Selection for high aerobic capacity has no protective effect against obesity in laboratory mice

Aerobic capacity (VO2max measured during intensive physical exercise) both trained and intrinsic (i.e. genetically determined) has recently been deemed a good predictor of cardiometabolic risks. However, the underlying mechanisms linking VO2max and health risk factors are not entirely clear, as it seems that not VO2max per se, but rather some correlated traits, like spontaneous physical activity (SPA) are responsible for sustaining the lean phenotype. Here we investigated the link between genetically determined aerobic capacity, SPA and resistance to diet-induced health risks using replicated lines of mice selected for high aerobic capacity during swimming in mid-cold water (25 °C) and Randomly Bred control mice. After four months of consumption of the western type HFat and HCarb diets and no forced nor voluntary training, we found no evidence of protective effects of intrinsic high VO2max. The Selected mice displayed similar levels of blood glucose, cholesterol, triglycerides and body fat as the Random Bred control animals. Most notably we found no correlation between VO2max and SPA levels. Our results therefore call into question the ubiquity of VO2max as a predictor of metabolic health and leanness, at least in animal models.