Summary: Breathing through a mouthpiece and noseclip can cause some patients anxiety, which may lead to hyperventilation and influence the results of a resting metabolic rate measurement. This study examines the usefulness of practice as a way to minimize these effects. The conclusion indicates that variability may be reduced when the patient practices breathing through the mouthpiece for 5 minutes prior to the actual metabolic rate measurement.
Introduction: The use of a mouthpiece and nose clip can alter breathing patterns and thereby result in changes in respiratory frequency and volume. Moreover, apprehension or anxiety caused by unfamiliarity with the mouthpiece and nose clip may influence arousal and produce additional error in a resting metabolic rate (RMR) measurement. Multiple practice sessions and/or multiple measures are not available or affordable for most individuals in a clinical setting in which only one RMR test is often conducted. It is in this context that a need is created for a practice technique that involves minimal interaction between the client and the testing facility.
Discussion: From this study and other investigations, it appears evident that practice is necessary for an accurate RMR measure on the first visit to a testing facility. The data further indicate that an acute exposure to practice (5 minutes of practice on the day of testing) is comparable to longer term practice. The variability (standard deviation) around an individual’s average energy expenditure (kJ/24 hours) measure also was lower for the acclimation (acute exposure) group; however, this was not statistically significant. Although chance cannot be ruled out for this finding, a low RMR that is similar to a longer term practice group in addition to the minimal variability for the acclimation group may warrant the clinical use of this method.
Scott CB, Resting Metabolic Rate Variability as Influenced by Mouthpiece and Noseclip Practice Procedures. Journal of Burn Care, Sept/Oct 1993.