Interrupting Prolonged Sitting and Endothelial Function in Polycystic Ovary Syndrome.

PURPOSE

In healthy adults, the impairment of vascular function associated with prolonged sitting can be mitigated with intermittent brief bouts of activity. It is unknown whether these benefits extend to women with polycystic ovary syndrome (PCOS), in whom vascular function is typically impaired and sitting time is high. We examined the acute impact of regularly interrupting sitting time with brief simple resistance activities (SRAs) on vascular function in PCOS.

METHODS

In a randomized crossover trial, 13 physically inactive women with PCOS (18-45 years) completed two 3.5h conditions: 1) uninterrupted sitting (SIT) and 2) sitting interrupted by 3-min bouts of SRAs every 30 min. Femoral artery flow-mediated dilation (FMD), resting shear rate and resting blood flow were measured at 0h, 1h and 3.5h.

RESULTS

Mean resting femoral shear rate, averaged across the 3.5h, significantly increased in the SRA condition relative to the SIT condition (40.1 ± 6.1/s vs 62.8 ± 6.1/s, P < 0.0001). In addition, mean resting blood flow also significantly increased across the 3.5h for SRA relative to SIT (45.0 ± 9.8 ml/min vs 72.8 ± 9.9 ml/min, P < 0.0001). There were no differences between conditions in the temporal change in femoral artery FMD across 3.5h (Ptime x condition > 0.05 for all).

CONCLUSION

Frequently interrupting sitting with SRAs acutely increased resting shear rate and blood flow in women with PCOS, but did not alter FMD. With sedentary behavior increasing in prevalence, longer term studies of similar interventions to reduce and break up sitting time are warranted.