Introduction & Purpose Low-intensity training dominates endurance training in elite rowing, commonly structured along intensity zones. These are often prescribed as percentages of maximum heart rate (%HRmax). Bishop (2025) suggests defining VeryLow, Low, and Moderate intensities relative to the first metabolic threshold (MT1), without clear cut between VeryLow and Low, and MT1 marking the upper boundary of Low. Given that minimizing Moderate-intensity training time may benefit elite endurance athletes pursuing a polarised training intensity distribution (Rosenblat et al., 2025), zone adherence is relevant. Whether elite rowers achieve intended intensities without external guidance remains unknown. The Purpose was to compare self-paced and HR-guided on-water rowing across three low intensity zones in elite rowers. Methods Fifteen national team rowers (7 female) completed an incremental step and ramp test on a rowing ergometer to determine the first lactate threshold (LT1, 1st rise) as a proxy for MT1, and V̇O2max. Each rower then performed four on-water trials in the single scull (two self-paced, two HR-guided, each on a different day), each comprising six 15-minute steps targeting VeryLow, Low, and Moderate intensities in ascending and descending order. During self-paced trials, rowers relied on self-regulation. During HR-guided trials, they received real-time HR feedback and were advised to stay within 60–72%, 72–79%, and 79–82%HRmax for VeryLow, Low, and Moderate, respectively. HR, %V̇O2max, blood lactate (BLa), and rating of perceived exertion (RPE) were recorded. Differences between zones, guidance modes, and deviations from LT1 were analysed via linear mixed models. Sex was not modelled, as sex differences occurred only for absolute V̇O2max, not for the relative intensity variables analysed. Results Across all zones, self-paced rowing elicited significantly higher %HRmax and %V̇O2max than HR-guided rowing (all p < 0.01; Figure 1). Relative to LT1, VeryLow was significantly below LT1 in both modes, whereas Low did not differ significantly from LT1 in either condition. %HRmax at self-paced Low was not significantly different from HR-guided Moderate, indicating that self-paced Low intervals were performed at Moderate intensities. At Moderate intensity, mean values exceeded LT1 in both modes, but the deviation was markedly larger during self-paced rowing. Standard deviations for %HRmax and %V̇O2max were consistently smaller when HR-guided. BLa did not distinguish VeryLow from Low (self-paced 1.2 ±0.3 vs. 1.2 ±0.4; HR-guided 1.1 ±0.3 vs. 1.1 ±0.3 mmol·L⁻¹). RPE increased across zones (self-paced 1.8 ±0.8 → 3.3 ±0.8 → 5.1 ±1.0) but did not significantly differ between modes. Discussion Self-paced rowing systematically resulted in higher and more variable intensities, particularly in Low, which overlapped with Moderate. Because BLa and RPE did not separate the guidance modes, HR appears most suitable for everyday intensity control. Conclusion HR-guidance improved adherence to the intended zones and reduced variability compared with self-paced rowing. However, fixed %HRmax targets did not consistently keep low-intensity rowing below LT1: even HR-guided, Low was not significantly different from LT1, and self-paced Low reached Moderate intensity. If the goal is to keep low-intensity training below LT1, prescription should be anchored to the individual LT1 rather than to fixed %HRmax cut-offs. References Bishop, D. J., Beck, B., Biddle, S. J. H., Denay, K. L., Ferri, A., Gibala, M. J., Headley, S., Jones, A. M., Jung, M., Lee, M. J., Moholdt, T., Newton, R. U., Nimphius, S., Pescatello, L. S., Saner, N. J., & Tzarimas, C. (2025). Physical activity and exercise intensity terminology: A joint American College of Sports Medicine (ACSM) expert statement and Exercise and Sport Science Australia (ESSA) consensus statement. Medicine & Science in Sports & Exercise, 57, 2599–2613. https://doi.org/10.1249/MSS.0000000000003795 Rosenblat, M. A., Watt, J. A., Arnold, J. I., Treff, G., Sandbakk, Ø. B., Esteve-Lanao, J., Festa, L., Filipas, L., Galloway, S. D., Muñoz, I., Ramos-Campo, D. J., Schneeweiss, P., Sellés-Pérez, S., Stöggl, T., Talsnes, R. K., Zinner, C., & Seiler, S. (2025). Which training intensity distribution intervention will produce the greatest improvements in maximal oxygen uptake and time-trial performance in endurance athletes? A systematic review and network meta-analysis of individual participant data. Sports Medicine, 55, 655–673. https://doi.org/10.1007/s40279-024-02149-3

