Work Rate Research Articles

Exercise testing in patients with tricuspid regurgitation undergoing transcatheter tricuspid valve intervention.

Transcatheter tricuspid valve intervention (TTVI) has shown promising results with persistent reduction of tricuspid regurgitation (TR) and improvements in functional class and quality of life (QOL). To analyze the impact of TTVI on maximal and submaximal exercise capacity (SEC). Constant work-rate exercise-time (CWRET) testing reflects SEC, which is more likely to be relevant for daily life activities and provides more differentiated physiological insight into the nature of exercise intolerance. Thus, 30 patients undergoing TTVI (21 direct annuloplasty and 9 edge-to-edge repair) received cardiopulmonary exercise testing (CPET) and CWRET (at 75% of maximum work rate in the initial CPET) before and 3months after TTVI. Patients' age was 80.5 [74.8-82.3] years and 53.3% were female. TR reduction ≥ 2 grades was achieved in 93.3% (TR grade ≤ moderate in 83.3%). Echocardiography revealed improved right ventricular (RV) characteristics with decreased RV basal diameter (47.0mm [43.0-54.3] vs. 41.5mm [36.8-48.0]; p < 0.001) and decreased inferior caval vein diameter. CWRET testing showed a significantly improved SEC (246.5s [153.8-416.8] vs. 338.5s [238.8-611.8] p = 0.001). Maximum oxygen uptake showed a positive trend without statistically significant differences (9.9ml/min/kg [8.6-12.4] vs. 11.7ml/min/kg [9.7-13.3]; p = 0.31). In contrast to the six-minute-walking distance (6MWD), SEC correlated moderately with effective regurgitation orifice area reduction (r = 0.385; p = 0.036), increased cardiac output (r = 0.378; p = 0.039), and improved QOL (r = 387; p = 0.035). Improvements in exercise capacity after TTVI mainly occur in the submaximal rather than in the maximal exercise range and correlate with hemodynamic effects and QOL. This may have a methodological impact on assessment of exercise capacity in these patients.

Application of inverse heat transfer to fatigue fracture

Cyclic actuation tends to cause self-heating in the material as the structure experiences fatigue, where the movement and coalescence of defects lead to crack formation, propagation, and eventual fracture. This study explores the modeling aspects of the self-heating phenomenon using a one-dimensional inverse heat problem to analyze heat generation and dissipation to quantify the plastic work rates needed for predicting fatigue life. The approach is based on analyzing the surface thermography obtained using an infrared camera and numerically solving an inverse Fourier heat conduction equation. Formulation of the inverse problem via constrained optimization and method of solution for analyzing the fatigue behavior of CS 1018 flat dog bone specimens subjected to fully reversed bending fatigue are presented. The proposed model demonstrates superior accuracy in predicting the location of maximum heat generation and identifying potential fracture zones compared to traditional methods.

IMPLIKASI KAWASAN WISATA TERHADAP PEREKONOMIAN DESA PUJON KIDUL

This study aims to determine the methods used by BUMDes Sumber Sejahtera to improve the economy of the community in Pujon Kidul Village by looking at the unemployment rate, income, and type of work owned by the community. This research uses qualitative methods with data collection through interviews and documentation. The results of the study explain that the tourist area, namely Cafe Sawah, has an impact on village funds in the allocation of funds, provides employment for youth in the village, and has a positive impact on bad habits, namely drunkenness, gambling, and others. It can be said that the tourist area in Pujon Kidul Village, especially Cafe Sawah, has a majorimpact on the existing economy and socio-culture.

