Development of global reference standards for directly measured cardiorespiratory fitness: A report from the Fitness Registry and Importance of Exercise National Database (FRIEND)

Objective: To begin the process of developing global reference standards for adults from directly measured cardiorespiratory fitness (CRF). Methods: Percentiles of maximal oxygen consumption (VOmax) 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 VOmax (