Int J Sports Med 2008; 29(8): 658-663
DOI: 10.1055/s-2007-989319
Training & Testing

© Georg Thieme Verlag KG Stuttgart · New York

How Accurately are Maximal Metabolic Equivalents Estimated Based on the Treadmill Workload in Healthy People and Asymptomatic Subjects with Cardiovascular Risk Factors?

M. T. Maeder1 , T. Muenzer2 , H. Rickli3 , H. P. Brunner-La Rocca1 , J. Myers4 , P. Ammann3
  • 1Division of Cardiology, University Hospital Basel, Basel, Switzerland
  • 2Center of Geriatric Medicine and Rehabilitation, Bürgerspital St. Gallen, St. Gallen, Switzerland
  • 3Division of Cardiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
  • 4Cardiology Division, Palo Alto Veterans Affairs Medical Center, Stanford University, Palo Alto, USA
Further Information

Publication History

accepted after revision September 20, 2007

Publication Date:
30 May 2008 (online)

Abstract

Maximal exercise capacity expressed as metabolic equivalents (METs) is rarely directly measured (measured METs; mMETs) but estimated from maximal workload (estimated METs; eMETs). We assessed the accuracy of predicting mMETs by eMETs in asymptomatic subjects. Thirty-four healthy volunteers without cardiovascular risk factors (controls) and 90 patients with at least one risk factor underwent cardiopulmonary exercise testing using individualized treadmill ramp protocols. The equation of the American College of Sports Medicine (ACSM) was employed to calculate eMETs. Despite a close correlation between eMETs and mMETs (patients: r = 0.82, controls: r = 0.88; p < 0.001 for both), eMETs were higher than mMETs in both patients [11.7 (8.9 – 13.4) vs. 8.2 (7.0 – 10.6) METs; p < 0.001] and controls [17.0 (16.2 – 18.2) vs. 15.6 (14.2 – 17.0) METs; p < 0.001]. The absolute [2.5 (1.6 – 3.7) vs. 1.3 (0.9 – 2.1) METs; p < 0.001] and the relative [28 (19 – 47) vs. 9 (6 – 14) %; p < 0.001] difference between eMETs and mMETs was higher in patients. In patients, ratio limits of agreement of 1.33 (*/÷ 1.40) between eMETs and mMETs were obtained, whereas the ratio limits of agreement were 1.09 (*/÷ 1.13) in controls. The ACSM equation is associated with a significant overestimation of mMETs in young and fit subjects, which is markedly more pronounced in older and less fit subjects with cardiovascular risk factors.

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Dr. Micha Tobias Maeder

University Hospital Basel
Division of Cardiology

Petersgraben 4

4031 Basel

Switzerland

Phone: + 41 6 12 65 25 25

Fax: + 41 6 12 65 45 98

Email: micha.maeder@bluewin.ch