Experimental Physiology最新文献

{"title":"Circadian rhythm of brain-derived neurotrophic factor in serum and plasma","authors":"Maren Ehrhardt,&nbsp;Stefanie Schreiber,&nbsp;Yves Duderstadt,&nbsp;Rüdiger Braun-Dullaeus,&nbsp;Katrin Borucki,&nbsp;Tanja Brigadski,&nbsp;Notger G. Müller,&nbsp;Volkmar Leßmann,&nbsp;Patrick Müller","doi":"10.1113/EP091671","DOIUrl":"10.1113/EP091671","url":null,"abstract":"<p>The neurotrophic growth factor brain-derived neurotrophic factor (BDNF) plays a crucial role in various neurodegenerative and psychiatric diseases, such as Alzheimer's disease, schizophrenia and depression. BDNF has been proposed as a potential biomarker for diagnosis, prognosis and monitoring therapy. Understanding the factors influencing BDNF levels and whether they follow a circadian rhythm is essential for interpreting fluctuations in BDNF measurements. We aimed to investigate the circadian rhythm of BDNF by collecting multiple peripheral venous blood samples from young, healthy male participants at 12 different time points over 24 h. In addition, vital parameters, cortisol and insulin like growth factor 1 (IGF1) were measured to explore potential regulatory mechanisms, interfering variables and their correlations with BDNF concentration. The findings revealed that plasma BDNF did not exhibit any significant fluctuations over 24 h, suggesting the absence of a circadian rhythm. However, serum BDNF levels decreased during sleep. Furthermore, serum BDNF showed a positive correlation with heart rate but a negative correlation with IGF1. No significant correlation was observed between cortisol and BDNF or IGF1. Although plasma BDNF suggests steady-state conditions, the decline of serum BDNF during the nocturnal period could be attributed to physical inactivity and associated with reduced haemodynamic blood flow (heart rate reduction during sleep). The type of sample collection (peripheral venous cannula vs. blood sampling using a butterfly system) does not significantly affect the measured BDNF levels. The sample collection during the day did not significantly affect BDNF analysis, emphasizing the importance of considering activity levels rather than timing when designing standardized protocols for BDNF assessments.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":"109 10","pages":"1755-1767"},"PeriodicalIF":2.6,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11442779/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141893216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of superimposed supine cycling and lower body negative pressure as an effective means of prolonging exercise tolerance in individuals experiencing persisting post-concussive symptoms: Preliminary results.","authors":"Raelyn Javra, Joel S Burma, Nathan E Johnson, Jonathan D Smirl","doi":"10.1113/EP091677","DOIUrl":"https://doi.org/10.1113/EP091677","url":null,"abstract":"<p><p>To examine the feasibility, utility and safety of superimposed lower body negative pressure (LBNP) and tilt during supine cycling in individuals suffering from persisting post-concussive symptoms (PPCS). Eleven individuals aged 17-31 (6 females/5 males) participated in two randomized separate visits, 1 week apart. A ramp-incremental test was performed during both visits until volitional failure. Visits included no pressure (control) or LBNP at -40 Torr (experimental) with head-up tilt at 15 degrees (females) or 30 degrees (males). Transcranial Doppler ultrasound was utilized to quantify middle cerebral artery velocity (MCAv), while symptom reports were filled out before and 0, 10, and 60 min post-exertion. Ratings of exertion and overall condition followed similar trends for participants across both tests. The relative increase in MCAv was blunted during the experimental condition (8%) compared to control (24%), while a greater heart rate (17 beats/min) was achieved during the LBNP condition (P = 0.047). Symptom severity at the 0 and 10 min post-exertion time points displayed negligible-to-small effect sizes between conditions (Wilcoxon's r < 0.11). Symptom reporting was lower at the 60 min post-exertion time point with these displaying a moderate effect size (Wilcoxon's r = 0.31). The combination of LBNP and tilt during supine cycling did not change the participants' subjective interpretation of the exertional test but attenuated the hyperpnia-induced vasodilatory MCAv response, while