Association of objectively measured physical activity with cardiovascular risk in mobility-limited older adults

Background:data are sparse regarding the impacts of habitual physical activity (pa) and sedentary behavior on cardiovascular (cv) risk in older adults with mobility limitations. methods and results:this study examined the baseline,cross-sectional association between cv risk and objectively measured pa among participants in the lifestyle interventions and independence for elders (life) study. the relationship between accelerometry measures and predicted 10-year hard coronary heart disease (hchd) risk was modeled by using linear regression,stratified according to cvd history. participants (n=1170,79±5 years) spent 642±111 min/day in sedentary behavior (ie,<100 accelerometry counts/min). they also spent 138±43 min/day engaging in pa registering 100 to 499 accelerometry counts/min and 54±37 min/day engaging in pa ≥500 counts/min. each minute per day spent being sedentary was associated with increased hchd risk among both those with (0.04%,95% ci 0.02% to 0.05%) and those without (0.03%,95% ci 0.02% to 0.03%) cvd. the time spent engaging in activities 100 to 499 as well as ≥500 counts/min was associated with decreased risk among both those with and without cvd (p<0.05). the mean number of counts per minute of daily pa was not significantly associated with hchd risk in any model (p>0.05). however,a significant interaction was observed between sex and count frequency (p=0.036) for those without cvd,as counts per minute was related to hchd risk in women (b=-0.94,-1.48 to -0.41; p<0.001) but not in men (b=-0.14,-0.59 to 0.88; p=0.704). conclusions:daily time spent being sedentary is positively associated with predicted 10-year hchd risk among mobility-limited older adults. duration,but not intensity (ie,mean counts/min),of daily pa is inversely associated with hchd risk score in this population-although the association for intensity may be sex specific among persons without cvd. © 2015 the authors.