Physical exercise-related manifestations of long COVID: A systematic review and meta-analysis.

Objective: This study aims to systematically assess physical exercise-related symptoms of post-acute sequelae of SARS-CoV-2 infection (PASC or long COVID) in coronavirus disease 2019 (COVID-19) survivors. Methods: Eight databases were systematically searched on March 03, 2024. Original studies that compared physical exercise-related parameters measured by exercise testing between COVID-19 survivors who recovered from SARS-CoV-2 infection over 3 months and non-COVID-19 controls were included. A random-effects model was utilized to determine the mean differences (MDs) or standardized MDs in the meta-analysis. Results: A total of 40 studies with 6241 COVID-19 survivors were included. The 6-min walk test, maximal oxygen consumption (VO2max), and anaerobic threshold were impaired in COVID-19 survivors 3 months post-infection compared with non-COVID-19 controls in exercise testing, while VO2 were comparable between the two groups at rest. In contrast, no differences were observed in SpO2, heart rate, blood pressure, fatigue, and dyspnea between COVID-19 survivors and non-COVID-19 controls in exercise testing. Conclusion: The findings suggest an underestimation of the manifestations of PASC. COVID-19 survivors also harbor physical exercise-related symptoms of PASC that can be determined by the exercise testing and are distinct from those observed at rest. Exercise testing should be included while evaluating the symptoms of PASC in COVID-19 survivors.

Assessing the Validity of Two Non-Exercise Regression Equations for Predicting Maximal Oxygen Consumption.

Purpose: This study aimed to develop two regression equations to predict maximal oxygen consumption (VO2max) using non-exercise data from a substantial cohort of healthy Iranian adult males. Additionally, this study sought to examine the predictive accuracy of these equations across four different levels of physical activity. Methods: A total of 126 participants (age: 34.9 ± 11.3 years, body mass index [BMI]: 24.9 ± 2.7 kg/m², and body fat percentage [BF%]: 18.3 ± 4.9) completed a maximal graded exercise test to measure VO2max, with a mean of 45.0 ± 3.4 ml.kg-1.min-1. Participants also provided information on age, current physical activity rating (PA-R), and either BMI or BF% to estimate VO2max using Jackson and colleagues' regression equations. The PA-R was assessed via a standardized questionnaire and categorized into four levels: sedentary, low, moderate, and high. Results: The key findings from this study indicate that both original models significantly underestimated actual VO2max in a large cohort of Iranian adults (both, p < .001 and mean differences exceeding 2.19 ml.kg-1.min-1). Nevertheless, these models provided accurate predictions for VO2max among individuals with moderate levels of physical activity (both, p > .08 and mean differences between 0.51 and 1.03 ml.kg-1.min-1). Furthermore, the models demonstrated moderate validity, as evidenced by an intraclass correlation coefficient (ICC) of 0.841 and a coefficient of variation averaging 10.9%, with a range from 8.5% to 13.6%. Conclusions: While Jackson's two non-exercise models showed limited accuracy in predicting VO2max among Iranian healthy male adults, they exhibited reasonable precision, particularly among moderately active men.

The association between body mass index, exercise capacity, and health-related quality of life in heart transplant recipients.

Introduction: Pre-transplant obesity and weight gain after heart transplantation are both associated with increased risk of poor clinical outcomes. We aimed to assess the association between overweight or obesity, exercise capacity, and health-related quality of life in heart transplant recipients. Methods: This study is based on baseline data from the IronIC trial, in which we randomized 102 heart transplant recipients with iron deficiency to ferric derisomaltose or placebo. We performed cardio pulmonary exercise testing in all participants. To assess quality of life, we used the SF-36v2 questionnaire, using two sum scores: the physical component summary and the mental component summary. A minimal clinically important difference was defined as ≥2 and ≥3 for the physical and the mental component summary, respectively. Results: 24/102 heart transplant recipients (24%) had a body mass index (BMI) ≥30 kg/m2. Peak oxygen consumption was 17.3 ± 4.6 ml/kg/min in the obese group vs. 24.7 ± 6.4 ml/kg/min in the group with a BMI <30 for a between-group difference of 7.4 (95% confidence interval 4.7-10.2) ml/kg/min: p < 0.001. The physical component summary score was on average 5.2 points lower in the patients with a body mass index ≥30 than in the lower weight group (p = 0.04). Conclusion: Almost a quarter of our heart transplant recipients in long-term follow-up had a BMI ≥30 kg/m2. These patients had substantially lower exercise capacity and lower quality of life in the physical domain.

