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 .
Leisure-time physical activity and the risk of primary cardiac arrest.
BACKGROUND Because the risks of sudden cardiac death and myocardial infa rct ion are transiently increased during acute bouts of high-intensity activity , it is an important question from the public health perspective whether regular participation in moderate-intensity activity confers overall protection from sudden cardiac death . PARTICIPANTS AND METHODS We used data from a population -based case-control study to assess the associations of regular high-intensity and moderate-intensity leisure-time physical activity with  primary cardiac arrest . Cases were patients with primary cardiac arrest , aged 25 to 74 years , attended by paramedics between 1988 and 1994 in King County , Washington ( n = 333 ) . Controls were r and omly identified from the same community ( n = 503 ) , matched for age and sex . All case patients and controls were free of prior clinical heart disease , major comorbidity , and self-reported poor health . Spouses of case patients and controls were interviewed to assess participation in 15 high-intensity and 6 moderate-intensity physical activities during the prior year . RESULTS Compared with subjects who performed none of the activities , the odds ratio for primary cardiac arrest from matched analyses was 0.34 ( 95 % confidence interval , 0.13 - 0.89 ) among subjects who performed only gardening activities for more than 60 minutes per week ; 0.27 ( 95 % confidence interval , 0.11 - 0.67 ) among subjects who walked for exercise for more than 60 minutes per week ; and 0.34 ( 95 % confidence interval , 0.16 - 0.75 ) among subjects who engaged in any high-intensity activities , after adjustment for age , smoking , education , diabetes , hypertension , and health status . CONCLUSIONS The results suggest that regular participation in moderate-intensity activities , such as walking and gardening , are associated with a reduced risk of PCA and support current exercise recommendations
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 .