Frontiers in Physiology最新文献

Introduction: Serum-based hormone analysis is considered essential for determining menstrual cycle phases in sport and exercise science. However, its reliance on venous blood sampling limits applicability in field-based or operational contexts. This study evaluated the validity of larger-volume capillary samples obtained from the earlobe for the quantification of progesterone (P4) and 17ß-estradiol (E2) in comparison to venous blood sampling.

Materials and method: Twelve eumenorrheic female soldiers (mean age: 24.4 ± 2.9 years; BMI: 24.4 ± 2.2 kg/m²) participated in a longitudinal protocol involving paired capillary and venous blood sampling twice weekly across one complete individual menstrual cycle. Blood was drawn from the earlobe (capillary, 100-250 µL) and antecubital vein (venous, 4 mL) and analyzed via ELISA for P4 and E2 concentrations.

Results: All participants completed six or more sampling timepoints and had ovulatory cycles, with a mean cycle length of 28.3 ± 3.6 days and ovulation occurring on day 16.6 ± 4.7. On average, P4 concentrations were 1.6 ng/mL higher in venous compared to capillary samples, while E2 values were 0.34 pg/mL lower. The concordance correlation coefficients were 0.911 for P4 and 0.919 for E2, indicating good to very good agreement between the sampling methods. Repeated measures Bland-Altman analysis with mixed effects revealed minimal mean bias for both hormones, with acceptable limits of agreement. Repeated measures correlation coefficients were 0.915 and 0.982 for E2 and P4, respectively.

Discussion and conclusion: The results demonstrate that earlobe-derived capillary sampling is a valid and practical alternative to venous sampling for hormonal assessment across the menstrual cycle. The method yielded robust results for both P4 and E2, with sufficient accuracy to support cycle phase classification and the detection of anovulatory or luteal-phase deficient cycles. The logistical advantages include minimal invasiveness, no need for medical personnel, and the ability to analyze the frozen samples at a later date. This makes capillary sampling particularly well suited for use with athletes and tactical populations. Future studies should explore its application in elite athletes and incorporate participant-reported burden to optimize feasibility in high-frequency sampling protocols.

Background: Vascular dysfunction has been described as worsening in Chronic Obstructive Pulmonary Disease (COPD), but there is a lack of knowledge regarding severe patients. This retrospective cross-sectional study aimed to investigate it in COPD with Chronic Respiratory Failure (CRF) versus COPD and controls.

Methods: A baseline screening was performed, including a health history, a physical examination, and an anthropometric assessment. All subjects underwent an arterial blood gas analysis, spirometry, a 6-min walking test, and a thigh muscle volume assessment. The vascular function was determined via single Passive Leg Movement (sPLM) on the dominant leg.

Results: Fifteen patients with moderate COPD (FEV₁ 53.3% ± 11.4%), 15 patients with severe COPD (CRF; FEV₁ 30.6% ± 10.3%), and 15 age-matched healthy controls (CTRL) were recruited. Reactive hyperemia following sPLM was decreased in CRF [peak LBF (Leg Blood Flow) 70 ± 38 mL/min)] compared to COPD (peak LBF 162 ± 115 mL/min) and CTRL (peak LBF 268 ± 134 mL/min), p < 0.05. Interestingly, when the vascular function was normalized to the thigh muscle volume, the difference in the hyperaemic response among the CRF, COPD, and CTRL groups was mitigated but not eliminated. Moreover, the peak LBF was associated with the 6-min walking test (r = 0.7027, p < 0,0001), FEV₁ (r = 0.5432, p = 0.0001), disease duration (r = 0.5062, p = 0.0004), oxygen saturation (SpO₂) (r = 0.4343, p = 0.0029), and prescribed oxygen flow (r = -0.5413, p < 0.0001).

Conclusion: These data provide evidence of an intrinsic vascular dysfunction during the progression of COPD, which depends only partially on locomotor muscle volume loss observed in this clinical population.

Introduction: Effects of cold exposure on human physiology are mainly studied after exercise. Therefore, this study aims to investigate the effects of gradually increasing cold exposure and physical exercise on steroid levels, body composition, and other biochemical markers in healthy male athletes immediately after 5-day exercise in cold and after 7 days of recovery.

