Plasma insulin concentration for carbohydrate (CHO) and carbohydrate and whey protein isolates (CHO + WPI) trials. The exercise trial day consisted of 60 min cycling at 70% VO2 max, with blood samples taken at rest and every 20 min (rest, 20, 40, 60). This was followed by time to fatigue at 90% VO2 max and blood was taken on completion of this effort (0). The 6 h recovery consisted of blood taken regularly for the first h (10, 20, 30, 40, 60) and every 60 min after that (120, 180, 240, 300, 360). Both trials, CHO (* P < 0.05) and CHO + WPI (# P < 0.05), were significantly elevated compared to rest, with CHO + WPI significantly higher than CHO at 180 min (^ P < 0.05) during the recovery period, before returning to resting levels at 240 min. Values are means ± SEM (n = 6).