Journal of applied physiology最新文献

{"title":"Chain of survival for a severe exertional heat stroke casualty.","authors":"David W DeGroot, Aaron C Litchfield, Cora A Blodgett, Blair B Rhodehouse, Kevin P Hudson","doi":"10.1152/japplphysiol.01006.2024","DOIUrl":"10.1152/japplphysiol.01006.2024","url":null,"abstract":"<p><p>Exertional heat stroke is characterized by profound central nervous system dysfunction and core (rectal) temperature typically >40°C. With prompt recognition and response, the probability of survival is excellent; however, there are limited cases with T_c >43.3°C associated with good outcomes. A 23-yr-old male soldier was conducting land navigation training and was found unresponsive by a nonmedical cadre. Emergency medical services personnel obtained a rectal temperature of 44.3°C, which is the highest-ever body core temperature recorded in a patient with exertional heat stroke who survived without significant sequelae. In this case, we report numerous key decisions that contributed to the good outcome. Among those were the use of a GPS-enabled tracking device that enabled the location of the patient on the land navigation course, and the rapid recognition and response by nonmedical personnel at the point of injury. In addition, prioritizing airway, breathing, and circulation over the choice of cooling modality was important in the setting of a patient in acute respiratory distress. Finally, the careful selection of pharmaceutical agents in the Emergency Department minimized additional stress, primarily on the liver and kidneys, which were already significantly stressed. After transfer to a higher level of care due to developing heat-induced disseminated intravascular coagulation and liver failure, the patient was transferred to inpatient rehabilitation 3 wk postinjury. He recovered by 14 mo postinjury, has been medically cleared to return to active duty without limitations, and is continuing his military service.<b>NEW & NOTEWORTHY</b> We present the details surrounding an exertional heat stroke casualty who had the highest-ever body core temperature, 44.3°C, and survived without significant sequelae. Critical decisions that contributed to this outcome, from the point of injury through the first 24 h, are detailed. Treatment considerations included rapid cooling, maintaining the patient's airway, and hemodynamic stability, and minimizing further physiological strain due to the choice of pharmaceutical agents.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"699-705"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143391006","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":"A case report of the female world record holder from 1,500 m to the marathon in the 75+ age category.","authors":"Bas Van Hooren, Zoi Balamouti, Michele Zanini","doi":"10.1152/japplphysiol.00974.2024","DOIUrl":"10.1152/japplphysiol.00974.2024","url":null,"abstract":"<p><p>This study assessed the cardiorespiratory fitness, running biomechanics, muscle architecture, and training characteristics of a 76-yr-old female runner who currently holds the world record 1,500 m to marathon in the women's 75-79 yr age category. Maximum oxygen uptake (V̇o_2max), running economy (RE), lactate threshold (LT), lactate turnpoint (LTP), maximal heart rate (HR_max), and running biomechanics were measured during a discontinuous treadmill protocol followed by a maximal incremental test. Muscle architecture was assessed using ultrasound. The testing was done in close proximity to her world record marathon performance in 2024. V̇o_2max was 47.9 mL·kg^-1·min^-1, and HR_max was 180 beats·min^-1. At marathon speed (11.9 km·h^-1) her RE was 210 mL·kg^-1·km^-1 and her fractional utilization was 88% of V̇o_2max. Fractional utilization at LT (11.1 km·h^-1) and LTP (12.5 km·h^-1) were 83% and 92% of V̇o_2max, respectively. Average weekly distance was 115 and 84 km·wk^-1 in the 6 wk prior to the marathon world record, and 2024 World Masters Athletics Championships (where she achieved 6 gold medals out of 6 events), respectively, with on average 90%, 9%, and 1% of training time performed in the moderate, heavy, and severe intensity domain, respectively. The 76-yr-old female world-record holder 1,500 m to marathon showed the highest V̇o_2max ever recorded for a female >75 yr old, a very high fractional utilization of V̇o_2max at LT, LTP, and marathon pace, while RE was found to be modest compared with other world-class master and younger elite runners.