Methods: Healthy male athletes (n = 12, aged 20.5 ± 1 year, height 181 ± 7.7 cm) were exposed to 5 days of outdoor physical training (2 °C-3 °C) with increasing intensity of exercise and cold exposure. Venous blood was collected, and body bioelectrical impedance measured before and after the 5-day experiment, and after 7-day recovery. Circulating levels of testosterone, cortisol, androstenedione, dehydroepiandrosterone sulphate, 17-hydroxyprogesterone, calcifediol, interleukin-6, C-reactive protein, and erythrocyte superoxide dismutase activity were analysed.

Results: Our data show a delayed effect of exercise in cold after 7 days of recovery in the total plasma levels of testosterone (56% increase vs. baseline) and cortisol (54% increase vs. baseline), with no difference immediately after physical training in cold. Bioelectrical impedance analysis showed a decrease in waist-to-hip ratio after the experiment, which normalised after 7 days. No significant changes were observed in Interleukin-6, C-reactive protein, or superoxide dismutase levels.

Conclusion: A 5-day period of daily exercise in a cold environment showed no immediate effects, but a potential to elicit adaptive changes delayed for up to 7 days, leading to a significant increase in steroid hormones, without changing the testosterone/cortisol ratio.

Objective: To determine whether a single 20-min bout of lower-limb intermittent negative pressure (INP) acutely improves microcirculation in competitive Tai Chi athletes.

Methods: Twenty-eight male athletes (20.3 ± 1.0 years) underwent pre- and post-INP assessment of microvascular blood flow, moving blood-cell concentration, velocity, and transcutaneous oxygen (TcPO₂) and carbon-dioxide (TcPCO₂) tensions at the biceps brachii and vastus lateralis using laser-Doppler flowmetry and gas sensors. Vascular reserve was quantified after 5-min local heating. INP consisted of 30 s at -55 to -60 mbar followed by 10 s at atmospheric pressure for 20 min. Paired t-tests compared pre- and post-values; Cohen's d gauged effect size.

Results: At baseline, TcPO₂ and TcPO₂/TcPCO₂ were lower in the lower limb (P < 0.001, d = 0.92-0.75). Post-INP, no significant changes occurred in the upper limb. In the lower limb, TcPO₂ increased from 63.9 ± 10.2 to 77.4 ± 10.4 mmHg (P < 0.001, d = 1.31) and TcPO₂/TcPCO₂ rose from 1.8 ± 0.4 to 2.4 ± 0.7 (P < 0.001, d = 1.05); hemodynamic variables were unchanged.

Conclusion: One session of lower-limb INP selectively enhances local oxygenation in Tai Chi athletes without affecting upper-limb microcirculation, offering a rapid, lower-limb-specific recovery strategy.

Aim: To investigate the association between long-term Yoga practice and changes in trapezius and hamstring biomechanics using shear-wave elastography (SWE), and to identify reliable measurement conditions.

Methods: Eighty-one healthy women were assigned to a Yoga group (n = 51) or non-Yoga control group (n = 30). The mean Young's modulus (E_mean) of the trapezius, biceps femoris long head, and semitendinosus was assessed at baseline, 1, 3, and 6 months under standardized postures (neutral, flexed, extended, and 90° knee flexion) and imaging planes (transverse/longitudinal) using a Siemens ACUSON Redwood system.

Results: Eighty-one healthy adult women were enrolled (Yoga: n = 51; non-Yoga: n = 30), with no significant baseline differences between groups (all p > 0.05). Muscle thickness did not differ between groups at any time point for any muscle (all p > 0.05). For the trapezius, significant main effects of position (p < 0.001) and time (p = 0.014), as well as a significant group × time interaction (p < 0.001), were observed, with a progressive reduction in Emean in the Yoga group only. In the hamstring muscles, significant group × time interactions were detected for both the biceps femoris long head (longitudinal: F (2.66, 210.24) = 12.11, p < 0.001; transverse: F (2.42, 191.04) = 9.19, p < 0.001) and the semitendinosus (longitudinal: F (2.05, 161.87) = 9.93, p < 0.001; transverse: F (2.47, 195.00) = 5.21, p = 0.002). Longitudinal measurements consistently showed greater sensitivity to temporal changes than transverse measurements, and weak inverse correlations were observed between cumulative yoga training duration and muscle elasticity (all p < 0.05).

