M. Hargreaves et al., INFLUENCE OF SODIUM ON GLUCOSE BIOAVAILABILITY DURING EXERCISE, Medicine and science in sports and exercise, 26(3), 1994, pp. 365-368
To examine the influence of beverage sodium content on glucose bioavai
lability during exercise, six trained men were studied during 30 min o
f cycle ergometer exercise at 65% VO2max. Immediately prior to exercis
e, subjects ingested 400 ml of a 10% glucose solution containing 100 m
u Ci of D-(3-H-3]-glucose, with a sodium concentration of either 0, 25
, or 50 mmol.l(-1). Trials were conducted in the morning after an over
night fast and in randomized order at least 1 wk apart. Blood samples
were obtained from a forearm vein before and during exercise and subse
quently analyzed for plasma glucose and H-3-glucose activity and blood
lactate. No differences in oxygen uptake, heart rate, or brood lactat
e were observed between trials. Resting plasma glucose levels were not
different between trials. The increases in plasma glucose and the pla
sma accumulation of H-3-glucose were similar in the three trials. Thes
e results indicate that alterations in beverage sodium content, from 0
-50 mmol.l(-1), have no effect on glucose bioavailability, as measured
by increases in plasma glucose and H-3-glucose activity during modera
te intensity exercise.