Differences in motivational dynamics between experienced cyclists and untrained participants during an incremental endurance exercise task

PurposeThe conflict between the desire to reduce effort during exercise and the performance goal of the exercise task contributes to explaining endurance exercise performance. However, whether the trajectories of these two motivational responses systematically differ across individuals with different characteristics is poorly understood. The present study examined whether changes in desire to reduce effort and performance goal value across moderate, heavy, and severe exercise intensity domains differed between cyclists and untrained, but active participants. MethodsFifty participants (14 cyclists and 36 untrained) completed an incremental step test on a cycle ergometer, in which work rate was increased by 25 W every 4 min until voluntary exhaustion. Desire to reduce effort, performance goal value, and blood lactate concentration (for determination of exercise intensity domains) were measured every 4 min and the data were analysed using multilevel modelling. ResultsDesire to reduce effort increased quicker for untrained participants in the moderate exercise intensity domain (b = 1.66, p < .001) and across the whole trial (b = 1.64, p < .001), compared to cyclists (b = .69, and b = 1.14, respectively, both p < .001). Untrained participants reported similar performance goal value at the beginning of the trial (b = 16.02, p < .001), compared to cyclists (b = 17.25, p < .001). Beyond moderate intensities, the performance goal value decreased significantly for the untrained participants (b = −.70, p < .001) but significantly increased for cyclists (b = .45, p = .01). This pattern was also observed when focusing solely on the severe intensity domain (cyclists: b = .90, p < .001; untrained: b = −.84, p < .001). ConclusionThere are distinct differences in the desire to reduce effort and performance goal value between cyclists and untrained athletes. Identifying these systematic differences enhances the credibility of the desire-goal conflict framework in explaining endurance performance and provides insight into the type and timing of interventions that might be successful in improving performance.

Using an Isolated Working Rat Heart Model to Test Donor Heart Preservation Strategies.

Optimization of donor heart preservation solutions has played a key role in reducing ischemia-reperfusion injury in donor hearts during organ retrieval, transportation, and transplantation. Previous work from our laboratory showed that the addition of glyceryl trinitrate and erythropoietin to donor heart preservation solutions could significantly improve cardiac functional recovery after prolonged cold storage and in donation after circulatory death hearts. This supplementation protocol has been implemented in clinical use in transplant units around Australia, Belgium, and the United Kingdom. Here, we outline a protocol for testing supplementation strategies using an ex vivo isolated working rat heart (IWRH) perfusion circuit. Using this methodology, supplementation strategies can be tested in the context of prolonged cold static storage, donation after brain death, and donation after circulatory death donor heart preservation. Cardiac functional recovery, measured by aortic flow, coronary flow, cardiac output, pulse pressure, and heart rate, can be used to determine whether a particular preservation strategy can minimize ischemia-reperfusion injury of the donor heart.

Arthroscopic Repair for Posterior Shoulder Instability is Associated with Favorable Outcomes and High Return to Sport or Work: A Systematic Review and Meta-Analysis

PurposeThe purposes of this systematic review and meta-analysis were to assess clinical outcomes of primary arthroscopic repair for unilateral PSI in all patients, to evaluate clinical outcomes in athletes, and to compare clinical outcomes between contact and overhead athletes. MethodsA systematic review was performed using PRISMA Guidelines. Included studies reported on primary arthroscopic treatment of PSI with at least 1 year of follow-up. Studies were excluded if they were not in English, included revisions/open procedures or anterior/multidirectional instability, had fewer than ten patients or no full text available, or were biomechanical analyses/descriptions of surgical technique. Primary outcomes were rates of return to sport (RTS), return to preinjury level (RTPL), recurrent instability, and revision surgery. Outcomes were evaluated in all patients and all athletes, with further subdivision for contact and overhead. ResultsOf the 1,504 screened studies, 30 met inclusion criteria (1,649 shoulders). Mean age at surgery was 23.3 years (range: 12.4-65 years), and mean follow-up was 35.5 months (range: 12-140.4 months). There were 1051 males and 196 females. RTS rates were 91.7% among all patients and 90.9% in all athletes, with no statistical difference between contact and overhead athletes (92.8% vs. 88.1%, P=.176). RTPL rates were 78.7% among all patients and 75.6% in all athletes, with no statistical difference between contact and overhead athletes (90.8% vs. 62.3%, P=.072). Recurrent instability rates were 7.0% among all patients and 8.0% in all athletes, with no statistical difference between contact and overhead athletes (7.3% vs. 7.4%, P=.981). Revision rates were 3.7% among all patients and 3.3% in all athletes, with no statistical difference between contact and overhead athletes (6.8% vs. 0%, P=1). ConclusionPrimary arthroscopic treatment of PSI is associated with favorable outcomes and high return to sport and work rates. Recurrent instability and pain were the most common reasons for revision. Level of EvidenceLevel IV: Systematic review and meta-analysis of Level II to IV studies

