Journal of applied physiology最新文献

{"title":"Quantifying the time course of changes in maximal skin wettedness with 7 days of heat acclimation.","authors":"Grant P Lynch, Yorgi Mavros, Ollie Jay","doi":"10.1152/japplphysiol.00919.2023","DOIUrl":"10.1152/japplphysiol.00919.2023","url":null,"abstract":"<p><p>The aim of the present study was to quantify the time course of changes in maximum skin wettedness (ω_max)-that is, the proportion of skin surface area covered in sweat at the point of uncompensable heat stress, throughout seven consecutive days of heat acclimation. Nine adults (6 M, 3 F) completed a humidity-ramp protocol (RAMP) on <i>days 1</i>, <i>3</i>, <i>5</i>, and <i>7</i> of seven consecutive days of heat acclimation. In each RAMP trial, participants cycled continuously at 275 W·m^-2 for 120 min at 37°C: 60 min at a vapor pressure of 2.05 kPa followed by 60 min with vapor pressure increased by 0.045 kPa·min^-1. An upward inflection in esophageal temperature (T_eso) signaled a transition to uncompensable heat stress with the critical water vapor pressure at that point used to calculate ω_max. In days between RAMP assessments, participants cycled for 90 min at 75% HR_max at 37°C, 60% RH. T_eso, whole body sweat rate (WBSR), local sweat rates on the back and forearm (LSR_back and LSR_arm, respectively), and activated sweat gland density (ASGD) were measured throughout. ω_max was progressively and significantly greater from <i>day 1</i> (0.68 ± 0.10) to <i>day 3</i> (0.75 ± 0.10; <i>P</i> = 0.002), to <i>day 5</i> (0.79 ± 0.10; <i>P</i> = 0.004), and to <i>day 7</i> (0.87 ± 0.06; <i>P</i> = 0.009). WBSR was higher on <i>days 5</i> (1.11 ± 0.30 L·h^-1; <i>P</i> = 0.01) and <i>7</i> (1.12 ± 0.19 L·h^-1; <i>P</i> < 0.001) compared with <i>day 1</i> (0.94 ± 0.21 L·h^-1). ASGD was higher on <i>day 5</i> (78 ± 15 glands·cm^-2; <i>P</i> < 0.001) and <i>day</i> 7 (81 ± 17 glands·cm^-2; <i>P</i> = 0.001) compared with <i>day 1</i> (65 ± 12 glands·cm^-2). There were no observed differences in sweat gland output (<i>P</i> = 0.21). In conclusion, ω_max significantly increased throughout 7 days of heat acclimation. These progressive increases in ω_max were predominantly mediated by an increase in the number of active sweat glands, not the output per gland.<b>NEW & NOTEWORTHY</b> Significant increases in ω_max were observed as early as 3 days into a 7-day heat acclimation protocol. These data are the first to report dynamic changes in ω_max with progressive heat acclimation and provide new information about ω_max levels between the standard \"unacclimated\" and \"acclimated\" states in existing heat stress models.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"136-143"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142667989","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":"Decreased cardio-respiratory information transfer is associated with deterioration and a poor prognosis in critically ill patients with sepsis.","authors":"Cecilia Morandotti, Matthew Wikner, Qijun Li, Emily Ito, Tope Oyelade, Calix Tan, Pin-Yu Chen, Anika Cawthorn, Watjana Lilaonitkul, Ali R Mani","doi":"10.1152/japplphysiol.00642.2024","DOIUrl":"10.1152/japplphysiol.00642.2024","url":null,"abstract":"<p><p>Assessing illness severity in the intensive care unit (ICU) is crucial for early prediction of deterioration and prognosis. Traditional prognostic scores often treat organ systems separately, overlooking the body's interconnected nature. Network physiology offers a new approach to understanding these complex interactions. This study used the concept of transfer entropy (TE) to measure information flow between heart rate (HR), respiratory rate (RR), and capillary oxygen saturation ([Formula: see text]) in critically ill patients with sepsis, hypothesizing that TE between these signals would correlate with disease outcome. The retrospective cohort study utilized the Medical Information Mart for Intensive Care III Clinical Database, including patients who met Sepsis-3 criteria on admission and had 30 min of continuous HR, RR, and [Formula: see text] data. TE between the signals was calculated to create physiological network maps. Cox regression assessed the relationship between cardiorespiratory network indices and both deterioration [Sequential Organ Failure Assessment (SOFA) score increase of ≥2 points at 48 h] and 30-day mortality. Among 164 patients, higher information flow from [Formula: see text] to HR [TE ([Formula: see text] → HR)] and reciprocal flow between HR and RR [TE (RR → HR) and TE (HR → RR)] were linked to reduced mortality, independent of age, mechanical ventilation, SOFA score, and comorbidity. Reductions in TE (HR → RR), TE (RR → HR), TE ([Formula: see text] → RR), and TE ([Formula: see text] → HR) were associated with an increased risk of 48-h deterioration. After adjustment for potential confounders, only TE (HR → RR) and TE (RR → HR) remained statistically significant. The study confirmed that physiological network mapping using routine signals in patients with sepsis could indicate illness severity and that higher TE values were generally associated with improved outcomes.