also enabling participants to achieve a higher heart rate during exercise and reduced symptoms 1 h later. As this protocol is safe and feasible, further research is warranted in this area for developing PPCS treatment options. HIGHLIGHTS: What is the central question of this study? What are the feasibility, safety and utility of combining head-up tilt with lower body negative pressure during supine cycling for blunting the increase in cerebral blood velocity seen during moderate-intensity exercise in individuals experiencing persisting post-concussion symptoms? What is the main finding and its importance? Although no differences were found in symptoms between conditions within the first 10 min following exertion, symptom severity scores showed a clinically meaningful reduction 60 min following the experimental condition compared to the non-experimental control condition.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141893217","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":"Circulating extracellular microvesicles associated with electronic cigarette use increase endothelial cell inflammation and reduce nitric oxide production","authors":"Nicholas G. Evanoff,&nbsp;Donald R. Dengel,&nbsp;Kelly A. Stockelman,&nbsp;Hannah Fandl,&nbsp;Noah M. DeSouza,&nbsp;Jared J. Greiner,&nbsp;Sheena R. Dufresne,&nbsp;Michael Kotlyar,&nbsp;Vinicius P. Garcia","doi":"10.1113/EP091715","DOIUrl":"10.1113/EP091715","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 \u0000 &lt;p&gt;The purpose of this study was to determine the effect of circulating microvesicles isolated from chronic electronic (e-)cigarette users on cultured human umbilical vein endothelial cell (HUVEC) expression of nuclear factor-κB (NF-κB), cellular cytokine release, phosphorylation of endothelial nitric oxide synthase (eNOS) and NO production. The HUVECs were treated with microvesicles isolated via flow cytometry from nine non-tobacco users (five male and four female; 22 ± 2 years of age) and 10 e-cigarette users (six male and four female; 22 ± 2 years of age). Microvesicles from e-cigarette users induced significantly greater release of interleukin-6 (183.4 ± 23.6 vs. 150.6 ± 15.4 pg/mL; &lt;i&gt;P&lt;/i&gt; = 0.002) and interleukin-8 (160.0 ± 31.6 vs. 129.4 ± 11.2 pg/mL; &lt;i&gt;P&lt;/i&gt; = 0.01), in addition to expression of p-NF-κB p65 (Ser536) (18.8 ± 3.4 vs. 15.6 ± 1.5 a.u.; &lt;i&gt;P&lt;/i&gt; = 0.02) from HUVECs compared with microvesicles from non-tobacco users. Nuclear factor-κB p65 was not significantly different between microvesicles from the non-tobacco users and from the e-cigarette users (87.6 ± 8.7 vs. 90.4 ± 24.6 a.u.; &lt;i&gt;P&lt;/i&gt; = 0.701). Neither total eNOS (71.4 ± 21.8 vs. 80.4 ± 24.5 a.u.; &lt;i&gt;P&lt;/i&gt; = 0.413) nor p-eNOS (Thr495) (229.2 ± 26.5 vs. 222.1 ± 22.7 a.u.; &lt;i&gt;P&lt;/i&gt; = 0.542) was significantly different between microvesicle-treated HUVECs from non-tobacco users and e-cigarette users. However, p-eNOS (Ser1177) (28.9 ± 6.2 vs. 45.8 ± 9.0 a.u.; &lt;i&gt;P &lt;/i&gt;&lt; 0.001) expression was significantly lower from e-cigarette users compared with non-tobacco users. Nitric oxide production was significantly lower (8.2 ± 0.6 vs. 9.7 ± 0.9 μmol/L; &lt;i&gt;P&lt;/i&gt; = 0.001) in HUVECs treated with microvesicles from e-cigarette users compared with microvesicles from non-tobacco users. This study demonstrated increased NF-κB activation and inflammatory cytokine production, in addition to diminished eNOS activity and NO production resulting from e-cigarette use.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Highlights&lt;/h3&gt;\u0000 \u0000 &lt;div&gt;\u0000 &lt;ul&gt;\u0000 \u0000 &lt;li&gt;\u0000 &lt;p&gt;&lt;b&gt;What is the central question of this study?&lt;/b&gt;&lt;/p&gt;\u0000 \u0000 &lt;p&gt;Circulating microvesicles contribute to cardiovascular health and disease via their effects on the vascular endothelium. The impact of electronic (e-)cigarette use on circulating microvesicle phenotype is not well understood.&lt;/p&gt;\u0000 &lt;/li&gt;\u0000 \u0000 &lt;li&gt;\u0000 &lt;p&gt;&lt;b&gt;What is the main finding and its importance?&lt;/b&gt;&lt;/p&gt;\u0000 \u0000 &lt;p&gt;Circulating microvesicles from e-cigarette users increase endothelial cell inflammation and impair endothelial nitric oxide production. Endothelial infla","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":"109 9","pages":"1593-1603"},"PeriodicalIF":2.