New research published in the British Journal of Sports Medicine has shown that cardiorespiratory fitness is a better predictor of both all-cause mortality and cardiovascular disease than body mass index (BMI).
The systematic review and meta-analysis included 20 journal articles featuring nearly 400,000 participants. All of the articles in the analysis included measures of cardiorespiratory fitness, BMI, and the effects of fitness and BMI on cardiovascular disease and/or all-cause mortality. All of the articles also included a control group of normal-weight, fit individuals. In most of the studies, participants were classified as fit if their measured or estimated VO2max was above the 20th percentile for their age group. The goal of the study was to assess how cardiorespiratory fitness and BMI jointly affect mortality and heart disease.
The results showed that that fitness was a better predictor of both heart disease and all-cause mortality than BMI. Across all BMI categories, individuals who were classified as fit had similar risks of mortality from any cause, including cardiovascular disease. In contrast, individuals who were not classified as fit had two to three times the risk of mortality from any cause across all weight categories. Counterintuitively, individuals who were obese and fit had a significantly lower risk of all-cause mortality than individuals who were normal weight and unfit.
The authors noted that fitness is a much better predictor of one’s health and risk of death than weight as measured by BMI. The authors further stated that the greatest reduction in risk happens when an individual who is classified as sedentary begins to exercise regularly, even if they only increase their activity by a modest amount. By increasing their activity levels to an average of about 30 minutes of moderate exercise per day, people can significantly reduce their risk of heart disease and all-cause mortality.