Journal of applied physiology最新文献

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The impact of warm-up intensity and duration on maximal effort limited cardiopulmonary exercise testing parameters in healthy young adults. 热身强度和持续时间对健康青年最大努力极限心肺运动测试参数的影响。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-22 DOI: 10.1152/japplphysiol.00774.2025
Bastien Pedrosa, Chantal Daucourt, Vincent Gremeaux, Brian D Duscha, Brian J Coyne, William E Kraus, Davide Malatesta, Fabio Borrani, Aaron L Baggish, Daria Neyroud
{"title":"The impact of warm-up intensity and duration on maximal effort limited cardiopulmonary exercise testing parameters in healthy young adults.","authors":"Bastien Pedrosa, Chantal Daucourt, Vincent Gremeaux, Brian D Duscha, Brian J Coyne, William E Kraus, Davide Malatesta, Fabio Borrani, Aaron L Baggish, Daria Neyroud","doi":"10.1152/japplphysiol.00774.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00774.2025","url":null,"abstract":"<p><p>The impact of warm-up protocols on peak oxygen uptake (V̇O<sub>2-PEAK</sub>) during cardiopulmonary exercise testing (CPET) remains unclear. This study investigated the effect of warm-ups of different durations and intensities on V̇O<sub>2-PEAK</sub> in healthy young adults during maximal-effort CPET cycle ergometry. Recreationally active participants (10 males, 4 females; 27 ± 4 years) performed five CPETs, each preceded by one of five randomized conditions: (i) no warm-up (NWU), (ii) short duration / low intensity (SD/LI) warm-up (5 min at 0.5 W/kg), (iii) long duration / low intensity (LD/LI) warm-up (10 min at 0.5 W/kg), (iv) short duration / moderate intensity (SD/MI) warm-up (5 min at 1 W/kg), and (v) a long duration / moderate intensity (LD/MI) warm-up (10 min at 1 W/kg). No significant differences were found in V̇O<sub>2-PEAK</sub>, peak heart rate, maximal or submaximal power output across the different warm-up protocols (p > 0.05 for all comparisons), except for greater absolute HR and power output observed at the first ventilatory threshold (VT1) following SD/MI <i>vs.</i> NWU (p < 0.05). Participant ratings of warm-up protocols indicated a preference for shorter and/or lower-intensity warm-ups. Among healthy young adults, the inclusion of warm-up exercise prior to CPET has no significant effects on maximal exercise parameters. These findings question the necessity of warm-up prior to CPET and provide flexibility in CPET warm-up protocol selection in this population. Recapitulation of this study in alternative clinical and scientific populations is warranted.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145345366","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}
引用次数: 0
Association between aging and in vivo mitochondrial oxygen tension (mitoPO2) and oxygen consumption (mitoVO2) in healthy volunteers. 衰老与健康志愿者体内线粒体氧张力(mitoPO2)和耗氧量(mitoVO2)之间的关系
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-20 DOI: 10.1152/japplphysiol.00270.2025
Calvin J de Wijs, Annika M van Smaalen, Lucia W J M Streng, Robert J Stolker, Egbert G Mik, Floor A Harms
{"title":"Association between aging and <i>in vivo</i> mitochondrial oxygen tension (mitoPO<sub>2</sub>) and oxygen consumption (mitoVO<sub>2</sub>) in healthy volunteers.","authors":"Calvin J de Wijs, Annika M van Smaalen, Lucia W J M Streng, Robert J Stolker, Egbert G Mik, Floor A Harms","doi":"10.1152/japplphysiol.00270.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00270.2025","url":null,"abstract":"<p><p>The Cellular Oxygen METabolism (COMET<sup>®</sup>) device provides validated bedside <i>in vivo</i> measurements of mitochondrial oxygen tension (mitoPO<sub>2</sub>) and consumption (mitoVO<sub>2</sub>). Because mitochondrial function has been shown in experimental <i>in vivo</i> and <i>ex vivo</i> studies to potentially alter with age, it is important to establish whether age itself influences these <i>in vivo</i> measurements. The aim of this single-center prospective observational study was to determine whether mitoPO<sub>2</sub> and mitoVO<sub>2</sub> values are influenced by age, thereby ensuring their validity for use across age groups. The aim of the study was not to evaluate COMET<sup>®</sup> as monitor of aging. Using the COMET<sup>®</sup> device, mitoPO<sub>2</sub> and mitoVO<sub>2</sub> were measured at the upper arm and sternum in 176 healthy participants