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11363099/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resistance exercise breaks during prolonged sitting augment the blood flow response to a subsequent oral glucose load in sedentary adults.","authors":"Emily M Rogers, Nile F Banks, Emma R Trachta, Morgan S Wolf, Alexander C Berry, Anna E Stanhewicz, Lucas J Carr, Bethany Barone Gibbs, Nathaniel D M Jenkins","doi":"10.1113/EP091535","DOIUrl":"https://doi.org/10.1113/EP091535","url":null,"abstract":"<p><p>Sitting-induced impairments in postprandial blood flow are an important link between sedentary behaviour and cardiometabolic disease risk. The objective of this work was to examine the effects of resistance exercise breaks (REB) performed every 30 min during an otherwise sedentary 3-h period on the vasodilatory response to a subsequent oral glucose load in sedentary adults. Twenty-four sedentary adults (27 ± 7 years, 16 females) completed two conditions. Fasting blood glucose, insulin, popliteal artery blood flow (PABF) and gastrocnemius perfusion were measured immediately before standardized breakfast consumption. After breakfast, the 3-h REB or uninterrupted (SIT) intervention period commenced. Participants sat at a workstation, and popliteal artery shear rate (PASR) was measured 60 and 120 min into this period. In the REB condition, participants performed a 3-min REB (3 × [20 s squats, 20 s high knees, 20 s calf raises]) every 30 min. Following the intervention period, baseline measurements were repeated. Participants then consumed a 75 g glucose beverage, and PABF and perfusion were measured every 30-60 min for the following 120 min. Relative to SIT, REB increased PASR at 60 min (+31.4 ± 9.2/s, P = 0.037) and 120 min (+37.4 ± 10.2/s, P = 0.019) into the intervention period. Insulin and glucose increased (P < 0.001) in response to glucose consumption, with no differences between conditions (P ≥ 0.299). In response to the glucose load, perfusion (1.57 vs. 1.11 mL/100 mL/min, P = 0.023) and PABF (+45.3 ± 11.8 mL/min, P = 0.001) were greater after REB versus SIT. Performing 3-min REB every 30 min during an otherwise sedentary 3-h period augmented leg blood flow responses to an oral glucose load. HIGHLIGHTS: What is the central question of this study? Can 3-min resistance exercise breaks (REB) performed during an otherwise sedentary 3-h period augment the vasodilatory response to a subsequent oral glucose load in sedentary adults? What is the main finding and its importance? Performing 3-min REB, which included squats, high knees, and calf raises, every 30 min augmented lower limb blood flow responses to a subsequent oral glucose load compared to 3 h of uninterrupted sitting in sedentary adults. Sitting-induced impairment in postprandial vasodilatory function has been identified as a link between sedentary behaviour and cardiometabolic disease. Thus, the current study presents a potentially effective strategy to offset this risk.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874542","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":"An electron paramagnetic resonance time-course study of oxidative stress in the plasma of electronic cigarette exposed rats","authors":"Murugesan Velayutham,&nbsp;Amber Mills,&nbsp;Valery V. Khramtsov,&nbsp;I. Mark Olfert","doi":"10.1113/EP092064","DOIUrl":"10.1113/EP092064","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 \u0000 <p>The long-term consequences of electronic cigarette (Ecig) use in humans are not yet known, but it is known that Ecig aerosols contain many toxic compounds of concern. We have recently shown that Ecig exposure impairs middle cerebral artery (MCA) endothelial function and that it takes 3 days for MCA reactivity to return to normal. However, the sources contributing to impairment of the endothelium were not investigated. We hypothesized that the increased levels of oxidative stress markers in the blood are correlated with impaired MCA reactivity. We used electron paramagnetic resonance (EPR) spectroscopy to examine plasma from 4-month-old male Sprague–Dawley rats that were exposed to either air (<i>n</i> = 5) or 1 h Ecig exposure, after which blood samples were collected at varying times after exposure (i.e., 1–4, 24, 48 and 72 h postexposure, <i>n</i> = 4 or 5 in each time group). The EPR analyses were performed using the