Effects of Exercise Intensity and Pre-Exercise Feeding on Splanchnic Tissue Blood Flow
Abstract
Difficulties in comparing studies, potentially causing many apparent discrepancies, have arisen from variations in EX intensity, EX duration,thermal responses to EX, and uncertainties regarding training and feeding status. We have demonstrated generalized declines in blood flows (BFs) to the gastrointestinal organs, spleen and kidney, with no change in liver BF in fasted untrained swine during graded exercise. These changes in visceral organ BFs were associated with progressive increments in heart rate, cardiac output, mean arterial pressure, left ventricular BF, and active muscle BF. Postprandial near maximal EX resulted in an increased hepatic artery blood flow, indicating activity of some vasodilatory mechanism not functioning in the fasted condition, and possibly demonstrating the 'hepatic arterial buffer response'. Postprandial EX also resulted in higher cardiac outputs, but lower active muscle BFs than for fasting EX. This information suggests a neurogenic autonomic reflex of gastrointestinal origin may be active in minimizing BF to organs when the additional stress of digestion is superimposed on the stress of exercise. This reflex appears to redirect blood away from active tissues in order to preserve the higher splanchnic blood flows required for digestion and absorption. These data confirm the importance of controlling for exercise intensity and pre- exercise feeding status when measurements of tissue BF or central cardiovascular variables are of interest.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 23, 1988
- Accession Number
- ADA211921
Entities
People
- Charles G. Gray
- Colin M. Bloor
- Francis C. White
- M. D. Mckirnan
- Michael R. Lawlor
Organizations
- Naval Health Research Center