aged 18-90 years. The mean arm mitoPO<sub>2</sub> was 75.3 ± 28.7 mmHg (mean ± SD), while the mean sternal mitoPO<sub>2</sub> was 65.8 ± 23.6 mmHg. Multivariable linear regression did not demonstrate a significant age-related change in mitoPO<sub>2</sub>. Conversely, the mean arm mitoVO<sub>2</sub> was 6.37 ± 2.07 mmHgꞏs<sup>-1</sup>, and the median sternal mitoVO<sub>2</sub> was 7.16 mmHgꞏs<sup>-1</sup> [IQR 5.63-9.17]. Multivariable linear models at both sites demonstrated a significant negative association between age and mitoVO<sub>2</sub>. No significant sex differences were observed for either parameter. These findings reveal that while mitoPO<sub>2</sub> remains unaffected by age, mitoVO<sub>2</sub> shows a significant negative association with increasing age. This distinction suggests that mitoPO<sub>2</sub> can be interpreted independent of age, whereas mitoVO<sub>2</sub> requires age-informed consideration. By profiling healthy volunteers across four decades, we establish preliminary age-informed normative ranges for epidermal mitoPO<sub>2</sub> and mitoVO<sub>2</sub>.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145337050","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}
引用次数: 0
Hypohydration Augments the Acute Increase in Urinary Biomarkers of Kidney Injury Following the 100-mile Western States Endurance Run. 在100英里西部州耐力跑后,缺水增加了肾脏损伤尿液生物标志物的急性增加。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-20 DOI: 10.1152/japplphysiol.00289.2025
Braxton A Linder, Soolim Jeong, Nina L Stute, Omar B El-Kurd, Joseph D Vondrasek, Andrew Pasternak, James R Bagley, Joseph C Watso, Zachary J Schlader, Matthew C Babcock, Gregory J Grosicki, Austin T Robinson
{"title":"Hypohydration Augments the Acute Increase in Urinary Biomarkers of Kidney Injury Following the 100-mile Western States Endurance Run.","authors":"Braxton A Linder, Soolim Jeong, Nina L Stute, Omar B El-Kurd, Joseph D Vondrasek, Andrew Pasternak, James R Bagley, Joseph C Watso, Zachary J Schlader, Matthew C Babcock, Gregory J Grosicki, Austin T Robinson","doi":"10.1152/japplphysiol.00289.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00289.2025","url":null,"abstract":"<p><p><b>Purpose:</b> Ultra-endurance races may transiently increase acute kidney injury (<b>AKI</b>) risk, yet data on contributing factors are sparse. Therefore, we examined the acute effects of the Western States Endurance Run (<b>WSER</b>; [100 miles; 161 kilometers]) on urinary AKI biomarkers and kidney blood flow, while also assessing the influence of race pace and hydration status. <b>Methods:</b> Blood and urine samples were collected to assess urine specific gravity (<b>USG</b>), creatinine, and AKI risk (nephrin, neutrophil gelatinase-associated lipocalin <b>[NGAL]</b>, insulin like growth factor binding protein 7 [IGFBP7], tissue inhibitor of metalloproteinase 2 <b>[TIMP2]</b>, and IGFBP-7●TIMP-2). Renal blood velocity and conductance were measured via Doppler ultrasonography. <b>Results:</b> Pre and post measures were obtained from 36 runners (29Males/7Females, age: 44±9 years, mean finish time: 25:45:55). Urinary AKI biomarkers increased post-race, with nephrin, IGFBP7, and IGFBP7●TIMP-2 remaining elevated after indexing to creatinine (<i>p</i>s < 0.008). Hydration status declined, with only 8 of 35 runners remaining euhydrated post-race. Finishing euhydrated attenuated increases in urinary creatinine and creatinine-indexed IGFBP-7●TIMP-2 (<i>p</i>s ≤ 0.006). Faster race pace correlated with increases in USG (rho, ρ=0.338, <i>p</i>=0.048) and urinary creatinine (rho, ρ=0.443, <i>p</i>=0.010), but not with creatinine-indexed AKI biomarkers (<i>p</i>s ≥ 0.382). Kidney blood velocity and conductance were unchanged (<i>p</i>s ≥ 0.186). <b>Conclusion:</b> Finishing hydrated appears to help mitigate transient increase in kidney injury following an ultra-endurance race.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145337023","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}
引用次数: 0
Intermuscular adipose tissue in healthy human aging - effects of exercise training and implications to metabolic health. 健康人衰老过程中的肌间脂肪组织——运动训练的影响及其对代谢健康的影响。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-20 DOI: 10.1152/japplphysiol.00719.2025
Andrew M Alexander, Lucy M Fitzgibbons, Hawley E Kunz, Zinnarky K Ortiz Correa, K Sreekumaran Nair, John Port, Ian R Lanza
