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Contribución del metaborreflex muscular a la regulación del nodo sinusal durante el ejercicio estático: ideas del
F Iellamo1, P Pizzinelli, M Massaro
1Dipartimento di Medicina Interna, Università di Roma "Tor Vergata," Rome, Italy. iellamo@med.uniroma2.it
Circulation
|July 7, 1999
Resumen
El metaboloreflejo del músculo ayuda a la regulación de la frecuencia cardíaca durante el ejercicio a través de la activación simpática. Los mecanismos de barorreflejo arterial explican la recuperación de la frecuencia cardíaca después del ejercicio, incluso con una estimulación metaborrefleja muscular sostenida.
Área de la Ciencia:
- Fisiología cardiovascular fisiología cardiovascular.
- Regulación del sistema nervioso autónomo.
- Fisiología del ejercicio Fisiología del ejercicio
Sus antecedentes:
- La comprensión actual sugiere que el comando central influye principalmente en la frecuencia cardíaca (HR) a través de la retirada parasimpática durante el ejercicio estático.
- Se cree que el metaboloreflejo muscular eleva la presión arterial (BP) únicamente a través de la vasoconstricción simpática, ya que la BP permanece alta mientras que la HR se recupera después del ejercicio.
- Este estudio investiga el papel del metaborreflejo en la regulación de la HR y la participación del barorreflejo en la recuperación de la HR después del ejercicio.
Objetivo del estudio:
- Para probar si el metaboloreflejo muscular contribuye a la regulación de la frecuencia cardíaca durante el ejercicio estático a través de la activación simpática.
- Para determinar si el barorreflejo arterial influye en la recuperación de la frecuencia cardíaca durante la isquemia muscular posterior al ejercicio.
Principales métodos:
- Once hombres sanos realizaron la extensión estática de la pierna (SLE) seguida de la circulación de la pierna detenida (ALC).
- El análisis espectral de la variabilidad de la frecuencia cardíaca (HRV) evaluó la regulación autónoma de la frecuencia cardíaca.
- El método de barorreflejo espontáneo evaluó el control barorreflejo del período cardíaco.
Principales resultados:
- La extensión estática de la pierna aumentó el componente de baja frecuencia de la VRC, lo que indica la activación simpática, que persistió durante la circulación de la pierna detenida.
- El componente normalizado de alta frecuencia de la VRC disminuyó durante el LES y se normalizó durante la ALC.
- La sensibilidad del barorreflejo se redujo durante el LES y se recuperó durante la ALC, coincidiendo con la recuperación elevada de la presión arterial y la HR.
Conclusiones:
- El metaboloreflejo muscular contribuye a la regulación de la frecuencia cardíaca durante el ejercicio estático a través de la activación del sistema nervioso simpático.
- La bradicardia post-ejercicio, a pesar de la estimulación simpática en curso, es probable que se deba a un aumento mediado por barorreflejo en el flujo de salida parasimpático que prevalece sobre el impulso simpático.
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