Anisotropic Optical Response of Ti-Doped VO2 Single Crystals.

This study delves into the effects of titanium (Ti) doping on the optical properties of vanadium dioxide (VO2), a material well known for its metal-to-insulator transition (MIT) near room temperature. By incorporating Ti into VO2's crystal lattice, we aim to uncover the resultant changes in its physical properties, crucial for enhancing its application in smart devices. Utilizing polarized infrared micro-spectroscopy, we examined TixV1-xO2 single crystals with varying Ti concentrations (x = 0.059, x = 0.082, and x = 0.187) across different crystal phases (the conductive rutile phase and insulating monoclinic phases M1 and M2) from the far-infrared to the visible spectral range. Our findings reveal that Ti doping significantly influences the phononic spectra, introducing absorption peaks not attributed to pure VO2 or TiO2. This is especially notable with polarization along the crystal growth axis, mainly in the x = 0.187 sample. Furthermore, we demonstrate that the electronic contribution to optical conductivity in the metallic phase exhibits strong anisotropy, higher along the c axis than the a-b plane. This anisotropy, coupled with the progressive broadening of the zone center infrared active phonon modes with increasing doping, highlights the complex interplay between structural and electronic dynamics in doped VO2. Our results underscore the potential of Ti doping in fine-tuning VO2's electronic and thermochromic properties, paving the way for its enhanced application in optoelectronic devices and technologies.

Preparation of Thermochromic Vanadium Dioxide Films Assisted by Machine Learning.

In recent years, smart windows have attracted widespread attention due to their ability to respond to external stimuli such as light, heat, and electricity, thereby intelligently adjusting the ultraviolet, visible, and near-infrared light in solar radiation. VO2(M) undergoes a reversible phase transition from an insulating phase (monoclinic, M) to a metallic phase (rutile, R) at a critical temperature of 68 °C, resulting in a significant difference in near-infrared transmittance, which is particularly suitable for use in energy-saving smart windows. However, due to the multiple valence states of vanadium ions and the multiphase characteristics of VO2, there are still challenges in preparing pure-phase VO2(M). Machine learning (ML) can learn and generate models capable of predicting unknown data from vast datasets, thereby avoiding the wastage of experimental resources and reducing time costs associated with material preparation optimization. Hence, in this paper, four ML algorithms, namely multi-layer perceptron (MLP), random forest (RF), support vector machine (SVM), and extreme gradient boosting (XGB), were employed to explore the parameters for the successful preparation of VO2(M) films via magnetron sputtering. A comprehensive performance evaluation was conducted on these four models. The results indicated that XGB was the top-performing model, achieving a prediction accuracy of up to 88.52%. A feature importance analysis using the SHAP method revealed that substrate temperature had an essential impact on the preparation of VO2(M). Furthermore, characteristic parameters such as sputtering power, substrate temperature, and substrate type were optimized to obtain pure-phase VO2(M) films. Finally, it was experimentally verified that VO2(M) films can be successfully prepared using optimized parameters. These findings suggest that ML-assisted material preparation is highly feasible, substantially reducing resource wastage resulting from experimental trial and error, thereby promoting research on material preparation optimization.

Influence of Physical Activity on Health-Related Fitness in Young Adults: An Observational Research.

