ObjectiveThis systematic review aims to comprehensively analyze the efficacy and underlying mechanisms of vagus nerve stimulation (VNS) in enhancing cognitive functions and its therapeutic potential for various cognitive impairments. The review focuses on the impact of VNS on emotional processing, executive functions, learning, memory, and its clinical applications in conditions such as epilepsy, depression, Alzheimer’s disease, and other neurological disorders.MethodsA systematic search of electronic databases (PubMed, Scopus, Web of Science) was conducted using the keywords “vagus nerve stimulation,” “cognitive enhancement,” “emotional processing,” “executive function,” “learning and memory,” “epilepsy,” “depression,” “Alzheimer’s disease,” “neurological disorders,” “attention-deficit/hyperactivity disorder,” “sleep disorders,” and “long COVID.” The inclusion criteria encompassed controlled trials, longitudinal studies, and meta-analyses published in English between 2000 and July 2024.ResultsA comprehensive review of 100 articles highlighted the cognitive effects of Vagus Nerve Stimulation (VNS). Studies show that VNS, especially through transcutaneous auricular VNS (taVNS), enhances emotional recognition, particularly for facial expressions, and improves selective attention under high cognitive demands. Additionally, VNS enhances learning and memory, including associative memory and spatial working memory tasks. In clinical applications, VNS exhibits promising benefits for improving cognitive functions in treatment-resistant epilepsy, depression, and Alzheimer’s disease.ConclusionVNS represents a promising therapeutic approach for enhancing cognitive function across diverse patient populations. The reviewed evidence highlights its efficacy in modulating cognitive domains in healthy individuals and improving cognition in neurological conditions. However, the comparative effectiveness of different VNS modalities and the differential effects of online versus offline VNS on cognitive psychology require further investigation. Future research should focus on optimizing VNS protocols and elucidating specific cognitive domains that benefit most from VNS interventions. This ongoing exploration is essential for maximizing the therapeutic potential of VNS in clinical practice.

The effects of face immersion and concurrent exercise on the diving reflex evoked by breath-hold (BH) differ, yet little is known about the combined effects of different BH conditions on aerobic fitness in elite athletes. This study aimed to assess the acute effects of various BH conditions on 18 male elite rugby players (age: 23.5 ± 1.8 years; height: 183.3 ± 3.4 cm; body mass: 84.8 ± 8.5 kg) and identify the BH condition eliciting the greatest aerobic fitness activation. Participants underwent five warm-up conditions: baseline regular breathing, dynamic dry BH (DD), static dry BH (SD), wet dynamic BH (WD), and wet static BH (WS). Significant differences (p < 0.05) were found in red blood cells (RBCs), red blood cell volume (RGB), and hematocrit (HCT) pre- and post-warm-up. Peak oxygen uptake (VO2peak) and relative oxygen uptake (VO2/kgpeak) varied significantly across conditions, with BH groups showing notably higher values than the regular breathing group (p < 0.05). Interaction effects of facial immersion and movement conditions were significant for VO2peak, VO2/kgpeak, and the cardiopulmonary optimal point (p < 0.05). Specifically, VO2peak and peak stroke volume (SVpeak) were significantly higher in the DD group compared to that in other conditions. Increases in VO2peak were strongly correlated with changes in RBCs and HCT induced by DD warm-up (r∆RBC = 0.84, r∆HCT = 0.77, p < 0.01). In conclusion, DD BH warm-up appears to optimize subsequent aerobic performance in elite athletes.

