title: Comparison of anaerobic threshold determined by visual and mathematical methods in healthy women.
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 (rs = 0.75) and VCO2 (rs = 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.
authors.affiliation: Departamento de Ginecologia e Obstetrícia, Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
authors.forename: M N
authors.initials: MN
authors.lastname: Higa
authors.forename: E
authors.initials: E
authors.lastname: Silva
authors.forename: V F C
authors.initials: VF
authors.lastname: Neves
authors.forename: A M
authors.initials: AM
authors.lastname: Catai
authors.forename: L
authors.initials: L
authors.lastname: Gallo
authors.forename: M F
authors.initials: MF
authors.lastname: Silva de Sá
mesh_terms: D000328:Adult; D000465:Algorithms; D015308:Anaerobic Threshold / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism*; D004562:Electrocardiography; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D008962:Models, Theoretical
chemical_list: D002245:Carbon Dioxide