redox-sensitive hydroxylamine spin probe 1-hydroxy-3-carboxymethyl-2,2,5,5-tetramethyl-pyrrolidine (CMH) to measure the level of reactive oxidant species in the plasma samples. We found that EPR signal intensity from the CM^• radical was significantly increased in plasma at 1-4, 24 and 48 h (<i>P </i>&lt; 0.05, respectively) and returned to control (air) levels by 72 h. When evaluating the EPR results with MCA reactivity, we found a significant negative correlation (Pearson's <i>P </i>= 0.0027). These data indicate that impaired cerebrovascular reactivity resulting from vaping is associated with the oxidative stress level (measured by EPR from plasma) and indicate that a single 1 h vaping session can negatively influence vascular health for up to 3 days after vaping.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Highlights</h3>\u0000 \u0000 <div>\u0000 <ul>\u0000 \u0000 <li>\u0000 <p><b>What is the central question of this study?</b></p>\u0000 \u0000 <p>Does the time course of oxidative stress triggered by electronic cigarette exposure follow the cerebral vascular dysfunction?</p>\u0000 </li>\u0000 \u0000 <li>\u0000 <p><b>What is the main finding and its importance?</b></p>\u0000 \u0000 <p>Electron paramagnetic resonance analysis shows that the oxidative stress induced after a single 1 h exposure to electronic cigarette aerosol takes ≤72 h to return to normal, which mirrors the time course for vascular dysfunction in the middle cerebral artery that we have reported previously.</p>\u0000 </li>\u0000 </ul>\u0000 </div>\u0000 </section>\u0000 </div>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":"109 9","pages":"1420-1425"},"PeriodicalIF":2.6,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11363090/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association analysis of indel variants and gene expression identifies MDM4 as a novel locus for skeletal muscle hypertrophy and power athlete status.","authors":"Hasan H Kazan, Anıl Kasakolu, Seyrani Koncagul, Mehmet A Ergun, George John, Rinat I Sultanov, Andrey V Zhelankin, Ekaterina A Semenova, Rinat A Yusupov, Nikolay A Kulemin, Andrey K Larin, Edward V Generozov, Celal Bulgay, Ildus I Ahmetov","doi":"10.1113/EP091992","DOIUrl":"https://doi.org/10.1113/EP091992","url":null,"abstract":"<p><p>Insertions and deletions (indels) are the second most common type of variation in the human genome. However, limited data on their associations with exercise-related phenotypes have been documented. The aim of the present study was to examine the association between 18,370 indel variants and power athlete status, followed by additional studies in 357,246 individuals. In the discovery phase, the D allele of the MDM4 gene rs35493922 I/D polymorphism was over-represented in power athletes compared with control subjects (P = 7.8 × 10^-9) and endurance athletes (P = 0.0012). These findings were replicated in independent cohorts, showing a higher D allele frequency in power athletes compared with control subjects (P = 0.016) and endurance athletes (P = 0.031). Furthermore, the D allele was positively associated (P = 0.0013) with greater fat-free mass in the UK Biobank. MDM4 encodes a protein that inhibits the activity of p53, which induces muscle fibre atrophy. Accordingly, we found that MDM4 expression was significantly higher in the vastus lateralis of power athletes compared with endurance athletes (P = 0.0009) and was positively correlated with the percentage of fast-twitch muscle fibres (P = 0.0062) and the relative area occupied by fast-twitch muscle fibres (P = 0.0086). The association between MDM4 gene expression and an increased proportion of fast-twitch muscle fibres was confirmed in two additional cohorts. Finally, we found that the MDM4 DD genotype was associated with increased MDM4 gene expression in vastus lateralis and greater cross-sectional area of fast-twitch muscle fibres. In conclusion, MDM4 is suggested to be a potential regulator of muscle fibre specification and size, with its indel variant being associated with power athlete status. HIGHLIGHTS: What is the central question of this study? Which indel variants are functional and associated with sport- and exercise-related traits? What is the main finding and its importance? Out of 18,370 tested indels, the MDM4 gene rs35493922 I/D polymorphism was found to be the functional variant (affecting gene expression) and the most significant, with the deletion allele showing associations with power athlete status, fat-free mass and cross-sectional area of fast-twitch muscle fibres. Furthermore, the expression of MDM4 was positively correlated with the percentage of fast-twitch muscle fibres and the relative area occupied by fast-twitch muscle fibres.