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 risk of myocardial infarction after the fourth decade of life.
BACKGROUND Scientific evidence shows that physically active people are protected from developing acute myocardial infa rct ion ( MI ) . However , the effect of the intensity , duration and type of activity remains unclear . OBJECTIVE To evaluate the relation between physical activity and MI , according to different intensity levels and types , we conducted a community-based case-control study , based on the Risk of Coronary Heart Disease ( EPIcardis ) study . METHODS We evaluated 381 consecutive cases of first MI ( 297 males ; 84 females ) and 726 community controls ( 310 males ; 416 females ) , older than 39 years , selected by r and om digit dialing ( 70 % participation rate among the controls ) . Data were collected using a structured question naire . For evaluation of physical activity , the question naire assessed all professional and leisure-time activities , specifying the type of exercise and the time spent in each activity . Activities were grouped according to intensity using energy expenditure at rest as the baseline ( 1.0 MET ) : very light ( 1.5 MET ) , light ( 2.5 MET ) , moderate ( 5.0 MET ) and strenuous ( 7.0 MET ) . Odds ratios ( OR ) and 95 % confidence intervals ( 95 % CI ) were calculated using unconditional logistic regression and separate models for each sex . RESULTS Among men , after adjusting for age , education , family history of MI , energy intake and smoking , the OR ( 95 % CI ) were 0.51 ( 0.29 - 0.91 ) , 0.36 ( 0.19 - 0.68 ) , 0.53 ( 0.30 - 0.93 ) , and 0.68 ( 0.39 - 1.20 ) , for increasing quintiles of activity ( p for trend = 0.199 ) . Among women , after adjusting for the same variables plus parity and menopausal status , the OR ( 95 % CI ) were 0.51 ( 0.25 - 1.03 ) , 0.37 ( 0.17 - 0.83 ) , and 0.34 ( 0.14 - 0.83 ) , for increasing quartiles of activity ( p for trend = 0.006 ) . We found a protective effect of leisure-time physical activity  in men ( p for trend < 0.001 ) and in women ( p for trend = 0.038 ) . In men , the U-shaped effect described for total physical activity was also found for occupational activities . CONCLUSIONS The present study supports an independent protective effect of leisure-time physical activity , but not of occupational activities , for risk of myocardial infa rct ion
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 .