Background In the pursuit of sporting success, some elite athletes prioritise peak performance over long-term health, frequently resulting in significant and enduring health consequences. The Enhanced Games (TEG) position themselves as a bold experiment in transhumanism, advocating for the use of performance-enhancing drugs (PEDs), including methods banned by World Anti-Doping Agency (WADA), to push the boundaries of human athletic potential. Objectives The aim of this study is to explore the perspectives of sport physicians, sport scientists, physiotherapists and other allied healthcare professionals on treating and supporting "enhanced athletes", with the view of informing future guidelines. Methods Participants were invited via email and personal contacts within sport medicine communities to complete a brief anonymous survey via QuestionPro (TM). Descriptive statistics were performed using Excel (TM) and RStudio (TM). Results A total of 323 healthcare professionals responded (82% were sport physicians), among whom 74% expressed a willingness to treat acute lesions and/or chronic diseases in "enhanced athletes". In comparison, a considerable minority (30%) expressed support for assisting athletes in their use of PEDs and methods under medically supervised conditions, with high consistency across professional roles. A relatively high readiness was observed in sport physicians treating acute (77% versus 58%; p < 0.01) and chronic (75% versus 63%; p = 0.11) diseases for "enhanced athletes". As far as WADA rules and/or national anti-doping laws apply, this support presupposes compliance with the code and the respective national laws to protect physicians from serious professional, legal and personal consequences. Conclusion The preliminary findings align with the broader goal of fostering a sport culture that values both peak performance and the short- and long-term health of all participants. These results emphasise the necessity of implementing professional guidelines and comprehensive support systems designed to safeguard the long-term well-being of all athletes and underscore the urgent need for further research into the impact of TEG on sport and its community.

Impaired left and right ventricular (LV/RV) function during acute SARS-CoV-2 infection has been predominantly reported in hospitalized patients, but long-term cardiac sequelae in large, well-characterized cohorts remain inconclusive. This study evaluated cardiac structure and function in individuals with post-Coronavirus disease (COVID) syndrome (PCS) compared to recovered controls (CON), focusing on associations with cardiopulmonary symptoms and rapid physical exhaustion (RPE). This multicenter, population-based study included 1154 participants (679 PCS, 475 age- and sex matched CON; mean age 49 ± 12 years; 760 women) 1.5 years post-infection. Transthoracic echocardiography assessed LV global longitudinal strain (GLS), RV GLS and RV free wall strain (FWS), and other measures. Cardiopulmonary exercise testing (CPET) measured maximum respiratory oxygen uptake (VO2max) as a marker of cardiopulmonary fitness. PCS participants exhibited significantly lower LV GLS (-20.25

BACKGROUND:During whole blood donation (BD), 500 mL of blood is drawn. The time interval between two BDs is at least 8-12 weeks. This period might be insufficient for restoring hemoglobin mass (Hbmass) and iron especially in women, who generally have lower Hbmass and iron availability. Since both variables influence physical performance, this pilot study aimed to monitor Hbmass, iron status, and maximum oxygen uptake (V̇O2max) recovery in women after a single BD. STUDY DESIGN AND METHODS:In 10 women (24.7 ± 1.7 years), Hbmass, hemoglobin concentration [Hb], iron status, and V̇O2max were assessed before and up to 12 weeks after a single BD. RESULTS:BD reduced Hbmass from 562 ± 70 g to 499 ± 64 g (p < .001). Although after 8 weeks no significant mean difference was detected, 7 women had not returned to baseline after 12 weeks. [Hb] did not return to initial values (13.4 ± 0.7 g/dL) after 12 weeks (12.9 ± 0.7 g/dL, p < .01). Ferritin decreased from baseline until week 6 (40.9 ± 34.2 ng/mL vs. 12.1 ± 6.9 ng/mL, p < .05) and was not restored after 12 weeks (18.4 ± 12.7 ng/mL, p < .05), with 6 out of 10 women exhibiting iron deficiency (ferritin <15 ng/mL). V̇O2max was reduced by 213 ± 47 mL/min (7.2 ± 1.2%; p < .001) and remained below baseline after 12 weeks (3.2 ± 1.4%, p < .01). DISCUSSION:For most pre-menopausal women, 12 weeks were not sufficient to recover from BD and achieve baseline Hbmass and iron stores resulting in prolonged reduction of aerobic capacity. A subsequent BD might lead to a severe anemia.

