Abstract
This work aimed to investigate accessory respiratory muscle oxygenation (RMO2 ) during exercise, using near-infrared spectroscopy, and to study relationships between RMO2 kinetics and breathing parameters. Nineteen young males (19.3 ± 1.5 years) performed a maximal incremental test on a cycle ergometer. Changes in breathing pattern were characterized by accelerated rise in the breathing frequency (fRacc ), plateau of tidal volume (VTplateau ) and inflection point in the V·E /VT relationship (V·E /VT inflection ). First and second ventilatory thresholds (VT1 and VT2) were also determined. RMO2 kinetics were monitored by NIRS on the serratus anterior. During exercise, all subjects showed reduced RMO2 (deoxygenation) with a breakdown (B‐RMO2 ) at submaximal workload (86 % V·O2max ). V·O2 corresponding to B‐RMO2 and to fRacc , VTplateau , V·E /VT inflection , or VT2 were not different. Relationships were found between the V·O2 at B‐RMO2 and the V·O2 at fRacc (r = 0.88, p < 0.001), VTplateau (r = 0.84, p < 0.001), V·E /VT inflection (r = 0.58, p < 0.05) or VT2 (r = 0.79, p < 0.001). The amplitude of RMO2 at maximal workload was weakly related to V·O2max (r = 0.58, p < 0.05). B‐RMO2 seems to be due to the change in breathing pattern and especially to the important rise in breathing frequency at the VT2 exercise level. Moreover, subjects who exhibit higher V·O2max also exhibit a higher decrease in respiratory muscle oxygenation during exercise.
Key words
NIRS - ventilatory thresholds - breathing pattern - healthy young men - respiratory muscle oxygenation kinetics
References
Control of blood flow to cardiac and skeletal muscle during exercise. Rowell LB, Shepherd JT Exercise: Regulation and Integration of Multiple Systems. Handbook of Physiology. New York; American Physiological Society Oxford 1996: 711
2 and exercise tidal volume.
J Appl Physiol.
1979;
46
322-325
patrick.mucci@univ-lille2.fr
