Development of Global Reference Standards for Directly Measured Cardiorespiratory Fitness: A Report From the Fitness Registry and Importance of Exercise National Database (FRIEND)

Mayo Clin Proc. 2020 Feb;95(2):255-264. doi: 10.1016/j.mayocp.2019.06.013. Epub 2019 Dec 26.


Objective: To begin the process of developing global reference standards for adults from directly measured cardiorespiratory fitness (CRF).

Methods: Percentiles of maximal oxygen consumption (VO2max) for men and women were determined for each decade from 20 through 79 years of age using International data from the Fitness Registry and Importance of Exercise: A National Database (FRIEND-I) along with previously published data from seven studies. FRIEND-I data from January 1, 2014, through January 1, 2019, included 11,678 maximal treadmill tests from three countries, whereas the previously published reports included 32,329 maximal treadmill tests from six countries.

Results: FRIEND-I data revealed significant differences between sex and age groups for VO2max (P<0.01). For the 20- to 29-years of age group, the 50th percentile VO2max in men and women were 49.5 mLO2⋅kg-1⋅min-1 and 40.6 mLO2⋅kg-1⋅min-1, respectively. VO2max declined an average of 9% per decade with the 50th percentile for the 70- to 79-years of age group having a VO2max of 30.8 mLO2⋅kg-1⋅min-1 in men and 25.0 mLO2⋅kg-1⋅min-1 in women. These results were similar in magnitude and direction to the previously published literature. Within both the FRIEND-I and previously published data there were CRF differences between countries.

Conclusion: This report begins to establish global reference standards for CRF. Continued development of FRIEND-I will increase global representation providing an improved ability to identify and stratify CRF risk categories.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cardiorespiratory Fitness / physiology*
  • Databases, Factual
  • Exercise Test / standards
  • Female
  • Humans
  • Male
  • Middle Aged
  • Oxygen Consumption / physiology
  • Reference Standards
  • Registries