Associations Between Habitual Sedentary Behavior and Endothelial Cell Health.

Endothelial dysfunction is a mechanism that may explain the link between prolonged sedentary time and cardiovascular disease. However, the relation between habitual sedentary behavior (SED) and endothelial function has yet to be explored. PURPOSE-: The purpose of this study was to examine the association of accelerometer-measured SED with markers of endothelial cell health. METHODS-: Healthy adult participants (n=83; 43.4% male; 25.5 ± 5.8 years old) were examined. SED was measured for 7-days by accelerometer. Endothelial function measures included endothelium-dependent vasodilation (EDV); endothelial microparticles (EMPs) [CD62E+ and CD31+/CD42- EMPs]; and endothelial progenitor cells (EPCs) [CD34+/CD133+/KDR+ and CD34+/KDR+EPCs]. Participants were classified as having low or high SED based on a median split. RESULTS-: Participants in the low and high SED group spent a mean ± SD of 8.6 ± 1.1 and 11.1 ± 1.0 h/day in SED, respectively. No significant differences between the low and high SED groups were detected in mean [95% confidence interval (CI)] EDV (2.51 [2.21-2.81] vs. 2.36 [2.07-2.64], p=0.50), EMPs (CD62E+: 6.70 [6.55-6.84] vs. 6.56 [6.42-6.69], p=0.20; CD31+/CD42‒: 6.26 [6.10-6.42] vs. 6.18 [6.03-6.33], p=0.50), or EPCs (CD34+/KDR+: 11.91 [9.23-14.48]×10-2 vs. 14.87 [12.41-17.32]×10-2, p=0.13); CD34+/CD133+/KDR+: 1.84 [1.28-2.39]×10-2 vs. 2.17 [1.64-2.70]×10-2, p=0.43). CONCLUSIONS-: Among healthy adults, habitual SED was not associated with markers of endothelial cell health.