Peak oxygen pulse responses during maximal cardiopulmonary exercise testing: Reference standards from FRIEND (Fitness Registry and the Importance of Exercise: an International Database)

Introduction: Cardiopulmonary exercise testing (CPX) is the gold-standard approach to assessing cardiorespiratory fitness (CRF). The current study puts forth reference standards for peak oxygen (O-2) pulse from the Fitness Registry and the Importance of Exercise: A National Data Base (FRIEND) Registry. Methods: The current analysis included 13,318 tests from CPX laboratories in the United States, Canada and Europe. Inclusion criteria included CPX data on apparently healthy men and women: 1) aged >= 20 years; 2) with exercise tests performed on a treadmill; and 3) achieving a peak respiratory exchange ratio >= 1.00. Results: Peak O2 pulse 50th percentile values decreased from 20.8 ml/beat in the 2nd decade to 11.2 ml/beat in the 8th decade inmen and from13.6 ml/beat in the 2nd decade to 7.9 ml/beat in the 8th decade inwomen. Linear regression analysis results produced the following statistically significant (p < 0.001) equation: peak O-2 pulse (ml/beat) = 23.2-0.09(age) - 6.6(sex); female = 1 and male = 0. Discussion: The assessment of CRF through CPX is an important healthmetric. Reference standards, such as those put forth in the current study, allow for the comparison of key measures of CRF to expected normal responses across the adult lifespan. (C) 2019 Elsevier B.V. All rights reserved.