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Med Sci Sports Exerc. 2006 May;38(5):1007-13.

A simplified strategy for the estimation of the exercise ventilatory thresholds.

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Pulmonary Function and Clinical Exercise Physiology Unit, Division of Respiratory Diseases, Federal University of Sao Paulo, Brazil.



To analyze the limits of agreement between exercise ventilatory threshold values (VT1 and VT2) estimated from a combination of pulmonary gas exchange and ventilatory variables (cardiopulmonary exercise testing) and those derived from an alternative approach based on the ventilatory response only (V(E), ventilometry).


Forty-two nontrained subjects (24 males, aged 18-48, peak VO(2) = 33.1 +/- 8.6 mL.min(-1).kg(-1)) performed a maximum incremental cardiopulmonary exercise testing on an electromagnetically braked cycle ergometer. The participants breathed through a Pitot tube (Cardio2 System, MGC) and a fixed-resistance ventilometer (Micromed, Brazil), which were connected in series. HR values at the estimated VT (VTHR1 and VTHR2) were obtained by the conventional method (ventilatory equivalents, end-expiratory pressures for O(2) and CO(2), and the V-slope procedure) and an experimental approach (V(E) vs time, V(E)/time vs time, and breathing frequency vs time).


There were no significant between-method differences on VT(HR1), VT(HR2), VT(VE1), VT(VE2), and peak V(E) (P > 0.05). After certification of data normality, a Bland-Altman analysis revealed that the mean bias +/- 95% confidence interval of the between-method differences were lower for VT(HR2) than VT(HR1) (2 +/- 9 and 0 +/- 17 bpm, respectively). VT(HR2) according to ventilometry differed more than 10 bpm from the standard procedure in 3 out of 42 subjects (9%). Between-method differences were independent of the level of fitness, as estimated from peak VO(2) (P > 0.05).


: A simplified approach, based on the ventilatory response as a function of time, can provide acceptable estimates of the exercise ventilatory thresholds--especially VT2--during ramp-incremental cycle ergometry. This new strategy might prove to be useful for exercise training prescription in nontrained adults.

[Indexed for MEDLINE]

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