<b>NEW & NOTEWORTHY</b> This study adopts an integrative approach through physiological network analysis to investigate sepsis, with the goal of identifying differences in information transfer between physiological signals in sepsis survivors versus nonsurvivors. We found that greater information flow between heart rate, respiratory rate, and capillary oxygen saturation was associated with reduced mortality, independent of age, disease severity, and comorbidities. In addition, reduced information transfer was linked to an increased risk of 48-h deterioration in patients with sepsis.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"289-300"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828500","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":"Detection and perception of inspiratory resistive loads in older adults with and without chronic obstructive pulmonary disease.","authors":"Isabella Epiu, David A T Nguyen, Claire L Boswell-Ruys, Simon C Gandevia, Jane E Butler, Anna L Hudson","doi":"10.1152/japplphysiol.00398.2024","DOIUrl":"10.1152/japplphysiol.00398.2024","url":null,"abstract":"<p><p>Impairments in the detection and perception of resistive loads in healthy aging and chronic obstructive pulmonary disease (COPD) have implications for airway protection and breathlessness. This study investigated load detection and perception in 18 participants with COPD, 17 older adults [i.e., age-matched controls (AMCs)] and 23 young adults [i.e., young controls (YCs)]. Load detection was assessed as the minimal change in airway resistance that could be detected and load perception as the perceived level of effort to breathe through a series of suprathreshold resistive loads, rated on a modified Borg scale. Young and older adults, with and without COPD, could detect similar changes in resistance (∼0.7 cmH₂O/L/s) and inspiratory pressure (∼0.5 cmH₂O), although this equated to a smaller proportion of predicted maximal inspiratory pressure (MIPpred) for young adults (∼0.5% MIPpred) compared with older adults with and without COPD (∼1.0% MIPpred; <i>P</i> < 0.001). For load perception, the relationship between Borg ratings and resistance was steeper in older adult controls compared with both young adults (<i>P</i> < 0.001) and older adults with COPD (<i>P</i> < 0.01). Borg rating slopes were comparable across all participant groups with changes in inspiratory pressure. There was no correlation between load detection threshold and load perception. In older adults, heightened perception of loaded breaths with large changes in breathing resistance may be due to an increased effort to breathe at these loads.<b>NEW & NOTEWORTHY</b> We demonstrated that young adults could detect a smaller change in pressure (as a proportion of predicted maximal inspiratory pressure) than older adults. The perceived effort to breathe with increases in the resistance of breathing was heightened in older, compared with young adults. There was no further impairment in chronic obstructive pulmonary disease. Heightened dyspnea perception related to the effort to breathe was not associated with load detection thresholds in older adults.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"250-258"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807150","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":"Training volume increases or maintenance based on previous volume: the effects on muscular adaptations in trained males.","authors":"Andrew Barsuhn, Tanuj Wadhi, Alan Murphy, Spencer Zazzo, Baron Thompson, Christopher Barakat, Josh Bradshaw, Joseph Walters, Jody C Andersen, Brad Jon Schoenfeld, Carlos Ugrinowitsch, Eduardo Oliveira De Souza","doi":"10.1152/japplphysiol.00476.2024","DOIUrl":"10.1152/japplphysiol.00476.2024","url":null,"abstract":"<p><p>This study investigated the effects of increasing previous resistance training (RT) weekly set volume by 30% (G30) and 60% (G60) on muscle hypertrophy and strength. Fifty-five resistance-trained men were randomly allocated to the experimental groups, whereas 29 completed the study, as follows: control group (CON): <i>n</i> = 10, G30: <i>n</i> = 10, and G60: <i>n</i> = 9. Participants underwent a lower body