Article Text
Abstract
The rate at which ingested fluid is emptied from the stomach is influenced by a number of factors. Exercise at intensities greater than 70% VO2max has been shown to reduce gastric emptying rates in healthy individuals,1 but to date, no studies have reported the effects of differing exercise intensities on gastric emptying characteristics after the cessation of exercise. Five males and three females participated in this investigation following prior ethical approval. Each subject undertook a measurement of VO2max and a familiarisation trial before participating in three randomly assigned experimental trials. These included 30 min of rest, continuous cycling at 33% of peak power obtained during the VO2max test (LI) and ten 1-min sprints at peak power separated by rest periods of 2 min (HI). 30 min after completion of rest or exercise, a gastric tube was inserted and the stomach emptied before ingestion of 595 ml of a 5% glucose solution. Stomach volumes were determined at 10-min intervals for 1 h using the double sampling technique.2 3 Subjective feelings of hunger were determined before and after rest or exercise, before drinking and at 10-min intervals after drink ingestion. No differences (p>0.05) in subjective feelings of hunger were observed from pre-exercise or pre-ingestion values at any time during the rest or LI trial. Subjective feelings of hunger were significantly reduced (p=0.005) from pre-exercise values during the HI trial but returned to pre-exercise values before fluid ingestion. Mean±SD half emptying times for the test drink were similar (p=0.999) during the three trials: rest 22±10 min; LI 22±8 min HI 22±7 min. Subjective feelings of hunger in the hour after fluid ingestion were negatively correlated with total stomach volume (R2 (rest) −0.655, p=0.110, LI:−0.897, p=0.006, HI−0.833, p=0.02). Previous investigations have observed that gastrointestinal function appears to be affected during high intensity exercise, but the results of the present study show that gastric emptying was not impaired 30 min after high intensity exercise. Perceived feelings of hunger and gastrointestinal function appear to be closely linked.