title: A Reference Equation for Normal Standards for VO2Max: Analysis from the Fitness Registry and the Importance of Exercise National Database (FRIEND Registry).
abstract: Existing normal standards for maximal oxygen uptake (VO2max) are problematic because they tend to be population specific, lack normal distribution and portability, and are poorly represented by women. The objective of the current study was to apply the Fitness Registry and the Importance of Exercise: A National Data Base (FRIEND) Registry to improve upon previous regression formulas for normal standards for VO2max using treadmill testing. Maximal treadmill tests were performed in 7783 healthy men and women (20-79years; maximal RER >1.0) from the FRIEND registry and a separate validation cohort of 1287 subjects. A regression equation for VO2max was derived from the FRIEND registry and compared to the validation cohort and two commonly used equations (Wasserman and European). Age, gender, and body weight were the only significant predictors of VO2max (multiple R=0.79, R2=0.62, p<0.001). The equation for predicting VO2max was: [Formula: see text] Marked differences were observed in percentage predicted VO2max achieved between commonly used reference equations, particularly among women, overweight and obese subjects. In the validation sample, the FRIEND equation closely paralleled measured VO2max, with the validation group yielding a percent predicted VO2max of 100.4% based on the FRIEND equation. An equation for age-predicted VO2max derived from the FRIEND registry provided a lower average error between measured and predicted VO2max than traditional equations, and thus may provide a more suitable normal standard relative to traditional equations.
authors.affiliation: Division of Cardiology, VA Palo Alto Healthcare System, Palo Alto, CA; Stanford University, Stanford, CA. Electronic address: drj993@aol.com.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Myers
authors.affiliation: Fisher Institute of Health and Well-Being and Clinical Exercise Physiology Laboratory, Ball State University, Muncie, IN.
authors.forename: Leonard A
authors.initials: LA
authors.lastname: Kaminsky
authors.affiliation: Division of Cardiology, VA Palo Alto Healthcare System, Palo Alto, CA.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Lima
authors.affiliation: Division of Cardiovascular Medicine, Stanford Center for Inherited Cardiovascular Disease, Stanford, CA.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Christle
authors.affiliation: Division of Cardiovascular Medicine, Stanford Center for Inherited Cardiovascular Disease, Stanford, CA.
authors.forename: Euan
authors.initials: E
authors.lastname: Ashley
authors.affiliation: Department of Physical Therapy and Integrative Physiology Laboratory, College of Applied Science, University of Illinois, Chicago, IL.
authors.forename: Ross
authors.initials: R
authors.lastname: Arena
keywords: Cardiopulmonary exercise testing; Exercise; Fitness; Gas exchange