Hand cooling induces changes in the kinetics of oxygen uptake

The objective of this investigation was to assess the impact of elevated catecholamine concentrations, induced through cold-water hand immersion, on the oxygen consumption (V̇O2) kinetics during intense exercise, and to contrast this effect with that of the priming effect. Ten active participants underwent three 8-minute constant work rate exercises (CWR) at ∆25%, with one CWR preceded by hand cooling (2 min at 0 °C, HC) and two consecutive CWR to induced priming effect on the second bout (SB). Pulmonary gas exchange and blood samples were analyzed to measure levels of epinephrine (E) and norepinephrine (NE). Results demonstrated a significant increase in the primary phase amplitude of V̇O2 kinetics in response to both hand HC (33.9 mL.min−1.kg−1; CI [32.2;35.7], p < 0.001) and SB (34.6 mL.min−1.kg−1; CI [33.0;36.3], p < 0.001) relative to the control (32.7 mL.min−1.kg−1; CI [31.5;35.1]). Additionally, the amplitude of the V̇O2 slow component was reduced for both HC (3.2 mL.min−1.kg−1; CI [2.2;4.1], p = 0.018) and SB (2.9 mL.min−1.kg−1; CI [1.8;4.2], p = 0.009) in comparison to control (3.9 mL.min−1.kg−1; CI [2.9;4.2]). These findings suggest that the increase in E and NE induced by hand cooling prior to exercise modifies V̇O2 kinetics in a manner akin to the priming effect. This research underscores the potential role of catecholamines in facilitating the priming effect and its subsequent impact on V̇O2 kinetics. However, further studies are necessary to clearly establish this link.

Work Rate Adjustments During High-intensity Interval Training In The Heat With Active And Passive Recovery

Work Rate Adjustments During High-intensity Interval Training In The Heat With Active And Passive Recovery

Two-day cardiopulmonary exercise testing in long COVID post-exertional malaise diagnosis

BackgroundLong COVID patients present with a myriad of symptoms that can include fatigue, exercise intolerance and post exertional malaise (PEM). Long COVID has been compared to other post viral syndromes, including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), where a reduction in day 2 cardiopulmonary exercise test (CPET) performance of a two-day CPET protocol is suggested to be a result of PEM. We investigated cardiopulmonary and perceptual responses to a two-day CPET protocol in Long COVID patients. Methods15 Long COVID patients [n=7 females; mean (SD) age: 53(11) yr; BMI = 32.2(8.5) kg/m2] performed a pulmonary function test and two ramp-incremental CPETs separated by 24 hr. CPET variables included gas exchange threshold (GET), peak oxygen uptake (V̇O2peak) and peak work rate (WRpeak). Ratings of perceived dyspnoea and leg effort were recorded at peak exercise using the modified 0–10 Borg Scale. PEM (past six months) was assessed using the modified DePaul Symptom Questionnaire (mDSQ). One-sample t-tests were used to test significance of mean difference between days (p<0.05). Results.mDSQ revealed PEM in 80 % of patients. Lung function was normal. Responses to day 1 CPET were consistent with the presence of aerobic deconditioning in 40 % of patients (V̇O2peak <80 % predicted, in the absence of evidence of cardiovascular and pulmonary limitations). There were no differences between day-1 and day-2 CPET responses (all p>0.05). ConclusionPEM symptoms in Long COVID patients, in the absence of differences in two-day CPET responses separated by 24 hours, suggests that PEM is not due to impaired recovery of exercise capacity between days.

A Pilot Study on the Effects of Exercise Training on Cardiorespiratory Performance, Quality of Life, and Immunologic Variables in Long COVID.

