Experimental Physiology最新文献

{"title":"Submaximal 2-day cardiopulmonary exercise testing to assess exercise capacity and post-exertional symptom exacerbation in people with long COVID.","authors":"Callum Thomas, Nik Kudiersky, Paul Ansdell, Ruth E Ashton, Calum Brown, Thomas Bewick, Jack Carr, Emily Hume, Padraig Spillane, Elisa Pastorio, Rebecca Owen, Tom Maden-Wilkinson, Ethan McNeil-Angopa, Tom Parkington, Ross Arena, Cemal Ozemek, Federico Formenti, Sundar Kumar Veluswamy, Rachita Gururaj, Mark A Faghy","doi":"10.1113/EP092576","DOIUrl":"https://doi.org/10.1113/EP092576","url":null,"abstract":"<p><p>Long COVID has a complex pathology and a heterogeneous symptom profile that impacts quality of life and functional status. Post-exertional symptom exacerbation (PESE) affects one-third of people living with long COVID, but the physiological basis of impaired physical function remains poorly understood. Sixty-eight people (age (mean ± SD): 50 ± 11 years, 46 females (68%)) were screened for severity of PESE and completed two submaximal cardiopulmonary exercise tests separated by 24 h. Work rate was stratified relative to functional status and was set at 10, 20 or 30 W, increasing by 5 W/min for a maximum of 12 min. At the first ventilatory threshold (VT1), <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <msub><mi>O</mi> <mn>2</mn></msub> </msub> <annotation>${dot V_{{{mathrm{O}}_2}}}$</annotation></semantics> </math> was 0.73 ± 0.16 L/min on Day 1 and decreased on Day 2 (0.68 ± 0.16 L/min; P = 0.003). Work rate at VT1 was lower on Day 2 (Day 1 vs. Day 2; 28 ± 13 vs. 24 ± 12 W; P = 0.004). Oxygen pulse on Day 1 at VT1 was 8.2 ± 2.2 mL/beat and was reduced on Day 2 (7.5 ± 1.8 mL/beat; P = 0.002). The partial pressure of end tidal carbon dioxide was reduced on Day 2 (Day 1 vs. Day 2; 38 ± 3.8 vs. 37 ± 3.2 mmHg; P = 0.010). Impaired <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <msub><mi>O</mi> <mn>2</mn></msub> </msub> <annotation>${dot V_{{{mathrm{O}}_2}}}$</annotation></semantics> </math> is indicative of reduced transport and/or utilisation of oxygen. <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <msub><mi>O</mi> <mn>2</mn></msub> </msub> <annotation>${dot V_{{{mathrm{O}}_2}}}$</annotation></semantics> </math> at VT1 was impaired on Day 2, highlighting worsened function in the 24 h after submaximal exercise. The data suggest multiple contributing physiological mechanisms across different systems and further research is needed to investigate these areas.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144293593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microelectrode recordings from the human cervical vagus nerve during maximal breath-holds.","authors":"Vaughan G Macefield, Anthony R Bain, Matthew I Badour, Marko Kumric, Ivan Drvis, Otto F Barak, Josko Bozic, Zeljko Dujic","doi":"10.1113/EP092890","DOIUrl":"https://doi.org/10.1113/EP092890","url":null,"abstract":"<p><p>Voluntary breath-holds can be sustained for a long time following training, but ultimately, regardless of duration, the asphyxic break-point is reached and the apnoea terminated. The physiological changes occurring during the apnoea include a marked increase in sympathetically-mediated vasoconstriction in non-essential organs, such as skeletal muscle, spleen and kidney, while the brain is protected by a marked increase in perfusion. What is not understood is what happens to cardiac vagal activity. Here, we performed microelectrode recordings from the right cervical vagus nerve in healthy participants [both trained breath-hold divers (n = 10) and untrained controls (n = 10)] during tidal breathing, slow-deep breathing, an inspiratory-capacity apnoea and an end-expiratory apnoea. Using cross-correlation analysis of multi-unit neural activity, we tested the hypothesis that breath-hold divers would have greater cardiac modulation of vagal activity, which primarily reflects the discharge of cardiac afferents, particularly during a maximal apnoea. We showed that there were no differences in cardiac modulation of vagus nerve activity either during tidal breathing or during any of the respiratory manoeuvres, nor was there a difference in cardiac modulation during the static phase of a maximal apnoea or when involuntary breathing movements occurred before reaching the asphyxic break-point. We conclude that changes in vagal sensory inputs from the heart are not responsible for the marked tolerance to asphyxia shown by breath-hold divers.