Brain derived neurotrophic factor (BDNF) is necessary for new synapses and call survival. A new study in J. Physiology (2023) reports that the increases in BDNF from short intense cycling exercise are much greater than from prolonged (90-minute) light cycling. The authors think that this is caused by the increases in lactate produced which helps up regulate BDNF production. This could be good for fighting depression and Alzheimer’s disease, where BDNF levels are low.