Similar performance after intake of carbohydrate plus whey protein and carbohydrate only in the early phase after non-exhaustive cycling

Abstract

Aim: The aim of the present study was to compare performance 5 h after a 90-min endurance training session when either carbohydrate only or carbohydrate with added whey hydrolysate or whey isolate was ingested during the first 2 h of the recovery period. Methods: Thirteen highly trained competitive male cyclists completed three exercise and diet interventions (double-blinded, randomized, crossover design) separated by 1 week. The 90-min morning session (EX1) included a 60 min time-trial (TT60). Immediately and 1 h after exercise, participants ingested either (1) 1.2 g carbohydrate∙kg−1∙h−1 (CHO), (2) 0.8 g carbohydrate∙kg−1∙h−1 + 0.4 g isolate whey protein∙kg−1∙h−1 (ISO) or (3) 0.8 g carbohydrate∙kg−1∙h−1 + 0.4 g hydrolysate whey protein∙kg−1∙h−1 (HYD). Additional intakes were identical between interventions. After 5 h of recovery, participants completed a time-trial performance (TTP) during which a specific amount of work was performed. Blood and urine were collected throughout the day. Results: TTP did not differ significantly between dietary interventions (CHO: 43:54 ± 1:36, ISO: 46:55 ± 2:32, HYD: 44:31 ± 2:01 min). Nitrogen balance during CHO was lower than ISO (p < 0.0001) and HYD (p < 0.0001), with no difference between ISO and HYD (p = 0.317). In recovery, the area under the curve for blood glucose was higher in CHO compared to ISO and HYD. HR, VO2, RER, glucose, and lactate during EX2 were similar between interventions. Conclusion: Performance did not differ after 5 h of recovery whether carbohydrate only or isocaloric carbohydrate plus protein was ingested during the first 2 h. Correspondingly, participants were not in negative nitrogen balance in any dietary intervention.