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144274565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topical application of the cold-mimetic l-menthol decreases wheel running without affecting the beneficial effects of voluntary exercise in mice.","authors":"Annalaura Bellucci, Bradley J Baranowski, Stewart Jeromson, Michael Akcan, Serena Trang, Meagan Arbeau, Hadil Alfares, Katelyn Eisner, David C Wright","doi":"10.1113/EP092754","DOIUrl":"https://doi.org/10.1113/EP092754","url":null,"abstract":"<p><p>Topical application of l-menthol, a pharmacological cold-mimetic and agonist of the cold-sensing receptor TRPM8 (transient receptor potential cation channel subfamily M member 8), has been shown to stimulate brown adipose tissue (BAT) thermogenesis and reduce weight gain in both obese and lean male mice, without affecting energy intake. While these findings suggest that l-menthol could offer a novel approach to prevent weight gain, its potential to enhance the benefits of exercise on whole-body metabolic health remains unexplored. In this study, we investigated whether daily topical l-menthol application, combined with voluntary wheel running, could enhance exercise-induced improvements in metabolic health in male and female C57BL/6J mice housed at thermoneutrality (29°C). Our results demonstrated that although l-menthol treatment reduced voluntary wheel running distance, there was still a main effect of exercise to reduce fat mass, weight gain and improve glucose tolerance. Indirect calorimetry revealed that l-menthol increased total energy expenditure, potentially explaining improvements in metabolic health despite reductions in voluntary wheel running. These findings suggest that although l-menthol does not enhance the effects of voluntary exercise, it remains a promising strategy for improving metabolic health.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144274566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visual and vestibular reweighting after cyber- and space-sickness.","authors":"Tess Bonnard, Emilie Doat, Jean-René Cazalets, Dominique Guehl, Etienne Guillaud","doi":"10.1113/EP092966","DOIUrl":"https://doi.org/10.1113/EP092966","url":null,"abstract":"<p><p>Sensory conflicts are widely recognized as the primary drivers of motion sickness (MS), though the underlying integrative processes remain poorly understood. This study investigated sensory reweighting following exposure to two different sensory conflict paradigms. Visual and vestibular reflexes were assessed before and after sensory conflict. In the first paradigm, participants were exposed to a visuo-vestibular conflict using visually induced illusory motion (vection) in two environments in immersive virtual reality. In the second paradigm, vestibular conflict was induced by gravitational changes in parabolic flight. Semi-circular canal integration was measured via the vestibulo-ocular reflex (VOR) suppression task, while visual weight was assessed through optokinetic nystagmus (OKN). Our findings revealed that, following virtual reality exposure, VOR response decreased by 12%, indicating a reduced reliance on vestibular inputs. Conversely, after parabolic flight, OKN performance was diminished by 13%, indicating a diminished weight of visual inputs. These findings suggest that the sensory modality failing to detect the motion was considered less reliable and therefore assigned a reduced contribution during the integration process, regardless of its actual accuracy. Additionally, visual sensitivity was associated with increased susceptibility to cybersickness, whereas vestibular sensitivity seemed to correlate MS severity in parabolic flight. Altogether, our data suggest that the sensitivity of the most stimulated sensory modality during a sensory conflict may predict an individual's susceptibility to MS.