Diaphragmatic fatigue during inspiratory muscle loading in normoxia and hypoxia

Walker, David; Farquharson, Franziska; Klenze, Hannes; Walterspacher, Stephan; Storz, Lucia; Duerschmied, Daniel; Röecker, Kai; Kabitz, Hans‐Joachim

doi:10.1016/j.resp.2016.01.006

Cited by 6 publications

(7 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Importantly, both trials were applied at same relative intensity (70% of maximal inspiratory mouth pressure) during threshold loading but maintained to task failure, which was different (∼14% shorter in hypoxia) between trials; however, a similar total diaphragmatic work between trials, as well as a trend towards more pronounced fatigue, was reported in hypoxia (Walker et al . 2016). A drawback of this design is the use of P m as target because it captures not only diaphragm, but also overall rib cage and neck inspiratory muscles pressure generation (Attali et al .…”

Section: Discussionmentioning

confidence: 99%

“…For example, Walker et al . (2016) studied a mixed sample of 19 subjects (seven females), and found a different progression of diaphragm contractility in hypoxia (‘linear’ decline in diaphragmatic force output) compared to normoxia (‘exponential’ decline). Importantly, both trials were applied at same relative intensity (70% of maximal inspiratory mouth pressure) during threshold loading but maintained to task failure, which was different (∼14% shorter in hypoxia) between trials; however, a similar total diaphragmatic work between trials, as well as a trend towards more pronounced fatigue, was reported in hypoxia (Walker et al .…”

Section: Discussionmentioning

confidence: 99%

“…2010) and inspiratory pressure‐threshold loading (PTL) (Walker et al . 2016) as a result of reduced O 2 availability and increased reliance upon glycolytic energy pathways (Kierans & Taylor, 2021). The underlying mechanisms responsible for augmented DF in acute hypoxia are complex, involving central (cardiorespiratory and cerebral) and peripheral (neuromuscular) factors (Calbet et al .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sex differences in diaphragmatic fatigue: Effects of hypoxia during inspiratory loading

Archiza

Reinhard

Welch

et al. 2020

The Journal of Physiology

View full text Add to dashboard Cite

Key points Under normoxic conditions, both healthy female and male diaphragms fatigue at a similar degree when matched for absolute diaphragmatic work during inspiratory loading. We investigated whether similarities in diaphragm fatigability persist under acute hypoxic conditions. We found that, in acute hypoxia, fatigue of the diaphragm is greater in women compared to men, whereas the magnitude of fatigue in normoxia did not differ between sexes. When matched for maximal diaphragm strength, women and men had a similar pressor response to work‐matched inspiratory loading, independent of oxygen availability. Abstract In normoxia, women and men display a comparable magnitude of diaphragmatic fatigue (DF) after work‐matched inspiratory loading. Whether these sex similarities are maintained under acute hypoxic conditions is unknown. We investigated the influence of acute hypoxia during work‐matched inspiratory pressure‐threshold loading (PTL) on DF in healthy women (n = 8) and men (n = 8). Two 5 min isocapnic PTL tasks targeting a transdiaphragmatic pressure (Pdi) of 92 cmH2O in normoxia and hypoxia (8% O2) were performed on separate days (≥48 h). DF was quantified by twitch Pdi (Pdi,tw) via cervical magnetic stimulation post‐PTL. Women and men had similar maximal Pdi (Pdi,max; women: 171 ± 16, men: 178 ± 20 cmH2O) and relative target workload (women: 54 ± 5%, men: 53 ± 6% Pdi,max). The absolute cumulative diaphragmatic work did not differ between sexes in normoxia (women: 12,653 ± 1796 cmH2O s−1, men: 13,717 ± 1231 cmH2O s−1; P = 0.202) or hypoxia (women: 11,624 ± 1860 cmH2O s−1, men: 12 722 ± 1502 cmH2O s−1; P = 0.189). In normoxia, the magnitude of reduction in Pdi,tw post‐PTL was similar between sexes (women: –21.1 ± 8.4%, men: –22.5 ± 4.9 %; P = 0.193); however, a higher degree of DF was observed in women compared to men following PTL in acute hypoxia (women: −27.6 ± 7.7%, men: −23.4 ± 9.6%, P = 0.019). We conclude that the female diaphragm is more susceptible to fatigue after inspiratory loading under acute hypoxic conditions. This finding may be related to sex differences in diaphragm muscle metabolism, such as fibre type composition, contractile properties, substrate utilisation and blood perfusion.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sex differences in diaphragmatic fatigue: Effects of hypoxia during inspiratory loading

Archiza

Reinhard

Welch

et al. 2020

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…A second method for detecting respiratory muscle fatigue is to determine the maximum relaxation rate (MRR) (104), which is obtained from the inspiratory pressure curve. Under experimental conditions fatigue can also be detected by a decrease in maximum respiratory pressure induced by stimulation (twitch) (105,106). Another method used for the diagnosis of fatigue, which is complex and restricted to specialized laboratories, is the analysis of the electromyographic signal, and more specifically the evaluation of the relationships between high and low frequencies, the centroid frequency and/or the root mean square (RMS) (107,108).…”

Section: More Specific Functional Techniquesmentioning

confidence: 99%

Clinical management of chronic obstructive pulmonary disease patients with muscle dysfunction

et al. 2016

View full text Add to dashboard Cite

Muscle dysfunction is frequently observed in chronic obstructive pulmonary disease (COPD) patients, contributing to their exercise limitation and a worsening prognosis. The main factor leading to limb muscle dysfunction is deconditioning, whereas respiratory muscle dysfunction is mostly the result of pulmonary hyperinflation. However, both limb and respiratory muscles are also influenced by other negative factors, including smoking, systemic inflammation, nutritional abnormalities, exacerbations and some drugs. Limb muscle weakness is generally diagnosed through voluntary isometric maneuvers such as handgrip or quadriceps muscle contraction (dynamometry); while respiratory muscle loss of strength is usually recognized through a decrease in maximal static pressures measured at the mouth. Both types of measurements have validated reference values. Respiratory muscle strength can also be evaluated determining esophageal, gastric and transdiaphragmatic maximal pressures although there is a lack of widely accepted reference equations. Non-volitional maneuvers, obtained through electrical or magnetic stimulation, can be employed in patients unable to cooperate. Muscle endurance can also be assessed, generally using repeated submaximal maneuvers until exhaustion, but no validated reference values are available yet. The treatment of muscle dysfunction is multidimensional and includes improvement in lifestyle habits (smoking abstinence, healthy diet and a good level of physical activity, preferably outside), nutritional measures (diet supplements and occasionally, anabolic drugs), and different modalities of general and muscle training.

show abstract

“…Indeed, during hypoxia, a linear decline in transdiaphragmatic twitch pressure has been described (Walker et al . 2016). The greater vulnerability of female diaphragm to fatigue during hypoxia, as described in Archiza et al .…”

mentioning

confidence: 99%

Diaphragm fatigue: Similarities and differences between sexes

O’Halloran

2020

The Journal of Physiology

View full text Add to dashboard Cite

Diaphragmatic fatigue during inspiratory muscle loading in normoxia and hypoxia

Cited by 6 publications

References 33 publications

Sex differences in diaphragmatic fatigue: Effects of hypoxia during inspiratory loading

Sex differences in diaphragmatic fatigue: Effects of hypoxia during inspiratory loading

Clinical management of chronic obstructive pulmonary disease patients with muscle dysfunction

Diaphragm fatigue: Similarities and differences between sexes

Contact Info

Product

Resources

About