Prolactin as a marker of heat stress fatigue during slow and fast increases in core temperature

Circulating concentrations of prolactin (PRL) have recently been suggested as an indicator of fatigue during exertional heat stress, given its strong relationship with core temperature (Tre). In addition, increased PRL secretion is associated with the increased 5-hydroxytyptamine (serotonin) and decreased dopamine concentrations, which define central fatigue. However, the strength of the PRL and Tre relationship is unknown when different rates of Tre increase are observed. This study examined the PRL response of endurance-trained individuals as an indicator of fatigue during slow and fast increases in Tre.Peer reviewed: YesNRC publication: N