However, during sustained exercise BCAAs are also taken up by the muscle and the plasma concentration decreases, potentially giving rise to more tryptophan crossing the blood brain barrier. Whey proteins also contain between 20-25% of alpha-lactalbumin, ingestion of which has been indirectly shown to increase brain serotonin activity [28]. Thus, the net effect

of the ingestion of a large bolus (33 g) of whey protein during endurance exercise may actually increase brain PI3K inhibitor serotonin activity and hastens central fatigue [29]. Interestingly, peak selleck compound torque during isokinetic contractions in all muscle groups showed no difference in the pattern of recovery which is in contrast to the differences discussed previously for maximal force of the isometric contractions. However, we have no clear explanation what learn more may explain the difference but it could be related to differences in cross-bridge action during isokinetic versus isometric contractions. Compared to most recent Institute of Medicine recommendations [30], the data in Table 1 suggested that during the 72 h after the load carriage bout the participants in the present study were approximately in deficit of 1173 Kcal·day-1 energy,

129 g·day-1 carbohydrate and 37 g·day-1 fat, but participants did consume 16 g·day-1 protein above recommended guidelines. However, it has been shown that self report food diaries consistently underreport nutritional intake [31]. Participants maintained their normal dietary intake throughout the Aspartate study and were weighed prior to each load carriage bout, the number of days between their first and last test was 41 ± 29 days. Assuming surplus energy is stored on a fat:fat free mass ratio of 75:25, a change

in body mass of 1 kg can be assumed to be equivalent of ~7170 kcal [32]. If the participants had been in negative energy balance of ~1173 Kcal (as the food diaries indicate) for ~41 days (time between first and last body mass measurement) participants would have lost an average ~6.7 kg. However, there was no difference in body mass between the first and last load carriage bout (82.0 ± 10.2 vs. 82.0 ± 10.7 kg, P = 0.990). These findings suggest participants were not in negative energy balance and therefore not in nutritional deficit during the recovery period. However, we did not standardize the characteristics of physical activity allowed by subjects between the three testing sessions including the recovery period. There were no differences in dietary intake of energy, carbohydrate, fat or protein over the 72 h that recovery of muscle function was measured after load carriage. Compared to the placebo the carbohydrate and whey protein beverages provided an additional 260 Kcal and 352 Kcal·day-1, respectively. However, Valentine et al.