Journal of applied physiology最新文献

{"title":"Effects of analgesic doses of opioids on cardiorespiratory responses and survival to hemorrhage and trauma in rats.","authors":"Stephanie M Marshall-Lipiec, Kathy L Ryan, Mariam L Calderon, Cassandra M Rodriguez, Brian S Connor, Carmen Hinojosa-Laborde, Harold G Klemcke","doi":"10.1152/japplphysiol.00708.2024","DOIUrl":"10.1152/japplphysiol.00708.2024","url":null,"abstract":"<p><p>Opioids are used for analgesia, but questions persist about their safety after traumatic hemorrhage. We investigated analgesic doses of three opioids (morphine, fentanyl, and sufentanil) on cardiorespiratory responses and survival to moderate or severe (37% or 50% blood volume) hemorrhage after trauma. A conscious hemorrhage model with extremity trauma (fibular fracture + soft tissue injury) was used; mean arterial pressure (MAP) and heart rate (HR) were measured by telemetry, whereas minute volume (MV) was determined by whole body plethysmography. Male rats (<i>n</i> = 10/group) received saline, morphine (2 mg/kg), fentanyl (10 µg/kg), or sufentanil (1 µg/kg) after traumatic hemorrhage. Neither survival times (for 37% hemorrhage: <i>P</i> = 0.209; for 50% hemorrhage: <i>P</i> = 0.88) nor survival percentages (for 37% hemorrhage: <i>P</i> = 0.357; for 50% hemorrhage: <i>P</i> = 1.0) differed among groups. For 37% hemorrhage, MAP of all opioid groups was higher than that in the saline-treated group 10 min post injection. By 75 min post injection, MAP after sufentanil was higher than saline; MAP for other opioids did not differ from saline. HR did not differ across treatments. Opioid injection decreased MV within 10 min but did not vary by treatment subsequently. For 50% hemorrhage, opioid injection did not immediately alter MAP but morphine and sufentanil were lower than saline at ≥75 min post injection, with no treatment effects on HR. Fentanyl produced an immediate (5 min) decrease in MV with no treatment effects thereafter. Opioid effects on cardiorespiratory function were therefore modest and did not alter survival during a 4-h observation period, supporting the judicious use of analgesic doses after traumatic hemorrhage.<b>NEW & NOTEWORTHY</b> Administration of an analgesic dose of either morphine, fentanyl, or sufentanil produced only modest and transient effects on cardiorespiratory function after either moderate (37% blood volume) or severe (50%) hemorrhage in conscious rats with extremity trauma. Under the conditions of these experiments, analgesic doses of these commonly used opioids also did not alter survival after traumatic hemorrhage.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"145-161"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143648592","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":"Corrigendum for Ortiz de Zevallos et al., volume 137, 2024, p. 1649-1658.","authors":"","doi":"10.1152/japplphysiol.00321.2024_COR","DOIUrl":"https://doi.org/10.1152/japplphysiol.00321.2024_COR","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":"139 1","pages":"164-166"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144528128","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":"Human skeletal muscle-specific hypertrophy with exercise training and aging: a comprehensive review.","authors":"Caroline S Vincenty, Gilhyeon Yoon, Kaitlyn Rogers, Masatoshi Naruse, Scott Trappe, Todd A Trappe","doi":"10.1152/japplphysiol.00892.2024","DOIUrl":"10.1152/japplphysiol.00892.2024","url":null,"abstract":"<p><p>Age-related skeletal muscle atrophy is a muscle group-specific process. Therefore, we were interested in understanding exercise-induced hypertrophy across different muscles in older individuals. This review provides a comprehensive summary of the available information on muscle-specific hypertrophy responses to exercise training with aging (≥60 yr). In total, 6,018 peer-reviewed publications were reviewed for inclusion [e.g., supervised resistance (RE) or aerobic (AE) exercise training; MRI, CT, or ultrasound-determined muscle size], resulting in 1,417 individuals from 68 studies (RE: <i>n</i> = 1,254; AE: <i>n</i> = 163). Data were divided across age (60-69, 70-79, 80-89, and ≥90 yr) and duration (≤9, 10-14, 15-19, 20-24, and ≥25 wk), with the majority coming from the sexa- and septuagenarians (<i>n</i> = 1,335, 94%) and 10-14 wk of training (<i>n</i> = 806, 57%). The number of muscle groups (RE: 7, AE: 8) and subcomponent muscles (RE: 10, AE: 16) was a low representation of the whole body musculature, with 79% of the data (<i>n</i> = 1,113) coming from the quadriceps. The 10-14 wk responses showed a range of unique muscle-specific hypertrophy and atrophy (RE: 60-69 yr: 2%-14% across 6 muscles; 70-79 yr: 1%-12% across 9 muscles; AE: 70-79 yr: -6% to +9% across 22 muscles). The large quadriceps-only resistance exercise training dataset (60-79 yr) showed that no additional hypertrophy was observed with increased training repetitions (i.e., dose) and that men and women elicited an equivalent hypertrophic training response. The optimal exercise training mode(s) and dose(s) for all of the skeletal muscles of sexa-, septa-, octo-, and nonagenarian women and men are far from being elucidated based on the current scientific literature.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"58-69"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12188863/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127740","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 exercise on peripheral hypercapnic chemosensitivity during high altitude acclimatization.","authors":"Jou-Chung Chang, Leah M Mann, Katherine M Taylor, Benjamin P Thompson, Scott T Thrall, Megan L Lance, Richard J A Wilson, Trevor A Day, Glen E Foster, Paolo B Dominelli","doi":"10.1152/japplphysiol.00283.2025","DOIUrl":"10.1152/japplphysiol.00283.2025","url":null,"abstract":"<p><p>Hypercapnic sensitivity of the peripheral chemoreceptors can be enhanced by sustained exposure to high altitude (HA), leading to a greater ventilatory response to hypercapnic stimulus. Exercise is known to also increase peripheral hypercapnic chemosensitivity (PHC) in an intensity-independent manner. We sought to determine how sustained exposure to hypobaric hypoxia influences exercise-induced potentiation of PHC. Twenty-one healthy participants were recruited to complete a maximal and submaximal exercise test at both low altitude (LA; Calgary, Canada, 1,100 m) and high altitude (HA; La Paz, Bolivia, 3,500 m). Both tests were conducted on a cycle ergometer with submaximal tests following 2-5 days after arrival at LA and 6-10 days after arrival at HA. The PHC was assessed at rest and throughout two 10-min submaximal exercise bouts by giving two breaths of a hypercapnic inspirate (10% CO₂, 21% O₂) and was repeated five times each separated by 40-60 s. The PHC response was quantified as the quotient of the change in ventilation (V̇_I) over the change in end-tidal PCO₂ ([Formula: see text]) following each hypercapnic stimulus. At HA, compared with LA, there was a greater resting V̇_I (15 ± 3 vs. 12 ± 2 L·min^-1, <i>P</i> = 0.0016) and lower resting [Formula: see text] (27 ± 3 vs. 37 ± 4 mmHg, <i>P</i> < 0.0001). Resting PHC at HA was greater than LA (1.8 ± 0.7 vs. 0.9 ± 0.4 L·min^-1·mmHg^-1, <i>P</i> < 0.0001). The increase in PHC induced by exercise was not different between LA and HA (+38 ± 60% vs. +24 ± 51%, <i>P</i> = 0.18). Sustained high-altitude exposure increases resting PHC, and exercise at HA sensitizes the peripheral chemoreceptors to a similar extent as LA.<b>NEW & NOTEWORTHY</b> Temporary residence at 3,500 m resulted in a greater resting peripheral hypercapnic chemosensitivity than at 1,100 m. Exercise increases hypercapnic sensitivity of the peripheral chemoreceptors from rest at both 1,100 m and 3,500 m, but the magnitude of increase from rest was not different between altitudes. The mechanism for the increased peripheral hypercapnic chemosensitivity induced by exercise is likely unaffected by altitude exposure.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"91-97"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144199224","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":"Combination of running and energy restriction impairs bone parameters but does not inhibit endurance adaptations in fast-twitch muscle in young female rats.","authors":"Yuki Aikawa, Yusuke Wakasugi, Tomoya Fukuyasu, Nobuaki Sasai, Takenori Yamashita, Makoto Ohtsuki, Amane Hori, Kazuki Kioka, Naomi Omi, Naoya Nakai, Kazuhiko Higashida","doi":"10.1152/japplphysiol.00978.2024","DOIUrl":"10.1152/japplphysiol.00978.2024","url":null,"abstract":"<p><p>Low energy availability refers to a state where the body cannot provide sufficient energy to maintain essential physiological functions due to excessive exercise and inadequate energy intake. In athletes, low energy availability impairs bone parameters but may assist muscle adaptation from endurance training. This study was conducted to explore the effect of the combination of running and energy restriction (ER) on bone parameters