Objectives: Fatigue is a prominent feature of long COVID (LC) and may be related to several pathophysiologic mechanisms, including immune hyperstimulation. Aerobic endurance exercise training may be a useful therapy, with appropriate attention to preventing post-exertional malaise. Methods: Fourteen participants completed a pilot study of aerobic exercise training (twenty 1.5 h sessions of over 10 weeks). Cardiorespiratory fitness, 6 min walk distance, quality of life, symptoms, 7-day physical activity, immunophenotype, and inflammatory biomarkers were measured before and after exercise training. Results: The participant characteristics at baseline were as follows: 53.5 ± 11.6 yrs, 53% f, BMI 32.5 ± 8.4, 42% ex-smokers, 15.1 ± 8.8 months since initial COVID-19 infection, low normal pulmonary function testing, V.O2peak 19.3 ± 5.1 mL/kg/min, 87 ± 17% predicted. After exercise training, participants significantly increased their peak work rate (+16 ± 20 W, p = 0.010) and V.O2peak (+1.55 ± 2.4 mL/kg/min, p = 0.030). Patients reported improvements in fatigue severity (-11%), depression (-42%), anxiety (-29%), and dyspnea level (-46%). There were no changes in 6MW distance or physical activity. The circulating number of CD3+, CD4+, CD19+, CD14++CD16, and CD16++CD14+ monocytes and CD56+ cells (assessed with flow cytometry) increased with acute exercise (rest to peak) and was not diminished or augmented by exercise training. Plasma concentrations of TNF-α, IL-6, IL-8, IL-10, INF-γ, and INF-λ were normal at study entry and not affected by training. Conclusions: Aerobic endurance exercise training in individuals with LC delivered beneficial effects on cardiorespiratory fitness, quality of life, anxiety, depression, and fatigue without detrimental effects on immunologic function.

Exploring the potential of cardiopulmonary exercise testing (CPET) for individualised pulmonary rehabilitation in people with interstitial lung disease (ILD): A systematic review protocol

Background This review aims to identify which cardiopulmonary exercise test (CPET) derived variables can be used to personalise pulmonary rehabilitation for people with interstitial lung diseases. A ‘one size fits all’ approach does not benefit every patient due to a multitude of unique characteristics, subsets and phenotypes. No condition specific personalised pulmonary rehabilitation guidelines exist in this area and exercise programme development is lacking. This leads to wide variation in the success within the literature and clinical practice. Methods MEDLINE, Embase, CINAHL, SPORTDiscus and the Cochrane Database of Systematic Reviews will be searched to identify studies that utilise CPET variables for PR development. Quality assessment is to be performed using the Critical Appraisal Skills Program (CASP) checklists for single cohort studies and randomised controlled studies. Discussion The primary outcomes found within the included studies for peak volume of oxygen consumption (VO2peak), work rate (WRpeak), oxygen consumption at anaerobic threshold (VO2-AT), heart rate and rate of perceived exertion (RPE) would help determine which variables are optimal for prescription success. Identification of reliable methods to personalise pulmonary rehabilitation for people with interstitial lung disease would enhance what is already known and potentially lead to best practice guideline development. Registration In accordance with the guidelines, this systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 07 May 2024 (registration number CRD42024543174).

A cross-sectional study on the understanding and attitudes toward influenza and influenza vaccines among different occupational groups in China

ABSTRACT This study aimed to assess the level of knowledge regarding influenza viruses and vaccines among different professional groups to investigate the reasons for vaccine hesitancy. We collected 2190 questionnaires regarding influenza vaccines in China in 2022. The respondents were categorized into the general population (GP), foreign affairs workforce population (FAWP), and veterinary workforce population (VWP) according to their job positions. Linear regression was used to assess the association between multiple factors and influenza vaccination rates. The association between work and influenza vaccination rates was also assessed by grouping different workforce populations. The vaccination rate of the GP was higher than that of the VWP (odds ratio: 1.342, 95% confidence interval: 1.025–1.853), surpassing the rates reported in previous studies. This may be attributed to heightened concerns about infectious diseases influenced by the ongoing coronavirus disease 2019 pandemic. Despite the VWP’s more in-depth knowledge of the VWP on zoonotic diseases and their recognition of their importance, there was no significant difference in influenza knowledge among the three populations. This discrepancy contrasts with the observed differences in vaccination rates. Further investigation revealed that, compared with FAWP, the price of vaccines emerged as a primary influencing factor for vaccination rates (odds ratio:0.398, 95%CI; 0.280–0.564). General concerns regarding the protective effects and side effects of vaccines were also noted.