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144265783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The perception of the position of an unseen limb: Investigation of the effect of thixotropic conditioning on drift and accuracy.","authors":"Simon C Gandevia, Georgia Fisher, Joanna Diong, Annie A Butler, Martin E Héroux","doi":"10.1113/EP092686","DOIUrl":"https://doi.org/10.1113/EP092686","url":null,"abstract":"<p><p>Proprioceptive judgements can be divided into two broad categories: low-level and high-level. Low-level judgements of limb position require a person to detect, discriminate or match the position of a body part, whereas high-level judgements require a person to report the position of an unseen body part relative to the external world. It has been suggested that muscle thixotropy - the influence of recent contraction or stretch on the passive properties of a muscle - impacts both the accuracy of low-level judgements of limb position and the degree to which these judgements drift over time. However, high-level proprioceptive judgements of upper limb position and the degree to which they drift over time may not be affected by thixotropy. This was investigated here. Twenty-five healthy adult participants made visual judgements about the perceived position of their hidden index finger after their elbow muscles had been conditioned with a flexion or extension contraction, or after a series of large passive elbow movements. After conditioning contractions, participants made small errors (∼2°) in perceived index finger position in the direction of elbow flexion, regardless of the contraction type. There was little to no effect of either contraction type on drift in perceived index-finger position in our test. Our results support the view that high-level proprioceptive judgements of hand position can be minimally affected by the effects of muscle thixotropy. Thus, we suggest that muscle spindle signals do not dominate the central, cross-modal transformations of sensory information that are required for high-level proprioceptive judgements.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144265782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surgery in space: The ultimate frontier.","authors":"Mohamad Bashir, Ali Murtada, Matti Jubouri, Adam Bashir, Ian Williams, Damian Bailey","doi":"10.1113/EP092765","DOIUrl":"https://doi.org/10.1113/EP092765","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144265781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aortic and cardiovascular remodelling after thoracic endovascular aortic repair for blunt traumatic aortic injury in younger patients: A narrative review of physiological and clinical outcomes.","authors":"Marco David Bokobza De la Rosa, Matti Jubouri, Thurkga Moothathamby, Mohamed Refaie, Ali Murtada, Idhrees Mohammed, Ian M Williams, Damian M Bailey, Mohamad Bashir","doi":"10.1113/EP092615","DOIUrl":"https://doi.org/10.1113/EP092615","url":null,"abstract":"<p><p>Blunt traumatic aortic injury (BTAI) is severe, often fatal in younger populations due to high-energy deceleration mechanisms. Thoracic endovascular aortic repair (TEVAR) has revolutionised BTAI treatment, surpassing the previously standard open surgical repair in mortality and complication rates. Despite its success, concerns arise regarding TEVAR's long-term effects, especially in younger BTAI patients. Key physiological changes following TEVAR include alterations in aortic size, shape, compliance and flow dynamics, leading to loss of the Windkessel effect and a consequent increased pulse wave velocity and decreased radial strain, which can contribute to the development of hypertension. These alterations also predispose patients to changes in cardiovascular flow (increased reverse systolic flow, reduced maximum velocity and altered helical flow), potentially increasing the risk of left ventricular dysfunction and coronary artery disease. Physiological changes also increase the likelihood of complications such as graft migration. Clinical outcomes of TEVAR for BTAI have generally been favourable, with significant reductions in mortality and cerebrovascular accident rates compared to open surgical repair. However, long-term complications, including the need for re-interventions, remain a concern, though studies suggest these are infrequent. The durability of TEVAR in younger patients, who may experience decades of device use, poses unique challenges, particularly due to the natural progression of aortic morphology over time. Therefore, adapting TEVAR to the physiological needs of younger BTAI patients is essential. Developing more compliant endografts and using shorter stents with improved materials can help minimise structural and haemodynamic changes and enhance cardiovascular outcomes, supporting the long-term health of this vulnerable population.