The purpose of this study was to compare sex-based differences in the mean arterial blood pressure (MAP) response to limb and inspiratory metaboreflex activation, during relative and absolute workloads. Healthy males ( = 9) and females ( = 8) completed pulmonary function testing, forearm volume and circumference measurements, and bouts of limb and inspiratory muscle exercise. The exercises performed included bouts of rhythmic handgrip exercise (RHG) and inspiratory pressure threshold loading (PTL) to task failure, performed in a randomized order and separated by 30 minutes of rest.
View Article and Find Full Text PDFThere is a significant effect of sex and muscle mass on the cardiorespiratory response to the skeletal muscle metaboreflex during isometric exercise. We therefore tested the hypothesis that sex differences would be present when isolated following dynamic exercise. We also tested the hypothesis that single and double leg post-exercise circulatory occlusion (PECO) following heavy exercise would elicit a cardiorespiratory response proportional to the absolute muscle mass.
View Article and Find Full Text PDFFollowing high-intensity, normoxic exercise there is evidence to show that healthy females, on average, exhibit less fatigue of the diaphragm relative to males. In the present study, we combined hypoxia with exercise to test the hypothesis that males and females would develop a similar degree of diaphragm fatigue following cycle exercise at the same relative exercise intensity. Healthy young participants (n = 10 male; n = 10 female) with a high aerobic capacity (120% predicted) performed two time-to-exhaustion (TTE; ~85% maximum) cycle tests on separate days breathing either a normoxic or hypoxic (FiO = 0.
View Article and Find Full Text PDFIntense inspiratory muscle work evokes a sympathetically mediated pressor reflex, termed the respiratory muscle metaboreflex, in which young females demonstrate an attenuated response relative to males. However, the effects of ageing and female sex hormones on the respiratory muscle metaboreflex are unclear. We tested the hypothesis that the pressor response to inspiratory work would be similar between older males and females, and higher relative to their younger counterparts.
View Article and Find Full Text PDFPurpose: In normotensive patients with obstructive sleep apnea (OSA), the muscle sympathetic nerve activity (MSNA) response to exercise is increased while metaboreflex control of MSNA is decreased. We tested the hypotheses that acute intermittent hypercapnic hypoxia (IHH) in males free from OSA and associated comorbidities would augment the MSNA response to exercise but attenuate the change in MSNA during metaboreflex activation.
Methods: Thirteen healthy males (age = 24 ± 4 yr) were exposed to 40 min of IHH.
The decline in cognition observed in obstructive sleep apnea is linked to intermittent hypercapnic hypoxia (IHH), which is known to impair cerebrovascular reactivity. Whether acute IHH impairs the matching of cerebral blood flow to metabolism (i.e.
View Article and Find Full Text PDFKey Points: Ventilatory long-term facilitation (vLTF) refers to respiratory neuroplasticity that develops following intermittent hypoxia in both healthy and clinical populations. A sustained hypercapnic background is argued to be required for full vLTF expression in humans. We determined whether acute intermittent hypercapnic hypoxia elicits vLTF during isocapnic-normoxic recovery in healthy males and females.
View Article and Find Full Text PDF