Experimental Physiology最新文献

{"title":"Trimethylamine N-oxide is elevated in postmenopausal women relative to age-matched men and premenopausal women among individuals with obesity.","authors":"Daniel J Battillo, Steven K Malin","doi":"10.1113/EP092550","DOIUrl":"https://doi.org/10.1113/EP092550","url":null,"abstract":"<p><p>Trimethylamine N-oxide (TMAO) is linked to arterial stiffness and atherosclerosis. Cardiovascular disease (CVD) risk increases following menopause in women. Whether menopause influences plasma TMAO metabolism to mediate CVD risk is unknown. Women with obesity were classified as premenopausal (n = 13; 40.3 ± 2.7 years; 39.4 ± 2.0 kg/m²) or postmenopausal (n = 22; 56.5 ± 1.1 years; 35.6 ± 0.9 kg/m²) via self-reported presence/absence of menses (last 12 months). Men were age- and body mass index-matched to postmenopausal women (n = 16; 55.9 ± 2.1 years; 34.3 ± 1.2 kg/m²) as controls to discern potential menopause-driven TMAO differences. Carotid-femoral pulse wave velocity (cfPWV) and pulse wave analysis (applanation tonometry) were analysed to assess arterial stiffness, aortic waveforms and blood pressure. Fasting plasma TMAO and precursors (carnitine, choline, betaine and trimethylamine (TMA)) were assessed (mass spectroscopy). A 180 min 75 g oral glucose tolerance test was performed to approximate insulin sensitivity and quantify vascular cell (vascular cell adhesion molecule 1 (VCAM-1)) and intercellular adhesion molecules (intercellular adhesion molecule 1 (ICAM-1)). Body composition (DXA/BodPod) and fitness ( <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> ) were measured. Premenopausal women were younger than men and postmenopausal women (P < 0.0001, η² = 2.29). Men had lower body fat (P = 0.001, η² = 0.80) and higher fat-free mass (P = 0.004, η² = 0.42) compared to both pre- and postmenopausal women. There were no differences among groups in fitness, insulin sensitivity, ICAM-1 or blood pressure (P > 0.05), but men had higher cfPWV (P = 0.040, η² = 0.27) and VCAM-1 (P = 0.041, η² = 0.32). Postmenopausal women had elevated TMAO (P = 0.040, η² = 0.29), compared with men and premenopausal women, yet men had elevated TMA (P = 0.041, η² = 0.17), carnitine (P = 0.003, η² = 0.27), choline (P = 0.022, η² = 0.35) and betaine (P < 0.0001, η² = 0.59). Thus when taken together, menopause may raise TMAO in women, while older men appear to have unique TMAO precursor metabolism linked to CVD risk.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144667498","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 reveals the latent effects of early life stress on respiratory and metabolic function in female rats: Novel insights into the sex-specific origins of sleep apnoea.","authors":"Danuzia Ambrozio-Marques, Loralie Mei Guay, Alicia A Koogler, Tim D Ostrowski, Richard Kinkead","doi":"10.1113/EP092722","DOIUrl":"https://doi.org/10.1113/EP092722","url":null,"abstract":"<p><p>Sleep apnoea (SA) is ∼2 times more prevalent in men than women. However, this changes at menopause as the occurrence of SA increases and matches that of men. Menopause is a natural process, but it remains unclear why SA emerges only in a subpopulation of ageing women. Early life stress has persistent and sex-specific effects on the brain. Since loss of ovarian hormones is commonly invoked to explain the emergence of various diseases in menopausal women, we tested the hypothesis that the impacts of early life stress on respiratory control remain latent until they reach old age. Newborn rats were either subjected to neonatal maternal separation (NMS; 3 h/day; postnatal days 3-12) or remained undisturbed (CTRL). Females were then raised under standard conditions until they reached adulthood (12-17 weeks), middle-age (35-40 weeks) or old age (60-65 weeks). Respiratory activity was measured with whole body plethysmography. Body weight and composition was assessed with nuclear magnetic resonance. NMS augmented the apnoea index; however, this effect was detected only in old females. Body mass index and the percentage of body fat increased progressively; these changes were enhanced by NMS and most notable in old females. We conclude that NMS compromises the ageing trajectory of female rats and leads to the development of a phenotype that shares many features reported in SA patients, including respiratory and metabolic dysfunction. Prior life experiences may be an important risk factor in the development of SA in ageing women.