RT program twice a week for 8 wk. We assessed pre- and poststudy thigh region-of-interest fat-free mass (ROI-FFM), anterior thigh muscle thickness (MT) at two sites: proximal (PMT) and distal (DMT) and their sum (ΣMT), one-repetition maximum (1RM), and strength-endurance via repetitions to failure (RTF) at 70% of 1RM. ROI-FFM and MT demonstrated a significant increase from pre- to posttraining (main time effect, <i>P</i> < 0.001) (ΔΣMT CON: 1.07 cm, G30: 0.76 cm, and G60: 0.70 cm; ΔROI-FFM CON: 1.57 kg, G30: 0.47 kg, and G60: 1.55 kg). All groups increased back squat 1RM (<i>P</i> < 0.0001). However, the main group effect (<i>P</i> < 0.0268) indicated that the CON group showcased a greater overall 1RM (174.7 kg), than the G30 (159.0 kg) and G60 (149.0 kg). Only the G30 group increased RTF at the posttest (CON: 0.13 reps, G30: 5.45 reps, and G60: -0.41 reps) (<i>P</i> < 0.0263). Our findings suggest that trained males can experience significant muscle growth and strength adaptations while maintaining their previous weekly set number above a certain weekly set volume threshold.<b>NEW & NOTEWORTHY</b> Increasing previous resistance training volume by 30% (G30), 60% (G60), or maintenance (CON) on muscular adaptations in trained individuals. Interestingly, CON group resulted in the greatest overall 1RM strength, whereas G30 showed the highest increase in repetitions to failure, with no differences between groups in muscle mass size. These findings suggest that more is not always better for muscle adaptations in a trained cohort, highlighting muscle growth across a wide range of weekly set numbers.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"259-269"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142813287","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":"Clinical and physiological effects of high-intensity aerobic training on metabolic syndrome: understanding the individual exercise response variability.","authors":"Alfonso Moreno-Cabañas, Felix Morales-Palomo, Laura Alvarez-Jimenez, Diego Mora-Gonzalez, Eva Garcia-Camacho, Belen Martinez-Mulero, Ricardo Mora-Rodriguez","doi":"10.1152/japplphysiol.00501.2024","DOIUrl":"10.1152/japplphysiol.00501.2024","url":null,"abstract":"<p><p>We analyzed the interindividual heterogeneity in health responses to a supervised high-intensity interval training (HIIT) program in individuals with metabolic syndrome (MetS). Two hundred and sixty-four adults with overweight/obesity (56.3 ± 7.3 yr, body mass index: 32.3 ± 4.7 kg/m²) and MetS were randomized to a standard health care nonexercise group (CONT group, <i>N</i> = 58) or standard health care plus HIIT (EXER group, <i>N</i> = 206). HIIT intervention was performed on a cycloergometer thrice a week (43 min/session). MetS components (i.e., MetS <i>z</i> score), cardiorespiratory fitness (V̇o_2peak), maximal cycling power (W_PEAK), and body weight/composition was assessed in both groups before (0 wk) and after the intervention (16 wk). Individual responses in the EXER group were considered attributable to HIIT when the improvements were larger than twice the typical error (>2TE). TE was calculated using pre- and postintervention data from the time-matched CONT group. The percentage of participants who improved MetS <i>z</i> score beyond 2TE was 51% driven by reductions in blood pressure (45%) and waist circumference (48%). Blood lipids and glucose response were only 21% and 16%, respectively (participants improving beyond 2TE). Sixty percent of individuals who improved MetS <i>z</i> score also improved V̇o_2peak (<i>r</i> = -0.013; <i>P</i> = 0.86), whereas 85% of individuals improving MetS <i>z</i> score also improved W_PEAK (<i>r</i> = 0.151; <i>P</i> = 0.03). In summary, health providers can expect that a 16-wk HIIT program would indisputably improve MetS in approximately 50% of individuals completing the program. Finally, W_PEAK better predicts which individuals would improve MetS than V̇o_2peak when the direct assessment of the five MetS factors is not feasible.<b>NEW & NOTEWORTHY</b> Our study offers healthcare providers the expected percentage of individuals who would improve their metabolic syndrome condition after completing a standardized HIIT program (16 wk, 43 min/session, 3 days/wk). Only half of the subjects achieved indisputable improvement in their MetS <i>z</i> score when we accounted for biological variability and instrument errors. Detection of individuals with a positive response in MetS <i>z</i> score could be inferred from gains in maximal cycling power (i.e., exercise functionality).