Comparação da resposta vascular e glicêmica à ingestão aguda de maltodextrina entre homens corredores e sedentários de meia idade e idosos

Abstract

Aging is associated with progressive impairment of endothelial function, whereas aerobic training relates to its preservation. Acute carbohydrate ingestion transiently perturbs vascular function, a phenomenon documented predominantly by ultrasoundassessed flow-mediated dilation and scarcely investigated by venous occlusion plethysmography, particularly using maltodextrin as substrate. The aim of this study was to compare the forearm vascular response, assessed by blood flow and vascular conductance, and the glycemic response to acute maltodextrin ingestion between recreational runners and sedentary men over 50 years of age. This was a crosssectional study with a single experimental visit, in which 24 men were evaluated, allocated into recreational runners (n = 16; 58.06 ± 5.38 years) and sedentary men (n = 8; 63.37 ± 4.95 years). Participants ingested 1 g/kg of maltodextrin diluted in 250 mL of water. Forearm blood flow was measured by venous occlusion plethysmography, using a mercury-filled silastic tube connected to a low-pressure transducer, at baseline and at peak reactive hyperemia induced by five minutes of suprasystolic occlusion, at baseline and 30 and 60 minutes after ingestion. Vascular conductance was obtained by normalizing flow to mean arterial pressure. Capillary glucose was determined at the same time points. Data were analyzed by repeatedmeasures analysis of variance, adopting p ≤ 0.05. Vascular conductance at peak reactive hyperemia was higher in runners (p = 0.043; η2p = 0.173; power = 0.536), with a difference of 5.03 mL·(100 mL)-1·min-1·mmHg-1 (95%CI 0.17 to 9.89). Baseline blood flow (p = 0.746), baseline conductance (p = 0.623), peak flow (p = 0.058) and the response to the reactive hyperemia maneuver (p = 0.051) did not reach the adopted significance criterion. Maltodextrin ingestion significantly and sustainedly increased blood glucose (p < 0.001), with no difference between groups (p = 0.160) and without altering vascular variables in either group. Mean arterial pressure showed a transient reduction at 30 minutes (p = 0.010), reverted at 60 minutes. It is concluded that recreational runners over 50 years of age exhibit higher vascular conductance at peak reactive hyperemia than sedentary men of the same age range, and that acute maltodextrin ingestion did not impair the forearm vasodilatory capacity in either group over 60 minutes. The difference between groups emerged only in the perfusion-pressure-corrected metric, and not in absolute flow measures.