Prolonged sitting can temporarily impair vascular function, even in healthy young adults, by reducing endothelial responsiveness in both the upper and lower limbs and increasing diastolic blood pressure. In this controlled crossover trial in 18 healthy young men (9 high-fit, 9 low-fit) tested whether cocoa flavanols can counteract vascular impairment from 2 hours of uninterrupted sitting. Participants consumed either a high-flavanol drink containing 540 mg total cocoa flavanols with 150 mg epicatechin or a low-flavanol control. Sitting decreased popliteal artery flow-mediated dilation by about 2 percentage points and reduced brachial dilation by roughly 1 percentage point while raising diastolic pressure by about 4 mmHg. The high-flavanol drink significantly preserved endothelial function in both limbs despite similar reductions in leg blood flow, shear rate and muscle oxygen saturation. Blood pressure, heart rate, and forearm hemodynamics were not altered by flavanols. These results suggest that a single dose of ~150 mg epicatechin can help maintain vascular responsiveness during prolonged sitting, a common real-world stressor on vascular health.
Source : https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP289038