AN NIH FUNDED STUDY pooled data from 12 different studies performed in the US and Europe that tracked leisure time moderate to vigorous physical activity, as reported by the subjects themselves, over 17 years (1987 to 2004). There were 1.44 million total participants, ranging in age from 19-98 years old, with median age of 59 years, of which 57% were female, included in the study. There were 186,932 cancers. Published results* showed the “high versus low levels of leisure-time physical activity were associated with lower risks” of 13 cancers. The abstract is available to the public but the full study has only been published online; as of this writing I could not get access to that piece.
Melissa Healy, contact reporter, discussed the research results it in an article for the LA Times, “Exercising Drives Down Cancer Risks For 13 Cancers”. She wrote, “researchers calculated that compared with people who reported spending the least time in ‘leisure-time physical activity,’ those who got the most moderate to intense exercise reduced their risk of developing seven kinds of cancer by at least 20%”.
According to Healy's piece, the greatest benefit was seen for a certain type of esophageal cancer, adenocarcinoma (decreased risk by 42%). Cancers of the liver (risk was down 27%), lung (26%) and kidney (23%) also took a significant risk hit in those who exercised; as well as malignancy of the upper stomach (22% decreased risk) and endometrium of the uterus (21%). Reduced risk of a type of white blood cell cancer (myeloid leukemia) was also diminished, by 20%. Six cancers that showed a decreased risk of less than 20%, related to more rather than less exercise activity, were multiple myeloma (a white blood cell tumor) and malignancies that developed in the colon, head and neck region, rectum, bladder, and breast.
Leisure-time physical activity was associated with higher risks of malignant melanoma (likely exercisers spent more time outdoors and experienced more sun exposure) and prostate cancer (men who exercise more are thought to be a more health conscious group, more likely to be screened for this cancer).
The study result is important in that it provides additional evidence that exercise has a protective effect against 3 cancers in which the association with decreased risk was already suspected (breast colon, and endometrium) as well as 10 others!
The devil is in the details it’s said, and it's true of this revelation. Exactly how exercise is protective, its type,” dose”, and duration remains to be determined for each malignancy. The point in life at which moderate to vigorous exercise must start in order to be protective is another big question. It’s probably safe to say that the earlier we initiate a healthy habit the more likely we will be to continue it over the years, with adjustments for life’s stages, or at least resume it, if lapsed, when possible.
Since there are other proposed benefits to higher levels of exercise in our “leisure” time, which include help with sleep, weight control, and a sense of well being, it could be said that the best time to start is ANYTIME! So why not start NOW to get organized and begin to incorporate a significant amount of moderate level and vigorous (running) level physical activity in your life and the lives of those you love?
Your plans needn’t be perfect. EarnedRuns has 3 suggested summertime running or walking challenges that may appeal to you, fit your schedule, and help you and friends or family ease into a “healthy–level” physical activity that can become a habit into the autumn and beyond. SEE the May 15, May 21, May 22 BLOG posts for previews of these activities and more posts to come for details.
*“Association Of Leisure-Time Physical Activity With Risk Of 26 Types Of Cancer in 1.44 Million Adults” by Steven C Moore and colleagues. http://archinte.jamanetwork.com/article.aspx?articleid=2521826
BRIDGE TO PHYSICAL SELF
Running, walking, and fitness activities enable us to experience our physical selves in a world mostly accessed through use of fingers on a mobile device.
EARNED RUNS is edited and authored by me, runner and founder. I began participating in road races before 5Ks were common. I've been a dietitian, practiced and taught clinical pathology, and been involved with research that utilized pathology. I am fascinated with understanding the origins of disease as well as health.
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