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 .
A prospective study of exercise and incidence of diabetes among US male physicians.
OBJECTIVE To examine prospect ively the association between regular exercise and the subsequent development of  non-insulin-dependent diabetes mellitus ( NIDDM ) . DESIGN Prospect i ve cohort study including 5 years of follow-up . PARTICIPANTS 21,271 US male physicians participating in the Physicians ' Health Study , aged 40 to 84 years and free of diagnosed diabetes mellitus , myocardial infa rct ion , cerebrovascular disease , and cancer at baseline . Morbidity follow-up was 99.7 % complete . MAIN OUTCOME MEASURE Incidence of NIDDM . RESULTS At baseline , information was obtained about frequency of vigorous exercise  and other risk indicators . During 105,141 person-years of follow-up , 285 new cases of NIDDM were reported . The age-adjusted incidence of NIDDM ranged from 369 cases per 100,000 person-years in men who engaged in vigorous exercise less than once weekly to 214 cases per 100,000 person-years in those exercising at least five times per week ( P , trend , less than .001 ) . Men who exercised at least once per week had an age-adjusted relative risk ( RR ) of NIDDM of 0.64 ( 95 % Cl , 0.51 to 0.82 ; P = .0003 ) compared with those who exercised less frequently . The age-adjusted RR of NIDDM decreased with increasing frequency of exercise : 0.77 for once weekly , 0.62 for two to four times per week , and 0.58 for five or more times per week ( P , trend , .0002 ) . A significant reduction in risk of NIDDM persisted after adjustment for both age and body-mass index : RR , 0.71 ( 95 % Cl , 0.56 to 0.91 ; P = .006 ) for at least once per week compared with less than once weekly , and P , trend , .009 , for increasing frequency of exercise . Further control for smoking , hypertension , and other coronary risk factors did not material ly alter these associations . The inverse relation of  exercise  to risk of NIDDM was particularly pronounced among overweight men . CONCLUSIONS Exercise appears to reduce the development of NIDDM even after adjusting for body-mass index . Increased physical activity may be a promising approach to the primary prevention of NIDDM
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 .