Background: Health-related fitness directly depends on the level of physical activity of the individual. Inactivity contributes to around 3.3% of all deaths, making the lack of exercise and sedentary lifestyles among the young generation a current source of concern. There is a paucity of research on the association between PA and health-related physical fitness among young people. In the perspective of this, the objective of this research was to find out the effect of PA levels on physical fitness in healthy adults. Methodology: A total of 419 students between the ages of 18 and 25 participated in this cross-sectional survey. The "Global Physical Activity Questionnaire (GPAQ)" was used to evaluate the PA. Their body fat percentage was measured using a skin fold caliper, followed by measurement of VO2max using a gas analyzer and hand grip strength and endurance assessment with the help of a computerized dynamometer. For statistical analysis, Karl Pearson's correlation coefficients and the ANOVA test were utilized. Results: PA was positively correlated with VO2 max (r=0.429), and handgrip strength (r=0.408) while negatively correlated with body fat % (r=-.315). VO2 max, body fat, and hand grip strength differ significantly amongst participants having different physical activity levels. (p-value =<0.05). Conclusion: This research concludes that PA is associated with physical fitness. PA will lead to a definite improvement in overall physical fitness. With the help of the results of this study, young adults can be motivated for physical fitness.

Multi-wavelength and broadband plasmonic switching with V-shaped plasmonic nanostructures on a VO2coated plasmonic substrate.

In this paper, periodic arrays of identicalV-shaped gold nanostructures and variableV-shaped gold nanostructures are designed on top of a gold-coated silicon dioxide (SiO2) substrate with a thin spacer layer of vanadium dioxide (VO2) to realize multi-wavelength and broadband plasmonic switches, respectively. The periodic array of identicalV-shaped nanostructures (IVNSs) with small inter-particle separation leads to coupled interactions of the elementary plasmons of aV-shaped nanostructure (VNS), resulting in a hybridized plasmon response with two longitudinal plasmonic modes in the reflectance spectra of the proposed switches when the incident light is polarized in thex-direction. Thex-direction is oriented along the axis that joins theV-junctions of all VNSs in one unit cell of the periodic array. On exposure to temperature, electric field, or optical stimulus, the VO2layer transforms from its monoclinic semiconducting state to its rutile metallic state, leading to an overall change in the reflectance spectra obtained from the proposed nanostructures and resulting in an efficient multi-wavelength switching action. Finite difference time domain modelling is employed to demonstrate that an extinction ratio (ER) >12 dB at two wavelengths can be achieved by employing the proposed switches based on periodic arrays of IVNSs. Further, plasmonic switches based on variableV-shaped nanostructures-i.e. multiple VNSs with variable arm lengths in one unit cell of a periodic array-are proposed for broadband switching. In the broadband operation mode, we report an ER >5 dB over an operational wavelength range >1400 nm in the near-IR spectral range spanning over all optical communication bands, i.e. theO, E, S, C, LandUbands. Further, it is also demonstrated that the wavelength of operation for these switches can be tuned by varying the geometrical parameters of the proposed switches. These switches have the potential to be employed in communication networks where ultrasmall and ultrafast switches with multi-wavelength operation or switching over a wide operational bandwidth are inevitably required.

Rational Regulation of Optimal Oxygen Vacancy Concentrations on VO2 for Superior Aqueous Zinc-Ion Battery Cathodes.

VO2 with its special tunnel structure and high theoretical capacity is an ideal candidate for cathode materials for aqueous zinc-ion batteries (ZIBs). However, the slow kinetics and structural instability due to the strong electrostatic interactions between the host structure of VO2 and Zn2+ hinder its application. Defect engineering is a well-recognized strategy for improving the intrinsic ion-electron dynamics and structural stability of this material. However, the preparation of oxygen vacancies poses significant difficulties, and it is challenging to control their concentration effectively. Excessive or insufficient vacancy concentration can have a negative effect on the cathode material. Herein, we propose electrode materials with controlled oxygen vacancies prepared in situ on carbon nanofibers (CNF) by a simple, one-step hydrothermal process (Ov-VO2@CNF). This method can balance the adsorption energy and migration energy barrier easily, and we maximized the adsorption energy of Zn2+ while minimizing the adsorption energy barrier. Notably, the Ov2-VO2@CNF electrode delivered a high specific capacity (over 450 mAh g-1 at 0.1 A g-1) and excellent cycle stability (318 mAh g-1 at 5 A g-1 capacity after 2000 cycles with a capacity retention of 85%). This rational design of precisely regulated defect engineering provides a way to obtain advanced electrode materials with excellent comprehensive properties.

