A ketogenic diet enhances aerobic exercise adaptation and promotes muscle mitochondrial remodeling in hyperglycemic male mice

VO₂peak is a key health benefit of aerobic exercise; however, chronic hyperglycemia is associated with persistently low VO₂peak due to an impaired adaptive response to training. Here, we show that reducing blood glucose with a carbohydrate-restricted, high fat ketogenic diet can restore aerobic exercise adaptation in male mice with hyperglycemia. Hyperglycemic mice received standard high-carbohydrate chow (CHOW), which sustains high blood glucose; or a ketogenic diet (KETO), which normalizes blood glucose levels. After aerobic exercise training, improvements in VO₂peak are blunted in CHOW, but restored by KETO. Increased VO₂peak in KETO is associated with enhanced aerobic remodeling of skeletal muscle, including a more oxidative fiber-type and increased capillary density. Moreover, KETO induces exercise-independent effects on muscle mitochondrial remodeling and substrate selection, significantly increasing fatty acid oxidation and down-regulating glucose metabolism. We identify a ketogenic diet as a potential therapy to improve aerobic exercise adaptation in the growing population with hyperglycemia.