Efficacy of respiratory support therapies during pulmonary rehabilitation exercise training in chronic obstructive pulmonary disease patients: a systematic review and network meta-analysis

BackgroundExercise training is fundamental in pulmonary rehabilitation (PR), but patients with chronic obstructive pulmonary disease (COPD) often struggle with exercise intolerance. Respiratory support during exercise in COPD patients may be a beneficial adjunct therapy. In this study, the effect of different respiratory support therapy during pulmonary rehabilitation exercise training in COPD patients was assessed through a network meta-analysis.MethodsFive databases were searched to obtain randomized controlled trials involving different respiratory support therapies during PR exercise training in COPD patients. The Cochrane Handbook tool was employed to assess the risk bias of included studies. Network meta-analysis was performed using the STATA software. The study protocol was registered at PROSPERO (CRD42023491139).ResultsA total of 35 studies involving 1321 patients and 6 different interventions were included. Network meta-analysis showed that noninvasive positive pressure ventilation (NPPV) is superior in improving exercise capacity (6-Minute Walk Test distance, peak work rate, endurance time), dyspnea, and physiological change (peak VO2, tidal volume, minute ventilation and lactate level) in stable COPD patients who were at GOLD stage III or IV during PR exercise training. The final surface under the cumulative ranking curve value indicated that NPPV therapy achieved the best assistive rehabilitation effect.ConclusionsThe obtained results indicate that NPPV is most powerful in assisting exercise in severe COPD patients under stable condition. Researchers should focus more on the safety, feasibility, and personalization of interventions. Furthermore, there is a need for additional high-quality trials to assess the consistency of evidence across various respiratory support approaches.Trial registrationThe study was registered at PROSPERO (CRD42023491139).

Development of a solar-ocean based integrated plant with a new hydrogen generation system

Considering the global urgency to decrease carbon emissions and shift to sustainable energy sources, combining solar and other renewables with hydrogen generation appears to offer an appealing answer. The combination of solar and ocean energies with hydrogen production, therefore, offers a great potential to improve energy efficiency and create a feasible route towards zero-emission energy systems. A new hybrid photoelectrochemical (PEC)-conventional electrolysis system was designed and incorporated into the proposed multigeneration system. The hybridized reactor combines the benefits of PEC and conventional electrolysis by using a developed bipolar anode to produce hydrogen continuously, even when there is no solar radiation. The main aim of this research is to investigate the integrated power process that utilizes solar power for several uses, such as generating electricity, producing freshwater, and synthesizing hydrogen. The proposed research involves integrating several components, including a solar through collector system, a combination of power cycles (steam and organic Rankine cycles), a multi-effect desalination (MED) unit, a new hybrid electrolyzer system, a wave energy system, and a hydrogen storage and refuelling station. The main outputs include 2.05 kg/s freshwater production, 0.125 kg/s hydrogen production, 16,284.24 kW net work rate, and 95,068 kW solar heat input. The highest exergy destruction rates were found in the solar collector (56,194.8 kW) and turbines T1 and T2 (6019.9 and 4627.6 kW). The overall energy and exergy efficiencies of the proposed system are obtained to be 15.83 % and 16.61 %, respectively.

Increased Ventilatory Efficiency in Supramaximal Compared to Graded Exercise in Athletes

