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

Researchers have primarily focused on investigating 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 (age 29.7±7.5years, VO2max 66.2±6mL.kg-1.min-1) took part in the randomised, double-blind, cross-over trial. Each trial consisted of a 2.5h morning training bout during which cyclists ingested a CHO+PRO or energy matched CHO beverage followed by a 4h recovery period and a subsequent performance time-trial (total work 7kJ.kg-1). Blood was collected pre- and post-exercise. Time-trial performance was 1.8% faster in the CHO+PRO trial compared with the CHO trial (p=0.149, 95%CI -13to87s; 75.8% likelihood of benefit). The increase in myoglobin level from pre- to post-training bout was lower for the CHO+PRO trial (0.74nmol•l-1, 95%CI 0.3to1.17nmol•l-1) compared to the CHO trial (1.16nmol•l-1, 95%CI 0.6to1.71nmol•l-1) (p=0.018). Additionally, the decrease in neutrophil count over the recovery period was greater for the CHO+PRO trial (p=0.034) and heart rate (p<0.022) and rating of perceived exertion (p<0.01) were lower during training compared to 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 to CHO alone. CHO+PRO ingestion during training is also likely to enhance recovery, providing a worthwhile improvement in subsequent cycling time-trial performance.