Physical fitness has been identified as one of the most important predictors of all-cause mortality among adults. Specifically, low cardiorespiratory fitness has been shown to be responsible for a greater number of deaths than other risk factors such as hypertension, smoking or metabolic disease.1 2 The relevance of achieving an adequate physical fitness status is such that people with obesity or metabolic disease who present adequate cardiorespiratory fitness exhibit a diminished mortality risk when compared with people without obesity or metabolic disease but presenting low cardiorespiratory fitness.3 This has been described as the ‘fat but fit’ paradox.4