Objective: To assess risk factors for persistence vs improvement and to describe clinical characteristics and diagnostic evaluation of subjects with post-acute sequelae of COVID-19/post-COVID-19 syndrome (PCS) persisting for more than one year. Design: Nested population-based case-control study. Setting: Comprehensive outpatient assessment, including neurocognitive, cardiopulmonary exercise, and laboratory testing in four university health centres in southwestern Germany (2022). Participants: PCS cases aged 18 to 65 years with (n=982) and age and sex-matched controls without PCS (n=576) according to an earlier population-based questionnaire study (six to 12 months after acute infection, phase 1) consenting to provide follow-up information and to undergo clinical diagnostic assessment (phase 2, another 8.5 months [median] after phase 1). Main outcome measures: Relative frequencies of symptoms and health problems and distribution of symptom scores and diagnostic test results between persistent cases and controls. Additional analysis included predictors of changing case or control status over time with adjustments for potentially confounding variables. Results: At the time of clinical examination (phase 2), 67.6% of the initial cases (phase 1) remained cases, whereas 78.5% of the controls continued to report no health problems related to PCS. In adjusted analyses, predictors of improvement among cases were mild acute index infection, previous full-time employment, educational status, and no specialist consultation and not attending a rehabilitation programme. Among controls, predictors of new symptoms or worsening with PCS development were an intercurrent secondary SARS-CoV-2 infection and educational status. At phase 2, persistent cases were less frequently never smokers, had higher values for BMI and body fat, and had lower educational status than controls. Fatigue/exhaustion, neurocognitive disturbance, chest symptoms/breathlessness and anxiety/depression/sleep problems remained the predominant symptom clusters, and exercise intolerance with post-exertional malaise for >14 h (PEM) and symptoms compatible with ME/CFS (according to Canadian consensus criteria) were reported by 35.6% and 11.6% of persistent cases, respectively. In adjusted analyses, significant differences between persistent cases and stable controls (at phase 2) were observed for neurocognitive test performances, scores for perceived stress and subjective cognitive disturbances, symptoms indicating dysautonomia, depression and anxiety, sleep quality, fatigue, and quality of life. In persistent cases, handgrip strength, maximal oxygen consumption, and ventilator efficiency were significantly reduced. However, there were no differences in measures of systolic and diastolic cardiac function, in the level of pro-BNP blood levels or other laboratory measurements (including complement activity, serological markers of EBV reactivation, inflammatory and coagulation markers, cortisol, ACTH and DHEA-S serum levels). Screening for viral persistence (based on PCR in stool samples and SARS-CoV-2 spike antigen levels in plasma in a subgroup of the cases) was negative. Sensitivity analyses (pre-existing illness/comorbidity, obesity, PEM, medical care of the index acute infection) revealed similar findings and showed that persistent cases with PEM reported more pain symptoms and had worse results in almost all tests. Conclusions: This nested population-based case-control study demonstrates that the majority of PCS cases do not recover in the second year of their illness, with patterns of reported symptoms remaining essentially similar, nonspecific and dominated by fatigue, exercise intolerance and cognitive complaints. We found objective signs of cognitive deficits and reduced exercise capacity likely to be unrelated to primary cardiac or pulmonary dysfunction in some of the cases, but there was no major pathology in laboratory investigations. A history of PEM >14 h which was associated with more severe symptoms as well as with more objective signs of disease may be a pragmatic means to stratify cases for disease severity. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was funded by the Baden-Wuerttemberg Federal State Ministry of Science and Art (grant number MR/S028188/1). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval was obtained from the Ethics Committee of the University of Freiburg, Engelberger Strasse 21, D-79106 Freiburg/Germany (#21/1484_1), the Ethics Committee of the Medical Faculty of Heidelberg University, Alte Glockengiesserei 11/1, D-69115 Heidelberg/Germany (#S-846/2021), the Ethics Committee at the Medical Faculty of the Eberhard-Karls-University and at the University Hospital of Tuebingen, Gartenstrasse 47, D-72074 Tuebingen/Germany (#845/2021BO2), and the Ethic Committee of the University of Ulm, Oberberghof 7, D-89081 Ulm/Germany (#337/21). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.

