Self-reported total sitting time on a non-working day is associated with blunted flow-mediated vasodilation and...

We divided the 466 subjects into two groups based on information on sitting time on a non-working day and evaluated flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation (NID). FMD was smaller in subjects with sitting time on a non-working day of ≥6 h/day than in subjects with sitting time on a non-working day of <6 h/day (2.5 ± 2.6% vs. 3.7 ± 2.9%; p < 0.001). NID was smaller in subjects with sitting time at non-working day of ≥ 8 h/day than in subjects with sitting time on a non-working day of < 8 h/day (10.1 ± 5.6% vs. 11.5 ± 5.0%; p = 0.01). After adjustment for confounding factors for vascular function, the odds of having the lowest tertile of FMD was significantly higher in subjects with sitting time on a non-working day of ≥6 h/day than in subjects with sitting time on a non-working day of <6 h/day. The odds of having the lowest tertile of NID was significant higher in subjects with sitting time on a non-working day of ≥ 8 h/day than in subjects with sitting time on a non-working day of < 8 h/day. These findings suggest that prolonged sitting time on a non-working day is associated with blunted FMD and blunted NID.