Acute Effects of a Mixed Meal on Arterial Stiffness and Central Hemodynamics in Healthy Adults

BACKGROUND: Elevated central pressures and arterial stiffness are associated with increased peripheral resistance and higher sympathetic nervous system activity. Additionally, consumption of a meal is known to be sympathoexcitatory. However, the acute effects of a meal on aortic wave reflection and stiffness are unknown. Therefore, we tested the hypothesis that aortic wave reflection and stiffness would increase after a meal. METHODS: We examined these effects using high-fidelity radial arterial pressure waveforms and carotid-femoral pulse wave velocity measured noninvasively by applanation tonometry before and 60 and 180 minutes after ingestion of a liquid mixed meal (Ensure; 40% of daily energy expenditure) in 17 healthy adults (9 men/8 women; aged 29 ± 2 years). Additionally, we measured sympathetic activity by microneurography at baseline and up to 60 minutes after the meal. RESULTS: Although sympathetic activity increased after the meal, both peripheral and central pressures were reduced at 180 minutes from baseline (all P < 0.05). Contrary to our hypothesis, augmentation index (14% ± 3% vs. 2% ± 3% vs. 8% ± 3%), augmentation index normalized for heart rate (8% ± 3% vs. -3% ± 3% vs. 3% ± 3%), augmented pressure (5 ± 1 mm Hg vs. 1 ± 1 mm Hg vs. 3 ± 1 mm Hg), and pulse wave velocity (7.1 ± 0.2 m/s vs. 6.7 ± 0.2 m/s vs. 6.7 ± 0.1 m/s) were substantially reduced at 60 and 180 minutes after the meal (all P < 0.05). CONCLUSIONS: Taken together, our results suggest that a liquid mixed meal acutely decreases central hemodynamics and arterial stiffness in healthy adults, which may be a result of meal-related increases in insulin and/or visceral vasodilation.