ABSTRACT Background: Supramaximal constant work rate tests (CWR) elicit intense hyperventilation, thus potentially up-shifting ventilation (⩒E)-to-carbon dioxide (CO2) responses when compared to graded exercise tests (GXT) in athletes. We predicted higher ventilatory efficiency on supramaximal CWR using a new method, challenging the classic orthodox interpretation of an increased ⩒ E -⩒CO2 as ventilatory inefficiency. This misinterpretation could make difficult to differentiate between physiological hyperventilation from heart disease conditions in athletes. Methods: On different days, a GXT and a CWR at 110% of the maximal velocity achieved in the GXT were performed. Twenty-seven athletes completed the two tests and were compared for usual (linear regression) and log-transformed new variables for ventilatory efficiency through paired t-Student statistics. Results: The ⩒ E -⩒CO2 slope (31.4 ± 4.9 vs. 26.2 ± 3.4, p < .001), ⩒ E -⩒CO2 intercept (7.2 ± 7.5 vs. 2.8 ± 4.2, p < .007), ⩒ E /⩒CO2 nadir (33.0 ± 3.6 vs. 25.4 ± 2.2, p < .001), ⩒CO2-log⩒ E slope (10.8 ± 2.9 vs. 6.9 ± 2.2 L*logL−1, p < .001), and η⩒ E (36.0 ± 12 vs. 22.8 ± 8.1%, p < .001) values were all significantly higher in the CWR compared to the GXT. We registered a bi-modal nadir response for ⩒E/⩒CO2 on CWR for 22 out of 27 subjects for the first time. A weak association was observed between ⩒ E /⩒CO2 nadir (coefficient of determination ~ 27%) and time to exhaustion. Conclusions: The new method allows us to improve the quantification and interpretation of ventilatory efficiency in athletes, avoiding misinterpretation due to the up-shifting elicited by the usual ⩒ E -⩒CO2 slope and ⩒ E /⩒CO2 nadir indices, which may be confounded with ventilatory inefficiency. This study suggests that ventilatory changes underpin better ventilatory efficiency during CWR.

The impact of cancer diagnosis on employment status in a working population

The aim of this study was to investigate the status of return to work and the influencing factors in patients with common cancers referring to three medical centers during the years 2020 to 2022. Material and Methods. In the present study (a retrospective cohort), all patients who visited three medical centers during the years 2020–2022 and were diagnosed with common cancers (non-Hodgkin’s lymphoma, Hodgkin’s lymphoma, gastrointestinal cancers and sarcoma), were included in the study. Work ability index (WAI) was assessed based on selected questions from the WAI questionnaire. Hospital Anxiety and Depression Scale (HADS) was used to assess depression and anxiety, and Multidimensional Fatigue Inventory (MFI-20) was used to assess the level of fatigue. Then, the data obtained from individuals who returned to work were compared with those who did not return. Results. Out of 750 eligible patients, 135 individuals were enrolled in the study. 114 patients were male (84.4 %). The mean age of individuals was 50.2 ± 10.4 years. The most of individuals were diagnosed with gastric cancer (n=66, 48.9 %). After treatment, 36 (26.7 %) individuals returned to work, with the majority (24 individuals: 66.6 %) reporting a decrease in physical ability to do work. Sixty-six (73.3 %) patients did not return to work, with the most common reason being physical inability to work in 60 (66.6 %) individuals. Higher quality of life score was reported in individuals who returned to work. Conclusion. The rate of return to work was approximately 27 %. The return to work rate was highest among individuals with non-Hodgkin’s lymphoma and lowest among individuals with oesophageal cancer and Hodgkin’s lymphoma. The most influential factors affecting the return to work include disease recurrence and quality of life.

The Significance of Body Surface Area to Mass Ratio for Thermal Responses to a Standardized Exercise-Heat Stress Test.

To evaluate the significance of body surface area-to-mass ratio (BSA/mass) on the heat-tolerance test (HTT) results. We hypothesized that individuals defined as heat tolerant (HT) would have on average higher BSA/mass compared to heat intolerant (HI) individuals. A retrospective reanalysis of the HTT results of 517 soldiers (age: 18-38 yrs., M/F: 96/4%), who were tested by the Israel Defense Forces (IDF) HTT protocol. The criterion for heat tolerance in the current analysis was a rectal temperature (Tre) plateau during the second hour of the test. A logistic regression analysis to evaluate the predictive power of BSA/mass for heat intolerance was performed; the spline model was applied to show the odds for heat intolerance across BSA/mass. In men BSA/mass of HI individuals was lower than HT individuals (248 ± 19 vs. 262 ± 18 cm2/kg, p < 0.01, d = 0.76). In women a similar trend was noted but with no statistical significance between HT and HI groups. The odd ratio for heat intolerance for every unit increase in BSA/mass was 0.97 (CI 95% 0.95-0.99). The spline model plateaued above BSA/mass of 270 cm2/kg. The results imply that body-core temperature responses to a standard exercise-heat stress (fixed external work rate and climatic conditions) are influenced by BSA/mass. More specifically, lack of a steady state in Tre (indicating heat intolerance) was more likely to occur with every unit decrease in BSA/mass. These findings contribute to a better understanding of the role of body anthropometry in the response to a standard exercise-heat task that might have an implication on clinical decision-making about return to duty/play of soldiers, athletes and others who deemed to be identified as HI.

