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 .
Relationship of changes in physical activity and mortality among older women.
CONTEXT Physical activity has been related to reduced mortality , but it is not clear whether changes in physical activity affect mortality among older women . OBJECTIVE To examine the relationship of changes in physical activity and mortality  among older women . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study conducted at 4 US research centers ( Baltimore , Md ; Portl and , Ore ; Minneapolis , Minn ; and Monongahela Valley , Pa ) among 9518 community-dwelling white women aged 65 years or older who were assessed at baseline ( 1986 - 1988 ) , 7553 of whom were reassessed at a follow-up visit ( 1992 - 1994 ; median , 5.7 years later ) . MAIN OUTCOME MEASURES  Walking and other physical activities at baseline and follow-up ; vital status , with cause of death confirmed by death certificates/discharge summaries , tracked for up to 12.5 years after baseline ( up to 6.7 years after the follow-up visit ) . RESULTS Compared with continually sedentary women , those who increased physical activity levels between baseline and follow-up had lower mortality from all causes ( hazard rate ratio [ HRR ] , 0.52 ; 95 % confidence interval [ CI ] , 0.40 - 0.69 ) , cardiovascular disease ( HRR , 0.64 ; 95 % CI , 0.42 - 0.97 ) , and cancer ( HRR , 0.49 ; 95 % CI , 0.29 - 0.84 ) , independent of age , smoking , body mass index , comorbid conditions , and baseline physical activity level . Associations between changes in physical activity and reduced mortality were similar in women with and without chronic diseases but tended to be weaker among women aged at least 75 years and among those with poor health status . Women who were physically active at both visits also had lower all-cause mortality ( HRR , 0.68 ; 95 % CI , 0.56 - 0.82 ) and cardiovascular mortality ( HRR , 0.62 ; 95 % CI , 0.44 - 0.88 ) than sedentary women . CONCLUSION Increasing and maintaining physical activity levels could lengthen life for older women but appears to provide less benefit for women aged at least 75 years and those with poor health 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 .