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144667494","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":"Noradrenergic regulation of skeletal muscle oxygen pressures: Impact of heart failure with preserved ejection fraction and heat therapy.","authors":"Edward T N Calvo, Jacob M Pontorno, Benjamin Zeidler, Taciane M M Pejon, Michael D Belbis, Scott K Ferguson, Craig J Goergen, Timothy P Gavin, Bruno T Roseguini, Igor A Fernandes, Daniel M Hirai","doi":"10.1113/EP092867","DOIUrl":"https://doi.org/10.1113/EP092867","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Attenuation of sympathetic vasoconstriction during exercise (functional sympatholysis) contributes to skeletal muscle oxygen delivery-utilization matching. However, the extent to which muscle contractions impact noradrenergic regulation of interstitial oxygen pressures ( &lt;math&gt; &lt;semantics&gt; &lt;msub&gt;&lt;msub&gt;&lt;mi&gt;P&lt;/mi&gt; &lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/msub&gt; &lt;mi&gt;is&lt;/mi&gt;&lt;/msub&gt; &lt;annotation&gt;${P_{{{mathrm{O}}_2}}}_{{mathrm{is}}}$&lt;/annotation&gt;&lt;/semantics&gt; &lt;/math&gt; ; the driving force for blood-myocyte oxygen flux) is unknown. We tested the hypotheses that (1) muscle contractions would attenuate the noradrenaline-induced reduction in muscle &lt;math&gt; &lt;semantics&gt; &lt;msub&gt;&lt;msub&gt;&lt;mi&gt;P&lt;/mi&gt; &lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/msub&gt; &lt;mi&gt;is&lt;/mi&gt;&lt;/msub&gt; &lt;annotation&gt;${P_{{{mathrm{O}}_2}}}_{{mathrm{is}}}$&lt;/annotation&gt;&lt;/semantics&gt; &lt;/math&gt; compared to rest (thus indicating functional sympatholysis) in healthy rats, and (2) functional sympatholysis would be impaired in rats with heart failure with preserved ejection fraction (HFpEF) but ameliorated with heat therapy. Skeletal muscle &lt;math&gt; &lt;semantics&gt; &lt;msub&gt;&lt;msub&gt;&lt;mi&gt;P&lt;/mi&gt; &lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/msub&gt; &lt;mi&gt;is&lt;/mi&gt;&lt;/msub&gt; &lt;annotation&gt;${P_{{{mathrm{O}}_2}}}_{{mathrm{is}}}$&lt;/annotation&gt;&lt;/semantics&gt; &lt;/math&gt; was determined via phosphorescence quenching in anaesthetized healthy (Sprague-Dawley, n = 14) and HFpEF rats (obese ZSF1, n = 20) at rest and during contractions following noradrenaline superfusion (5 × 10&lt;sup&gt;-4 &lt;/sup&gt; M). HFpEF rats underwent 8 weeks of heat therapy (HEAT, n = 10) or control treatment (CON; n = 10). Functional sympatholysis was evaluated based on the noradrenaline-induced changes in &lt;math&gt; &lt;semantics&gt; &lt;msub&gt;&lt;msub&gt;&lt;mi&gt;P&lt;/mi&gt; &lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/msub&gt; &lt;mi&gt;is&lt;/mi&gt;&lt;/msub&gt; &lt;annotation&gt;${P_{{{mathrm{O}}_2}}}_{{mathrm{is}}}$&lt;/annotation&gt;&lt;/semantics&gt; &lt;/math&gt; at rest and during contractions normalized to mean arterial pressure (Δ &lt;math&gt; &lt;semantics&gt; &lt;msub&gt;&lt;msub&gt;&lt;mi&gt;P&lt;/mi&gt; &lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/msub&gt; &lt;mi&gt;is&lt;/mi&gt;&lt;/msub&gt; &lt;annotation&gt;${P_{{{mathrm{O}}_2}}}_{{mathrm{is}}}$&lt;/annotation&gt;&lt;/semantics&gt; &lt;/math&gt; /MAP; %/mmHg). Consistent with our hypothesis, muscle contractions attenuated the noradrenaline-evoked &lt;math&gt; &lt;semantics&gt; &lt;msub&gt;&lt;msub&gt;&lt;mi&gt;P&lt;/mi&gt; &lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/msub&gt; &lt;mi&gt;is&lt;/mi&gt;&lt;/msub&gt; &lt;annotation&gt;${P_{{{mathrm{O}}_2}}}_{{mathrm{is}}}$&lt;/annotation&gt;&lt;/semantics&gt; &lt;/math&gt; reductions in healthy rats (rest: -0.50 ± 0.23, contractions: -0.25 ± 0.16; P &lt; 0.05). Compared to healthy rats, the noradrenergic response at rest was exacerbated in HFpEF-CON (-0.85 ± 0.13; P &lt; 0.05) but restored in HFpEF-HEAT (-0.61 ± 0.25; P &gt; 0.05). During contractions, the noradrenergic response was not different between HFpEF-CON and HFpEF-HEAT (-0.94 ± 0.07 and -0.86 ± 0.09, respectively; P &gt; 0.05). Moreover, the magnitude of sympatholysis was lower in both HFpEF-CON and HFpEF-HEAT compared to healthy. Taken together, these