Abstract

Background: Several studies have evaluated the accuracy of portable metabolic gas analysis systems, which measure physical activity energy expenditure. Since the Cosmed K2 telemetric system, two K4 devices (RQ and b2) have been developed.

Objective: To compare measurements using the Cosmed K4 RQ with measurements by a traditional method (mass spectrometer) for a sample of healthy subjects performing physical exercise of various intensities.

Methods: Nine healthy male footballers (mean (SD) age 18.3 (2.2) years) performed an incremental exercise running test from 8 km/h to exhaustion, with an increase of 2 km/h for each level of the test protocol. The expired air was collected simultaneously using the Cosmed K4 RQ and Airspec QP9000 mass spectrometer. Oxygen consumption (Vo₂) and carbon dioxide production (Vco₂) were measured at rest and at each exercise intensity.

Results: No significant differences were found between Vo₂ and Vco₂ measured by the two instruments, at rest or during exercise.

Conclusions: The application of the Cosmed K4 RQ system for Vo₂ and Vco₂ measurements at rest and during both submaximal and maximal exercise may be of interest to sport physiologists, nutritionists, and doctors.