Objective: While long-term dynamic breath-holding training has been extensively studied to enhance cardiopulmonary function in athletes, limited research has explored the impact of a single breath-holding session on subsequent athletic capacity. In addition, Dry Dynamic Apnea (DA) has a more immediate physiological response than wet and static breath-holding. This study aims to assess the immediate effects of a single session of DA on the aerobic power and hematological parameters of elite athletes.Methods: Seventeen elite male rugby athletes (average age 23.5 ± 1.8) participated in this study. Two warm-up protocols were employed prior to incremental exercise: a standard warm-up (10 min of no-load pedaling) and a DA warm-up (10 min of no-load pedaling accompanied by six maximum capacity breath holds, with 30 s between each breath hold). Fingertip blood indicators were measured before and after warm-up. The incremental exercise test assessed aerobic parameters with self-regulation applied throughout the study.Results: Compared to the baseline warm-up, the DA warm-up resulted in a significant increase in VO2peak from 3.14 to 3.38 L/min (7.64% change, p < 0.05). HRmax increased from 170 to 183 bpm (7.34% change, p < 0.05), and HRpeak increased from 169 to 182 bpm (7.52% change, p < 0.05). Hematocrit and hemoglobin showed differential changes between the two warm-up methods (PHematocrit = 0.674; Phemoglobin = 0.707).Conclusion: This study investigates how DA influences physiological factors such as spleen contraction, oxygen uptake, and sympathetic nerve activation compared to traditional warm-up methods. Immediate improvements in aerobic power suggest reduced vagus nerve stimulation, heightened sympathetic activity, and alterations in respiratory metabolism induced by the voluntarily hypoxia-triggered warm-up. Further research is warranted to comprehensively understand these physiological responses and optimize warm-up strategies for elite athletic performance.

Heart rate and vascular tension baroreflex exhibit resonance characteristics at approximately 0.1 and 0.03 Hz. In this study, we aimed to induce postural resonance (PR) through rhythmic postural adjustments. To assess the viability of this technique, we investigated the acute impacts of postural resonance on blood pressure, sympathetic nerve activity, and mood. Fifteen healthy study participants, consisting of 8 males and 7 females, were selected for this self-controlled study. Skin sympathetic nerve activity was continuously monitored during both the intervention and stress test on the experimental day. After PR intervention, the diastolic blood pressure and mean arterial pressure in the PR group exhibited significant reductions compared to the CON group (P = 0.032, CON = 71.67 ± 2.348, PR = 64.08 ± 2.35; P = 0.041, CON = 75.00 ± 2.17, PR = 81.67 ± 2.17). After PR intervention both left brachial ankle pulse wave velocity and right brachial ankle pulse wave velocity exhibited a significant reduction compared to pre-intervention levels (from 1115.86 ± 150.08 to 1048.43 ± 127.40 cm/s, p < 0.001; 1103.86 ± 144.35 to 1060.43 ± 121.35 cm/s, p = 0.018). PR intervention also led to a significant decrease in burst frequency and duration (P = 0.049; CON = 8.96 ± 1.17, PR = 5.51 ± 1.17) and a noteworthy decrease in burst amplitude and burst threshold during the cold-pressor test (P = 0.002; P = 0.002). Additionally, VAS scores exhibited a substantial increase following PR (P = 0.035, CON = 28.4 ± 4.49, PR = 42.17 ± 4.10). PR can induce resonance effects within the cardiovascular system, resulting in the effective reduction of blood pressure, skin sympathetic nerve activity and pulse wave velocity, and decreased burst amplitude and burst threshold of the sympathetic nerve during the cold-pressor test.

背景:最大摄氧量作为评估心肺耐力的"金标准",根据其概念的逻辑关系,除心肺功能外,外周组织(肌肉)对氧气的利用能力应作为心肺耐力水平的关键和决定因素.心肺功能水平是人体运动过程中氧气供应的重要保证因素,但或并不能作为氧气利用的"关键因素".目的:通过评估有氧代谢过程中人体CO2耐受力,探究其与心肺耐力的关联.方法:在北京5所高校筛选92名健康在校大学生,经受试者知情同意,进行心肺运动试验采集CO2耐受及心肺耐力评估指标,并进行关联分析.试验经国家体育总局体育科学研究所伦理委员会批准.结果与结论:①人体CO2耐受力指标与最大摄氧量相对值和绝对值存在显著正相关(P＜0.01),与身高、体质量和体质量指数存在显著正相关(P＜0.01);②通过CO2耐受指标构建的多元线性回归模型可准确解释及预测最大摄氧量的变化(校正R2分别为0.847,0.668,P＜0.01),模型验证评价提示预测值与实测值相比差异均无显著性意义(P＞0.05);③有氧代谢过程中人体CO2耐受指标与最大摄氧量之间存在高度相关,有氧代谢过程中高CO2耐受力预示着更强的心肺耐力水平,且通过数理模型发现有氧代谢过程中CO2耐受指标可在较大程度上对最大摄氧量的变化提供解释与预测.