Conclusion: Six months of regular Yoga was associated with improved muscle elasticity, while SWE provides a robust and quantitative assessment of posture-dependent biomechanical adaptations.

Background: Space exploration, especially long-duration missions such as those to Mars, presents unique and significant challenges to astronaut health. Space medicine, which focuses on maintaining health in extreme environments without access to definitive medical care, emphasizes preventive measures. Lifestyle medicine (LM), grounded in six pillars such as healthy nutrition, regular physical activity, restorative sleep, stress management, positive social connections, and avoidance of risky substances, has proven effective for disease prevention on Earth. However, its application to spaceflight and remote Earth environments remains underexplored. This raises the question of how LM framework can sustain astronaut health and inform preventive and primary care strategies for remote Earth populations.

Objective: This narrative review examines how LM can support astronaut health during long-duration missions and draws parallels with healthcare needs in remote Earth populations. It establishes principles for integrating lifestyle and space medicine and provides recommendations for their application in both contexts.

Results: Each LM pillar is uniquely challenged in space. Nutritional constraints arise from limited food variety and storage capacity; microgravity and workload restrictions limit physical activity; circadian disruption and environmental noise affect sleep; isolation, confinement, and mission stress compromise stress regulation and social connections; restricted crew size and communication delays limit social connection; and strict medication policies highlight the dual role of substance use as both risks and necessity. While individual countermeasures have been tested in space, no integrated framework addressing all pillars simultaneously has yet been implemented. Technological innovations, such as wearable devices for continuous monitoring, telehealth modules for remote support, and virtual reality platforms for mental health and social engagement, appear as promising enablers of such an integrated approach for both astronauts and populations in medically underserved areas on Earth.

Conclusion: LM provides a preventive framework that complements traditional countermeasure and may enhance resilience and autonomy during space missions. Future research should prioritize integrated, longitudinal studies in analog environments to quantify the synergistic effects of integrated LM interventions versus single pillar countermeasures. Its translation to remote and underserved populations on Earth could help reduce healthcare disparities and support scalable, autonomy-centered models of care, underscoring the bidirectional value of combining lifestyle and space medicine.

Objective: To evaluate the clinical application value of capsule endoscopy (CE) in the diagnosis of small intestinal diseases in children in Wuhan.

Methods: A retrospective analysis was conducted on the clinical data of children who underwent CE examination at the Digestive Endoscopy Center of Wuhan Children's Hospital from July 2021 to November 2024. The completion rate of CE examination, disease detection rate, small intestinal transit time, and adverse reactions were analyzed.

Results: Among the 151 children, 97 were male (64.24%) and 54 were female (35.76%), with an average age of 10.9 years. CE was swallowed orally in 133 cases (88.08%) and placed through gastroscopy in 18 cases (11.92%). Complete small intestinal examination was achieved in 144 cases (95.36%), with an average small intestinal transit time of 4 h and 11 min for those swallowed orally and 4 h and 16 min for those placed through gastroscopy. Seven cases (4.64%) did not complete the full small intestinal examination. Abdominal pain (99 cases, 65.56%), anemia (19 cases, 12.58%), and hematochezia and melena (23 cases, 15.23%) were the most common indications for examination. Among the 151 children, 116 (76.82%) had positive results, including 68 cases of nonspecific small intestinal inflammation, 29 cases of Crohn's disease, 4 cases of Henoch-Schönlein purpura, 6 cases of Meckel's diverticulum, 4 cases of small intestinal parasitic disease, 2 cases of collagenous gastritis, 1 case of melanocytic polyp, 1 case of lymphangiectasia, and 1 case of blue rubber bleb nevus syndrome. Nonspecific small intestinal inflammation was the most common in all age groups, while Crohn's disease was mainly seen in the 7-12 years and 13-18 years age groups, accounting for 55.17% and 44.83%, respectively. No adverse reactions occurred in all children.

