Abstract
BACKGROUND: Walking is part of obesity management. Assessment of ventilatory impairments and consequences for gait induced by obesity could be clinically helpful. We aimed to develop a method to accurately monitor ventilation with respiratory inductive plethysmography (RIP) in subjects with high body mass indices (BMIs) during a 6-min walk test (6MWT).
METHODS: 25 volunteers were divided into 2 groups based on BMI (<25 or >30 kg/m2) and performed a 6MWT with a calibrated RIP. Ventilatory parameters (tidal volume [VT], inspiratory [TI] and expiratory [TE] times, VT/TI ratio, and TI/Ttot ratio) were determined after processing RIP signals with a custom-made algorithm designed to discriminate tissue motion artifacts and respiratory cycles in the time domain. Six-min walk distance and average speed by minute were collected.
RESULTS: The number of artifacts removed by the algorithm used for artifact removal was higher for high-BMI subjects and was correlated to their individual values (r = 0.66, P < .001). Six-min walk distance was lower for the group with a higher BMI (P = .001). ANOVA revealed effects of exercise for VT, TI, and TE (P < .001) and also BMI effects in the course of the 6MWT for VT, TI, TE, VT/TI, and TI/Ttot (P < .001 for each of them).
CONCLUSIONS: This respiratory monitoring method is sufficiently sensitive to point out differences between rest and exercise as well as locomotor and ventilatory differences relative to BMI during the 6MWT. Thus, this system gives useful information from the 6MWT for clinicians who want to assess respiratory patterns of patients during this commonly used test.
- respiratory inductive plethysmography
- 6-min walk test
- tidal ventilation
- body mass index
- artifacts
- submaximal exercise
Footnotes
- Correspondence: Yann Retory MSc, Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré AP-HP, 9, Avenue Charles de Gaulle, 92100 Boulogne Cedex, France. E-mail: yann.retory{at}aphp.fr.
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