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Size, more than oxygen need, determines the number of capillaries around a muscle fibre.","authors":"Christopher S Fry, Carlo Reggiani","doi":"10.1113/EP092911","DOIUrl":"https://doi.org/10.1113/EP092911","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144247096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diffusion and physical constraints limit oxidative capacity, capillary supply and size of muscle fibres in mice and humans.","authors":"Hans Degens, Guy A M Messa, Jason Tallis, Alessandra Bosutti, Tomas Venckunas, Ismail Adeniran, Rob C I Wüst, Paul W Hendrickse","doi":"10.1113/EP092750","DOIUrl":"https://doi.org/10.1113/EP092750","url":null,"abstract":"<p><p>It has been suggested that angiogenesis during skeletal muscle fibre hypertrophy allows escape from the 'size constraint', which is the inverse relationship between oxidative capacity and muscle fibre cross-sectional area (FCSA). It is, however, not known whether there are any limitations to the combinations of FCSA, oxidative capacity and capillary supply to an individual fibre. We determined the FCSA, oxidative capacity and capillary supply to fibres from highly resistance-trained men before and after superimposed endurance training, recreationally active men and women, and different mouse muscles. Both the oxidative capacity and the number of capillaries around a fibre (CAF) per FCSA (CAF/FCSA) showed an upper limit at each FCSA, irrespective of species, muscle origin or training status. The upper limit of fibre oxidative capacity was likely determined by diffusion constraints. The upper limit of CAF/FCSA was determined by physical constraints where (i) there is no further reduction in maximal diffusion distance to the core of a fibre beyond a CAF of 2, and (ii) the reduction in fibre area supplied by a capillary diminishes exponentially with an increase in CAF. The calculated upper limits of oxidative capacity and CAF/FCSA of a fibre of a given FCSA were linearly related. Irrespective of species, sex, muscle of origin and training status, our data indicate that diffusion limitations and physical limitations to capillary placement around a fibre place an upper limit on the oxidative capacity and capillary supply to a fibre of a given size, respectively.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144247095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ageing exacerbates the adverse effects of respiratory muscle fatigue on vascular function, locomotor muscle fatigue and exercise performance in males.","authors":"Valentin Mons, Colin Lavigne, Olivier Meste, Benjamin Mauroy, Gregory M Blain","doi":"10.1113/EP092897","DOIUrl":"https://doi.org/10.1113/EP092897","url":null,"abstract":"<p><p>This study investigated the effect of respiratory muscle fatigue on cardiovascular function, locomotor muscle fatigue and exercise performance in young and master athletes, a model of successful ageing. Ten young male (YA, 27.4 ± 4.4 years) and 11 male master endurance athletes (MA, 65.0 ± 5.1 years) performed, on separate days, two constant workload cycling tests at 90% of peak power to exhaustion (CWT) following a fatiguing inspiratory loading task at 60% (ILT_60%) and a sham task at 2% (ILT_2%) of their maximal inspiratory pressure. On a third day, the sham task was replicated but CWT was interrupted at the time equal to that performed during CWT_ILT60% (CWT_ILT2%-ISO). Quadriceps fatigue was assessed by changes in maximal voluntary isometric contraction (MVC), potentiated twitch force (QT_SINGLE) and voluntary activation (VA) from 15 s to 15 min post-exercise. Mean arterial pressure (MAP) was measured using finger pulse photoplethysmography. Blood flow (Q̇_L) and limb vascular conductance (LVC) were measured using Doppler ultrasound. During ILT_60%, MA demonstrated reduced Q̇_L (P = 0.036), a greater increase in MAP (P < 0.001) and a larger decrease in LVC (P = 0.044) compared to YA. During CWT_ILT60%, MA experienced a larger decrease in time to exhaustion (-39.7 ± 14.0%) than YA (-15.5 ± 13.9%, P = 0.010). Exercise-induced reductions in MVC and QT_SINGLE (both P < 0.039) were also more pronounced during CWT_ILT60% compared to CWT_ILT2%-ISO in MA. Ageing exacerbates the adverse effects of respiratory muscle fatigue on limb vascular function and locomotor muscle fatigue during subsequent exercise, resulting in greater impairments in exercise performance.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144233641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}