and muscular endurance adaptations in young female rats. Seven-week-old female rats were divided into four groups: <i>1</i>) sedentary and ad libitum feeding (AL); <i>2</i>) voluntary wheel running and AL; <i>3</i>) sedentary and ER; and <i>4</i>) voluntary wheel running and ER. The experimental period was 11.5 wk. The ER groups were fed a 28% restricted diet compared with the sedentary and AL group. Our results demonstrated that the combination of running and ER decreased the body weight, uterus weight, plantaris and soleus muscle weight, bone mineral density of femur, tibia, and lumbar, and trabecular number of tibia. However, running increased the cross-sectional area (CSA) of type I and IIA fibers and the mitochondrial proteins levels in plantaris muscle under both AL and ER conditions. In the soleus muscle, running exerted no significant main effects on the transition to the myofiber type. ER did not affect the transition to the myofiber type and the mitochondrial protein levels in plantaris and soleus muscles. Our study reveals that the combination of running and ER impairs bone parameters; however, running induces endurance adaptations of plantaris muscle under both AL and ER conditions in young female rats.<b>NEW & NOTEWORTHY</b> Low energy availability impairs bone parameters but may assist muscle adaptation from endurance training. Our study demonstrated that the combination of running and energy restriction (ER) impaired bone mineral density and bone microarchitecture in young female rats. However, running increased the cross-sectional area of type I and IIA fibers, and the levels of mitochondrial proteins in plantaris muscle under both ad libitum feeding and ER conditions in young female rats.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"14-26"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127739","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":"Corrigendum for Hogwood et al., volume 137, 2024, p. 1503-1511.","authors":"","doi":"10.1152/japplphysiol.00323.2024_COR","DOIUrl":"https://doi.org/10.1152/japplphysiol.00323.2024_COR","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":"139 1","pages":"162-163"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144528127","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":"Incorporating gravity into synergistic control of upper limb movements using phasic synergies with positive and negative weights.","authors":"Alessandro Scano, Cristina Brambilla, Marta Russo, Andrea d'Avella","doi":"10.1152/japplphysiol.00779.2024","DOIUrl":"10.1152/japplphysiol.00779.2024","url":null,"abstract":"<p><p>Two models have been proposed to describe how motor control is affected by gravity. According to the gravity-compensation model, accelerating and decelerating the limb through phasic muscle activations is independent of the control of gravity forces, with tonic muscle activations counteracting gravity force. The effort-optimization model, instead, hypothesizes that muscles exploit gravity, decreasing tonic activity to minimize effort using negative phasic EMG components. Muscle synergies have been used for assessing motor control in neurophysiological studies, but synergistic models so far have neglected explicit representations of gravity forces. Therefore, we aimed at incorporating the pervasive presence of gravity into muscle synergies by extracting synergies with negative weights to capture negative phasic EMG components. Muscle synergies with positive and negative weights were extracted using the mixed-matrix factorization (MMF) algorithm on a set of upper limb reaching movements performed by 15 healthy participants across targets in different planes designed to elicit positive and negative phasic activations. Movements were grouped depending on the tonic components at movement onset, needed for gravity exploitation, and identified as \"increasing tonic EMG\" (ITE) and \"decreasing tonic EMG\" (DTE). ITE showed better reconstruction accuracy than DTE when extracting five or fewer synergies. DTE exhibited more negative phasic activations and synergy weights showed more negative values. A bootstrap procedure showed that synergies extracted from ITE and DTE are different in structure, and cluster analysis found nine clusters for ITE and ten for DTE. These results indicate that compensation and effort minimization models can coexist within the muscle synergy framework.