Hemodynamic effects of carbohydrate and protein meals in man: rest and exercise.

Abstract

Changes in cardiac output (Q), heart rate (HR), blood pressure (Pb), and O2 consumption (V02) were observed for 4. 5 hr. following carbohydrate or protein-rich meals. Observations were made at rest and during light exercise (300 kg-m/ min). In 8 control subjects who fasted for the same length of time there was no change in Pb or HR but there were small increments in Q and Vo2 both at rest and exercise during the last 1. 5 hr of study. Eight subjects consumed a protein-rich meal. At rest there were increments of Q (+ 2. 44/min, 46%), systolic Pb (+ 10 mm Hg, 9%), and Vo2 (+ 79 ml/min, 31%). These changes were significantly greater than those of the fasting subjects at equivalent times and were maximal from 180 to 270 min. During exercise each parameter was increased by approximately the same quantity. Eight subjects consumed a carbohydrate-rich meal. At rest there were increments of Q (+ 1. 66/min, 34%), systolic Pb (+ 10 mm Hg, 9%) and Vo2 (+ 63 ml/min, 22%), but maximal values were reached earlier, (within the first 1. 5 hr). These changes were again significantly greater than those observed in the fasting subjects. The increments which followed carbohydrate ingestion were of comparable magnitude and timing during exercise.