Interleukin-6, undercarboxylated osteocalcin, and brain-derived neurotrophic factor responses to single and repeated sessions of high-intensity interval exercise

•A practical model of low-volumeHIIE elicits significant increase in plasma IL-6, ucOC, and BDNF concentrationsin recreational endurance athletes.•Two consecutive low-volume HIIEsinvolving 10 x 60 sec of high-intensity cycling at PPO, separated by 75 s oflight exercise, provide a similar stimulus for the plasma IL-6, ucOC, and BDNFresponses compared to a single session of HIIE.