Overall , the current literature supports clearly the dose-response relationship between physical activity and the seven chronic conditions identified .
Moreover , higher levels of physical activity reduce the risk for premature all-cause mortality .
The current Canadian guidelines appear to be appropriate to reduce the risk for the seven chronic conditions identified above and all-cause mortality
This systematic review examines critically the scientific basis for Canada 's Physical Activity Guide for Healthy Active Living for adults .
Particular reference is given to the dose-response relationship between physical activity and premature all-cause mortality and seven chronic diseases ( cardiovascular disease , stroke , hypertension , colon cancer , breast cancer , type 2 diabetes ( diabetes mellitus ) and osteoporosis ) .
The strength of the relationship between physical activity and specific health outcomes is evaluated critically .
Physical activity and breast cancer risk: the Women's Health Study (United States)
Abstract Objective : It is biologically plausible for physical activity to decrease breast cancer risk ; however , epidemiologic studies have yielded inconsistent findings . We therefore examined physical activity and breast cancer risk in the Women 's Health Study . Methods : We assessed physical activity among 39,322 apparently healthy women , aged ≥45 years , and prospect ively followed them for an average of 48 months . Four hundred eleven women developed breast cancer , with 222 positive for both estrogen and progesterone receptors . Results : Among all women the multivariate relative risks of all breast cancer associated with < 840 , 840–2519 , 2520–6299 , and ≥6300 kJ/week expended on recreational activities and stair climbing  were 1.00 ( referent ) , 1.04 ( 95 % confidence interval , 0.77–1.40 ) , 0.86 ( 0.64–1.17 ) , and 0.80 ( 0.58–1.12 ) , respectively ; p-trend = 0.11 . However , among postmenopausal women there was a significant inverse trend for all breast cancer ; the corresponding relative risks were 1.0 ( referent ) , 0.97 ( 0.68–1.4 ) , 0.78 ( 0.54–1.1 ) , and 0.67 ( 0.44–1.0 ) , respectively ; p-trend = 0.03 . Physical activity was unrelated to breast cancers positive for both estrogen and progesterone receptors either among all or postmenopausal women ( p-trend = 0.50 and 0.26 , respectively ) . When we assessed only vigorous recreational activity , requiring ≥6 METs or multiples of resting metabolic rate , we observed no significant associations with all or steroid hormone receptor positive breast cancer , either among all or postmenospausal women . Conclusions : These data suggest that physical activity during middle age and older is not uniformly associated with decreased breast cancer risk . Among postmenopausal women only , higher levels of physical activity may decrease the risk of breast cancer . This study , however , had limited statistical power to detect small effects
Overall , the current literature supports clearly the dose-response relationship between physical activity and the seven chronic conditions identified .
Moreover , higher levels of physical activity reduce the risk for premature all-cause mortality .
The current Canadian guidelines appear to be appropriate to reduce the risk for the seven chronic conditions identified above and all-cause mortality
This systematic review examines critically the scientific basis for Canada 's Physical Activity Guide for Healthy Active Living for adults .
Particular reference is given to the dose-response relationship between physical activity and premature all-cause mortality and seven chronic diseases ( cardiovascular disease , stroke , hypertension , colon cancer , breast cancer , type 2 diabetes ( diabetes mellitus ) and osteoporosis ) .
The strength of the relationship between physical activity and specific health outcomes is evaluated critically .