{"title":"Intermuscular adipose tissue in healthy human aging - effects of exercise training and implications to metabolic health.","authors":"Andrew M Alexander, Lucy M Fitzgibbons, Hawley E Kunz, Zinnarky K Ortiz Correa, K Sreekumaran Nair, John Port, Ian R Lanza","doi":"10.1152/japplphysiol.00719.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00719.2025","url":null,"abstract":"<p><p>Intermuscular adipose tissue (IMAT) is an anatomically distinct depot that is associated with metabolic dysfunction and aging. IMAT decreases with exercise in older adults with obesity, but less is known about how exercise influences IMAT in healthy, non-obese older adults in relation to insulin sensitivity. The purpose of this study was to determine if lower leg IMAT accumulates in healthy older adults in the absence of obesity, diabetes, or frailty and its relationship to insulin sensitivity. We also determined the influence of exercise training on lower leg IMAT. 29 young (25.0 ± 3.7 years) and 22 older (70.0 ± 4.0 years) adults underwent MRI-based measurements of lower leg IMAT and insulin sensitivity measurements by hyperinsulinemic euglycemic clamp before and after 12 weeks of exercise training. IMAT was higher in older compared to young adults (521 ± 217 mm<sup>3</sup> vs 278 ± 131 mm<sup>3</sup>; p<0.0001). The glucose infusion rate (GIR) during hyperinsulinemia was similar in young and older adults (13.5 ± 2.9 mg/kg FFM/min vs 14.1 ± 4.2 mg/kg FFM/min; p=0.38), but negatively associated with IMAT (r=-0.43; p=0.002), particularly in older adults (r=-0.55; p=0.01). Exercise training reduced IMAT in young (p=0.04) but not older adults. GIR increased in response to exercise but dissociated from changes in IMAT. These data demonstrate that lower leg IMAT accumulated even in healthy aging, and although IMAT may have metabolic implications, the metabolic improvements with exercise training appear to be independent of lower leg IMAT in this population of older adults.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145336956","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}
引用次数: 0
Effects of exercise intensity on post-exercise oxygen consumption of the vastus lateralis. 运动强度对股外侧肌运动后耗氧量的影响。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-17 DOI: 10.1152/japplphysiol.00815.2025
Rian Q Landers-Ramos, Nicolas D Knuth, Thomas Silva, Kevin K McCully
{"title":"Effects of exercise intensity on post-exercise oxygen consumption of the vastus lateralis.","authors":"Rian Q Landers-Ramos, Nicolas D Knuth, Thomas Silva, Kevin K McCully","doi":"10.1152/japplphysiol.00815.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00815.2025","url":null,"abstract":"<p><p>Post-exercise muscle oxygen consumption rate (mVO<sub>2</sub>) may contribute to understanding responses to and recovery from exercise. <b>Purpose:</b> To measure post-exercise mVO<sub>2</sub> of the vastus lateralis (VL) muscle after various exercise intensities using near-infrared spectroscopy (NIRS). <b>Methods:</b> Twenty healthy individuals, 18-35 years old, participated in two testing sessions. A NIRS device was placed on the belly of the VL to measure differences in oxygenated and deoxygenated hemoglobin (Hb<sub>diff</sub>). Electrodes were placed proximally and distally to the NIRS device, and a cuff capable of rapid inflation was placed on the upper leg. mVO<sub>2</sub> at rest was assessed as the slope of the Hb<sub>diff</sub> signal (% s<sup>-1</sup>) during 3 x 30 second cuff inflations at 300 mmHg. Neuromuscular electrical stimulation (NMES) was applied for 30 seconds, and mVO<sub>2</sub> was assessed 5 minutes later. Participants performed maximal and submaximal (60% VO<sub>2</sub>peak) cycling tests 1 week apart, and mVO<sub>2</sub> was assessed 15 min later. Desaturation slopes (% s<sup>-1</sup>) were calculated in Hb<sub>diff</sub> signals to measure mVO<sub>2</sub>. <b>Results:</b> On average, mVO<sub>2</sub> 5 minutes post-NMES was 1.8-fold higher compared to resting (<i>p</i> < 0.001). mVO<sub>2</sub> was 4.2-fold and 2.7-fold higher 15 minutes after maximal and submaximal cycling, respectively, compared with resting (both <i>p</i> < 0.001). Blood lactate was elevated 10 minutes after maximal (10 ± 3 mmol/L) and submaximal (4 ± 3 mmol/L) cycling (both <i>p</i> < 0.001). <b>Conclusions:</b> Muscle metabolism remained highly elevated 15 minutes after cycling exercise. NIRS-based mVO<sub>2</sub> may have value as an indicator of post-exercise muscle metabolism.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145312912","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}
