Journal of applied physiology最新文献

{"title":"Are we addressing study limitations the right way? A conceptual framework to distinguish design constraints from methodological shortcomings.","authors":"Rhaí A Arriel, Moacir Marocolo, Jéssica Ferreira Rodrigues","doi":"10.1152/japplphysiol.00403.2026","DOIUrl":"10.1152/japplphysiol.00403.2026","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"591-594"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148536209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dose- and time-dependent physiological effects of fentanyl in adult goats.","authors":"Reiauna Taylor, Suzanne E Neumueller, John DeSalvo, Grace Hilbert, Lawrence G Pan, Hubert V Forster, Matthew R Hodges","doi":"10.1152/japplphysiol.00115.2026","DOIUrl":"10.1152/japplphysiol.00115.2026","url":null,"abstract":"<p><p>Osverdoses (ODs) involving the synthetic opioid fentanyl annually contribute to thousands of deaths in the United States and are largely attributed to opioid-induced respiratory depression (OIRD). However, fentanyl OD negatively affect several aspects of cardiorespiratory function, including respiratory muscle rigidity and pulmonary gas exchange. Here, we tested the hypothesis that high doses of intravenous fentanyl (50-750 µg/kg) cause unique, time- and dose-dependent changes in physiologic functions and behaviors consistent with OIRD, muscle rigidity, impaired gas exchange, and acute withdrawal in a large animal model (adult female goats; <i>n</i> = 12). Within the first 15 min after injection, intravenous fentanyl dose-dependently reduced minute ventilation (V̇i; <i>P</i> < 0.0001), breathing frequency (Fb; <i>P</i> < 0.0001), swallowing (<i>P</i> < 0.001), and [Formula: see text] (<i>P</i> < 0.0001) but increased tidal volume (Vt; <i>P</i> = 0.0029), [Formula: see text] (<i>P</i> < 0.0001), the alveolar-arterial O₂ gradient (A-a; <i>P</i> = 0.0024), and respiratory pump and airway muscle electromyographic (EMG) activity. Thereafter (30-90 min postfentanyl), swallowing and [Formula: see text] remained reduced, whereas the A-a O₂ gradient and muscle EMG activity remained increased. Beginning 90 min postfentanyl, overall movement (cumulative vector magnitude, g; <i>P</i> < 0.0001) and the total behavioral response (sum of withdrawal behaviors; <i>P</i> < 0.001) were dose-dependently increased for 4 h. Thus, high-dose fentanyl caused significant and transient OIRD, sustained respiratory muscle activation, impaired gas exchange, and dose-dependent acute withdrawal-like behaviors. We conclude that fentanyl elicits dose- and time-dependent impairments of vital physiologic systems in adult goats similar to those reported in humans, suggesting that the goat is a unique and valuable model for translational hypothesis testing for future novel countermeasure development in vivo.<b>NEW & NOTEWORTHY</b> Here, we defined the time course of integrated physiologic effects of high doses of fentanyl in adult goats. High-dose fentanyl caused hypoventilation and sustained increases in tonic respiratory-related chest wall and airway muscle activity, increased the alveolar-to-arterial O₂ gradient, and caused dose-dependent increases in acute withdrawal-like behaviors. These data suggest that the integrated physiologic responses to fentanyl in adult goats closely resemble those in humans.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"642-652"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13575953/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148536167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of 8-wk exercise snacks on muscle oxygenation and cardiometabolic, mitochondrial, and subclinical atherosclerosis markers in sedentary women.","authors":"Omar A Hernández-López, Alejandro Martínez-Lucas, Alberto Hermo-Argibay, Julia Cacace, Clara Luna-Marco, Rodrigo Yañez-Sepulveda, Pablo Fernández-Collazo, Laura Perea-Galera, Celia Bañuls, Carlos Morillas, Milagros Rocha, Víctor M Víctor, Susana Rovira-Llopis","doi":"10.1152/japplphysiol.00267.2026","DOIUrl":"10.1152/japplphysiol.00267.2026","url":null,"abstract":"<p><p>\"Exercise snacks\" (ExS) are brief, structured bouts of physical activity designed to counteract the metabolic effects of sedentary behavior. This pilot study examined whether ExS improves metabolic markers, body