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January 16, 2018

Fitness or Fatness: Which Is More Important?

Author Affiliations
  • 1Department of Biomedical Sciences, Division of Behavioral, Social, and Population Health, University of South Carolina School of Medicine, Greenville
  • 2Department of Cardiovascular Diseases, Ochsner Clinical School, The University of Queensland School of Medicine, New Orleans, Louisiana
  • 3Departments of Exercise Science and Epidemiology/Biostatistics, Arnold School of Public Heath, University of South Carolina, Columbia
JAMA. 2018;319(3):231-232. doi:10.1001/jama.2017.21649

Three decades ago, the relative importance of the detrimental effects of obesity on health was called into question by a longitudinal study1 that included 10 224 men and 3120 women who were followed up for more than 8 years. The findings showed that better cardiorespiratory fitness (CRF), as measured by a maximal treadmill exercise test, was associated with decreased all-cause mortality in both sexes. Based on the maximal treadmill tests, participants were stratified into quintiles of fitness categories, with 1 equaling the lowest level of fitness and 5 being the highest level of fitness. Analysis of lifestyle behaviors and clinical measures, such as blood pressure, hyperlipidemia, smoking, and body mass index (BMI, calculated as weight in kilograms divided by height in meters squared), found that for both men and women, all variables, except BMI and familial coronary heart disease (CHD) only for women, were associated with a statistically significantly higher risk of mortality across fitness categories. For example, individuals who were current smokers and were in higher fitness categories had lower relative risk of death compared with current smokers who were in lower fitness categories.