results indicate that heat therapy failed to impr","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144667495","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":"Sex differences in cerebral pulsatility and damping: A 4D flow MRI study.","authors":"Sarean Harmoni A Gaynor-Metzinger, Alexander M Norby, Brandon G Fico, M Erin Moir, Nicole A Loggie, Kathleen B Miller, Adam T Corkery, Andrew G Pearson, Anna J Howery, Leonardo A Rivera-Rivera, Kevin M Johnson, Sterling C Johnson, Oliver Wieben, Ryan D Zea, Jill N Barnes","doi":"10.1113/EP092630","DOIUrl":"10.1113/EP092630","url":null,"abstract":"<p><p>Cerebral pulsatility is a potential marker of cerebrovascular health, yet little is understood about sex differences in cerebral pulsatility with age, especially within different cerebral arteries. Additionally, cerebral damping can blunt cerebral pulsatility and might decline with age. Therefore, we aimed to identify sex differences in cerebral pulsatility and damping across the adult lifespan. Forty-three young, 67 middle-aged and 54 older adults had cerebral haemodynamics measured in the internal carotid arteries (ICAs), middle cerebral arteries (MCAs) and basilar artery using 4D flow MRI. Cerebral pulsatility index (PI) and damping factor (DF) were calculated. Young females had lower PI than young males in the ICAs (p < 0.05 for both), and middle-aged females had lower PI than middle-aged males in the right ICA (p < 0.01). In contrast, older females had greater PI than older males in the right ICA (p < 0.01) and in the right MCA (p < 0.05). Only the DF between the right ICA and MCA was lower in young females than in young males (p < 0.001). Taken together, females experience greater age-related elevations in cerebral pulsatility in comparison to males, especially within the proximal arteries of the anterior circulation. Damping was not different between males and females within the proximal arteries of anterior circulation, suggesting a different underlying mechanism. Overall, our findings suggest sex-specific trends in cerebral pulsatility with age, although the mechanisms driving this require further exploration.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144667497","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":"Computed cardiopulmonography: Effects of physical characteristics on lung parameter estimates.","authors":"Asma Alamoudi, Dominic Sandhu, Thomas D E Bithell, Nicholas M J Smith, Graham Richmond, Lorenzo S Petralia, Snapper Magor-Elliott, Haopeng Xu, Nick P Talbot, Grant A D Ritchie, Nayia Petousi, Peter A Robbins","doi":"10.1113/EP092423","DOIUrl":"https://doi.org/10.1113/EP092423","url":null,"abstract":"<p><p>Computed cardiopulmonography (CCP) is a technique that measures lung volumes (functional residual capacity and deadspace) together with novel parameters reflecting lung inhomogeneities (non-uniformities in lung inflation and deadspace path length). First, highly precise measurements of gas exchange are made during a nitrogen washout with a purpose-built molecular flow sensor. Second, an individual's lung physiology is then described by personalising the parameters of a bespoke cardio-respiratory model obtained by fitting the model to the data. The present study examines the effects of participants' physical characteristics on these parameter values, and from this also provides preliminary estimates for normal ranges. Data from 92 healthy individuals (27% female, age 40 ± 19 (mean ± SD) years, height 1.75 ± 0.09 m, mass 74 ± 14 kg) were used. A prediction equation for each CCP parameter was written as: y = α + βln(age) + γln(height) + δln(BMI) + ε(is_Female) + error, where BMI is body mass index. Non-significant terms (P > 0.1) were removed sequentially to identify just the significant characteristics. Physical characteristics exerted a large influence on volume-related CCP parameters. In contrast, only age had a significant influence on inhomogeneity-related CCP parameters. The prediction equations, together with their mean squared errors, were used to calculate z-scores for CCP data from three previously published studies in asthma, chronic obstructive pulmonary disease, and early cystic fibrosis. Values for these z-scores often lay beyond those commonly used to define a normal range (±1.65). In conclusion, reference values for inhomogeneity-based CCP parameters may only need correcting for age, and often appear as abnormal in airways disease.