composition, fitness indicators, peripheral blood mononuclear cells (PBMC) mitochondrial dynamics, autophagy, and subclinical atherosclerosis. Twenty-two women [11 physically active (PA), 11 sedentary; International Physical Activity Questionnaire-classified] were enrolled. Sedentary participants completed daily 12-min ExS sessions for 8 wk. Assessments included body composition, blood biomarkers, muscle oxygenation, cardiorespiratory fitness, grip strength, PBMC mitochondrial dynamics/autophagy markers, and neutrophil-endothelial interactions. Age-adjusted comparisons revealed that sedentary women (34 ± 9 yr) had similar body composition to PA participants (26 ± 5 yr). Cholesterol, low-density lipoprotein, and antioxidant capacity were reduced in sedentary women (<i>P</i> < 0.05). ExS reduced insulin (<i>P</i> < 0.01). Sedentary women displayed higher resting and maximal heart rates, lower estimated [Formula: see text], and reduced muscle reoxygenation versus PA (<i>P</i> < 0.05), all of which improved after ExS, though resting heart rate remained elevated versus PA (<i>P</i> < 0.01). Grip-strength was comparable between sedentary and PA women and increased after ExS (<i>P</i> < 0.01). Neutrophil-rolling velocity was decreased in sedentary versus PA (<i>P</i> < 0.01) and restored by ExS (<i>P</i> < 0.05). Expression of mitochondrial dynamics-related genes (mitofusins, OPA1, and FIS1) was lower in sedentary versus PA (<i>P</i> < 0.05) without changes in protein levels. Autophagy and mitophagy-related genes (Beclin1, LC3b, p62, and Pink/Parkin) were downregulated in sedentary versus PA (<i>P</i> < 0.05), whereas only LC3b mRNA and BECLIN1 protein increased after ExS (<i>P</i> < 0.01). Our findings indicate that ExS can improve cardiometabolic health, functional fitness, PBMC mitochondrial markers, and neutrophil-rolling velocity in sedentary women.<b>NEW & NOTEWORTHY</b> Brief daily \"exercise snacks\" improved metabolic health, cardiorespiratory fitness, and muscle oxygenation in sedentary women. These changes were accompanied by modulation of PBMC mitochondrial dynamics, autophagy-related markers, and neutrophil-endothelial interactions. Our findings provide mechanistic support for time-efficient exercise as a feasible strategy to counteract sedentary-induced cardiometabolic dysfunction.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"676-688"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148520618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The association of elevated pleural pressures with airway collapse during inspiration and expiration in mechanically ventilated patients.","authors":"Eduardo Messias Hirano Padrao, Ioana A Sopuch, Mara Bassi, Alper Gulluoglu, Maria Alejandra Alape Moya, Samantha Harrison, Andrea L Forman, Daniel S Talmor, Elias N Baedorf-Kassis","doi":"10.1152/japplphysiol.00136.2026","DOIUrl":"10.1152/japplphysiol.00136.2026","url":null,"abstract":"<p><p>Airway collapse may be identified during inspiration, resulting in an airway opening pressure (AOP) that needs to be overcome to initiate inspiratory flow, and, during expiration, may lead to expiratory flow limitation (EFL). We hypothesized that elevated pleural pressures are associated with airway collapse. Mechanically ventilated patients with respiratory failure were enrolled. Esophageal pressure (Pes) was used to estimate pleural pressure and calculate transpulmonary pressure (P_L). After a long washout with zero positive end-expiratory pressure (PEEP), we obtained slow-flow pressure-volume curves. The EFL was detected by visual inspection of the curves, \"PEEP absorber\" behavior, and by the expiratory resistance (Rex) method. Twenty patients were included. Our primary outcomes were the frequency of AOP and EFL, the association of AOP and baseline Pes after washout, AOP and total PEEP after washout, EFL and Pes after washout, and the association of AOP with EFL. AOP occurred in 12 patients, whereas nine had EFL. Of the 12 patients with AOP, eight also had EFL. Among the eight patients with no AOP, only one had EFL (<i>P</i> = 0.028). The AOP correlated with the patients' Pes after washout at zero PEEP (<i>R</i>² = 0.5686, <i>P</i> = 0.005). The auto-PEEP during washout was associated with both the Pes (<i>R</i>² = 0.5136, <i>P</i> = 0.009) and the AOP (<i>R</i>² = 0.352, <i>P</i> = 0.042). The mean Pes after washout was 11.3 ± 4.3 cmH₂O in the AOP group versus 7.0 ± 5.5 cmH₂O in the non-AOP group (<i>P</i> = 0.061). The Pes after washout was 12.4 ± 4.3 cmH₂O in the EFL group versus 7.3 ± 4.9 cmH₂O in the non-EFL group (<i>P</i> = 0.024). EFL and AOP correlated with elevated Pes, suggesting that elevated pleural pressures may be an important component of airway collapse. Measuring EFL and AOP could help improve ventilator support in critically ill patients.