Cardiorespiratory fitness levels among US adults 20-49 years of age: findings from the 1999-2004 National Health and Nutrition Examination Survey

Am J Epidemiol. 2010 Feb 15;171(4):426-35. doi: 10.1093/aje/kwp412. Epub 2010 Jan 15.


Data from the 1999-2004 National Health and Nutrition Examination Survey were used to describe the distribution of cardiorespiratory fitness and its association with obesity and leisure-time physical activity (LTPA) for adults 20-49 years of age without physical limitations or indications of cardiovascular disease. A sample of 7,437 adults aged 20-49 years were examined at a mobile examination center. Of 4,860 eligible for a submaximal treadmill test, 3,250 completed the test and were included in the analysis. The mean maximal oxygen uptake ( max) was estimated as 44.5, 42.8, and 42.2 mL/kg/minute for men 20-29, 30-39, and 40-49 years of age, respectively. For women, it was 36.5, 35.4, and 34.4 mL/kg/minute for the corresponding age groups. Non-Hispanic black women had lower fitness levels than did non-Hispanic white and Mexican-American women. Regardless of gender or race/ethnicity, people who were obese had a significantly lower estimated maximal oxygen uptake than did nonobese adults. Furthermore, a positive association between fitness level and LTPA participation was observed for both men and women. These results can be used to track future population assessments and to evaluate interventions. The differences in fitness status among population subgroups and by obesity status or LTPA can also be used to develop health policies and targeted educational campaigns.

MeSH terms

  • Adult
  • Body Mass Index
  • Cardiovascular Diseases / epidemiology
  • Ethnicity / statistics & numerical data
  • Exercise Test
  • Female
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Nutrition Surveys
  • Oxygen Consumption / physiology*
  • Physical Fitness / physiology*
  • Sex Factors
  • United States / epidemiology