Introduction: The maximum oxygen consumption (VO2max) is the gold standard in the cardiorespiratory endurance assessment. Objective: This study aimed to develop a mathematical model that contains variables to determine the VO2max of sedentary people. Methods: Twenty participants (10 men and 10 women) with a mean age of 19.8±1.77 years were included. For each participant, body composition (percentage of fat and muscle), heart rate variability (HRV) at rest (supine and standing), and VO2max were evaluated through an indirect test on a cycloergometer. A multivariate linear regression model was developed from the data obtained, and the model assumptions were verified. Results: Using the data obtained, including percentage of fat (F), percentage of muscle (M), percentage of power at very low frequency (VLF), α-value of the detrended fluctuation analysis (DFAα1), heart rate (HR) in the resting standing position, and age of the participants, a model was established for men, which was expressed as VO2max = 4.216 + (Age*0.153) + (F*0.110) - (M*0.053) - (VLF*0.649) - (DFAα1*2.441) - (HR*0.014), with R2 = 0.965 and standard error = 0.146 L/min. For women, the model was expressed as VO2max = 1.947 - (Age*0.047) + (F*0.024) + (M*0.054) + (VLF*1.949) - (DFAα1*0.424) - (HR*0.019), with R2 = 0.987 and standard error = 0.077 L/min. Conclusion: The obtained model demonstrated the influence exerted by body composition, the autonomic nervous system, and age in the prediction of VO2max.

Despite the recommendations for physical activity in children and adolescents, sedentary behaviors that may affect health are frequent in today's schools. Evidence suggests that physical activity has a beneficial effect on the development of attention, however, there is no clarity on the characteristics that physical activity should have to optimize the improvement of attention in schoolchildren. A search for articles in databases published between 2013 and 2023 was performed, and after applying the inclusion and exclusion criteria and after analyzing their results, thirty-three articles were identified. The results suggest that the practice of physical activity has a positive effect on attention, mainly selective attention, but it is not possible to establish the characteristics in relation to frequency, time, intensity, or type of exercise that yield the best results, probably due to the heterogeneity of the interventions and populations studied. More experimental studies are therefore required to help identify the characteristics of physical activity that best contribute to the development of attention as a cognitive indicator. Keywords: Attention, physical activity, school children, sedentary behaviors, cognitive indicators.