Background Health (in)equity has a high priority on research and policy agendas. Even though it is known that inequalities in overweight prevalence accumulate with age and are already existent among children below the age of six, research on this topic is scarce. In this young age group, parents play an important role in preventing overweight and associated adverse consequences. This study examines the magnitude of parental misclassification of child weight status and its correlates, focussing on the factors that determine social status and equity. Methods Preschool children’s weight and height was measured objectively. Parents gave information on their socioeconomic background. Family education was dichotomised into tertiary and non-tertiary educational level, according to CASMIN. Binary logistic regression, adjusted for parental BMI, was applied to detect odds of childhood overweight. Results Data on family educational level and anthropometrics were available from 643 children (4.5 ± 0.82 years, 52.7% male) and their parents of which 46.5% (n = 299) had a tertiary educational background. The groups (tertiary vs. non-tertiary educational level) differ significantly in overweight prevalence (3.7% vs. 11.9%, p ≤ 0.001). Odds of overweight were two times higher in children with non-tertiary educational background (OR: 2.123, CI: 1.010–4.461, p < 0.05), adjusted for parental BMI. Conclusion Children from families with low educational background have an elevated risk of overweight, already at a very young age. Education in general (not explicitly health education) seems to play a tremendous role in the prevention of overweight and obesity and should therefore be implied in policies enhancing health equity. Trial registration DRKS-ID: DRKS00010089.

A better understanding of the cellular and molecular mechanisms that are involved in skeletal muscle adaptation to exercise is fundamentally important to take full advantage of the enormous benefits that exercise training offers in disease prevention and therapy. The aim of this study was to elucidate the transcriptional signatures that distinguish the endurance-trained and untrained muscles in young adult males (24 ± 3.5 years). We characterized baseline differences as well as acute exercise-induced transcriptome responses in vastus lateralis biopsy specimens of endurance-trained athletes (ET; n = 8; VO2max, 67.2 ± 8.9 mL/min/kg) and sedentary healthy volunteers (SED; n = 8; VO2max, 40.3 ± 7.6 mL/min/kg) using microarray technology. A second cohort of SED volunteers (SED-T; n = 10) followed an 8-week endurance training program to assess expression changes of selected marker genes in the course of skeletal muscle adaptation. We deciphered differential baseline signatures that reflected major differences in the oxidative and metabolic capacity of the endurance-trained and untrained muscles. SED-T individuals in the training group displayed an up-regulation of nodal regulators of oxidative adaptation after 3 weeks of training and a significant shift toward the ET signature after 8 weeks. Transcriptome changes provoked by 1 h of intense cycling exercise only poorly overlapped with the genes that constituted the differential baseline signature of ETs and SEDs. Overall, acute exercise-induced transcriptional responses were connected to pathways of contractile, oxidative, and inflammatory stress and revealed a complex and highly regulated framework of interwoven signaling cascades to cope with exercise-provoked homeostatic challenges. While temporal transcriptional programs that were activated in SEDs and ETs were quite similar, the quantitative divergence in the acute response transcriptomes implicated divergent kinetics of gene induction and repression following an acute bout of exercise. Together, our results provide an extensive examination of the transcriptional framework that underlies skeletal muscle plasticity.

Abstract Background and Aims Patients on chronic hemodialysis benefit from intradialytic exercise with improvements in endurance, muscle strength and health-related quality of life. It is not known whether the increased oxygen demand during intradialytic exercise negatively affects cerebral oxygenation and cerebral function. The aim of the study was to assess the risk of cerebral undersupply by measuring cerebral oxygenation, perfusion and cognitive function during and after intradialytic ergometer training. Method Twelve patience on maintenance hemodialysis (HD) trice weekly were included in the study. In an initial ramp test, using bed cycle ergometer, we first determined the maximum physical strength (Pmax) at the level of exhaustion (HD A). Then, one hour after start of a second HD (HD B), patients performed 40%, 50% and 60% of Pmax for 6 min. Pulmonary function tests, blood volume (BVM), cardiac output (by electrical cardiometry), regional cerebral oxygen saturation (rSO2) (by near-infrared spectroscopy) and cerebral blood flow (CBF, by Doppler sonography) were measured. The relative changes in rSO2, CBF and hematocrit were used to calculate cerebral oxygen supply (DO2). Cognitive tests (Stroop, Trail Making and Mini Addenbrookes Cognitive Examination Test) were performed before and after HD sessions with and, as controls, without ergometry (HD-C). Results Median age was 68 (42-85) years, 9/12 were male, complete data set was obtained in 10 patients. During step test exercise (HD B), at the highest exercise level (according to Borg (1-10) 6.75 ± 2.9), rSO2 increased (+6 ± 9%, p=0.034) without a significant change in CBF. In the meantime, relative blood volume decreased during ergometry (-5.8 ± 2.73%; p=0.002), causing a temporary increase of hematocrit. Despite a small decrease in CBF in 3 patients, the mean change of rSO2, CBF and hematocrit always had a positive trend in all patients, as a surrogate of stable cerebral oxygen supply (Table 1). In comparative cognitive tests (B vs. C), we observed no significant changes in cognitive functions. Conclusion In this pilot study, intradialytic bed-cycle ergometry during the first hour of HD for <20 min at 40-60% of patients’ individual maximum intensity had no negative effects on cerebral oxygenation and function. Specific studies testing the safety intradialytic exercise with different conditions, such as increasing intensity or duration, are needed.