引用次数: 0
Breathless but buoyed: A female athlete's record-breaking ultraendurance swim 1900 meters above sea level. 屏息而浮起:一位女运动员在海拔1900米的超长耐力游泳中打破纪录。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-17 DOI: 10.1152/japplphysiol.00844.2025
Hunter L Paris, Ashley E Ganey, Ara F Goll, Adam W Kroeze, Tay M Thomas, Faith E Webster, Adam Pennell
{"title":"Breathless but buoyed: A female athlete's record-breaking ultraendurance swim 1900 meters above sea level.","authors":"Hunter L Paris, Ashley E Ganey, Ara F Goll, Adam W Kroeze, Tay M Thomas, Faith E Webster, Adam Pennell","doi":"10.1152/japplphysiol.00844.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00844.2025","url":null,"abstract":"<p><p>We describe the physiological adaptations evoked during a 3-month training block in an elite female swimmer building towards a 34.3 km ultraendurance solo swim across Lake Tahoe (ambient temperature ~13.9°C, water temperature ~17.5°C, elevation 1900 m). The athlete underwent physiological assessments including measures of resting metabolic rate, peak oxygen uptake (V˙O<sub>2</sub>peak), cycling exercise economy, simple reaction time, and grip strengths. In addition to training history and measures taken prior to the record attempt, we captured the physiological responses immediately following completion of the 34.3 km distance. The athlete completed the ultra-swim across Lake Tahoe in a record-setting 10:34:48 (hh:mm:ss)-the fastest time ever recorded for a woman. From the beginning of training to the weeks preceding the Lake Tahoe swim, resting metabolic rate increased from 1382.9 kcal∙day<sup>-1</sup> to 1647.6 kcal∙day<sup>-1</sup>. Exercise economy and V˙O<sub>2</sub>peak remained relatively constant throughout training. Following the 10.5 h swim, body mass changed by less than 1 kg. Simple reaction time and grip strength values declined to substantial and mixed quantities, respectively. This study provides insights into the training regimen adopted by a female swimmer and the physiological ramifications of a record-breaking ultraendurance performance.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145312930","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}
引用次数: 0
Large artery and cerebral pulsatile hemodynamics during high altitude sojourn. 高原旅居期间大动脉和脑搏动血流动力学。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-17 DOI: 10.1152/japplphysiol.00412.2025
Spencer M Romanowski, Carolyn G Steffen, Abigail J Burkhart, Julio A Chirinos, Denise L Smith, Trevor A Day, Abigail W Bigham, Tom D Brutsaert, Wesley K Lefferts
{"title":"Large artery and cerebral pulsatile hemodynamics during high altitude sojourn.","authors":"Spencer M Romanowski, Carolyn G Steffen, Abigail J Burkhart, Julio A Chirinos, Denise L Smith, Trevor A Day, Abigail W Bigham, Tom D Brutsaert, Wesley K Lefferts","doi":"10.1152/japplphysiol.00412.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00412.2025","url":null,"abstract":"<p><p>High altitude sojourn elicits a unique challenge to the cerebrovascular system to compensate for hypoxemia. Exposure to hypoxia appears to decrease pulsatile cerebral blood flow. Yet, the mechanism remains unclear owing to competing vasoconstrictor and vasodilatory responses in the intra- and extra-cranial vasculature. This study examined changes in large artery and cerebral pulsatile hemodynamics, and the potential sex-specific responses, during high-altitude sojourn in 17 young, healthy adults. Nine females (23±4 yrs) and 8 males (24±4 yrs) underwent vascular assessments at 1,400 m and after a 6-day incremental ascent to 4,300 m. Carotid and middle cerebral artery pulsatility were measured via Doppler ultrasound. Aortic stiffness and carotid β-stiffness index were assessed via applanation tonometry and ultrasound, respectively. Pressure-flow and wave-power analyses were used to derive characteristic impedance and hydraulic power/energy parameters at the aorta, carotid, and MCA. Ascent from 1,400 to 4,300 m elicited increases in aortic, and decreases in carotid stiffness, as well as reductions in carotid and MCA pulsatility, and characteristic impedance of all vessels (p<0.05). Mean hydraulic energy increased at the carotid and MCA from 1,400 to 4,300 m (p<0.05), and medium to large effect sizes (η<sup>2</sup>=0.36-0.21) were observed for sex-by-altitude interaction terms indicating potential sex-specific changes in MCA pulsatility, characteristic impedance, and MCA hydraulic energy/power. These data suggest the potential for sex differences in the general reductions in cerebrovascular pulsatility with ascent to 4,300 m that likely stem from vasodilation-induced reductions in characteristic impedance and augmented cerebral blood flow.