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 .
Long-term recreational physical activity and risk of invasive and in situ breast cancer: the California teachers study.
BACKGROUND Long-term physical activity may affect breast cancer risk . Few prospect i ve studies have evaluated in situ or invasive breast cancer risk , or breast cancer receptor subtypes , in relation to long-term activity . METHODS We examined the association between recreational physical activity and risk of invasive and in situ breast cancer in the California Teachers Study , a cohort of women established in 1995 - 1996 . Of 110 599 women aged 20 to 79 years with no history of breast cancer followed up through December 31 , 2002 , 2649 were diagnosed as having incident invasive breast cancer and 593 were diagnosed as having in situ breast cancer . Information was collected at cohort entry on participation in strenuous and moderate recreational activities during successive periods from high school through the current age or age 54 years ( if older at enrollment ) and in the past 3 years . A summary measure of  long-term activity up to the current age , or age 54 years if older , was constructed for each woman . RESULTS Invasive breast cancer risk was inversely associated with long-term strenuous activity  ( > 5 vs < /=0.5 h/wk per year : relative risk , 0.80 ; 95 % confidence interval , 0.69 - 0.94 ; P trend = .02 ) , as was in situ breast cancer risk ( > 5 vs < /=0.5 h/wk per year : relative risk , 0.69 ; 95 % confidence interval , 0.48 - 0.98 ; P trend = .04 ) . Strenuous and moderate long-term activities were associated with reduced risk of ER-negative ( strenuous : P trend = .003 ; moderate : P trend = .003 ) but not ER-positive ( strenuous : P trend = .23 ; moderate : P trend = .53 ) invasive breast cancer . CONCLUSION These results support a protective role of strenuous long-term exercise activity against invasive and in situ breast cancer and suggest differing effects by hormone receptor status
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 .