TITLE:
Modeling VO2max with Relative Fitness and BMI
AUTHORS:
James M. Gregory
KEYWORDS:
VO2max, BMI, Body Mass Index, Exercise, Health, Body Fat Percentage
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.12 No.12,
December
26,
2024
ABSTRACT: Cardiorespiratory fitness (CRF) is considered a foundation for good health and longevity. The variable, VO2max, is considered a reliable measure of cardiorespiratory health. The measurement of VO2max is stressful and is not a common practice, thus, it is desirable to relate VO2max to other variables including age, gender, Body Mass Index (BMI), body fat percentage (BFP), and physical activity. Mathematical models are presented to relate VO2max to age, gender, BMI, body fat percentage, and aerobic exercise. Predictions match well with measured VO2max data published in the literature. The robust models are stable for all boundary conditions including young adults to old age and lower sedentary to Olympic-trained levels of relative fitness for both male and female applications. The relationship may be especially helpful for older people who are dealing with elevated values of BMI. The models build on two levels of relative fitness (sedentary and endurance-trained) and boundary conditions of Olympic-trained athletes and lower sedentary conditions. Thus, the model responds to a full range of fitness conditions. Four equations are provided: one with relative fitness related to distance walked or ran each week, one using BMI to estimate relative fitness, and two using both BMI and BFP to estimate relative fitness (one interacting with age). An equation is also provided to evaluate the dynamic change in relative fitness using input of distance walked or ran each day, which can be estimated by a smart watch. The equation that only uses age, gender, and BMI as inputs overestimates VO2max for people with low BMI and who are physically inactive. This weakness is partially overcome by adding BFP as a variable when available. The most accurate equation is the one that uses distance walked or ran each day to estimate relative fitness based on the individual’s physical activity. Unfortunately, this method requires the individual to keep track of their physical activity daily. Relative fitness may be a more appropriate variable than VO2max to indicate fitness because it is independent of age.