Priority of blood flow to splanchnic organs in humans during pre‐ and post‐meal exercise

Abstract

Cardiac output and superior mesenteric arterial flow in five healthy young men were followed using Doppler ultrasound techniques at rest and during 4 min bouts of bicycle exercise in both a pre- and a post-meal situation. The meal given was mixed and heavy, with an energy content (related to body size) of about 1400-1600 kcal (5.9-6.9 MJ). Two levels of exercise, 50-65 W and 150-200 W (about 75% of VO2max), were tested, with the subjects cycling in a reclining position. Superior mesenteric arterial flow increased threefold, to about 1.1 l min-1, after the meal. During exercise in the fasting situation there were only modest changes in splanchnic vascular conductance, and moderate increases in superior mesenteric arterial flow were actually recorded. Exercise in the post-prandial state caused appreciable reductions in splanchnic vascular conductance, and a 38% reduction was observed during the most heavy exercise. However, not even such a decrease in conductance resulted in any definite reduction in superior mesenteric arterial blood flow, which was maintained at the pre-exercise level. Cardiac output increased by about 1.3 l min-1 after the meal. The exercise-induced increases in cardiac output were of the same order in the fasting and in the post-prandial state. Variance analyses showed the high cardiac output levels reached during post-prandial exercise to be no different from levels that would be reached by pure summation of the changes caused by eating alone and by exercise alone. It is concluded that blood flow to the splanchnic organs in reclining man retains its high pre- and post-prandial priority during short exercise bouts of up to 75% of VO2max.

Mesenteric, coeliac and splanchnic blood flow in humans during exercise

“…In contrast to our hypothesis, Qamar & Read (1987) noted a 43 % reduction in the superior mesenteric artery (SMA) blood flow after treadmill exercise. However, Eriksen & Waaler (1994) reported a maintained SMA flow after fasting and postprandial short-duration (4 min) cycling, corroborating observations during submaximal exercise in the dog (Herrick et al 1940;Van Citters & Franklin, 1969;Vatner, 1975). To evaluate these contradictory results, we assessed splanchnic blood flow (SBF) during fasting and postprandial exercise in healthy volunteers by both Indocyanine Green dye-elimination (dye-elimination) and duplex ultrasound techniques, which permitted separation of the hepato-splenic from the mesenteric circulations.…”

“…The coeliac artery response to exercise has not been investigated previously, while the conclusions from studies on the mesenteric circulation during exercise are conflicting. Qamar & Read (1987) noted a reduction in mesenteric blood flow, while Eriksen & Waaler (1994) observed no change in blood flow during postprandial cycling, with an increase in flow during fasting exercise. Both studies were based on duplex ultrasound, but they presented neither the diameter nor the blood velocity of the artery, which hinders interpretation of the results.…”

Different patterns of brisk walking are equally effective in decreasing postprandial lipaemia

“…33 Furthermore, an effect of this kind would have delayed peak TAG concentrations during the walking trials Ð something we did not observe. There could be decreased hepatic VLDL-TAG secretion during the walking trials but plasma concentrations of NEFA and insulin, both important in¯uences on this, 34 did not differ between trials.…”

The effect of exercise on postprandial lipidemia in type 2 diabetic patients

“…3, 4). Correspondingly, neither gastric emptying nor postprandial splanchnic blood flowing is influenced by moderate exercise (Fordtran and Saltin 1967;Eriksen and Waaler 1994).…”