<b>NEW & NOTEWORTHY</b> This case study investigates the physiological determinants of exceptional performance in a 76-yr-old female world-record holder across distances from 1,500 m to the marathon. It reveals the highest V̇o_2max ever recorded in females aged >75 yr and exceptional fractional utilization at metabolic thresholds and marathon speed, comparable to younger world-class distance runners. The modest running economy found can be partially explained by biomechanical and training data.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"603-611"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143039000","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":"Polycystic ovary syndrome potentiates blood pressure and vascular responses to the cold pressor test.","authors":"Danielle E Berbrier, Yasmine Coovadia, Divine Malenda, Charlotte W Usselman","doi":"10.1152/japplphysiol.00697.2024","DOIUrl":"10.1152/japplphysiol.00697.2024","url":null,"abstract":"<p><p>Polycystic ovary syndrome (PCOS) predisposes women to cardiovascular diseases. Blood pressure (BP) responses to the cold pressor test (CPT) predict future cardiovascular risk but have yet to be characterized in PCOS. Therefore, we compared BP responses to the CPT between females with PCOS [<i>n</i> = 10; age: 22 ± 3 yr, body mass index (BMI): 23.9 ± 3 kg/m²] and healthy controls (CTRL; <i>n</i> = 10; age: 22 ± 2 yr, BMI: 22.1 ± 2 kg/m²). BP (finger photoplethysmography calibrated to manual sphygmomanometry-derived values), femoral blood flow (duplex ultrasound), and vascular resistance [FVR; mean arterial pressure (MAP)/blood flow] were measured continuously at baseline and across a 3-min hand CPT. Venous blood samples were used to quantify the free androgen index (FAI; total testosterone/sex hormone binding globulin × 100). Baseline MAP was not different between PCOS and CTRL (87 ± 7 vs. 82 ± 11 mmHg, respectively; <i>P</i> = 0.25), nor was systolic BP (SBP; 109 ± 9 vs. 106 ± 7 mmHg; <i>P</i> = 0.42). Across the CPT, MAP and SBP were higher in PCOS than CTRL (main effects of group, both <i>P</i> < 0.05). Peak CPT induced increases in MAP (+12 ± 5 vs. +7 ± 4 mmHg; <i>P</i> = 0.04) and corresponding changes in SBP (+13 ± 7 vs. +7 ± 3 mmHg; <i>P</i> = 0.04) and FVR (+0.17 ± 0.08 vs. +0.02 ± 0.13 mmHg/mL/min; <i>P</i> = 0.01) were larger in PCOS than CTRL. Within-group regressions indicated that FAI was positively associated with relative increases in peak MAP (<i>R</i>² = 0.72, <i>P</i> < 0.01) and corresponding changes in FVR (<i>R</i>² = 0.83, <i>P</i> < 0.01) in females with PCOS but not in CTRL (MAP: <i>R</i>² = 0.03, <i>P</i> = 0.62; FVR: <i>R</i>² = 0.12, <i>P</i> = 0.41). Young, lean females with PCOS demonstrate exaggerated BP and vascular responses to the CPT that may be indicative of elevated cardiovascular risk mediated in part by the detrimental effects of elevated androgens.<b>NEW & NOTEWORTHY</b> Young, lean, and otherwise healthy females with polycystic ovary syndrome (PCOS) demonstrated exaggerated blood pressure responses to the cold pressor test (CPT) relative to controls. CPT responses were associated with bioavailable androgens, suggesting that hyperandrogenism contributes to exaggerated responses to the CPT in PCOS. Given associations between CPT responsiveness and the subsequent development of hypertension, these findings add to mounting evidence for increased cardiovascular risk even in lean females with PCOS.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"404-414"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807178","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":"Shear wave elastography reveals passive and active mechanics of triceps surae muscles in vivo: from shear modulus-ankle angle to stress-strain characteristics.","authors":"Manuela Zimmer, Louis Fabian Straub, Filiz Ateş","doi":"10.1152/japplphysiol.00459.2024","DOIUrl":"10.1152/japplphysiol.00459.2024","url":null,"abstract":"<p><p>Characterizing individual muscle behavior is crucial for understanding joint function and adaptations to exercise, diseases, or aging. Shear wave elastography (SWE) is a promising tool for measuring the intrinsic material properties of muscle. This study assessed the passive and active shear modulus of the triceps surae muscles in 14 volunteers (7 females, 25.9 ± 2.5 yr) using SWE. Ankle moment, surface electromyography, and SWE of the gastrocnemius medialis (GM), gastrocnemius lateralis (GL), and soleus (SOL) muscles were measured from 30° plantar flexion (PF) to 15° dorsiflexion (DF) ankle angles during passive and isometric contractions at 25%, 50%, and 75% of maximum voluntary contraction (MVC). Muscle length, passive and active ankle moment, and passive shear modulus