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 .
Walking and leisure-time activity and risk of hip fracture in postmenopausal women.
CONTEXT Physical activity can reduce the risk of  hip fractures in older women , although the required type and duration of activity have not been determined . Walking is the most common activity among older adults , and evidence suggests that it can increase femoral bone density and reduce fracture risk . OBJECTIVE To assess the relationship of walking , leisure-time activity , and risk of hip fracture among postmenopausal women . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve analysis begun in 1986 with 12 years of follow-up in the Nurses ' Health Study cohort of registered nurses within 11 US states . A total of 61,200 postmenopausal women ( aged 40 - 77 years and 98 % white ) without diagnosis of cancer , heart disease , stroke , or osteoporosis at baseline . MAIN OUTCOME MEASURES Incident hip fracture result ing from low or moderate trauma , analyzed by intensity and duration of leisure-time activity  and by  time spent walking , sitting , and st and ing  , measured at baseline and up date d throughout follow-up . RESULTS From 1986 to 1998 , 415 incident hip fracture cases were identified . After controlling for age , body mass index , use of postmenopausal hormones , smoking , and dietary intakes in proportional hazards models , risk of hip fracture was lowered by 6 % ( 95 % confidence interval [ CI ] , 4%-9 % ; P<.001 ) for each increase of 3 metabolic equivalent (MET)-hours per week of activity ( equivalent to 1 h/wk of walking at an average pace ) . Active women with at least 24 MET-h/wk had a 55 % lower risk of hip fracture ( relative risk [ RR ] , 0.45 ; 95 % CI , 0.32 - 0.63 ) compared with sedentary women with less than 3 MET-h/wk . Even women with a lower risk of hip fracture due to higher body weight experienced a further reduction in risk with higher levels of activity . Risk of hip fracture decreased linearly with increasing level of activity among women not taking postmenopausal hormones ( P<.001 ) , but not among women taking hormones ( P = .24 ) . Among women who did no other exercise , walking for at least 4 h/wk was associated with a 41 % lower risk of hip fracture ( RR , 0.59 ; 95 % CI , 0.37 - 0.94 ) compared with less than 1 h/wk . More time spent st and ing was also independently associated with lower risks . CONCLUSION Moderate levels of activity , including walking , are associated with substantially lower risk of hip fracture in postmenopausal women
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 .