Mediates beneficial effects of muscular exercise. Induces browning of white adipose tissue by stimulating UCP1 expression, at least in part, via the nuclear receptor PPARA (By similarity). Imported in peroxisomes through the PEX5 receptor pathway. Detected in the blood of individuals subjected to endurance exercise. N-Glycosylated. The extracellular domain is cleaved and released from the cell membrane.