<b>NEW & NOTEWORTHY</b> In our hypothesis-generating study, elevated pleural pressures and auto-PEEP correlate with the degree of AOP (measured by slow-flow pressure-volume curves). Elevated pleural pressures also correlated with the presence of EFL. There is an association between the presence of AOP and EFL when measured by the Rex method. In patients with EFL, resolution occurred in most patients with 80% of the measured auto-PEEP at zero PEEP.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"653-660"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148549069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 changes in cerebral blood flow induced by short-term mild +Gz hypergravity in young males and females.","authors":"Kazue Miyake, Yojiro Ogawa, Tomokazu Kato, Kodai Sugimura, Ken-Ichi Iwasaki","doi":"10.1152/japplphysiol.00082.2026","DOIUrl":"10.1152/japplphysiol.00082.2026","url":null,"abstract":"<p><p>Understanding sex differences in the physiological changes resulting from exposure to hypergravity is important as the proportion of females participating in spaceflight continues to increase. To reveal possible sex differences in changes in CBF during mild hypergravity, the present study evaluated changes in mean cerebral blood velocity in the middle cerebral artery (MCAV) in healthy young males (<i>n</i> = 20; age, 20-26 yr) and females (<i>n</i> = 20; 20-32 yr) during 6-min exposure to +1.5 Gz hypergravity using a short-arm human centrifuge. Changes in mean arterial pressure at the middle cerebral artery level (MAP_MCA) were also evaluated. Mean MCAV showed different changes between sexes (analysis of variance, significant interaction effect, <i>P</i> = 0.026, partial η² = 0.124). Mean MCAV decreased significantly in males at +1.5 Gz hypergravity compared with prehypergravity +1.0 Gz baseline [46 ± 8 → 43 ± 8 cm/s (-6.5%), <i>P</i> < 0.001], but did not change significantly in females [61 ± 10 → 60 ± 11 cm/s (-1.6%), <i>P</i> = 0.148]. MAP_MCA decreased significantly in both males [51 ± 6 → 46 ± 6 mmHg (-10.7%), <i>P</i> < 0.001] and females [55 ± 8 → 51 ± 7 mmHg (-5.5%), <i>P</i> = 0.002]. From the results for mean MCAV as an index of CBF, we identified for the first time that sex differences exist in the changes in CBF induced by acute short-term exposure to mild +Gz hypergravity. Specifically, our results suggest that CBF would be maintained in females, but reduced in males during +1.5 Gz hypergravity. Sex differences in changes in CBF induced by hypergravity should be considered when managing the health of astronauts and space travelers.<b>NEW & NOTEWORTHY</b> Previous studies have shown that cerebral blood flow (CBF) was reduced by hypergravity in males, and we obtained similar results from young males in the present study. Moreover, we identified for the first time that CBF in young females was maintained and higher than in young males during acute short-term mild +Gz hypergravity.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"770-779"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148578837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of age on intramuscular fascicle kinematics of the medial gastrocnemius muscle of track and field masters athletes.","authors":"Sarah Michely, Uwe Mittag, Edwin Mulder, Wolfram Sies, Thomas Voigtmann, Jochen Zange, Benjamin Aretz, Jörn Rittweger, Dominik Pesta","doi":"10.1152/japplphysiol.00121.2026","DOIUrl":"10.1152/japplphysiol.00121.2026","url":null,"abstract":"<p><p>Aging results in a decline in muscle mass and intrinsic mechanical properties, yet its impact on intramuscular force transmission and fascicle kinematics remains poorly understood. We investigated whether age, sex, and habitual high-intensity athletic training modulate medial gastrocnemius (GM) muscle mechanics in 172 competitive masters athletes (<i>n</i> = 108 male, <i>n</i> = 64 female; aged 35-90 yr). Participants performed ramp plantar flexion to maximum voluntary contraction, whereas GM architecture was assessed via B-mode ultrasound. Fascicle length, pennation angle, fascicle rotation, and strain were quantified at rest and during contraction. Resting pennation angles did not vary with age (<i>P</i> ≥ 0.30) or sex (<i>P</i> ≥ 0.39). During contraction, superficial, but not deep fascicle rotation (change in pennation angle) decreased by 6.6 ± 51.3% per decade (<i>P</i> = 0.003), whereas deep fascicle rotation remained stable (<i>P</i> = 0.27). Furthermore, resting fascicle length showed a significant age-related decline of 1.8 ± 13.7% per decade (<i>P</i> = 0.002). Finally, Achilles tendon force decreased with age (-4.3 ± 16.3% per decade, <i>P</i> < 0.001), independent of sex (<i>P</i> = 0.12). Exploratory subgroup analyses showed that while athletic specialization (endurance vs. power) did not significantly influence fascicle kinematics, high-performing athletes (>85% age grade) maintained significantly greater superficial fascicle rotation than lower-performing peers (<i>P</i> = 0.027). These findings indicate that while age-related alterations in superficial fascicle kinematics occur even in well-trained individuals, preserved architectural gearing remains a distinct marker of elite athletic performance. In conclusion, our results suggest that aging alters intramuscular force transmission pathways independently of lifelong training status, highlighting the limits of exercise in fully mitigating structural neuromuscular aging.<b>NEW & NOTEWORTHY</b> This study suggests an age-related, nonuniform disruption of fascicle kinematics in the medial gastrocnemius of masters athletes. Although deep fascicle mechanics remain largely preserved (<i>P</i> = 0.27), superficial fascicle rotation declines significantly by 6.6% ± 51.3% per decade (<i>P</i> = 0.003). These findings identify a region-specific decline in \"architectural gearing,\" suggesting a potential mechanistic hypothesis for the age-related loss of muscle power that persists even in athletes with a long training history.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"780-794"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148603356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced footwear technology improves sprinting mechanics and performance.","authors":"Sunil K Prajapati, Lance C Brooks, Emily M Farina, Peter G Weyand","doi":"10.1152/japplphysiol.01129.2025","DOIUrl":"10.1152/japplphysiol.01129.2025","url":null,"abstract":"<p><p>Sprint running performances have improved with the use of advanced footwear technology, but the mechanisms responsible are unknown. Here, we tested two hypothesized mechanisms: <i>1</i>) faster maximal speeds resulting from greater ground force application, and <i>2</i>) associated contact time decreases and step length increases that could enable faster late-race velocities. Ten track and five soccer athletes (<i>n</i> = 15) completed randomized, linear 130-m sprint trials in conventional and prototype footwear. The prototypes were highly compliant and resilient in cushioning and stiff in forefoot bending. Instantaneous velocities were recorded with a radar device; contact and aerial times were acquired from ankle-mounted accelerometers throughout; split and final times (60, 100, and 130 m) were recorded with dual-beam laser timing gates. Contact times were also determined from 960 Hz video acquired from 10-m zones between 45 and 80 m. Performance times for the 130-m trials were 1.7% shorter in the prototype versus the conventional spike. Footwear condition differences in velocity were distance-dependent, increasing from a minimum of 0.1% in the first 10 m to a maximum of 3.9% at the 130-m finish line. Video capture zone contact periods were shorter (-1.9%), and estimated stance-averaged ground forces were greater (+1.6%) in the prototype versus conventional footwear. Progressive gait and velocity effects resulted in relatively large prototype versus conventional condition differences in the final 30-m segment for: contact times (-2.5%), aerial times (+6.0%), step lengths (+2.0%), and velocities (+3.0%). We conclude that the prototype footwear enabled gait mechanics that increased both maximal and late-trial sprinting velocities.