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145312993","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}
引用次数: 0
Dietary nitrate and muscle contractile function in women: effect of menstrual cycle phase. 膳食硝酸盐与女性肌肉收缩功能:月经周期的影响。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-17 DOI: 10.1152/japplphysiol.00676.2025
Madison J Fry, William S Zoughaib, Richard L Hoffman, Andrew R Coggan
{"title":"Dietary nitrate and muscle contractile function in women: effect of menstrual cycle phase.","authors":"Madison J Fry, William S Zoughaib, Richard L Hoffman, Andrew R Coggan","doi":"10.1152/japplphysiol.00676.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00676.2025","url":null,"abstract":"<p><p>Dietary nitrate (NO<sub>3</sub><sup>-</sup>), a source of nitric oxide (NO), enhances muscle contractility in numerous populations, but it is still unclear whether young women also benefit. The efficacy of NO<sub>3</sub><sup>-</sup> supplementation might vary with menstrual cycle phase, due to lower endogenous NO bioavailability when estradiol (E<sub>2</sub>) is low. Using a double-blind, placebo-controlled, crossover design we determined the effects of acute ingestion of 200 μmol/kg of NO<sub>3</sub><sup>-</sup> (from concentrated beetroot juice) or placebo on muscle function in 12 normally menstruating women during the early follicular (EF) and late follicular (LF) phases of their cycle. Muscle function was determined via maximal knee extensions on an isokinetic dynamometer and electrical stimulation of the quadriceps, with menstrual phase confirmed via plasma hormone measurement. E<sub>2</sub> concentrations were significantly lower in EF vs. LF (220 ± 90 vs. 583 ± 260 pM; p<0.001), whereas progesterone levels did not differ. Despite this, dietary NO<sub>3</sub><sup>-</sup> had no effect on maximal muscle power or velocity during either phase. Dietary NO<sub>3</sub><sup>-</sup> also had no effect on unpotentiated or potentiated peak twitch torque, rate of torque development (RTD), rate of relaxation (RR), or the torque frequency relationship during either phase. However, the RTD was 2-8% greater in the LF vs. EF phase, especially in the unpotentiated state (p<0.01). The RR was also 9% slower in the LF vs. EF phase (p<0.05). Variations in E<sub>2</sub> during the menstrual cycle seem to subtly influence muscle contractile function. Acute NO<sub>3</sub><sup>-</sup> supplementation, on the other hand, has no apparent effect on muscle contractility in young women.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145312911","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}
引用次数: 0
Deep inflations maintain surfactant function and alveolar fluid balance in lungs with reduced Surfactant Protein B levels during mechanical ventilation. 机械通气时表面活性物质蛋白B水平降低,深度充气维持表面活性物质功能和肺泡液平衡。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-16 DOI: 10.1152/japplphysiol.00768.2025
Maximilian Löwe, Franziska Roeder, Dirk Wedekind, Oliver Dittrich-Breiholz, Jannik Ruwisch, Jens Hansen, Clemens Ruppert, Christoph Wrede, Jan Hegermann, Bradford J Smith, Lars Knudsen