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141747837","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":"My sojourn with cerebral sympathetic nervous activity","authors":"Patrice Brassard","doi":"10.1113/EP092029","DOIUrl":"10.1113/EP092029","url":null,"abstract":"&lt;p&gt;In 2006, I took one critical decision which would completely alter the trajectory of my career. Being in the final year of my PhD training under the mentorship of Dr Paul Poirier at Université Laval, Quebec, Canada, I decided The Copenhagen Muscle Research Center would be the place I wanted to complete my postdoctoral fellowship. Having focused my PhD work on exercise physiology in patients with type 2 diabetes (Brassard et al., &lt;span&gt;2006a,b&lt;/span&gt;, &lt;span&gt;2007&lt;/span&gt;; Caron et al., &lt;span&gt;2017&lt;/span&gt;), I initially approached Prof. Michael Kjær at the annual meeting of the American College of Sports Medicine, which was in Denver, Colorado, in the same year. However, Prof. Kjær had recently changed his research focus away from diabetes, so it was not really possible for him to become my postdoc supervisor. During that brief meeting, he mentioned that one of his colleagues, who also happened to be present at the meeting, would most likely be interested in my profile. That colleague was Prof. Niels Secher (Aalkjaer et al., &lt;span&gt;2023&lt;/span&gt;). The rest is history!&lt;/p&gt;&lt;p&gt;During my stay in Copenhagen in Prof. Secher's laboratory, I had the opportunity to develop a new research expertise. While I examined the influence of well-controlled type 2 diabetes on exercise responses during my PhD, I switched gears for my postdoc, and studied cerebral blood flow (CBF) regulation and cerebral metabolism in health and disease. For example, I got involved in a plethora of studies, looking at the impact of hypoxia (Avnstorp et al., &lt;span&gt;2015&lt;/span&gt;; Bailey et al., &lt;span&gt;2017&lt;/span&gt;; Overgaard et al., &lt;span&gt;2012&lt;/span&gt;), endotoxaemia (Brassard et al., &lt;span&gt;2012&lt;/span&gt;), and diabetes (Kim et al., &lt;span&gt;2015&lt;/span&gt;) on CBF and cerebral oxygenation (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;S&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;annotation&gt;${{S}_{{mathrm{c}}{{{mathrm{O}}}_{mathrm{2}}}}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) at rest and during exercise. We also studied the impact of acute and chronic exercise on brain-derived neurotrophic factor (Rasmussen et al., &lt;span&gt;2009&lt;/span&gt;; Seifert et al., &lt;span&gt;2010&lt;/span&gt;) and the influence of varying the speed of a left ventricular assist device during aerobic exercise on cerebral haemodynamics and exercise tolerance in patients in heart failure (Brassard et al., &lt;span&gt;2011&lt;/span&gt;). During that time period, I was introduced to the cerebral pressure–flow relationship and dynamic cerebral autoregulation concepts. I also learned the basics of transfer function analysis with Johannes van Lieshout (Brassard et al., &lt;span&gt;2012&lt;/span&gt;), a regular visiting scholar (and good friend) of Prof. Secher, who was present at the beg","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":"109 10","pages":"1623-1626"},"PeriodicalIF":2.6,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11442745/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141731029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Apnoea as a novel method to improve exercise performance: A current state of the literature.","authors":"Janne Bouten, Louise Declercq, Jan Boone, Franck Brocherie, Jan G Bourgois","doi":"10.1113/EP091905","DOIUrl":"https://doi.org/10.1113/EP091905","url":null,"abstract":"<p><p>Acute breath-holding (apnoea) induces a spleen contraction leading to a transient increase in haemoglobin concentration. Additionally, the apnoea-induced hypoxia has been shown to lead to an increase in erythropoietin concentration up to 5 h after acute breath-holding, suggesting long-term haemoglobin enhancement. Given its potential to