Author(s): COURISH, M., WICKENS, A., CONSMUELLER, C., MEKARI, S., O'BRIEN, M.W., KIMMERLY, D.S., Institution: DALHOUSIE UNIVERSITY, Country: CANADA, Abstract-ID: 1080

INTRODUCTION:
Aging is associated with reduced brachial artery endothelial-dependent vasodilation, which is linked with an elevated cardiovascular disease risk. This risk may be worsened by engaging in more sedentary time (ST) or attenuated with higher levels of aerobic-based physical activity. The aim of this study was to explore differences in brachial flow-mediated dilation (FMD), light-intensity physical activity (LPA), moderate-to-vigorous intensity physical activity (MVPA), and ST between healthy younger and older adults.
METHODS:
Brachial FMD was assessed via duplex ultrasonography in 12 younger (27 +/- 8 years) and 9 older (64 +/- 8 years) adults. Habitual ST and intensity-based physical activity were assessed via a thigh-positioned inclinometer and accelerometer (activPAL) worn continuously for 6.0 +/- 0.8 days. Aerobic fitness was quantified as V̇O2 peak via indirect calorimetry during a graded cycle ergometer test.
RESULTS:
Unexpectedly, brachial FMD was not different (p=0.32) between younger (5.9 +/-1.8%) and older adults (5.0 +/- 2.3%). As a group, older adults achieved international MVPA guidelines (150 minutes/week) but accumulated less habitual MVPA than younger adults (202 +/- 103 versus 269 +/- 81 minutes per week, p=0.05). However, they also engaged in less ST (10.2 +/- 2.7 versus 12.2 +/- 1.8 hours per day, p=0.04) and accrued more LPA (575 +/- 91 versus 402 +/- 89 minutes per week, p=0.02) compared to younger adults. There were no differences in V̇O2 peak between younger and older adults (38.3 +/- 10.5 versus 32.3 +/-7.3 ml/kg/min, p=0.14).
CONCLUSION:
Despite engaging in less total MVPA, older adults who achieved MVPA guidelines, engaged in more LPA, less ST and maintained aerobic fitness levels exhibited preserved brachial FMD responses compared with their younger peers.