Effect of moderate exercise on salt and water transport in the human jejunum

Abstract

The effect of moderate exercise on jejunal absorption was examined in seven healthy subjects using a triple lumen perfusion technique. Moderate exercise on a bicycle ergometer significantly reduced net absorption of water from 32·0 (4·0) to 16·2 (6·1) ml/30 cm/50 min (p<0·02), sodium from 2·4 (0·4) to 0·5 (0·9) mmol/30 cm/50 cm (p<0·05), chloride from 2·0 (0·4) to 0·3 (0·7) mmol/30 cm/50 min (p<0·05), and potassium from 0·20 (0·02) to 0·01 (0·04) mmol/30 cm/50 min (p<0·01). After exercise, water, sodium, and chloride absorption returned towards basal values, but potassium absorption remained significantly decreased. These results suggest that moderate exercise can influence jejunal absorption of salt and water in man. They support the possibility that the autonomic nervous system has a physiological role in the control of intestinal transport, although other mechanisms may be involved.