Abstract P431: The Effect of Ten Days of Reduced Physical Activity (rPA) on Markers of Vascular Function
Flow-mediated dilation (FMD) is an early marker of cardiovascular disease. Circulating angiogenic cells (CAC) are hypothesized to support endothelial health and repair and have been related to Framingham risk score. Both FMD and CAC have been investigated as early biomarkers of vascular dysfunction and are related to physical activity. Low physical activity is a risk factor for cardiovascular disease however, the effect of a short-term reduction in physical activity on FMD and CACs is unclear.
Purpose: To use a novel, objectively monitored model of rPA wherein participants maintain energy balance to evaluate changes in a physiological and cellular marker of vascular function.
Hypothesis: rPA will result in lower FMD and CAC compared with baseline.
Methods: Physical activity was measured via Actigraph GT3X before and during 10 days of rPA in healthy trained men (n=6). Baseline caloric intake was assessed and participants were instructed to reduce their intake to match the reduction in energy expenditure during rPA. FMD was assessed via duplex ultrasound of the brachial artery. Artery diameter and shear rate were analyzed with FMD Studio software (Quipu, Pisa). Data for baseline shear rate, baseline vessel diameter, peak shear rate, peak vessel diameter, absolute FMD, relative FMD, area under the curve (AUC), and normalized FMD were calculated for each subject. CAC colony forming units (CFU-EC) were measured before and after rPA. Paired T-tests were used to determine differences between variables before and after rPA.
Results: Actigraph data revealed increased sedentary time (656 ± 42 to 758 ± 36 min/day, p=0.02) and decreased moderate to vigorous physical activity with rPA (MVPA, 87 ± 16 to 59 ± 9, p=0.03). Weight did not change with rPA. There was a 60 ± 27% increase in baseline shear rate (p=0.03) and a 22 ± 5% decrease in peak shear rate with rPA (p=0.003). We also found a 39% decrease in CAC with rPA (21 ± 5 to 14 ± 6, p=0.03).
Conclusion: Our preliminary data show that short-term rPA results in significant changes in shear stress and CACs, two markers of vascular function. Future research should explore the independent influence of changes in physical activity and sedentary behavior on vascular function.
Author Disclosures: S. Witkowski: None. K. Tassinari: None. G. Guhanarayan: None.
- © 2014 by American Heart Association, Inc.