exercise-induced immunosuppression

A very interesting article: http://www.nature.com/icb/journal/v78/n5/full/icb200076a.html

Prolonged exercise and heavy training are associated with depressed immune cell function.

Consuming carbohydrate during prolonged strenuous exercise attenuates rises in stress hormones and appears to limit the degree of exercise-induced immune depression. (www.ncbi.nlm.nih.gov/pubmed/16572599)

An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. Conversely, consuming carbohydrate during exercise attenuates rises in stress hormones such as cortisol and appears to limit the degree of exercise-induced immunosuppression, at least for non-fatiguing bouts of exercise.

(http://www.ncbi.nlm.nih.gov/pubmed/11897880)