Effects of 9 Weeks of High- or Moderate-Intensity Training on Cardiorespiratory Fitness, Inhibitory Control, and Plasma Brain-Derived Neurotrophic Factor in Danish Adolescents-A Randomized Controlled Trial.

PURPOSE: The primary aims of this study were to examine the effects of 9 weeks of aerobic training, comprising three 30-min sessions per week, on V̇O2max, inhibitory control, and plasma brain-derived neurotrophic factor (BDNF) levels among adolescents aged 16-19 years. METHODS: One hundred twenty-one untrained or recreationally active adolescents from a Danish high school were enrolled in the study, with 58 females (17.8 ± 0.8 years) and 27 males (18.0 ± 0.9 years) completing it. Participants were randomly divided into three groups performing aerobic training at either moderate-intensity (MIT: 60%-70% heart rate reserve [HRR]) or high-intensity (HIT: 80%-100% HRR) or a passive control group (CON) continuing their habitual lifestyle. Both the training groups exercised for 3×30 min per week for 9 weeks using a combination of cycling and running. Before and after the intervention period maximal oxygen uptake (V̇O2max) and the primary outcomes (inhibitory control measured by a modified flanker task, and resting plasma levels of BDNF) were evaluated. RESULTS: After the intervention period, the HIT group demonstrated a larger increase in V̇O2max compared to both the CON and MIT groups, while no significant effects were observed on inhibitory control or plasma BDNF levels in any training group. However, compared to the CON group, the HIT group exhibited a tendency for greater improvement in the flanker interference score (accuracy), attributable to enhanced accuracy on the incongruent stimuli from pre to post. CONCLUSION: Aerobic training in adolescents increased cardiorespiratory fitness in an intensity-dependent manner, but no clear effects were observed on neither inhibitory control nor resting plasma BDNF levels. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02075944.

Assessing the Accuracy of Smartwatch-Based Estimation of Maximum Oxygen Uptake Using the Apple Watch Series 7: Validation Study.

BACKGROUND: Determining maximum oxygen uptake (VO2max) is essential for evaluating cardiorespiratory fitness. While laboratory-based testing is considered the gold standard, sports watches or fitness trackers offer a convenient alternative. However, despite the high number of wrist-worn devices, there is a lack of scientific validation for VO2max estimation outside the laboratory setting. OBJECTIVE: This study aims to compare the Apple Watch Series 7's performance against the gold standard in VO2max estimation and Apple's validation findings. METHODS: A total of 19 participants (7 female and 12 male), aged 18 to 63 (mean 28.42, SD 11.43) years were included in the validation study. VO2max for all participants was determined in a controlled laboratory environment using a metabolic gas analyzer. Thereby, they completed a graded exercise test on a cycle ergometer until reaching subjective exhaustion. This value was then compared with the estimated VO2max value from the Apple Watch, which was calculated after wearing the watch for at least 2 consecutive days and measured directly after an outdoor running test. RESULTS: The measured VO2max (mean 45.88, SD 9.42 mL/kg/minute) in the laboratory setting was significantly higher than the predicted VO2max (mean 41.37, SD 6.5 mL/kg/minute) from the Apple Watch (t18=2.51; P=.01) with a medium effect size (Hedges g=0.53). The Bland-Altman analysis revealed a good overall agreement between both measurements. However, the intraclass correlation coefficient ICC(2,1)=0.47 (95% CI 0.06-0.75) indicated poor reliability. The mean absolute percentage error between the predicted and the actual VO2max was 15.79%, while the root mean square error was 8.85 mL/kg/minute. The analysis further revealed higher accuracy when focusing on participants with good fitness levels (mean absolute percentage error=14.59%; root-mean-square error=7.22 ml/kg/minute; ICC(2,1)=0.60 95% CI 0.09-0.87). CONCLUSIONS: Similar to other smartwatches, the Apple Watch also overestimates or underestimates the VO2max in individuals with poor or excellent fitness levels, respectively. Assessing the accuracy and reliability of the Apple Watch's VO2max estimation is crucial for determining its suitability as an alternative to laboratory testing. The findings of this study will apprise researchers, physical training professionals, and end users of wearable technology, thereby enhancing the knowledge base and practical application of such devices in assessing cardiorespiratory fitness parameters.