<b>NEW & NOTEWORTHY</b> Footwear design advances have improved limb-ground dynamics to increase racing speeds across both shorter and longer track racing distances. The mechanisms of footwear-enabled performance improvements are well-established for endurance, but unknown for sprint racing events. Comparisons of advanced versus standard sprinting footwear in track and soccer athletes indicated that the advanced footwear elevated stance-average ground forces and reduced foot-ground contact times. These prototype-enabled gait mechanics improved sprinting performance by increasing maximal and late-trial sprinting speeds.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"830-839"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148760212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of acute sleep fragmentation on muscle blood flow responses to handgrip exercise.","authors":"Gabriel Narvaez, Joaquin U Gonzales","doi":"10.1152/japplphysiol.00509.2026","DOIUrl":"10.1152/japplphysiol.00509.2026","url":null,"abstract":"<p><p>Sleep fragmentation is reported to impair resting vascular function. The aim of this study was to test the hypothesis that acute sleep fragmentation would impair muscle blood flow during exercise. Twenty adults (10 females and 10 males) participated in a randomized crossover study that included one night of habitual sleep and one night of fragmented sleep. Sleep was assessed at home using wrist actigraphy. Arousals from sleep were increased by an audio alarm sounding every 30 min. The morning following each sleep condition, participants performed single handgrip contractions and rhythmic handgrip exercise at 15%, 30%, and 45% MVC. Forearm blood flow (FBF) was measured using Doppler ultrasound. Nightly awakenings and wake after sleep onset significantly increased by 18% and 43%, respectively, after fragmented sleep, leading to lower sleep duration (<i>P</i> < 0.001). Peak FBF and total hyperemic responses following single contractions were similar between sleep conditions (all <i>P</i> > 0.05). During rhythmic handgrip exercise, brachial artery dilation was reduced after fragmented sleep (main effect: 5.5 ± 4.8 vs. 3.3 ± 3.7%; <i>P</i> = 0.01), leading to a lower FBF response to rhythmic exercise (main effect: 122 ± 58 vs. 110 ± 56 mL/min; <i>P</i> = 0.04). Endothelial sensitivity to shear rate was similar between sleep conditions (habitual vs. fragmented: 0.039 ± 0.024 vs. 0.042 ± 0.031%/s^-1; <i>P</i> = 0.77). In summary, acute sleep fragmentation decreases skeletal muscle blood flow during exercise. This finding suggests that blunted oxygen delivery may be a contributing factor for exercise performance deficits after disturbed sleep.<b>NEW & NOTEWORTHY</b> We demonstrate that one night of fragmented sleep decreases steady-state blood flow and vascular conductance during low- to moderate-intensity handgrip exercise. This impairment was not due to an impaired rapid vasodilation to single contractions nor altered endothelial sensitivity to shear rate as these variables were unchanged after acute sleep fragmentation. These results reveal a negative impact of disrupted sleep on the steady-state muscle vasodilatory response to rhythmic contractions.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"802-812"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148684590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cardiometabolic benefits and risks for transgender youth with the initiation of gender-affirming hormone therapy: a case series.","authors":"Nina S Stachenfeld, Cheryl A Leone, Stuart A Weinzimer","doi":"10.1152/japplphysiol.00519.2026","DOIUrl":"10.1152/japplphysiol.00519.2026","url":null,"abstract":"<p><p>Interventions for transgender (TG) youth include puberty suppression and gender-affirming hormone therapy (GAHT). Studies have begun to show changes in cardiometabolic outcomes in adolescent transgender males (TGM) and females (TGF). We hypothesized that in TGM and TGF youth, GAHT would increase total cholesterol, low-density lipoprotein cholesterol, insulin resistance (IR), and adiposity while decreasing high-density lipoprotein cholesterol (HDL-C) and endothelium-dependent vasodilation. We measured IR (oral glucose tolerance test), lipid profile, and endothelial function (flow-mediated vasodilation) before and following 6 mo of GAHT in TGM (<i>n</i> = 3) and TGF (<i>n</i> = 2). This case series shows attenuated endothelium-mediated vasodilation in TGM, but improved endothelium-mediated vasodilation in TGF. Our data also support earlier findings showing reduced HDL-C with GAHT in TGM. Two of three TGMs showed increased IR, whereas one TGF showed decreased IR following GAHT. These data indicate rapid, but divergent, changes in lipids and endothelial function in TG youth with GAHT.