{"title":"Deep inflations maintain surfactant function and alveolar fluid balance in lungs with reduced Surfactant Protein B levels during mechanical ventilation.","authors":"Maximilian Löwe, Franziska Roeder, Dirk Wedekind, Oliver Dittrich-Breiholz, Jannik Ruwisch, Jens Hansen, Clemens Ruppert, Christoph Wrede, Jan Hegermann, Bradford J Smith, Lars Knudsen","doi":"10.1152/japplphysiol.00768.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00768.2025","url":null,"abstract":"<p><p>Surfactant Protein B (SP-B) is essential for surface tension reducing function of pulmonary surfactant and alveolar unfolding processes during inspiration. SP-B is reduced early in acute lung injury. Hence, we hypothesize that 1) reduced SP-B expression increases susceptibility to ventilation-induced lung injury (VILI), and 2) deep inflations (DI) are protective against VILI. Conditional SP-B knockout mice were randomized into OFF- (reduced SP-B) and ON-groups (normal SP-B) and subjected to mechanical ventilation at zero end-expiratory pressure. Over 4 hours of ventilation, either 4 or 16 DI were administered. Lung mechanics was recorded and pulmonary structure quantified by design-based stereology. Inflammatory cells and bulk RNA-sequencing were measured in bronchoalveolar lavage (BAL) and tissue, respectively. No differences in inflammatory cells in BAL were detected between ON and OFF-groups. During ventilation alveolar derecruitment-related increase in elastance was most pronounced in OFF-4DI but reversible by DI so that lung mechanics did not worsen. Finally, volumes of the alveolar liquid lining layer and the intracellular surfactant were largest while the surface area of apical plasma membrane of type II pneumocytes was smallest in OFF-4DI suggesting impaired surfactant secretion. A higher frequency of DI prevented these abnormalities. Electron microscopy revealed disorganized tight junctions between alveolar epithelial cells in OFF-4DI, which was linked with decreased expression of genes relevant to the apical junctional complex. Reduced SP-B resulted in progressive increase in surface tension and a disturbed fluid balance without triggering definite VILI. Maintenance of residual surfactant function is highly dependent on DI in conditions of reduced SP-B levels.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145308047","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}
引用次数: 0
Biomarkers of organ stress and injury following the Boston Marathon. 波士顿马拉松后器官压力和损伤的生物标志物。
IF 3.3 3区 医学
Journal of applied physiology Pub Date : 2025-10-16 DOI: 10.1152/japplphysiol.00775.2025
Zachary J McKenna, Whitley C Atkins, Cory L Butts, Xiujing Zhao, Abigail K Morris, Rosie Perez, Shawn C Wierick, Sarah Gustus, Brendon P McDermott
{"title":"Biomarkers of organ stress and injury following the Boston Marathon.","authors":"Zachary J McKenna, Whitley C Atkins, Cory L Butts, Xiujing Zhao, Abigail K Morris, Rosie Perez, Shawn C Wierick, Sarah Gustus, Brendon P McDermott","doi":"10.1152/japplphysiol.00775.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00775.2025","url":null,"abstract":"<p><p>We examined changes in blood and urine-based biomarkers of organ stress/injury and hydration before and after the 2024 Boston Marathon. Our primary aims were to compare responses between males and females, and euhydrated and hypohydrated runners. Seventy-two runners (34 males/38 females; 50 ± 11 years; finish time 3:45 ± 0:32 hrs:min) had blood and/or urine samples taken before and after the race. Average temperature on race day was 19±3 °C and relative humidity was 47±15%. Samples were assayed for markers of hydration, intestinal injury (IFABP, sCD14), skeletal muscle damage (CK), and acute kidney injury (TIMP-2, IGFBP7, NGAL, KIM-1, creatinine). Markers of hydration were elevated from pre- to post-race, but only 25-34% of runners were deemed hypohydrated post-race. All markers of organ stress/injury were increased post-race (fold change: 1.3-1455; p≤.007 for all indices), however there were no differences based on sex or hydration status (p≥.099 for all indices). Our findings show that the Boston Marathon produces a significant level of stress on the gastrointestinal and renal organ systems, and that these effects do not appear to be modulated by biological sex. In addition, our findings suggest that the substantial increases in markers of kidney and intestinal barrier injury persist even when severe hypohydration is prevented suggesting that during the marathon maintaining hydration cannot fully offset risk for organ injury. These findings should be considered when considering interventions to minimize gastrointestinal and renal related health complications associated with marathon running to promote both health and performance in recreational, but completive marathon runners.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145308080","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}
引用次数: 0
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