<b>NEW & NOTEWORTHY</b> For the first time, a novel approach based on muscle synergies with positive and negative weights allows to account for the exploitation of gravity into synergistic models. This is achieved by a synergistic controller that incorporates both simplicity, as a reduced set of synergies underlying movement and static gravity compensation (phasic and tonic synergies), and effort optimization, based on the exploitation of gravity through negative phasic components.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"112-126"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144248000","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":"Normal variation in brain volumetrics, CSF dynamics, and ocular structures from magnetic resonance images of healthy participants over two years.","authors":"Katrina J Carter, Steven S Laurie, Katherine G Warthen, Stuart H Sater, Bryn A Martin, Ching Mei Feng, Millennia Young, Khader M Hasan, Larry A Kramer, Brandon R Macias","doi":"10.1152/japplphysiol.00596.2024","DOIUrl":"10.1152/japplphysiol.00596.2024","url":null,"abstract":"<p><p>Changes in ocular and brain structure and cerebral spinal fluid (CSF) dynamics from magnetic resonance imaging (MRI) data have been reported in astronauts following long-duration spaceflight. The purpose of this study was to quantify normal variation in these outcomes over a 2-year period in a healthy cohort similar in age to astronauts, but without spaceflight experience. Variation in MRI acquisition, observer measurement, or normal aging over a 2-year period was used to determine thresholds for interpreting measures following long-duration spaceflight. Ten healthy participants (5 male), aged 38 ± 8 yr (mean ± SD), underwent five MRI sessions at baseline, 2, 6, 12, and 24 mo to quantify intracranial volumetry, CSF dynamics, pituitary morphology, and ocular structures. Total within-person variation ([Formula: see text]), modeled as the sum of the variance components for each outcome measure, was used to define a sensitivity threshold of 2.00 × [Formula: see text]. Changes greater than these thresholds can be interpreted as a result of an intervention and have <5% probability of occurring due to expected variability. Thresholds for change due to all sources of variability were: 27 mL for gray matter volume, 16 mL for white matter volume, 0.9 mL for lateral ventricular volume, 26.0 µL for CSF aqueductal stroke volume, 3.2 cm/s for peak-to-peak aqueductal CSF velocity, 0.5 mm for pituitary height, 0.50 mm for optic nerve sheath diameter, and 10.2 mm³ for posterior optic globe volume displacement. Changes on brain MR images after an intervention need to exceed these thresholds to be attributable to that intervention.<b>NEW & NOTEWORTHY</b> We report estimated thresholds of normal variability from methodological and physiological sources in brain and ocular outcomes in healthy participants. Outcomes that exceed these thresholds have less than a 5% probability of occurring due to these sources of variation. One of the present findings suggests that about 50% of the spaceflight-induced increase in lateral ventricular volume exceeds contributions of expected sources of measurement variability.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1-13"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144119753","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-based differences in peak oxygen uptake among individuals with heart failure: systematic review and meta-analysis.","authors":"Rachel J Skow, Stephen J Foulkes, Jing Wang, Devyn Walesiak, Thomas McMurtry, Megan Kennedy, Martin Halle, Stephan Mueller, Isabel Fegers-Wustrow, Frank Edelmann, Corey R Tomczak, Mark J Haykowsky","doi":"10.1152/japplphysiol.00153.2025","DOIUrl":"10.1152/japplphysiol.00153.2025","url":null,"abstract":"<p><p>Heart failure (HF) studies examining peak oxygen uptake (V̇o₂) have largely focused on males, leaving a significant gap in the understanding of the magnitude and the mechanisms underpinning the impairment in females with HF. The objective of this systematic review and meta-analysis is to examine sex differences in peak V̇o₂ in HF. Studies were found through Medline, EMBASE, Scopus, CINAHL, and SPORTDiscus and included if they compared peak V̇o₂ in males and females with HF. Data extraction and methodological quality assessment were completed by two independent coders. Main outcomes and measures included peak V̇o₂ (mL/kg/min, primary outcome) and its Fick determinants (secondary outcome). The weighted mean difference (WMD) was calculated for each outcome between females and males. After screening 1,579 articles, 33 studies were included. Peak V̇o₂ was