背景:研究证明最大摄氧量被认为是评价有氧运动能力的"金标准",但测试其所需运动强度较大且存在指标再现性低、测试者主观影响效应等限制因素.目的:通过反向传播神经网络采用新型次最大运动评估指标"心肺最佳点"构建最大摄氧量预测模型.方法:试验经国家体育总局体育科学研究所伦理委员会批准,招募80名健康大学生受试者(男40名,女40名),了解试验流程、目的并自愿签署知情同意书配合完整试验过程.受试者进行递增负荷心肺运动试验,采集最大摄氧量与心肺最佳点等相关指标,进行相关性分析获得具有统计学意义的指标,并构建最大摄氧量预测模型.结果 与结论:①最大摄氧量与心肺最佳点、体质量指数、性别、心肺最佳点对应的摄氧量和功率均存在显著相关性(P<0.01);②运用反向传播神经网络构建经典3层拓扑结构最大摄氧量预测模型(包含5个输入层、10个隐藏层和1个输出层),该模型预测值与实测值绝对误差均值为0.227 L/min、相对误差均值为12％,提示基于心肺最佳点构建的反向传播神经网络可准确且有效预测最大摄氧量;③反向传播神经网络模型最大摄氧量预测值与多元线性回归预测值相比差异无显著性意义(P>0.05),但依据心肺最佳点构建的反向传播神经网络模型预测精度要优于多元线性回归模型.

目的 通过递增负荷运动试验,筛选能有效评估有氧耐力的动态心肺功能指标.方法 于2019年3-11月,从北京市5所高校随机招募能够理解试验并自愿配合整个测试过程的266名志愿者.采用德国Cortex Metalyzer 3B系统和美国Cheetah NICOM系统实时监测气体代谢和心功能,通过线性递增负荷方案测得最大摄氧量.根据研究设计选取有氧耐力和动态心肺功能指标,采用相关和典型性相关分析两者间的关系.结果 男生最大摄氧量(VO2max)绝对值、V02max相对值、最大每搏输出量(SVmax)、最大每搏输出量指数(SVImax)均显著高于女生,动态心肺功能指标K值低于女生(t值分别为17.8,10.1,8.5,4.3,-6.3,P值均＜0.05).简单相关发现,VO2max绝对值、VO2max相对值与K值、b值呈负相关,VO2mnax绝对值、VO2max相对值与SVmax、SVImax呈正相关(P值均＜0.01).典型相关分析发现,有氧耐力和动态心肺功能2组指标呈正相关(r=0.94,P＜0.01);与动态心肺功能密切相关的有氧耐力指标为VO2max绝对值、VO2max相对值;与有氧耐力密切相关的动态心肺功能指标为K值、b值、SVmax、SVImax.结论 动态心肺功能的提高有助于有氧耐力的提高,动态心肺功能指标K值、b值、SVmax、SV1mo可以作为预测评估有氧运动能力的重要候选指标.