improve haemoglobin content, an important determinant for oxygen transport, apnoea has been suggested as a novel training method to improve aerobic performance. This review aims to provide an update on the current state of the literature on this topic. Although the apnoea-induced spleen contraction appears to be effective in improving oxygen uptake kinetics, this does not seem to transfer into immediately improved aerobic performance when apnoea is integrated into a warm-up. Furthermore, only long and intense apnoea protocols in individuals who are experienced in breath-holding show increased erythropoietin and reticulocytes. So far, studies on inexperienced individuals have failed to induce acute changes in erythropoietin concentration following apnoea. As such, apnoea training protocols fail to demonstrate longitudinal changes in haemoglobin mass and aerobic performance. The low hypoxic dose, as evidenced by minor oxygen desaturation, is likely insufficient to elicit a strong erythropoietic response. Apnoea therefore does not seem to be useful for improving aerobic performance. However, variations in apnoea, such as hypoventilation training at low lung volume and repeated-sprint training in hypoxia through short end-expiratory breath-holds, have been shown to induce metabolic adaptations and improve several physical qualities. This shows promise for application of dynamic apnoea in order to improve exercise performance. HIGHLIGHTS: What is the topic of this review? Apnoea is considered as an innovative method to improve performance. This review discusses the effectiveness of apnoea (training) on performance. What advances does it highlight? Although the apnoea-induced spleen contraction and the increase in EPO observed in freedivers seem promising to improve haematological variables both acutely and on the long term, they do not improve exercise performance in an athletic population. However, performing repeated sprints on end-expiratory breath-holds seems promising to improve repeated-sprint capacity.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141731027","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":"Blood flow restriction training attenuates changes in local muscle endurance: At odds with previous work?","authors":"William B. Hammert,&nbsp;Ryo Kataoka,&nbsp;Yujiro Yamada,&nbsp;Jun Seob Song,&nbsp;Jeremy P. Loenneke","doi":"10.1113/EP091924","DOIUrl":"10.1113/EP091924","url":null,"abstract":"&lt;p&gt;Ida and Sasaki (&lt;span&gt;2024&lt;/span&gt;) reported that exercising to failure without blood flow restriction resulted in greater increases in local muscle endurance than exercising to failure with blood flow restriction. The authors attributed their results (of their second experiment) to the differences in total exercise volume (i.e., load multiplied by the total number of repetitions over the training period) between conditions, and provided a correlation for support (Ida &amp; Sasaki, &lt;span&gt;2024&lt;/span&gt;). Their correlation, however, appears to count each individual twice (i.e., &lt;i&gt;n &lt;/i&gt;= 8 with 16 dots), which would violate the assumption of independence. Dr. Wernbom (&lt;span&gt;2024&lt;/span&gt;) recently provided a viewpoint on Ida and Sasaki's study. We agree that more research is needed to better understand how low load resistance exercise with blood flow restriction impacts the mechanisms underlying improvements in muscle endurance. However, we also believe it is important to discuss Ida and Sasaki's findings in the context of the existing literature. More specifically, we believe their observation that blood flow restriction attenuated changes in local muscle endurance, and their explanation for such, should be acknowledged as being at odds with published studies.