Comparison of anaerobic threshold determined by visual and mathematical methods in healthy women

Author(s)

M.N. Higa ^[1] ; E. Silva ; V.F.C. Neves ^[3] ; A.M. Catai ^[4] ; L. Gallo Jr. ^[5] ; M.F. Silva de Sá ^[6]

Affiliation

^[1] Universidade de São Paulo. Faculdade de Medicina de Ribeirão Preto. Hospital das Clínicas

^[3] Universidade Federal de São Carlos. Departamento de Fisioterapia. Laboratório de Fisioterapia Cardiovascular - Brasil

^[4] Universidade Federal de São Carlos. Departamento de Fisioterapia. Laboratório de Fisioterapia Cardiovascular - Brasil

^[5] Universidade de São Paulo. Faculdade de Medicina de Ribeirão Preto. Hospital das Clínicas - Brasil

^[6] Universidade de São Paulo. Faculdade de Medicina de Ribeirão Preto. Hospital das Clínicas

• Document type: Journal article
• Source: Brazilian Journal of Medical and Biological Research; v. 40, n. 4, p. 501-508, 2007-04-00.

Abstract

Several methods are used to estimate anaerobic threshold (AT) during exercise. The aim of the present study was to compare AT obtained by a graphic visual method for the estimate of ventilatory and metabolic variables (gold standard), to a bi-segmental linear regression mathematical model of Hinkley's algorithm applied to heart rate (HR) and carbon dioxide output (VCO2) data. Thirteen young (24 ± 2.63 years old) and 16 postmenopausal (57 ± 4.79 years old) healthy and sedentary women were submitted to a continuous ergospirometric incremental test on an electromagnetic braking cycloergometer with 10 to 20 W/min increases until physical exhaustion. The ventilatory variables were recorded breath-to-breath and HR was obtained beat-to-beat over real time. Data were analyzed by the nonparametric Friedman test and Spearman correlation test with the level of significance set at 5%. Power output (W), HR (bpm), oxygen uptake (VO2; mL kg-1 min-1), VO2 (mL/min), VCO2 (mL/min), and minute ventilation (VE; L/min) data observed at the AT level were similar for both methods and groups studied (P > 0.05). The VO2 (mL kg-1 min-1) data showed significant correlation (P < 0.05) between the gold standard method and the mathematical model when applied to HR (r s = 0.75) and VCO2 (r s = 0.78) data for the subjects as a whole (N = 29). The proposed mathematical method for the detection of changes in response patterns of VCO2 and HR was adequate and promising for AT detection in young and middle-aged women, representing a semi-automatic, non-invasive and objective AT measurement. (AU)