Descending motor drive does not interact with muscle metaboreflex for ventilation regulation during rhythmic exercise in healthy humans.
Am J Physiol Lung Cell Mol Physiol
; 327(5): L783-L795, 2024 Nov 01.
Article
en En
| MEDLINE
| ID: mdl-39254090
ABSTRACT
The muscle metaboreflex effect on pulmonary ventilation (VÌE) regulation is more apparent during rhythmic exercise than rest, possibly because this reflex interacts with other mechanisms regulating VÌE during voluntary contractions, such as central command. Therefore, we tested whether one part of central command, the descending component of motor execution (i.e., descending motor drive), and the muscle metaboreflex interact synergistically to regulate VÌE. Thirteen healthy adults (9 men) completed four experiments in random order under isocapnia. The muscle metaboreflex was activated by rhythmic handgrip exercise at 60% maximal voluntary contraction (MVC) force with the dominant hand. Then, the muscle metaboreflex remained active during a 4-min recovery period via postexercise circulatory occlusion (PECO), or it was inactivated, maintaining free blood flow to the dominant upper limb. During the last 2 min of the handgrip exercise recovery, participants either performed rhythmic voluntary plantar flexion with the dominant leg at 30% MVC torque to generate descending motor drive or the dominant leg's calf muscles were involuntarily activated by electrical stimulation at a similar torque level (i.e., without descending motor drive). VÌE increased to a similar level during handgrip exercise in all conditions (≈22 L/min, P = 0.364). PECO maintained VÌE elevated above recovery with free blood flow (≈17 L/min vs. ≈13 L/min, P = 0.009). However, voluntary and involuntary plantar flexion with or without PECO evoked similar VÌE responses (Δ ≈ 4 L/min, P = 0.311). Therefore, an interaction between descending motor drive and muscle metaboreflex is not ubiquitous for VÌE regulation during rhythmic exercise.NEW & NOTEWORTHY Voluntary (i.e., with descending motor drive) and involuntary (i.e., no descending motor drive) plantar flexion elicited similar ventilatory responses when postexercise circulatory occlusion was or was not used in an upper limb. These results indicate that the descending motor drive component of the central command and the muscle metaboreflex do not interact to regulate pulmonary ventilation during rhythmic exercise, which suggests that a supposed interaction between central command-muscle metaboreflex is more complex than previously thought.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Reflejo
/
Ejercicio Físico
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Músculo Esquelético
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Ventilación Pulmonar
Límite:
Adult
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Female
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Humans
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Male
Idioma:
En
Revista:
Am J Physiol Lung Cell Mol Physiol
Asunto de la revista:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Estados Unidos