increased from PF to DF (<i>P</i> < 0.001 for all). At 15° DF, the passive shear modulus of the SOL was 76% lower than that of the GM (<i>P</i> < 0.001), suggesting that the SOL operates within a lower strain range. The active shear modulus decreased from PF to DF (e.g., by 36.8% at 75% MVC, <i>P</i> = 0.009) and was lowest in SOL. The decreasing active shear modulus suggests that the muscles operate at shorter-than-optimal to optimal lengths. Contraction intensity also affected the shear modulus (<i>P</i> < 0.001), indicating distinct force-sharing strategies, with GL possibly playing a crucial role at higher-intensity contractions and longer lengths. This study demonstrated SWE's potential to characterize muscle mechanics in vivo. If validated, predictions from SWE could facilitate studying muscle behavior and force-sharing strategies, serving as a diagnostic or monitoring tool for muscle function and performance.<b>NEW & NOTEWORTHY</b> This study assessed the length- and activation-dependent shear moduli of the triceps surae muscles using shear wave elastography. By combining joint moment, muscle fascicle geometry, and electromyography data, we characterize the muscles' in vivo passive and active mechanical behaviors. Our results indicate that the muscles operate at shorter-than-optimal to optimal lengths with soleus force production being least impacted by joint position. We observed muscle-specific shear modulus characteristics, providing insights into stress-strain behavior and force-sharing strategies.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"577-591"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143046731","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":"Leg blood flow during exercise with blood flow restriction: evidence for and implications of compensatory cardiovascular mechanisms.","authors":"Stuart P S Mladen, Stacey P A Forbes, Abby K Zedic, Vaughn S England, Patrick J Drouin, Michael E Tschakovsky","doi":"10.1152/japplphysiol.00772.2024","DOIUrl":"10.1152/japplphysiol.00772.2024","url":null,"abstract":"<p><p>Proximal limb cuff inflation to 40% arterial occlusion pressure (AOP) is assumed to reduce exercising leg perfusion, creating \"blood flow restriction\" (BFR). However, no study has validated this assumption. Eighteen healthy young participants (9 F) performed two-legged knee flexion/extension exercise at 25% WR_peak with bilateral cuffs applied to the proximal thigh at 0% AOP (CTL), 20% AOP, and 40% AOP. Leg blood flow (LBF; Doppler and echo ultrasound) and cardiac output (CO; finger photoplethysmography) were measured during rest and exercise. LBF values were doubled to account for both exercising legs. AOP (20% and 40%) reduced exercising LBF in a dose-response manner (<i>P</i> < 0.01). However, the magnitude of the leg blood flow restriction by 40% AOP was progressively attenuated across the exercise bout (5-15 s: 37%, 50-70 s: 20%, 240-300 s: 16%; <i>P</i> < 0.01) due to compensatory increases in leg vascular conductance (LVC) (<i>P</i> < 0.01). Between 5 and 15 s of exercise, 40% AOP significantly reduced CO compared with CTL and 20% AOP (8.0 ± 1.3 vs. 8.4 ± 1.5 L/min, <i>P</i> < 0.001 and 8.5 ± 1.5, <i>P</i> < 0.001). By 240-300 s, there were no significant differences in CO between cuff pressures (all <i>P</i> > 0.13). Pneumatic cuff inflation at 20% and 40% AOP reduces LBF in a dose-response manner, but this impairment was progressively attenuated across the exercise bout by an increase in LVC. Importantly, this compensatory response differed across participants, which may have implications for the degree of adaptations following BFR training. Furthermore, restoration of normal CO during BFR despite compromised limb perfusion suggests that other tissue perfusion is increased as part of the response.<b>NEW & NOTEWORTHY</b> It remained to be determined whether BFR set below 60% AOP impairs leg blood flow during continuous exercise. We showed that BFR at 20% and 40% AOP impairs exercising leg blood flow in a dose-response manner. However, the leg blood flow impairment was progressively attenuated across the exercise bout. Both initial compromise and partial restoration varied across participants, which may have implications for the degree of muscle adaptations following BFR training.