Development a nomogram prognostic model for survival in heart failure patients based on the HF-ACTION data.

BACKGROUND: The risk assessment for survival in heart failure (HF) remains one of the key focuses of research. This study aims to develop a simple and feasible nomogram model for survival in HF based on the Heart Failure-A Controlled Trial Investigating Outcomes of Exercise TraiNing (HF-ACTION) to support clinical decision-making. METHODS: The HF patients were extracted from the HF-ACTION database and randomly divided into a training cohort and a validation cohort at a ratio of 7:3. Multivariate Cox regression was used to identify and integrate significant prognostic factors to form a nomogram, which was displayed in the form of a static nomogram. Bootstrap resampling (resampling = 1000) and cross-validation was used to internally validate the model. The prognostic performance of the model was measured by the concordance index (C-index), calibration curve, and the decision curve analysis. RESULTS: There were 1394 patients with HF in the overall analysis. Seven prognostic factors, which included age, body mass index (BMI), sex, diastolic blood pressure (DBP), exercise duration, peak exercise oxygen consumption (peak VO2), and loop diuretic, were identified and applied to the nomogram construction based on the training cohort. The C-index of this model in the training cohort was 0.715 (95% confidence interval (CI): 0.700, 0.766) and 0.662 (95% CI: 0.646, 0.752) in the validation cohort. The area under the ROC curve (AUC) value of 365- and 730-day survival is (0.731, 0.734) and (0.640, 0.693) respectively in the training cohort and validation cohort. The calibration curve showed good consistency between nomogram-predicted survival and actual observed survival. The decision curve analysis (DCA) revealed net benefit is higher than the reference line in a narrow range of cutoff probabilities and the result of cross-validation indicates that the model performance is relatively robust. CONCLUSIONS: This study created a nomogram prognostic model for survival in HF based on a large American population, which can provide additional decision information for the risk prediction of HF.

Mo modulating the structure of monoclinic vanadium dioxide boosting the aqueous ammonium-ion storage for high-performance supercapacitor.

Supercapacitors (SCs) using ammonium-ion (NH4+) as the charge carrier (NH4+-SCs) have attracted continuous attention and vanadium-based materials are proved to have high-efficient NH4+-storage properties. Monoclinic vanadium dioxide, VO2(B), as an anode material applied to SCs has been rarely reported and modulating its electronic structure for boosted NH4+-storage is full of challenge. In this work, molybdenum-doped VO2(B) (Mo-doped VO2(B)) is designed and synthesize to enhance its NH4+-storage. The introduction of Mo atom into the crystal structure of VO2(B) can modulate its crystal structure and bring in some defects. Experimental results manifest that Mo-doped VO2(B) with 2 % Mo-doping shows the best electrochemical properties. Mo-doped VO2(B) achieves the specific capacitance of 1403 F g-1 (390 mAh g-1) at 0.1 A g-1 and the capacitance retention of about 98 % after 5000 cycle, superior to that of VO2(B) (893 F g-1, 248 mAh g-1 at 0.1 A g-1 and 60 % capacitance retention. The hybrid supercapacitor (HSC) assembled by Mo-doped VO2(B) and active carbon delivers good electrochemical performance with the energy density of 38.6 Wh kg-1 at power density of 208.3 W kg-1. This work proves that the Mo-doping is an efficient strategy for boosted NH4+-storage of VO2(B) and this strategy is like a Chinese idiom "like adding wings to a tiger" to guide the design of electrode materials for high-efficient NH4+-storage.