</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"144-156"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142716127","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":"Mild hypohydration in healthy older adults increases pain-related brain activity without affecting pain perception: a single-blind study.","authors":"Thomas A Deshayes, Félix-Antoine Savoie, Timothée Pancrate, Antoine Jolicoeur Desroches, José A Morais, Pierre-Michel Bernier, Guillaume Léonard, Ivan L Simoneau, Eric D B Goulet","doi":"10.1152/japplphysiol.00870.2024","DOIUrl":"10.1152/japplphysiol.00870.2024","url":null,"abstract":"<p><p>Understanding how hydration status influences pain perception is particularly important in older adults, as both dehydration and pain are prevalent in this population. Ten individuals (70 ± 4 yr) completed two randomized and counterbalanced trials. They were exposed to passive heat until they lost 1% body mass through sweat and urine (∼100 min), with the loss either unreplaced (sham infusion, HYPO) or fully replaced via 0.45% saline infusion (EUH). Nociceptive electrical stimulation was applied to the sural nerve <i>1</i>) before heat exposure (baseline), <i>2</i>) 60 min following hydration manipulation (R60, ∼160 min after baseline), <i>3</i>) after mouth rinsing with water (MR, ∼170 min after baseline), and <i>4</i>) following water ingestion (ING, ∼185 min after baseline). Pain-related event-related potentials were assessed using electroencephalography (EEG) at R60, MR, and ING. After hydration manipulation, body mass loss and plasma osmolality were greater, and plasma volumes were lower in HYPO than in EUH, although thirst did not differ between the conditions. There were no differences between the two conditions regarding pain intensity and unpleasantness. Still, EEG analyses revealed that the peak-to-peak amplitude of the pain-related N200-P300 potential (∼136-310 ms) was significantly greater in HYPO than in EUH (<i>P</i> = 0.036) and significantly greater in R60 compared with both MR (<i>P</i> = 0.01) and ING (<i>P</i> = 0.03), either with HYPO and EUH. These results suggest that mild hypohydration in healthy older adults may influence some neurophysiological processes related to nociception without significantly affecting pain perception.<b>NEW & NOTEWORTHY</b> This study reveals, for the first time, that mild hypohydration equivalent to ∼1% of body mass does not alter pain perception in healthy older adults when they are blinded to their hydration status, despite electroencephalography signals showing modulation of pain-related brain responses.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"238-249"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828572","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 two carbonic anhydrase inhibitors on exercise performance in acute hypoxia.","authors":"Jou-Chung Chang, Benjamin P Thompson, Connor J Doherty, Leah M Mann, Antonia N Berdeklis, Glen E Foster, A Russell Tupling, Erik R Swenson, Paolo B Dominelli","doi":"10.1152/japplphysiol.00589.2024","DOIUrl":"10.1152/japplphysiol.00589.2024","url":null,"abstract":"<p><p>Acute mountain sickness (AMS) occurs due to rapid altitude ascents and/or insufficient acclimatization. Acetazolamide (AZ) is commonly prescribed for AMS prophylaxis but inhibits exercise performance. Methazolamide (MZ), an analogous drug, has similar prophylactic benefits but does not impair isolated muscle mass exercise performance in normoxia. We sought to compare whole body exercise performance in acute hypoxia (fraction of inspired oxygen, [Formula: see text] = 0.15) between AZ, MZ, and placebo (PLA). Fifteen healthy participants completed five testing visits: <i>day 1</i> for maximal exercise test, <i>day 2</i> for familiarization, and <i>days 3</i>-<i>5</i> were the experimental visits. Each experimental visit involved a 5-km hypoxic cycling time trial (TT) performed after a 2-day dosing protocol of either AZ (250 mg three times a day), MZ (100 mg twice a day), or PLA (three times a day); the order was randomized and double-blinded. Before exercise, capillary blood samples were taken, and maximal voluntary contractions of quadriceps were performed. AZ and MZ resulted in a partially compensated metabolic acidosis at rest compared with PLA [capillary hydrogen ions (H⁺) 47 ± 3, 43 ± 2, and 39 ± 2 nmol for AZ, MZ, and PLA respectively, <i>P</i> < 0.01]. Time to complete 5 km with PLA (562 ± 32 s, <i>P</i> < 0.01) was significantly faster than AZ and MZ (577 ± 38 vs. 581 ± 37 s, respectively), with no differences between AZ and MZ (<i>P</i> = 0.96). There were no differences in average ventilation (124 ± 27, 127 ± 24, 127 ± 19 L/min) and oxyhemoglobin saturation (87 ± 2, 88 ± 2, 88 ± 3%) between AZ, MZ, and PLA, respectively (<i>P</i> > 0.05). Overall, both AZ and MZ impair whole body exercise performance in acute normobaric hypoxia.