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"492-507"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143006008","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":"Efficacy of a hands-free vascular ultrasound probe holder in active and inactive limbs during cycling exercise.","authors":"Jeremy N Cohen, Rebecca T Sole, Eudoxia Zafiris, Jason S Au","doi":"10.1152/japplphysiol.00628.2024","DOIUrl":"10.1152/japplphysiol.00628.2024","url":null,"abstract":"<p><p>Measurement of blood flow during exercise is crucial for understanding physiological responses and performance outcomes. However, traditional methods are often invasive, costly, or require substantial training, limiting widespread research in this area. This study introduces the innovative use of limb-affixed ultrasound probe holders for vascular imaging during exercise to overcome these challenges. We investigated a commercially available probe holder, the Usono ProbeFix dynamic (PFD), in capturing artery diameter and blood velocity during dynamic exercise compared with a trained sonographer. Twenty healthy adults (11 females) underwent simultaneous imaging of the brachial artery and superficial femoral artery (SFA) using both manual and PFD imaging on separate days. Data were collected for 60 s at rest on a cycle ergometer and after 4 min of cycling at 50, 100, and 150 W. The PFD was comparable with a trained sonographer at rest (both 99 ± 2%) but demonstrated superiority in capturing blood velocity in the inactive limb (main effect of scanning condition <i>P</i> < 0.01; e.g., 150 W exercise: 85 ± 21% vs. 74 ± 25%). There was no effect of scanning condition on velocity capture success in the SFA (main effect: 69 ± 21% vs. 65 ± 16%; <i>P</i> = 0.42). A systematic constriction of brachial artery diameter (∼0.02 cm) was noted in the PFD condition (<i>P</i> < 0.01), likely due to the compression of the shallow artery. The findings suggest that ultrasound probe holders offer a promising solution for increasing accessibility to exercising blood flow in vascular physiology research, though require considerations for data cleaning and diameter assessment. Further investigation is warranted to optimize the application of these devices in dynamic exercise scenarios.<b>NEW & NOTEWORTHY</b> This study explores an ultrasound probe holder (PFD) for measuring blood flow during exercise, addressing the limitations of traditional methods. We compared PFD imaging with manual scanning in capturing artery diameter and blood velocity during cycling exercise. Results showed that the PFD matched trained sonographer accuracy at rest and outperformed them in capturing blood velocity during exercise in the inactive limb but not active limb. We highlight the PFD's potential impact in vascular physiology research.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"389-396"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142921808","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":"New evidence for baroreflex and respiratory chemoreflex-mediated cerebral sympathetic activation in humans.","authors":"Michael M Tymko, Audrey Drapeau, Maria Augusta Vieira-Coelho, Lawrence Labrecque, Sarah Imhoff, Geoff B Coombs, Stephan Langevin, Marc Fortin, Nathalie Châteauvert, Philip N Ainslie, Patrice Brassard","doi":"10.1152/japplphysiol.00688.2024","DOIUrl":"10.1152/japplphysiol.00688.2024","url":null,"abstract":"<p><p>The brain is highly innervated by sympathetic nerve fibers; however, their physiological purpose is poorly understood. We hypothesized that unilateral cerebral norepinephrine (NE) spillover, an index of cerebral sympathetic nerve activity (SNA), would be elevated when engaging the baroreflex [via lower-body negative pressure (LBNP; -20 and -40 Torr)] and respiratory chemoreflexes [via carbon dioxide (CO₂) administration (+8 Torr)], independently and in combination. Twelve young and healthy participants (five females) underwent simultaneous blood sampling from the right radial artery and internal jugular vein. Tritiated NE was infused through the participants' right forearm vein. Right internal jugular vein and internal carotid artery blood flow were measured using duplex ultrasound. Unilateral cerebral NE spillover remained unchanged when only LBNP was applied (<i>P</i> = 0.29) but increased with hypercapnia (<i>P</i> = 0.035) and -40 Torr LBNP + CO₂ (<i>P</i> < 0.01). There were no changes in total NE spillover during the LBNP and LBNP + CO₂ trials (both <i>P</i> = 0.66), nor during CO₂ alone (<i>P</i> = 0.13). No correlations were present between the increase in unilateral cerebral NE spillover during -40 Torr LBNP + CO₂ and reductions in internal carotid artery blood flow (<i>P</i> = 0.56). These results indicate that baroreflex and respiratory chemoreflex stressors elevate cerebral SNA; however, the observed cerebral sympathetic activation has no impact on blood flow regulation in the internal carotid artery.