Toronto, May 4 (IANS): Performing vigorous physical activity over one's lifetime may lower the risk of non-Hodgkin lymphoma (NHL), says a new study.

"Our findings suggest that people who do vigorous physical activity may also have a lower risk for NHL," said study author Terry Boyle, a post-doctoral fellow at the University of British Columbia's department of cancer control research.

"We found that vigorous-intensity physical activity, such as activities that increase breathing and heart rates to a high level, was the most effective at lowering risk," he added.

There is evidence that people who are physically active have a lower risk of some cancers such as colon and breast cancers.

Boyle and colleagues used data from a case-control study, conducted between 2000 and 2004, which recruited 820 NHL patients (59 percent men) of various ages from the British Columbia Cancer Registry and 848 randomly selected controls matched for age, gender and residential location from the Client Registry of the British Columbia Ministry of Health.

Participants were asked to record the average number of days per week and average number of hours per day they performed mild, moderate, or vigorous physical activity for each decade of life.

The researchers assigned a metabolic-equivalent (MET) value to the different types of physical activity, and calculated the average number of MET-hours per week of physical activity for each participant's lifetime.

Study participants who were in the higher (second, third, and fourth) quartiles of vigorously-intense physical activity performance in their lifetimes had about 25 percent to 30 percent lower risk for NHL, compared with those who were in the lowest (first) quartile of vigorously-intense physical activity.

"In this case-control study, we found that the most physically active participants had a lower risk for NHL than the least active participants," Boyle said.

The study appeared in the journal Cancer Epidemiology, Biomarkers & Prevention.