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144648923","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":"A comparison of methods to predict ovulation day, menstrual cycle characteristics and variability in professional female soccer players.","authors":"Rosie Anderson, Ian Rollo, Daniel Martin, Richard Burden, Rebecca K Randell, Craig Twist, Samantha L Moss","doi":"10.1113/EP092476","DOIUrl":"https://doi.org/10.1113/EP092476","url":null,"abstract":"<p><p>This study aimed to compare three methods of predicting ovulation day: (1) a positive urinary luteinising hormone test (LH), (2) a sustained rise in salivary progesterone above critical difference (SP), and (3) a countback regression equation (CB), to determine variability in the menstrual cycle (MC) lengths and reproductive hormone concentrations of professional female soccer players. Eight players provided daily morning saliva samples for three consecutive cycles. Samples were analysed for oestradiol and progesterone concentrations. Each MC was separated into the follicular (FP) and luteal (LP) phases relative to the day of ovulation, using the three different methods. MC length ranged from 24 to 32 days (28.3 ± 2.4 days); intra-assay coefficient of variation (7.5%) exceeded inter-assay coefficient of variation (4.6%). Ovulation estimated using SP (15.4 ± 3.0 days) occurred later than LH (13.3 ± 2.0 days) (P = 0.017). The CB method (14.1 ± 1.8 days) did not differ from SP (P = 0.102) or LH (P = 0.262). Oestradiol and progesterone levels varied significantly between sub-phases (P < 0.001). Inter-variability surpassed intra-variability for both hormones. Differences in methods for predicting ovulation indicate the need for standardised protocols. Individual variation in MC length and hormone concentrations challenges the narrative for group-level MC recommendations, emphasising the need for individualised hormone monitoring across multiple cycles.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144642112","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 attenuates regional vasoconstriction during acute lowering of upper and lower limbs.","authors":"John D Akins, Jeung-Ki Yoo, Dan-Dan Sun, Rosemary S Parker, Marcus A Urey, Steven A Romero, Justin S Lawley, Satyam Sarma, Wanpen Vongpatanasin, Craig G Crandall, Qi Fu","doi":"10.1113/EP092882","DOIUrl":"https://doi.org/10.1113/EP092882","url":null,"abstract":"<p><p>The venoarteriolar and myogenic response (VMR) is a non-adrenergic, non-baroreflex-mediated mechanism that increases local vascular resistance and contributes to blood pressure (BP) regulation during orthostasis. Despite the importance of the VMR in human cardiovascular control, no information exists elucidating possible differences in the VMR with ageing and sex. We studied 26 healthy young adults [9 male; mean (SD) 28 (4) years old] and 18 healthy older adults [7 male; 71 (3) years old] during acute arm and leg dependency (i.e., limb lowering below heart level) to evoke the VMR. Brachial and femoral artery blood flows were assessed with duplex ultrasound. The VMR was estimated as the percentage reduction in vascular conductance (blood flow/mean arterial BP; in millilitres per minute per millimetre of mercury) from baseline during 5 min of limb dependency. Arm VMR was attenuated in the older versus young adults [-8.7 (1.9)% vs. -26.6 (2.4)%, p < 0.001]. Likewise, leg VMR was also attenuated in the older versus young adults [-14.4 (0.8)% vs. -29.1 (2.2)%, p < 0.001]. Despite these age-related differences, there were no sex differences for leg (p = 0.096) or arm VMR (p = 0.825). These data suggest that ageing attenuates the VMR in both the upper and lower limbs, but sex does not impact these responses. This phenomenon might contribute to altered BP regulation in older adults, either protecting against excessive orthostatic BP elevations or contributing to orthostatic hypotension. Future research is needed to determine the mechanisms of an attenuated VMR with ageing and whether these findings extend to populations with hypertension and cardiovascular/metabolic disease.