<b>NEW & NOTEWORTHY</b> The results of the current study suggest that baroreflex and respiratory chemoreflex stressors elevate cerebral sympathetic nervous activity, quantified using the brain norepinephrine spillover method. However, the observed cerebral sympathetic activation has no impact on blood flow regulation in the internal carotid artery.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"366-377"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142882057","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 the maximal metabolic steady state of fitness-matched women and men.","authors":"Brad W Wilkins, Kathleen G Fisher, Emma F Flood, Logan J Heenan, Ian R Matthews","doi":"10.1152/japplphysiol.00655.2024","DOIUrl":"10.1152/japplphysiol.00655.2024","url":null,"abstract":"<p><p>We tested the hypothesis that power at maximal metabolic steady state is similar between fitness-matched men and women. Eighteen participants (9 men and 9 women) performed a cycling graded exercise test for maximal oxygen consumption (V̇o_2max). Men and women were matched for V̇o_2max normalized to fat-free mass (FFM), which was 50.4 ± 4.7 mL·min^-1·kg·FFM^-1 and 52.1 ± 8.2 mL·min^-1·kg·FFM^-1, respectively (<i>P</i> = 0.62). Participants completed a muscle oxygenation (%SmO₂) zero-slope prediction trial and a 3-min all-out trial (3MT). The %SmO₂ zero-slope trials included three, 5-min cycling bouts (30-s rest) spanning intensity domains. Linear regression of trial work rate and %SmO₂ slope over the final 3 min established the work rate occurring at the predicted zero slope in %SmO₂. The 3MT required cycling all-out until the word \"stop\" without providing time elapsed. End test power (ETP) was calculated as the mean power output over the last 30 s and work above end test power (WEP) as the power-time integral above ETP. Independent of method, means ± SD absolute power at the maximal metabolic steady state was similar between fitness-matched women and men (<i>P</i> = 0.72), yet became higher in women when expressed relative to FFM (<i>P</i> = 0.02). Furthermore, V̇o₂ at the power associated with %SmO₂ zero-slope represented a significantly higher fraction of V̇o_2max for women compared with men (<i>P</i> = 0.03). Normalized WEP (W/kg·FFM) remained higher in men (<i>P</i> < 0.01). Although highly correlated (<i>r</i> = 0.88, <i>P</i> < 0.01), ETP was ∼8% higher than %SmO₂ zero-slope power (<i>P</i> = 0.03). Compared with fitness-matched men, women displayed higher FFM normalized power associated with the heavy-severe exercise domain boundary. When matched for fitness, women have a higher power associated with the heavy-severe domain boundary compared with men, when expressed relative to FFM. This exercise intensity also represents a higher fraction of maximal oxygen uptake for women; suggesting women can sustain a higher relative V̇o₂ compared with men. Power at the heavy-severe domain boundary, in both sexes, was lower using muscle oxygenation-derived slope methods compared with 3-min all-out determinations.<b>NEW & NOTEWORTHY</b> When matched for fitness, women have a higher power associated with the heavy-severe domain boundary compared with men, when expressed relative to FFM. This exercise intensity also represents a higher fraction of maximal oxygen uptake for women; suggesting women can sustain a higher relative V̇o₂ compared with men. Power at the heavy-severe domain boundary, in both sexes, was lower using muscle oxygenation derived slope methods compared with 3-min all-out determinations.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"612-622"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143006020","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":"Spirometry estimation of central airway dysanapsis on computed tomography in healthy subjects without active lung diseases.","authors":"Takafumi Shimada, Naoya Tanabe, Fumi Mochizuki, Hiroaki Iijima, Kaoruko Shimizu, Shotaro Chubachi, Kazuya Tanimura, Susumu Sato, Toyohiro Hirai, Nobuyuki Hizawa","doi":"10.1152/japplphysiol.00765.2024","DOIUrl":"10.1152/japplphysiol.00765.2024","url":null,"abstract":"<p><p>The original concept of the airway-to-lung size mismatch, termed dysanapsis, was introduced on spirometry and was extended by computed tomography (CT) evaluation of the central airways. CT-assessed dysanapsis allows a risk estimation of lung disease development in healthy subjects, although radiation exposure limits its use, particularly for younger subjects. This study investigated which spirometry indices can be used to estimate CT-assessed central airway dysanapsis in