&lt;/p&gt;&lt;p&gt;Table 1 summarizes the characteristics and results of 10 blood flow restriction training studies that examined changes in local muscle endurance using pre- to post-intervention changes in the number of repetitions to failure (i.e., in a manner similar to that of Ida and Sasaki (&lt;span&gt;2024&lt;/span&gt;)). In their introduction, Ida and Sasaki (&lt;span&gt;2024&lt;/span&gt;) pointed out that, to their knowledge, the impact of blood flow restriction on exercise volume, muscle endurance adaptations, and their association has not been studied systematically. Over 10 years ago, however, Kacin and Strazar (&lt;span&gt;2011&lt;/span&gt;) reported that exercising to failure with blood flow restriction improved local muscle endurance to a greater extent than a repetition-matched, low load training protocol performed without blood flow restriction (Table 1). In their discussion, Ida and Sasaki (&lt;span&gt;2024&lt;/span&gt;) acknowledged the work of Kacin and Strazar (&lt;span&gt;2011&lt;/span&gt;), and suggested that the discrepancies between studies highlight the importance of exercise volume for improving muscle endurance capacity. A few years after the Kacin and Strazar study was published, Fahs et al. (&lt;span&gt;2015&lt;/span&gt;) compared muscular adaptations between low load resistance training with and without blood flow restriction in middle-aged men and women (i.e., 42–62 years). In comparison to Kacin and Strazar's study, Fahs et al.’s study was unique in that both training protocols exercised to failure. Fahs et al. (&lt;span&gt;2015&lt;/span&gt;) observed similar increases in local muscle endurance, despite the fact that blood flow restriction significantly reduced the total exercise training volume. Two other studies (Buckner et al., &lt;span&gt;2020&lt;/span&gt;; Jesse","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":"109 8","pages":"1395-1398"},"PeriodicalIF":2.6,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11291865/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141731028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Setting sail for Paris 2024: Retrospective analysis of world-class ILCA 7 Olympic sailors' cardiorespiratory fitness (2015-2020).","authors":"Damir Zubac, Zoran Valić, Vladimir Ivančev","doi":"10.1113/EP091913","DOIUrl":"https://doi.org/10.1113/EP091913","url":null,"abstract":"<p><p>The aim of this retrospective analysis was to provide a more comprehensive understanding of the cardiorespiratory profile of world-class ILCA-7 sailors (n = 3, all males), through a longitudinal evaluation offering real-world data on physiological profile and exercise intensity domains. The cardiopulmonary exercise testing (CPET) was performed by the same researchers using the same equipment during the study. Assessments took place twice a year, aligning with major international competition preparations. Participants trained and competed at the same sailing club in Split, Croatia, under consistent supervision from the same team throughout the study, winning a total of 21 medals at major international competitions. The recorded <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>${{dot{V}}_{{{{mathrm{O}}}_{mathrm{2}}}{mathrm{peak}}}}$</annotation></semantics> </math> ranged from 51.7 ± 1.6 to 61.9 ± 3.0 mL min^-1 kg^-1, respectively. Similarly, peak power output varied from 352 ± 10 to 426 ± 34 W. The changes in physiological responses at the ventilatory thresholds were proportional to the changes in peak cardiorespiratory fitness capacity. Interestingly, the oxygen pulse measured in 2015 was 25 ± 1 mL O₂ beat^-1. Over the subsequent 6 years, the O₂ pulse marginally increased and appeared to stabilize at 27 ± 1 mL O₂ beat^-1 in 2020, when these athletes were 32 ± 3 years old. This work offers a broader understanding of world-class Olympic sailors' cardiorespiratory fitness, going beyond the standard assessment of peak <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <msub><mi>O</mi> <mn>2</mn></msub> </msub> <annotation>${{dot{V}}_{{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> to incorporate an analysis of ventilatory thresholds. While a direct link between cardiorespiratory fitness and competitive success remains ambiguous, the importance of a well-rounded aerobic capacity for excellence in ILCA-7 sailing class is evident. HIGHLIGHTS: What is the central question of this study? What are the temporal changes in the physiological profiles of three world-class ILCA-7 sailors? What is the main finding and its importance? Data on oxygen pulse adjustments suggest the involvement of compensatory cardiovascular mechanisms, likely associated with the isometric and quasi-isometric contractions inherent in ILCA-7 sailing. This is evidenced by the absence of an age-related increase in oxygen pulse, a phenomenon often observed in endurance athletes throughout their competitive careers.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141633098","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}