<b>NEW & NOTEWORTHY</b> Administration of acetazolamide (AZ) and methazolamide (MZ) both resulted in a significantly slower 5-km time trial in acute normobaric hypoxia compared with a placebo. Both drugs lead to a partially compensated metabolic acidosis, but ventilation and oxyhemoglobin saturation were not different across the conditions. Overall, acetazolamide and methazolamide both impaired whole body exercise performance in acute normobaric hypoxia but potentially have different mechanisms of action.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1566-1579"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545675","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":"Cadence-based energy expenditure in able-bodied male people comparing cadence-based energy expenditure and oxygen cost indices in able-bodied male people.","authors":"Juntaek Hong, Jehyeon Yu, Juyeon Lee, Dain Shim, Tae Young Choi, Ye Bin Cho, Jeuhee Lee, Dong-Wook Rha","doi":"10.1152/japplphysiol.00294.2024","DOIUrl":"10.1152/japplphysiol.00294.2024","url":null,"abstract":"<p><p>Walking is a fundamental aspect of daily life and exercise, with clinical benefits for cardiovascular health and muscle strength. However, accurately measuring energy efficiency during walking poses challenges due to equipment and spatial constraints. In this study, we proposed the cadence-based energy expenditure index (cEEI) and analyzed its correlation with the previously proposed index for measuring energy expenditure under various gait conditions. We enrolled 15 healthy participants and conducted an experimental protocol on a treadmill to measure the following energy expenditure-related indices: oxygen cost index (OCI), energy expenditure index (EEI), and cEEI. The participants underwent stages of walking at different speeds and inclinations that comply with the modified Bruce protocol, whereas their heart rate, oxygen uptake, and cadence were recorded. Participants showed significant increases in heart rate, oxygen uptake, and cadence with higher walking speeds and inclinations. Correlation analysis revealed strong associations between cEEI and OCI, especially during walking conditions. Bland-Altman plots and interclass correlation coefficient analysis demonstrated a favorable agreement between cEEI and OCI, outperforming EEI. In conclusion, this study proposes cEEI as a reliable metric for estimating energy expenditure during walking by proving a strong correlation and agreement with OCI across various gait conditions. This suggests the potential for cEEI to provide real-time, individualized feedback on energy expenditure during walking, facilitating more personalized exercise prescriptions.<b>NEW & NOTEWORTHY</b> We proposed cEEI as a reliable metric for estimating energy expenditure under various walking conditions. Its demonstrated accuracy and potential for real-time individualized feedback could revolutionize personalized exercise prescriptions for diverse sexes and age groups, as well as individuals with disabilities requiring real-time physical monitoring and home care.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1604-1611"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142466234","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":"Marked hemoglobin mass expansion and plasma volume contraction in Sherpas acclimatizing to 5,400 m altitude.","authors":"Johanna Roche, Santosh Baniya, Suraj Bhatta, Sachin Subedi, Hannes Gatterer, Peter Rasmussen, Matthias Peter Hilty, Anne-Aylin Sigg, Santosh Timalsina, Christoph Siebenmann","doi":"10.1152/japplphysiol.00247.2024","DOIUrl":"10.1152/japplphysiol.00247.2024","url":null,"abstract":"<p><p>In lowlanders, high altitude (HA) acclimatization induces hemoconcentration by reducing plasma volume (PV) and increasing total hemoglobin mass (Hb_mass). Conversely, Tibetan highlanders living at HA are reported to have a similar hemoglobin concentration ([Hb]) as lowlanders near sea level, and we investigated whether this reflects alterations in the PV or the Hb_mass response to HA. Baseline assessment of PV and Hb_mass was performed by carbon monoxide rebreathing at low altitudes (∼1,400 m) in Sherpas (an ethnic group of Tibetans living in Nepal) and native lowlanders. Participants then ascended to the Everest Base Camp (EBC) (5,400 m), where further measurements were performed after ∼2 days (EBC 1) and ∼6 wk (EBC 2). While on EBC 1 an increase in [Hb] was observed in lowlanders (<i>P</i> = 0.004) but not in Sherpas (<i>P</i> = 0.179), marked increases in [Hb] were observed