healthy subjects. In consecutive lung cancer screening subjects without active lung diseases, the dysanapsis ratio (DR), forced mid-expiratory flow/forced vital capacity (FEF_25-75/FVC), forced expiratory volume in 1 s/FVC (FEV₁/FVC), and peak expiratory flow/FVC (PEF/FVC) were obtained via spirometry. The airway-to-lung size ratio for four locations, including the trachea, both main bronchi, and bronchus intermedius (ALR4), and for 14 locations, including the same four airways and 10 segmental and subsegmental airways (ALR14), were obtained via CT. According to the quartiles of the ALR14 or ALR4, 163 male and 190 female subjects were divided into four groups. CT-assessed dysanapsis was defined as the lowest quartile of the ALR14 (or ALR4). Among the spirometry indices, the area under the curve (AUC) for detecting the lowest ALR14 group was the highest for DR (0.80 and 0.78 for males and females, respectively). In contrast, the AUC for detecting the lowest ALR4 group was the highest for PEF/FVC (0.67 and 0.77 for males and females, respectively). DR and PEF/FVC on spirometry could be associated with CT-assessed dysanapsis, but the associations varied depending on the airway locations used for the ALR calculation.<b>NEW & NOTEWORTHY</b> The airway-to-lung size discrepancy on computed tomography (CT-assessed dysanapsis) highlights a lifelong risk for developing lung diseases. This study demonstrated that the spirometric index of the dysanapsis ratio can be used for estimating CT-assessed dysanapsis of the entire central airway tree from the trachea to subsegmental airways, whereas a novel index, peak expiratory flow/forced vital capacity (PEF/FVC), can be used for estimating CT-assessed dysanapsis of the extrapulmonary airways (the trachea, main bronchus, and bronchus intermedius).</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"483-491"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143006024","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":"Running in the heat similarly reduces lipid oxidation and peak oxygen consumption in trained runners and inactive individuals.","authors":"Loïs Mougin, Heather Z Macrae, Alisha Henderson, Thomas G Cable, Lee Taylor, Lewis J James, Stephen A Mears","doi":"10.1152/japplphysiol.00710.2024","DOIUrl":"10.1152/japplphysiol.00710.2024","url":null,"abstract":"<p><p>This study compared oxygen consumption and substrate oxidation while exercising in hot and temperate conditions in individuals with different physical activity statuses (i.e., inactive individuals vs. trained runners). Ten inactive individuals (IA: 26 ± 6 yr; 79.1 ± 14.1 kg; 40.7 ± 5.1 mL·kg^-1·min^-1) and 10 trained runners (TR: 25 ± 6 yr; 69.5 ± 9.1 kg; 63.1 ± 5.1 mL·kg^-1·min^-1) completed two incremental exercise tests (4-min stages) until exhaustion in temperate (TEMP: 18.7 ± 0.1°C; 43.2 ± 4.1% relative humidity) and hot (HOT: 34.4 ± 0.2°C and 42.6 ± 1.6% relative humidity) conditions. Expired gas and blood lactate concentrations were measured at the end of each stage. Peak oxygen consumption similarly decreased in HOT compared with TEMP for IA and TR [-13.2 ± 4.5% vs. -15.2 ± 7%; <i>P</i> = 0.571; effect size (ES) = 0.25]. In HOT compared with TEMP, lipid oxidation, from 30% to 70% of peak oxygen consumption (V̇o_2peak), was reduced for both groups (IA: <i>P</i> = 0.023, ES = 0.43; TR: <i>P</i> < 0.001, ES = 0.72), whereas carbohydrate oxidation was increased for TR (<i>P</i> = 0.011; ES = 0.45) but not for IA (<i>P</i> = 0.268; ES = 0.21). Core temperature was different between conditions for TR (higher in HOT, <i>P</i> = 0.017; ES = 0.66) but not for IA (<i>P</i> = 0.901; ES = 0.25). Despite reduced physiological capacities in IA, both populations demonstrated reductions in lipid utilization and peak oxygen consumption in hot compared with temperate conditions. However, the increased carbohydrate oxidation in HOT for TR was not observed in IA, potentially explained by lower thermal strain. <b>NEW & NOTEWORTHY</b> This study shows that lipid oxidation and oxygen consumption are similarly affected by heat exposure in trained runners and inactive individuals. Carbohydrate oxidation and core temperature are greater in hot conditions in trained runners but not in inactive individuals. A lower metabolic heat production in inactive individuals for a similar relative intensity compared with trained runners could explain these differences in core temperature.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"508-517"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143039005","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}