Background The Composite Dietary Antioxidant Index (CDAI), a composite score of multiple dietary antioxidants (including vitamin A, C, and E, selenium, zinc, and carotenoids), represents an individual’s comprehensive dietary antioxidant intake profile. CDAI was developed based on its combined effect on pro-inflammatory markers Tumor Necrosis Factor-α (TNF-α) and anti-inflammatory effects of Interleukin-1β (IL-1β), which are associated with many health outcomes, including depression, all-cause mortality, colorectal cancer, etc. Handgrip strength is used as a simple measure of muscle strength, not only is it highly correlated with overall muscle strength, but also serves as a diagnostic tool for many adverse health outcomes, including sarcopenia and frailty syndromes. Purpose The association between CDAI and Handgrip strength (HGS) is currently unclear. This study investigated the association between CDAI (including its components) and HGS in 6,019 American adults. Method The research data were selected from the 2011–2014 National Health and Nutrition Survey (NHANES), and a total of 6,019 American adults were screened and included. A weighted generalized linear regression model was used to evaluate CDAI (including its components) and HGS. Results (1) CDAI was significantly positively correlated with HGS (β = 0.009, 0.005∼0.013, P < 0.001), and the trend test showed that compared with the lowest quartile of CDAI, the highest quartile of CDAI was positively correlated with HGS (β = 0.084, 0.042∼0.126, P = 0.002) and significant in trend test (P for trend < 0.0100). Gender subgroup analysis showed that male CDAI was significantly positively correlated with HGS (β = 0.015, 0.007∼0.023, P = 0.002), and the trend test showed that compared with the lowest quartile of CDAI, the highest quartile of CDAI was positively correlated with HGS (β = 0.131, 0.049∼0.213, P = 0.006) and the trend test was significant (P for trend < 0.0100). There was no correlation between female CDAI and HGS, and the trend test was not statistically significant (P > 0.05). (2) The intake of dietary vitamin E, Zinc and Selenium showed a significant positive correlation with HGS (β = 0.004, 0.002∼0.007, P = 0.006; β = 0.007, 0.004∼0.009, P < 0.001; β = 0.001, 0.001∼0.001, P < 0.001), vitamin A, vitamin C and carotenoid were significantly associated with HGS in the Crude Model, but this significant association disappeared in the complete model with the increase of control variables. Gender subgroup analysis showed that in model 3, male dietary intake levels of vitamin E, Zinc, and Selenium were significantly positively correlated with HGS (β = 0.005, 0.002∼0.009, P = 0.011; β = 0.007, 0.004∼0.011, P = 0.001; β = 0.001, 0.001∼0.001, P = 0.004), the rest of the indicators had no significant correlation with HGS. Among the female subjects, dietary zinc intake was significantly positively correlated with HGS (β = 0.005, 0.001∼0.008, P = 0.008), and there was no significant correlation between other indicators and HGS (P > 0.05). Conclusion There was an association between the CDAI and HGS, but there was a gender difference, and there was an association between the CDAI and HGS in male, but the association was not significant in female. Intake of the dietary antioxidants vitamin E, selenium, and zinc was associated with HGS in male, but only zinc was associated with HGS among dietary antioxidants in female.

(1) Background: The Systemic immune-inflammatory index (SII) has been proven to be an effective biomarker of human immune and inflammatory levels and has prognostic significance for most diseases. Handgrip strength (HGS) is a simple and low-cost strength measurement method, which is not only highly correlated with overall muscle strength but also accurately and reliably predicts the risk of multiple chronic diseases and mortality; (2) Purpose: Association between HGS and the SII is unclear. The purpose of this study was to investigate the association between HGS and the SII in American adults; (3) Methods: We used the data from the 2011–2012 and 2013–2014 cycles of the National Health and Nutrition Examination Survey (NHANES), involving a total of 8232 American adults (aged 18–80 years). The SII was calculated as the Platelet count × Neutrophil count/Lymphocyte count; HGS was recorded as the ratio of the sum of the highest grip-strength values of each hand to body mass index taken as the relative grip strength. A weighted generalized linear regression model and analysis of restricted cubic spline regression, adjusted for confounding factors, were used in this study to assess associations between HGS and the SII in American adults; (4) Results: There was a negative correlation between the HGS and the SII of different sexes (p < 0.05), and there was a significant negative nonlinear relationship between the HGS and the SII in males (p for nonlinear = 0.0035), and the SII showed a downward trend with the increase in the HGS in males (Q2: β = −61.03, p = 0.01; Q3: β = −61.28, p = 0.04, Q4: β = −64.36, p = 0.03, p for trend = 0.04), when the HGS exceeds 3.16, with the HGS increasing, the downward trend of increasing the SII slowed down. The nonlinear relationship between the HGS and the SII in females was not significant (p for nonlinear = 0.1011), and the SII showed a linear downward trend with the increase in the HGS (Q2: β = −24.91, p = 0.25; Q3: β = −62.01, p = 0.03, Q4: β = −74.94, p = 0.03, p for trend = 0.01); (5) Conclusions: HGS is inversely and independently associated with SII levels, and although the limited cubic spline regression analysis showed gender differences, the overall trend of the HGS and the SII in different genders was consistent, with both showing that the SII decreased with increasing the HGS. In addition, HGS has high general applicability based on its ease of measurement; it is possible to understand one’s own grip-strength level through routine grip-strength tests, and to make preliminary predictions on the current level of immunity and inflammation in the body.

