Ghrelin is an orexigenic gastrointestinal hormone composed of two isoforms—namely acyl and des-acyl ghrelin, which exert both analogous and opposite effects on metabolism.

Literature data on the effects of physical exercise on ghrelin production are controversial due to the heterogeneity of the studies, making an accurate interpretation of outcomes challenging.

Acute exercise is generally associated with the suppression of acyl ghrelin, while prolonged training resulted in increased total and des-acyl ghrelin, most likely due to weight loss.

Exercise-induced changes in ghrelin isoforms, namely decreased acyl ghrelin and increased des-acyl ghrelin, are expected to be metabolically beneficial.