No effect of aerobic fitness on exercise-induced diaphragm fatigue in females.
J Appl Physiol (1985)
; 137(5): 1145-1157, 2024 Nov 01.
Article
en En
| MEDLINE
| ID: mdl-39236143
ABSTRACT
We tested the hypothesis that the incidence and magnitude of diaphragm fatigue following high-intensity exercise would be lower in females with a high aerobic capacity (Hi-Fit) compared with healthy females with an average aerobic fitness (Avg-Fit). Participants were assigned to groups based on their peak O2 uptake (VÌo2peak) obtained during cycle exercise Hi-Fit n = 9, VÌo2peak ≥ 56.1 ± 3.4 mL·kg-1·min-1 versus Avg-Fit n = 9, VÌo2peak ≤ 35.7 ± 4.9 mL·kg-1·min-1. On the second day, diaphragm fatigue was assessed before and after constant load exercise test to exhaustion. Magnetic stimulation of the phrenic nerve roots was used to nonvolitionally assess diaphragm fatigue by measurement of transdiaphragmatic twitch pressure (Pdi,tw). Both groups exercised at >90% of VÌo2peak for a similar duration (Hi-Fit 546.1 ± 177.8 vs. Avg-Fit 559.3 ± 175.0 s, P = 0.9). Diaphragm fatigue was defined as a ≥15% reduction in Pdi,tw, approximately two times greater than the coefficient of variation. The mean group average reduction in Pdi,tw following exercise in the Hi-Fit (17.5%) and Avg-Fit groups (12.2%) was not different between groups (P = 0.2). The Hi-Fit group performed exercise at a higher absolute work rate that elicited significantly greater ventilatory work and inspiratory muscle force output. The Hi-Fit group did not experience greater fatigue compared with the Avg-Fit group, which we attribute to a greater reliance on accessory respiratory muscle recruitment, to training-induced increases in the aerobic capacity of the diaphragm, or a combination of the two. In summary, aerobic fitness is not predictive of exercise-induced diaphragm fatigue in healthy females.NEW & NOTEWORTHY We hypothesized that females with a high aerobic capacity would be resistant to exercise-induced diaphragm fatigue relative to healthy but untrained females. We assessed the pressure generated by the diaphragm following exhaustive exercise by stimulating the phrenic nerves. The magnitude and incidence of fatigue were similar between groups. Despite having higher ventilatory demands during exercise highly trained females were resistant to greater diaphragm fatigue. Aerobic fitness is not predictive of exercise-induced diaphragm fatigue in females.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Diafragma
/
Ejercicio Físico
/
Fatiga Muscular
Límite:
Adult
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Female
/
Humans
Idioma:
En
Revista:
J Appl Physiol (1985)
Asunto de la revista:
FISIOLOGIA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
Estados Unidos