Cardiac autonomic regulation during submaximal exercise in women with fibromyalgia.

Fibromyalgia (FM) patients present impaired cardiac autonomic regulation during maximal exercise; however, it is unknown whether these alterations also manifest during submaximal exercise. The aim of this study was to compare the on-transient heart rate (HR) response and HR variability during a constant-load submaximal cycling exercise between FM and control (CON) women. Ten women with FM (age: 45.2±9.3 years) and 10 age-matched CON women (age: 48.4±6.1 years) performed a 15-min cycling exercise, with the work rate fixed at 50% of the individual peak power output attained in a maximal graded exercise test. The time intervals between consecutive heartbeats were recorded regularly during the exercise for subsequent analysis of on-transient HR response and HR variability indices. The on-transient HR time constant was similar (P=0.83) between the FM (41.0±14.1 sec) and CON (42.2±10.4 sec). During the 5-10 and 10-15 min of exercise, HR variability indices indicating sympathetic and parasympathetic activities were similar (P>0.05) between FM and CON groups. In conclusion, women with FM presented a normal cardiac autonomic response to submaximal cycling exercise. These findings have clinical relevance, as submaximal exercises are commonly prescribed for FM patients.

The Responsiveness of Exercise Tests in COPD: A Randomized Controlled Trial

BackgroundChronic obstructive pulmonary disease (COPD) is characterised by reduced exercise tolerance and improving physical performance is an important therapeutic goal. A variety of exercise tests are commonly used to assess exercise tolerance, including laboratory and field-based tests. The responsiveness of these tests to common COPD interventions is yet to be compared, but may inform test selection in clinical and research settings. Research QuestionWhat exercise test possesses the greatest sensitivity to change pre- to post-intervention in patients with COPD? Study Design and Methods154 patients with symptomatic COPD were recruited and randomised (2:1:1) to six weeks of long-acting muscarinic antagonist (LAMA), pulmonary rehabilitation (PR), or usual care (UC). Pre- and post-intervention, participants performed a ramp-incremental and constant work rate cycle ergometer exercise test (ICET and CWRCT), incremental and endurance shuttle walk test (ISWT and ESWT), six-minute walk test (6MWT), and a four metre gait speed test (4MGS). Results103 participants (67 ± 8 y; 75 [73%] males; FEV1: 50.6 ± 16.8 % predicted) completed the study. Significant improvements in the ICET, CWRCT, ISWT, ESWT, and 6MWT were observed following PR (p<0.05), with the greatest improvements seen in the constant work rate protocols (% change: CWRCT: 42%; ESWT: 41%). InterpretationThe ESWT and CWRCT appeared to be the most responsive exercise test protocols to LAMA and PR. The magnitude of change was much greater after a programme of rehabilitation compared to bronchodilator therapy.

Participation of the transcription factor CREB1 in the regulation of the Mdh2 gene encoding malate dehydrogenase in the liver of rats with alloxan diabetes

The aim of the study was to study the role of transcription factor CREB1 in regulating the expression of the gene encoding the mitochondrial form of malate dehydrogenase (MDH, EC 1.1.1.37) in the liver of rats with experimental diabetes. An increase in the rate of work of NAD-dependent malate dehydrogenase in rat liver cells during the development of experimental diabetes was shown, associated with the activation of the Mdh1 and Mdh2 genes encoding this enzyme. The analysis of the promoters of these genes showed that only in the Mdh2 gene there is a specific binding site with the transcription factor CREB1. It was found that in the liver of rats with pathology, there is an increase in the rate of expression of the gene encoding this transcription factor, which correlates with the expression of the Mdh2 gene. Thus, the data obtained by us confirm the possibility of positive regulation of the rate of the Mdh2 gene by the transcription factor CREB1.