Conclusion: CE examination in children in Wuhan has a high disease detection rate and good safety. CE can be further promoted in the diagnosis of small intestinal diseases in children.

Objectives: This meta-analysis aimed to identify gender-based differences of both overall Functional Movement Screen (FMS) and individual FMS components in male and female groups.

Methods: A comprehensive search was performed across three major databases (PubMed, Web of Science, and Google Scholar) to ensure rigorous inclusion criteria. Data collection took place from 2016 to 2024, and 1,235 articles were identified. After scrutiny, 20 met the requirements for inclusion. The Review Manager 5.4 and CMAv4 software were utilized to examine the FMS score results to ensure rigorous statistical evaluation. Data were synthesized using a random-effect model, with the Mean difference (MD) and 95% confidence interval (CI) used to calculate effect size.

Results: The overall FMS score showed that the functional movement capacities of males and females differed; females performed higher (MD = -0.46, 95% CI = -0.83 to -0.08, P = 0.02) compared to males. A meta-analysis of 7 individual FMS components was conducted to assess the importance for both sexes. However, tests on specific areas showed significant gender differences: females outperformed males in shoulder mobility (p < 0.00001), active straight leg raise (p < 0.00001), hurdle step (p = 0.01), and rotary stability (p = 0.002). In contrast, males demonstrated significantly greater trunk stability (p < 0.0001) compared to females. Despite this, the in-line lunge (p = 0.42) and deep squat (p = 0.20) demonstrated no significant difference across gender.

Conclusion: These outcomes highlight significant gender-based differences that can help identify weaknesses and strengths, which may assist coaches, trainers, and individuals in recommending gender-specific exercises and training programs.

Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=1043946, identifier CRD420251043946.

Background: To investigate differences in diaphragmatic function between women undergoing term labor and healthy non-pregnant women, and to analyze the correlation between diaphragmatic function and duration of the second stage of labor. Key obstetric factors such as pre-labor BMI, estimated fetal weight, parity, oxytocin and epidural use were considered as potential confounders.

Methods: This prospective study was conducted at a tertiary perinatal center and included 94 women with term, singleton, cephalic pregnancies who underwent spontaneous vaginal delivery between December 2024 and April 2025. Diaphragmatic excursion and thickness were measured under different states during labor. A control group of 31 healthy non-pregnant women, matched for age, height, weight, and BMI, was also recruited. Differences in diaphragmatic excursion, thickness, and thickening ratio between the two groups were compared. Associations between diaphragmatic parameters and the duration of the second stage of labor were analyzed after adjusting the covariates selected by LASSO. It should be noted that over half of the controls had prior childbirths, which may modify baseline diaphragmatic morphology and introduce residual confounding.

Results: In the labor group, tidal excursion and deep breath excursion were significantly lower than in controls (Effect size (95% CI) = -0.31 (-0.46, -0.16), P < 0.001, and -0.45 (-0.58, -0.30), P < 0.001). Deep inspiratory and Valsalva thickness were significantly lower in the labor group (-0.29 (-0.44, -0.11), P = 0.001, and -0.26 (-0.41, -0.10), P = 0.003). The deep breath and Valsalva thickness fractions were also reduced (-0.20 (-0.36, -0.04), P = 0.026, and -0.19 (-0.36, -0.01), P = 0.037). After LASSO regression, covariates including pre-labor BMI, parity and epidural use were selected. After adjusting for covariates (pre-labor BMI, parity and epidural), tidal expiratory and inspiratory thickness were positively correlated with the duration of the second stage of labor (β (95% CI) = 0.229 (3.286, 39.628), P = 0.021, and 0.201 (0.917, 32.855), P = 0.0380, whereas the deep breath thickness fraction was negatively correlated (-0.187 (-0.463, -0.005), P = 0.046).

Conclusion: Women in term labor exhibited reduced diaphragmatic excursion and thinner diaphragmatic thickness under functional conditions compared with non-pregnant women. Observed associations indicated that tidal inspiratory thickness and deep breath thickness fraction were related to the duration of the second stage of labor. It should be noted that over half of the control participants had prior childbirths, which may influence baseline diaphragmatic morphology and introduce residual confounding. Given the observational design, causal inferences cannot be drawn.