Coingestion of carbohydrate and protein during training reduces training stress and enhances subsequent exercise performance

Researchers have focused primarily on investigating the effects of coingesting carbohydrate (CHO) and protein (PRO) during recovery and, as such, there is limited research investigating the benefits of CHO+PRO coingestion during exercise for enhancing subsequent exercise performance. The aim of this study was to investigate whether coingestion of CHO+PRO during endurance training would enhance recovery and subsequent exercise performance. Ten well-trained male cyclists (aged 29.7 +/- 7.5 years; maximal oxygen uptake, 66.2 +/- 6 mL.kg(-1).min(-1)) took part in a randomized, double-blind, cross-over trial. Each trial consisted of a 2.5-h morning training bout during which the cyclists ingested a CHO+PRO or energy-matched CHO beverage followed by a 4-h recovery period and a subsequent performance time trial (total work, 7 kJ.kg(-1)). Blood was collected before and after exercise. Time-trial performance was 1.8% faster in the CHO+PRO trial compared with the CHO trial (p = 0.149; 95% CI, -13 to 87 s; 75.8% likelihood of benefit). The increase in myoglobin level from before the training bout to after the training bout was lower in the CHO+PRO trial (0.74 nmol.L-1; 95% CI, 0.3-1.17 nmol.L-1) compared with the CHO trial (1.16 nmol.L-1; 95% CI, 0.6-1.71 nmol.L-1) (p = 0.018). Additionally, the decrease in neutrophil count over the recovery period was greater in the CHO+PRO trial (p = 0.034), and heart rate (p < 0.022) and rating of perceived exertion (RPE) (p < 0.01) were lower during training in the CHO+PRO trial compared with the CHO trial. Ingesting PRO, in addition to CHO, during strenuous training lowered exercise stress, as indicated by reduced heart rate, RPE, and muscle damage, when compared with CHO alone. CHO+PRO ingestion during training is also likely to enhance recovery, providing a worthwhile improvement in subsequent cycling time-trial performance.