in both groups on EBC 2 (<i>P</i> < 0.001). On EBC 1, Hb_mass (Sherpas, <i>P</i> = 0.393; lowlanders, <i>P</i> = 0.123) and PV (Sherpas, <i>P</i> = 0.348; lowlanders, <i>P</i> = 0.172) were not different from baseline in either group, while circulating erythropoietin was increased in both groups (<i>P</i> < 0.001). On EBC 2, large increases in Hb_mass and reductions in PV were observed along with elevated circulating erythropoietin in both groups (all <i>P</i> < 0.002). Neither the increases in erythropoietin on EBC 1 (<i>P</i> = 0.846) or EBC 2 (<i>P</i> = 0.564) nor the expansion of Hb_mass (<i>P</i> = 0.771) or reduction in PV (<i>P</i> = 0.099) on EBC 2 differed between the groups. We conclude that the hematological response of Sherpas to extended exposure to very high altitudes does not fundamentally differ from that of native lowlanders.<b>NEW & NOTEWORTHY</b> We measured the hematological response to ∼6 wk exposure to an altitude of 5,400 m in Sherpa highland natives and Nepalese lowlanders. While the increase in hemoglobin concentration at high altitudes tended to be smaller in Sherpas than in lowlanders, the two groups experienced a similar reduction in plasma volume and increase in hemoglobin mass. We conclude that the hematological response of Sherpas to high-altitude exposure does not fundamentally differ from that of lowlanders.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1632-1641"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11687824/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142604670","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":"Impact of dietary supplementation of glycocalyx precursors on vascular function in type 2 diabetes.","authors":"James A Smith, Francisco I Ramirez-Perez, Katherine Burr, Juan D Gonzalez-Vallejo, Mariana Morales-Quinones, Neil J McMillan, Larissa Ferreira-Santos, Neekun Sharma, Christopher A Foote, Luis A Martinez-Lemus, Jaume Padilla, Camila Manrique-Acevedo","doi":"10.1152/japplphysiol.00651.2024","DOIUrl":"10.1152/japplphysiol.00651.2024","url":null,"abstract":"<p><p>Degradation of the endothelial glycocalyx in type 2 diabetes (T2D) is thought to contribute to impaired shear stress mechanotransduction, leading to endothelial dysfunction and the development of cardiovascular disease. Herein, we tested the hypothesis that restoration of the endothelial glycocalyx with dietary supplementation of glycocalyx precursors (DSGPs, containing glucosamine sulfate, fucoidan, superoxide dismutase, and high-molecular weight hyaluronan) improves endothelial function and other indices of vascular function in T2D. First, in db/db mice, we showed that treatment with DSGP (100 mg/kg/day) for 4 wk restored endothelial glycocalyx length, as assessed via atomic force microscopy in aortic explants. Restoration of the glycocalyx with DSGP was accompanied by improved flow-mediated dilation (FMD) and reduced arterial stiffness in isolated mesenteric arteries. Further corroborating these findings, the treatment of cultured endothelial cells with that same mixture of glycocalyx precursors promoted glycocalyx growth. Next, as an initial step to investigate the translatability of these findings, we conducted a pilot (<i>n</i> = 22) double-blinded randomized placebo-controlled clinical trial to assess the effects of DSGP (3,712.5 mg/day) for 8 wk on endothelial glycocalyx integrity and indices of vascular function, including FMD, in Veterans with T2D. Contrary to the hypothesis, DSGP neither enhanced endothelial glycocalyx integrity nor improved vascular function indices relative to placebo. Together, these findings conceptually support the notion that restoration of the endothelial glycocalyx can lead to improvements in vascular function in a mouse model of T2D; however, DSGP as a therapeutic strategy to enhance vascular function in individuals with T2D does not appear to be efficacious.<b>NEW & NOTEWORTHY</b> Endothelial glycocalyx degradation in type 2 diabetes (T2D) is thought to contribute to impaired shear stress mechanotransduction, leading to vascular dysfunction. The findings of this study support the notion that restoration of the endothelial glycocalyx using a dietary supplementation of glycocalyx precursors can lead to improvements in vascular function in diabetic mice. However, the utilized dietary supplement as a therapeutic strategy to enhance vascular function in individuals with T2D is not efficacious.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1592-1603"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11687847/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545677","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}