lower in females versus males (<i>n</i> = 20,115, WMD: -2.1 mL/kg/min, 95% CI: -2.4 to -1.8 mL/kg/min). In studies reporting the Fick determinants, peak exercise cardiac output (<i>n</i> = 1,219, WMD: -1.3 L/min, 95% CI: -1.7 to -1.0 L/min), stroke volume (<i>n</i> = 1,151, WMD: -15.2 mL, 95% CI: -18.8 to -11.7 mL), and arterial-venous oxygen difference (<i>n</i> = 1,131, WMD: -1.4 mL/dL, 95% CI: -2.3 to -0.5 mL/dL) were lower, whereas peak heart rate was higher compared with males (<i>n</i> = 10,103, WMD: 2.4 beats/min, 95% CI: 0.1-4.7 beats/min). The greater peak V̇o₂ impairment among females with HF is likely due to lower peak exercise cardiac output and arterial-venous oxygen difference. Future research should prioritize interventions aimed at addressing these physiological constraints in females with HF.<b>NEW & NOTEWORTHY</b> This meta-analysis revealed that peak exercise oxygen uptake is 2.1 mL/kg/min lower in females with heart failure compared with males, which may be due to having a lower peak cardiac output and arterial-venous O2 content difference. These findings highlight the importance of developing sex-specific therapeutic approaches to better address the added physiological challenges faced by females with heart failure to improve cardiovascular and skeletal muscle health outcomes.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"45-57"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225591","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":"Interindividual variability in renal and muscle sympathetic responses to mental stress: contributions to blood pressure regulation.","authors":"André L Teixeira, Jordan B Lee, Massimo Nardone, Jamie F Burr, Philip J Millar","doi":"10.1152/japplphysiol.00575.2024","DOIUrl":"10.1152/japplphysiol.00575.2024","url":null,"abstract":"<p><p>Laboratory-based mental stress induces consistent increases in arterial blood pressure, while muscle sympathetic nerve activity (MSNA) responses are highly variable. Given the ability of sympathetic nervous system to be regulated in an organ-dependent manner, we hypothesized that interindividual variability in renal sympathetic vasoconstriction interacts with MSNA to control blood pressure during mental stress. Herein, renal artery blood velocity (Doppler ultrasound; <i>n</i> = 33, 19M/14F), MSNA (microneurography; <i>n</i> = 25, 17M/8F), and beat-to-beat mean arterial pressure (MAP; finger photoplethysmography) were measured at rest and during mental stress (arithmetic task) in young, healthy adults. Renal vascular resistance (RVR) was calculated as an index of sympathetically mediated renal vasoconstriction. Participants were classified as negative responders, nonresponders, or positive responders if RVR or MSNA was below, within, or above the baseline variability, respectively. The proportions of negative responders (24% vs. 36%), nonresponders (18% vs. 16%), and positive responders (58% vs. 48%) were significantly different between RVR and MSNA-responder types, respectively (<i>P</i> = 0.02). Within the participants in whom both MSNA and RVR were obtained (<i>n</i> = 25), only 13 (52%) displayed concordant response patterns (3 negative responders, 1 nonresponder, and 9 positive responders). Participants were further classified based on the combination of RVR and MSNA responsiveness as typically negative, mixed, or typically positive responders. Within this subanalysis, MAP reactivity was lower in typically negative compared with mixed and typically positive responders (2 ± 3 mmHg vs. 6 ± 3 mmHg vs. 7 ± 3 mmHg, respectively; <i>P</i> = 0.02). These findings suggest that the interindividual variability in renal and muscle vasoconstrictor responses contributes to blood pressure regulation during mental stress in young, healthy adults.<b>NEW & NOTEWORTHY</b> We found large interindividual variability in renal vascular resistance (RVR) and muscle sympathetic nerve activity (MSNA) responses to mental stress, with only 52% of participants exhibiting concordant response patterns. Individuals with typically negative responses (i.e., decreases in RVR and MSNA, or decreases in one and no changes in the other) displayed lower blood pressure reactivity than typically positive responders, highlighting the integrative contribution of renal and muscle vasoconstriction on blood pressure regulation during mental stress.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"27-36"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144199226","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}