Detraining's Effects on Cardiorespiratory Fitness and Maximal and Explosive Strength in Army Soldiers: Does Age Matter?

PURPOSE: This study investigated the impact of four weeks of age-dependent detraining on army soldiers' cardiorespiratory fitness and maximal and explosive strength. METHODS: Fourteen volunteer tactical athletes participated, divided into two age groups (20 to 29 and 30 to 40 years). Before and after the detraining period, we assessed their anthropometric measurements (weight, height, body mass index, fat mass, and fat-free mass), cardiorespiratory fitness (maximal oxygen uptake [VO2max] and ventilatory thresholds [VT1 and VT2]), and kinematic properties during a single-leg counter-moving jump (CMJ) test for both the dominant and non-dominant legs. Two-way ANOVA followed by the Holm-Sidak post hoc test was used. RESULTS: The anthropometric and cardiovascular variables did not show significant differences between the groups. However, both groups exhibited a significantly reduced maximum time and speed at the VO2max. Furthermore, the flight time and maximum height during the CMJ significantly decreased in the non-dominant leg for both age groups. Notably, the dominant leg's concentric impulse (CI) significantly reduced during the CMJ, but this effect was observed only in the 30-40 age group. There were significant differences between the two age groups. CONCLUSIONS: Our findings suggest that four weeks of detraining negatively impacts aerobic fitness and muscular strength, independently of age. However, the dominant leg may be more susceptible to detraining effects in army soldiers aged 30-40. Furthermore, as a perspective, our results strongly suggest that a detraining period could affect successful missions (aerobic performance deterioration), as well as promote a muscle imbalance between the legs, which could encourage muscle injuries and endanger combat missions.

The validity of cardiopulmonary exercise testing for assessing aerobic capacity in neuromuscular diseases.

OBJECTIVES: To determine the content validity of cardiopulmonary exercise testing (CPET) for assessing peak oxygen uptake (VO2peak) in neuromuscular diseases (NMD). DESIGN: Baseline assessment of a randomized controlled trial. SETTING: Academic hospital. PARTICIPANTS: Eighty-six adults (age: 58.0 ± 13.9 years) with Charcot-Marie-Tooth disease (n=35), post-polio syndrome (n=26), or other NMD (n=25). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Workload, gas exchange variables, heart rate, and ratings of perceived exertion were measured during CPET on a cycle ergometer, supervised by an experienced trained assessor. Muscle strength of the knee extensors was assessed isometrically with a fixed dynamometer. Criteria for confirming maximal cardiorespiratory effort during CPET were established during 3 consensus meetings with an expert group. The percentage of participants meeting these criteria was assessed to quantify content validity. RESULTS: The following criteria were established for maximal cardiorespiratory effort; a plateau in oxygen uptake (VO2plateau) as primary criterion, or 2 out of 3 secondary criteria; 1) peak respiratory exchange ratio (RERpeak) ≥1.10, 2), peak heart rate (HRpeak) ≥85% of predicted maximal heart rate, and 3) peak rating of perceived exertion (RPEpeak) ≥17 on the 6-20 Borg scale. These criteria were attained by 71 participants (83%). VO2plateau, RERpeak ≥1.10, HRpeak ≥85%, and RPEpeak ≥17 were attained by respectively 31%, 73%, 69%, and 72% of the participants. Peak workload, VO2peak, and knee extension muscle strength were significantly higher, and body mass index was lower (all p<0.05), in participants with maximal cardiorespiratory effort compared to other participants. CONCLUSIONS: Most people with NMD achieved maximal cardiorespiratory effort during CPET. Therewith, this study provides high quality evidence of sufficient content validity of VO2peak as a maximal aerobic capacity measure. Content validity may be lower in more severely affected people with lower physical fitness.

