Effects of leptin treatment and Western diet on wheel running in selectively bred high runner mice

► We used mice from lines selectively bred for high voluntary wheel running. ► We examined how leptin regulates volitional exercise across different diets. ► Western diet increased wheel running only in mice bred for high running (HR mice). ► Leptin treatment also increased wheel running only in HR mice. ► Western diet may stimulate HR's running indirectly through elevated leptin.