Exercise found to lower risk of 13 types of cancer by up to 42 percent
A study of 1.4 million people has found that those who engaged in more physical activity dramatically slashed their risk of 13 types of cancer.
People involved in regular physical activity were 42 percent less likely to develop oesophageal cancer, and were 27 percent, 26 percent and 23 percent less likely to develop tumours in their liver, lungs and kidneys respectively.
The study found that exercise also lowers the risk of uterine cancer by 21 percent, myeloid leukaemia by 20 percent, and myeloma (cancer of the white blood cells) by 17 percent.
Physical activity was also found to protect against colon cancer, with a 16 percent lower risk, head and neck cancer (15 percent lower risk), rectal and bladder cancer (both 13 percent lower) and breast cancer with a 10 percent lower risk.
The study, which was published by JAMA Internal Medicine, said that overall a higher level of physical activity reduced the risk of developing any type of cancer by seven percent.
Physical inactivity is nevertheless common, with 31 percent of people worldwide not meeting recommended levels of exercise, the researchers said.
Dr Steven Moore, of the National Cancer Institute in Maryland, said if working-out decreases the risk of cancer this should be relevant to public health officials and anyone involved in prevention of the disease.
For the study, researchers pooled data from 12 American and European studies conducted from 1987 to 2004 and compared levels of physical activity with the incidence of 26 kinds of cancer.
During an average of 11 years of follow-up 186,932 cancers were identified among the 1.4 million people in the study.
The findings supported promoting physical activity as a key component of population-wide cancer prevention and control efforts, Dr Moore said.
A previous study by the University College London showed that only two-and-a-half hours of moderate activity a week can suppress inflammation in the body which is believed to contribute to disease.
The study of more than 4,000 civil servants found that active middle-aged people were found to have lower “inflammatory markers” in their blood at the end of the ten-year study.
Inflammation levels remained lower in those who were active when approaching retirement or who had already stopped working compared with those who did relatively little.
Dr Marilie Gammon, of North Carolina University, who reviewed the study for JAMA, said: “These exciting findings underscore the importance of leisure-time physical activity as a potential risk reduction strategy to decrease the cancer burden in the United States and abroad.
“They demonstrate high vs. low levels of physical activity engagement are associated with reduced risk of 13 cancer types, including three of the top four leading cancers among men and women worldwide.”