Effects of combined aerobic, resistance and inspiratory training in patients with pulmonary hypertension: A systematic review.

BACKGROUND: Pulmonary hypertension (PH) is a serious progressive disorder of the modern world, characterized by endothelial dysfunction and impaired vasoreactivity. Patients with PH usually present exercise intolerance from the very early stages and reduced exercise capacity. Exercise training has been shown to have beneficial effects in patients with cardiovascular comorbidities. However, data regarding the effects of combined exercise training programs in patients with PH still remains limited. AIM: To investigate the effects of combined exercise training programs on exercise capacity and quality of life in patients with PH. METHODS: Our search included all available randomized controlled trials (RCTs) regarding combined aerobic, resistance and inspiratory training programs in patients with PH in 4 databases (Pubmed, PEDro, Embase, CINAHL) from 2012 to 2022. Five RCTs were included in the final analysis. Functional capacity, assessed by peak VO2 or 6-min walking test (6MWT), as well as quality of life, assessed by the SF-36 questionnaire, were set as the primary outcomes in our study. RESULTS: Peak VO2 was measured in 4 out of the 5 RCTs while 6MWT was measured in all RCTs. Both indices of functional capacity were significantly increased in patients with PH who underwent combined exercise training compared to the controls in all of the included RCTs (P < 0.05). Quality of life was measured in 4 out of 5 RCTs. Although patients improved their quality of life in each group, however, only 2 RCTs demonstrated further improvement in patients performing combined training compared to controls. CONCLUSION: By this systematic review, we have demonstrated that combined aerobic, resistance and inspiratory exercise training is safe and has beneficial effects on aerobic capacity and quality of life in patients with PH. Such exercise training regimen may be part of the therapeutic strategy of the syndrome.

Relationship between Simulated Fire Suppression Activities and Acute Cardiac and Respiratory Events in Firefighters.

Cardiac deaths account for the largest share of on-duty firefighter deaths. To help ensure duty fitness and minimize injury risk, many fire departments require the passing of an annual physical ability test, consisting of a battery of simulated fire suppression activities (sFSAs). The purpose of the study was to determine the relationship of sFSA performance to acute cardiac and respiratory events (ACREs) and the effect that estimated VO2max has on sFSA performance. The study was retrospective. As part of an annual physical ability test, five timed sFSAs were performed, summed for a composite time, and categorized into three performance levels (fast, moderate, and slow). Estimated VO2max was determined using the Forestry Step Test. A significant (p = 0.023) linear trend was observed with higher sFSA performance times being associated with a higher proportion of firefighters going on to suffer an ACRE. The estimated VO2max was significantly (p < 0.001) higher in the fast group compared to the slow group. There was not a significant (p = 0.70) difference in estimated VO2max between the moderate and slow groups. Estimated VO2max performance and sFSA performance were significantly correlated, with rs(488) = -0.272 and p < 0.001. Poorer sFSA performance was found to be associated with a higher proportion of ACREs. The results suggest that sFSA performance may be a valid indicator of ACRE injury risk and aerobic capacity.

The Effects of Exercise Training on Functional Capacity and Quality of Life in Patients with Rheumatoid Arthritis: A Systematic Review.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation. The purpose of this systematic review is to evaluate the effectiveness of exercise training on functional capacity and quality of life (QoL) in patients with RA. We performed a search in four databases, selecting clinical trials that included community or outpatient exercise training programs in patients with RA. The primary outcome was functional capacity assessed by peak VO2 or the 6 min walking test, and the secondary outcome was QoL assessed by questionnaires. Seven studies were finally included, identifying a total number of 448 patients. The results of the present systematic review show a statistically significant increase in peak VO2 after exercise training in four out of seven studies. In fact, the improvement was significantly higher in two out of these four studies compared to the controls. Six out of seven studies provided data on the patients' QoL, with five of them managing to show statistically significant improvement after exercise training, especially in pain, fatigue, vitality, and symptoms of anxiety and depression. This systematic review demonstrates the beneficial effects of exercise training on functional capacity and QoL in patients with RA.

