Saurabh S. Thosar, Sylvanna L. Bielko, Chad C. Wiggins, James E. Klaunig, Kieren J. Mather, Janet P. Wallace
Department of Kinesiology, Indiana University School of Public Health, Indiana University, Bloomington, IN, USA
Med Sci Monit 2015; 21:1015-1021
This study was designed to test the hypothesis that antioxidant Vitamin C prevents the impairment of endothelial function during prolonged sitting.
Material and Methods: Eleven men (24.2±4.4 yrs) participated in 2 randomized 3-h sitting trials. In the sitting without vitamin C (SIT) and the sitting with vitamin C (VIT) trial, participants were seated for 3 h without moving their legs. Additionally, in the VIT trial, participants ingested 2 vitamin C tablets (1 g and 500 mg) at 30 min and 1 h 30 min, respectively. Superficial femoral artery (SFA) flow-mediated dilation (FMD) was measured hourly for 3 h.
Results: By a 1-way ANOVA, there was a significant decline in FMD during 3 h of SIT (p<0.001). Simultaneously, there was a significant decline in antegrade (p=0.04) and mean (0.037) shear rates. For the SIT and VIT trials by a 2-way (trial x time) repeated measures ANOVA, there was a significant interaction (p=0.001). Pairwise testing revealed significant between-SFA FMD in the SIT and VIT trial at each hour after baseline, showing that VIT prevented the decline in FMD 1 h (p=0.009), 2 h (p=0.016), and 3 h (p=0.004). There was no difference in the shear rates between SIT and VIT trials (p>0.05).
Conclusions: Three hours of sitting resulted in impaired SFA FMD. Antioxidant Vitamin C prevented the decline in SFA FMD, suggesting that oxidative stress may contribute to the impairment in endothelial function during sitting.
Keywords: Antioxidants - pharmacology, Adult, Ascorbic Acid - pharmacology, Demography, Endothelium, Vascular - physiopathology, Femoral Artery - physiopathology, Posture, Regional Blood Flow - drug effects, Vasodilation - drug effects