Protein feeding and exercise recovery

Abstract

The importance of protein feeding for maximising the anabolic effect of resistance exercise is well established. Ingestion of amino acids or intact protein sources with and without carbohydrate during exercise recovery further stimulates muscle protein synthesis. Less clear is the impact of an acute bout of resistance exercise on the protein synthetic rate of muscle already stimulated by food intake. This thesis demonstrates that an acute bout of resistance exercise further augments the protein synthetic rate of muscle already stimulated by food intake. Simulating everyday practice, whereby resistance exercise is typically performed in the fed state, an exercise-induced elevation in muscle protein synthesis was accompanied by an increased phosphorylation status of signaling proteins downstream of mammalian target of rapamycin (mTOR). Recent studies advocate the potential role for protein feeding in improving subsequent performance following acute bouts of fatiguing endurance-type exercise. However, previous studies have focussed upon carbohydrate nutrition, rather than examining the role of protein feeding for exercise recovery in the context of an intense period of endurance training. Increasing dietary protein intake partially countered the blunted minimal mobilisation of antiviral lymphocytes during exercise following intensified training. In addition, the number of negative symptoms of psychological stress experienced following intensified training was attenuated with additional dietary protein intake. The mechanism(s) underpinning the suggestion that a high protein diet may potentiate a better maintainence of endurance performance following intensified training could not be definitively elucidated from our experimental design. The most likely explanation appears to be related to psychological status