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144648921","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":"Cardiac vagal activity is not a determinant of apnoea tolerance in trained breath-hold divers.","authors":"Benjamin S Stacey, Giorgio Manferdelli","doi":"10.1113/EP092998","DOIUrl":"https://doi.org/10.1113/EP092998","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144648922","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":"Applying lessons from limb muscle disuse and ageing to better understand ventilator-induced diaphragm dysfunction.","authors":"P H C Mesquita, J L Halle, J D Fuqua, B F Miller","doi":"10.1113/EP092707","DOIUrl":"10.1113/EP092707","url":null,"abstract":"<p><p>Mechanical ventilation (MV) is a life-saving intervention applied to critically ill patients. A common consequence of MV is ventilator-induced diaphragm dysfunction (VIDD), which is characterized by significant diaphragm atrophy and reduced contractile function. Older patients who receive MV are more likely to develop VIDD, have worse recovery, and higher mortality rates compared to younger adults. Despite the greater susceptibility of older adults to develop VIDD and lower survival rates compared to young adults, studies investigating the effects of ageing on VIDD and the recovery from MV are scarce. The field of limb skeletal muscle disuse has extensively shown that compared to adult limb muscles, aged limb muscles respond differently and have blunted recovery after disuse. This review summarizes the literature on the effects of MV on the diaphragm, discussing the available data on the effects of ageing and the recovery process after MV. We also provide an overview of the effects of ageing and the recovery of limb muscle from periods of disuse. We conclude with recommendations for future studies to apply lessons learned from the field of limb muscle disuse to the field of MV and VIDD.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144607870","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 modified Borg cycle strength test (mBCST): Feasibility and physiological response in people with COPD and healthy older adults.","authors":"Jana De Brandt, Johan Jakobsson, Mattias Hedlund, Thomas Sandström, André Nyberg","doi":"10.1113/EP092151","DOIUrl":"https://doi.org/10.1113/EP092151","url":null,"abstract":"<p><p>Accurate prescription of supramaximal exercise requires exercise tests covering the intensity domain between maximal aerobic and peak power output. All-out tests are commonly used for this objective but are considered challenging for people with chronic obstructive pulmonary disease (COPD) due to the extreme physiological demand. The modified Borg cycle strength test (mBCST), previously used in older adults to achieve supramaximal intensities, might be a suitable alternative in people with COPD. We aimed to determine the feasibility of the mBCST in people with COPD and to compare the physiological response with that of healthy older adults. Eighteen people with COPD and 16 age-, sex- and physical activity-matched healthy adults performed a cardiopulmonary exercise test and a mBCST. The mBCST is an incremental test [30 s:30 s cycling:rest; with individualized starting load and step size (15-50 W)] with end-of-test criteria of a rating of perceived exertion of ≥17 or cadence of <75 RPM for >5 s. Feasibility was assessed using a framework covering the aim, interpretability, familiarity, duration, scoring/completion complexity, costs and safety. Measurements of external exercise intensity, rating of perceived exertion, symptoms and cardiorespiratory demand were obtained. The mBCST was deemed feasible according to the feasibility framework. Expressed relative to the cardiopulmonary exercise test, all participants reached supramaximal external exercise intensities during the mBCST [COPD, 145 (125-168)%; healthy, 154 (148-163)%], without differences in intensity or physiological response between groups (p > 0.05). The mBCST is feasible in people with COPD and enables supramaximal external exercise intensities, with similar physiological response to healthy older adults. The mBCST could be considered when selecting an exercise test to prescribe supramaximal exercise.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144607871","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}