Abstract des Autors

The effects of rice (compared to bread and aspartame) on submaximal exercise performance were investigated. A first study included ten healthy subjects who performed three sessions in random order. After a 150 minute low intensity cycling session in fasting conditions to slightly reduce blood glucose, they were fed either aspartame (40 mg) given in water, rice (65 g rice, ie, 50 g carbohydrate) or bread (100 g, ie, 50 g carbohydrate). Subjects then exercised at 85% of their theoretical maximal heart rate (ie, 75% VO2max) until exhaustion. A second study included six healthy volunteers who performed three sessions in random order with either aspartame, rice or bread under the same protocol without a previous fatiguing exercise session. The chemical composition of bread compared to rice revealed mainly significant (P<0.05) higher protein and amylose contents. In the first study, the subjects performed greater work after rice (91.20+/-7.2 kJ) than either aspartame (29.86+/-4.28 kJ, P<0.01) or bread (54.99+/-6.36 kJ, P<0.01), because the duration of exercise until exhaustion was longer after rice (19.20+/-1.28 vs 8.4+/-0.97 or 11+/-1.03 min, respectively, P<0.01). In the second study, subjects performed greater work (P<0.01) after rice (83.77+/-11.90 kJ) than after either aspartame (49.98+/-10.62 kJ) or bread (49.98+/-10.62 kJ). Exercise duration was longer after rice (16+/-1.52 vs 9.16+/-1.87 or 11+/-1.88 min, respectively, P<0.01). In both studies, blood lactate was lower after rice than either aspartame or bread. This study shows that rice is more effective than bread in improving the duration of submaximal exercise until exhaustion. Verf.-Referat