<b>NEW & NOTEWORTHY</b> Although these data are preliminary, they show changes in FMD in transgender youth and suggest divergent responses, indicating attenuated FMD and lower HDL-C in males, whereas some improvement in endothelial function and little impact on lipids in females.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"988-993"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13599813/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vasoactive response of the thoracic aorta to phenylephrine infusion during cardiac surgery.","authors":"Stan M R L Toonen, Frederique M de Raat, Cindy van Loo, Luuk van Knippenberg, Joris van Houte, Tammo Delhaas, Leon J Schurgers, Ana Jerončić, Massimo Mischi, R Arthur Bouwman, Leon J Montenij, Bart Spronck","doi":"10.1152/japplphysiol.00996.2025","DOIUrl":"10.1152/japplphysiol.00996.2025","url":null,"abstract":"<p><p>The human aorta is commonly viewed as a passive conduit, but its potential vasoactive behavior could affect its Windkessel function and thereby its response to hypertension treatment involving vasoactive drugs. This study aims to investigate the in vivo vasoactive response of the thoracic aorta to phenylephrine during cardiac surgery. Patients undergoing elective cardiac surgery receiving phenylephrine for intraoperative hypotension were included. Transesophageal echocardiography was used to record the descending thoracic aorta before and after phenylephrine administration, while simultaneously recording pressure. The following parameters were calculated while correcting for pressure by exponential curve fitting: luminal area, distensibility, local pulse wave velocity (PWV), and the pressure-independent stiffness index (γ). Autonomic nervous system activity was assessed via heart rate variability analysis. Of the 70 recruited patients, 29 patients with 60 paired measurements were included. Phenylephrine administration significantly increased blood pressure (+22.3 ± 13.3/+11.1 ± 8.3 mmHg, mean ± SD; <i>P</i> < 0.001), thereby increasing uncorrected luminal area (systolic: +0.21 ± 0.21 cm², <i>P</i> < 0.001) and PWV (+1.4 ± 1.3 m/s, <i>P</i> < 0.001) and decreasing distensibility. Interestingly, these effects persisted after correcting for blood pressure, although smaller in mean magnitude (isobaric luminal area: +0.06 ± 0.16 cm², <i>P</i> = 0.007; PWV: +0.4 ± 1.1 m/s, <i>P</i> = 0.004; γ: +0.90 ± 2.26, <i>P</i> = 0.003). A decrease in sympathetic tone is suggested by elevated R-R interval variability (+0.24 ± 0.69 ms, <i>P</i> = 0.019) and decreased heart rate (-3 ± 3 min^-1, <i>P</i> < 0.001). The thoracic aorta showed a pressure-independent vasodilative response to phenylephrine, thereby challenging its traditional role as a passive conduit. This paradoxical response may be explained by the observed decrease in sympathetic tone. Responses showed strong patient-to-patient variability, highlighting the need to measure effects patient specifically.<b>NEW & NOTEWORTHY</b> This original work challenges the traditional view of the aorta as a passive conduit by investigating its vasoactive response to phenylephrine during cardiac surgery. Luminal area was measured by transesophageal echocardiography while simultaneously recording blood pressure. A mean pressure-independent increase in luminal area and stiffness was observed, suggesting a paradoxical vasodilative response. However, strong patient-to-patient variability in the response to phenylephrine highlights the need to measure effects patient specifically.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"863-872"},"PeriodicalIF":3.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148470443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}