Objective: Although regular and moderate physical activity has been shown to improve the cardiovascular and autonomic nervous systems, little has been done to study the effects of postural changes in the movement on the heart and autonomic nervous system. To uncover changes in cardiac function and autonomic nerves induced by different underlying posture transitions and explore which trunk postures lead to chronic sympathetic activation. Therefore, this study investigated the effects of trunk posture on the cardiovascular and autonomic nervous systems.Methods: Twelve male subjects (age 24.7 ± 1.3) underwent this study. The non-invasive cardiac output NICOM monitoring equipment and the FIRSTBEAT system are used to dynamically monitor seven trunk postures in the sitting position simultaneously (neutral position, posterior extension, forward flexion, left lateral flexion, right lateral flexion, left rotation, right rotation). Each posture was maintained for 3 min, and the interval between each movement was 3 min to ensure that each index returned to the baseline level. Repeated analysis of variance test was used to compare and analyze the differences in human cardiac function, heart rate variability index, and respiratory rate under different postures.Results: Compared with the related indicators of cardiac output in a neutral trunk position: the cardiac index (CI) was significantly reduced in forwarding flexion and left rotation (3.48 ± 0.34 vs. 3.21 ± 0.50; 3.48 ± 0.34 vs. 3.21 ± 0.46, Δ L/(min/m2)) (p = 0.016, p = 0.013), cardiac output decreased significantly (6.49 ± 0.78 vs. 5.93 ± 0.90; 6.49 ± 0.78 vs. 6.00 ± 0.96, Δ L/min) (p = 0.006, p = 0.014), the stroke volume (stroke volume)decreased significantly (87.90 ± 15.10 vs. 81.04 ± 16.35; 87.90 ± 15.10 vs. 79.24 ± 16.83, Δ ml/beat) (p = 0.017, p = 0.0003); heart rate increased significantly in posterior extension (75.08 ± 10.43 vs. 78.42 ± 10.18, Δ beat/min) (p = 0.001); left rotation stroke volume index (SVI) decreased significantly (47.28 ± 7.97 vs. 46.14 ± 8.06, Δ ml/m2) (p = 0.0003); in the analysis of HRV-related indicators, compared with the neutral trunk position, the LF/HF of the posterior extension was significantly increased (1.90 ± 1.38 vs. 3.00 ± 1.17, p = 0.037), and the LF/HF of the forward flexion was significantly increased (1.90 ± 1.38 vs. 2.85 ± 1.41, p = 0.041), and the frequency-domain index LF/HF of right rotation was significantly increased (1.90 ± 1.38 vs. 4.06 ± 2.19, p = 0.008). There was no significant difference in respiratory rate (p > 0.05).Conclusion: A neutral trunk is the best resting position, and deviations from a neutral trunk position can affect the cardiovascular and autonomic nervous systems, resulting in decreased stroke volume, increased heart rate, and relative activation of sympathetic tone.

Lactate threshold or gas exchange threshold is commonly used to guide exercise intensity, but direct measurement of these two are never easy for general population. Among all physiological indicators, heart rate is very easy to obtain. And the heart rate deflection point is consistent with the lactate threshold during incremental exercise. However, previous studies suffer from expertise or a priori information requirement, computation inefficiency, lack of cohort diversity, etc. Based on prior knowledge, this contribution proposes a computer-aided methods to automatically identity heart rate intersection points by sections, and further optimization. As result, among 200 healthy college student volunteers, only 8 subjects fall beyond the 95% confidence interval in residual analysis. Therefore, a self-consistent, economic, noninvasive method to estimate the lactate threshold with heart rate data only is demonstrated.