Polarization and Incident Angle Independent Multifunctional and Multiband Tunable THz Metasurface Based on VO2.

Aiming at the limitations of single-functionality, limited-applicability, and complex designs prevalent in current metasurfaces, we propose a terahertz multifunctional and multiband tunable metasurface utilizing a VO2-metal hybrid structure. This metasurface structure comprises a top VO2-metal resonance layer, a middle polyimide dielectric layer, and a gold film reflective layer at the bottom. This metasurface exhibits multifunctionality, operating independently of polarization and incident angle. The varying conductivity states of the VO2 layers, enabling the metasurface to achieve various terahertz functionalities, including single-band absorption, broadband THz absorption, and multiband perfect polarization conversion for linear (LP) and circularly polarized (CP) incident waves. Finally, we believe that the functional adaptability of the proposed metasurface expands the repertoire of options available for future terahertz device designs.

The Effects of Aquatic Exercise Training on Functional and Hemodynamic Responses in Patients With Heart Failure: A Systematic Review and Meta-Analysis.

Objective: This study aimed to investigate the impacts of water exercise training on functional and hemodynamic responses in HF patients. Methods: A systematic review and meta-analysis were conducted until February 15, 2024, using multiple databases. Mean difference (MD) with corresponding 95% confidence intervals (CIs) were calculated. Results: Sixteen studies, comprising 349 participants with HF, were included. Water exercise led to enhancements in peak VO2 (MD, 2.85 mL/kg/min; 95% CI, 1.89 to 3.80; p < .00001) and resting heart rate (MD, -4.16 bm; 95% CI, -6.85 to -1.46; p = .002) compared to no exercising controls. Water plus land exercise reduced resting heart rate (MD, -1.41 bm; 95% CI, -2.13 to -0.69; p = .0001) compared to land exercise alone. Furthermore, acute water exercises decreased resting heart rate (MD, -3.85 bm; 95% CI, -6.49 to -1.21; p = .004) and increased stroke volume (MD, 14.68 mL/beat; 95% CI, 8.57 to 20.79; p < .00001) and cardiac output (MD, 0.5 L/min; 95% CI, 0.27 to 0.73; p < .00001) compared to baseline. Conclusion: These findings suggest that water exercise holds promise as an effective intervention for enhancing functional capacity and hemodynamic parameters in individuals with HF, highlighting the importance of further research to optimize its implementation and elucidate long-term benefits.

Using cardiorespiratory fitness to operationalize vitality: a path analysis on the hierarchical structure of intrinsic capacity.

BACKGROUND: There is a lack of consensus about the operationalization of vitality, which is one of the intrinsic capacity (IC) domains. In particular, no study has investigated whether cardiorespiratory fitness (CRF) can be considered a vitality indicator. OBJECTIVE: To examine whether vitality is the upstream domain of IC, and establish the validity of CRF as a vitality indicator, using maximal oxygen consumption (VO2 max) as a representative. METHODS: 561 older adults from a longitudinal cohort study were included. Variables under consideration were VO2 max, other IC domains, instrumental activities of daily living (IADL), and handgrip strength, which was considered an already validated indicator of vitality. Using handgrip strength as the reference point, path analyses were performed to examine whether VO2 max followed a similar hierarchical structure in predicting change in IADL difficulty through other IC domains. RESULTS: The mean age of the participants was 75.5 years. The path model in which vitality was measured by VO2 max demonstrated adequate fit, which was similar to the model in which vitality was measured by handgrip strength. Regarding the path coefficients, the model using VO2 max demonstrated significant total and indirect effects. Notably, the indirect effect was due to the locomotor domain (standardized coefficient = -0.148, p < .001), but not the cognitive or psychological domain. CONCLUSION: Vitality is the upstream domain of IC. VO2 max can be considered an indicator to operationalize the vitality concept.