BACKGROUND: The aim of the study was to provide an isotemporal substitution model to predict how changes in physical behavior may affect the cardiovascular parameters (CVPs) of older adults. METHODS: Participants wore a thigh-mounted accelerometer for 7 days. Phenotype of the carotid, brachial, and popliteal artery was conducted using ultrasound. Isotemporal substitution was used to simulate the degree to which replacing 1 hour of physical behavior with another would affect CVP. RESULTS: Substitution of sedentary behavior with Standing and sporadic moderate- to vigorous-intensity physical activity (MVPA accumulated in bouts <10 min) would reduce resting heart rate [-6.20 beats per minute (-12.1 to -0.22) and -3.72 beats per minute (-7.01 to -0.44), respectively]. Substitution of sedentary behavior with light-intensity physical activity would reduce carotid artery diameter [-0.54 mm (-1.00 to -0.07)]. Substitution of Standing with sporadic MVPA would increase popliteal artery diameter [1.31 mm (0.11 to 2.51)]. CONCLUSIONS: Our modeling suggests that an accumulation of MVPA bouts that are shorter than the recommended 10-minute minimum may still improve CVP, with lower intensity physical activity also influencing CVP. Our findings are a promising avenue for lifestyle interventions in older adults to reduce the aging effects on CVP for those who cannot engage or sustain sufficient MVPA.
Ryan, D. J., Wullems, J., Stebbings, G., Morse, C., Stewart, C., & Onambele-Pearson, G. (2018). Segregating the distinct effects of sedentary behaviour and physical activity on older adults’ cardiovascular profile: Part 2- Isotemporal substitution approach. Journal of Physical Activity and Health, 15(7), 537-542. . https://doi.org/10.1123/jpah.2017-0326