchers found that an increase of 1.2 METs in the average intensity of leisure-time physical activity was associated with a 15 percent decrease in the relative risk of cancer-related death, after adjusting for a variety of factors including age, smoking, alcohol use, body weight and fat intake. This was mainly due to decreased risks of lung and gastrointestinal cancers.

Compared with men with physical activity of less than 3.7 METs, those with physical activity of more than 5.2 METs had a 36 percent lower relative risk of cancer-related death.

"The mean intensity of physical activity was related to cancer deaths only among those who exercise more than 30 minutes per day on average," Kurl and colleagues note in their report.