Abstract Background Worldwide, the prevalence of childhood overweight and obesity increases. Children with low socioeconomic status (SES) are more often affected by overweight and obesity. SES is also associated with health behaviours. In order to avoid health disparities, school-based health promotion programmes such as “Join the Healthy Boat” can help. Intervention outcomes can differ by SES; therefore, the purpose of this study was to investigate whether the intervention had equal or differential effects both on weight status and health-related behaviours in children from high and low SES. Methods One thousand six hundred twenty children’s data (7.1 ± 0.6 years; 50.6% male) was analysed; anthropometric data was taken on-site, other health-related parameters, such as physical activity, nutrition, and screen media use, as well as SES were assessed subjectively. Logistic regression models and GEEs were calculated. Results Comparisons by SES show that there were significant differences in children’s characteristics and health behaviours such as migration background, height, weight, BMI percentiles, weight status, family education level, household income, physical activity behaviour, screen media use, soft drink intake and breakfast skipping. After one year, there were no intervention effects for overweight status, physical activity, or screen media use, but children with high SES in the intervention group skipped breakfast significantly less often than in the control group (5.34 [1.44;19.85], p = 0.01). Parental education level and household income were also assessed separately, with similar results. Interaction analysis revealed no significant effects apart from an interaction effect for breakfast behaviour (p = 0.02). Conclusions The health-promotion programme “Join the Healthy Boat” has the potential to promote children’s health via a school-based intervention and therefore, reach all children independent from their background. This study shows vast gaps between several health behaviours of primary school children depending on their SES, favouring those children coming from more privileged families. A longer implementation may possibly show more effects. Trial registration DRKS00000949.

Patients suffering from chronic fatigue syndrome (CFS) or post-COVID syndrome (PCS) exhibit a reduced physiological performance capability. Impaired mitochondrial function and morphology may play a pivotal role. Thus, we aimed to measure the muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity and assess mitochondrial morphology in CFS and PCS patients in comparison to healthy controls (HCs). Mitochondrial OXPHOS capacity was measured in permeabilized muscle fibers using high-resolution respirometry. Mitochondrial morphology (subsarcolemmal/intermyofibrillar mitochondrial form/cristae/diameter/circumference/area) and content (number and proportion/cell) were assessed via electron microscopy. Analyses included differences in OXPHOS between HC, CFS, and PCS, whereas comparisons in morphology/content were made for CFS vs. PCS. OXPHOS capacity of complex I, which was reduced in PCS compared to HC. While the subsarcolemmal area, volume/cell, diameter, and perimeter were higher in PCS vs. CFS, no difference was observed for these variables in intermyofibrillar mitochondria. Both the intermyofibrillar and subsarcolemmal cristae integrity was higher in PCS compared to CFS. Both CFS and PCS exhibit increased fatigue and impaired mitochondrial function, but the progressed pathological morphological changes in CFS suggest structural changes due to prolonged inactivity or unknown molecular causes. Instead, the significantly lower complex I activity in PCS suggests probably direct virus-induced alterations.

Hypnosis is a clinically accepted relaxation technique known for stress reduction. Results from hematological research provide evidence of changes in blood components through hypnosis. However, these hematological effects have been rarely examined. Hence, we exploratively investigated the effect of a single relaxation hypnosis on the hemogram in stressed individuals, assuming a reduction of leukocytes, thrombocytes, and erythrocytes (primary outcomes). Additionally, a reduction in the erythrocyte-related parameters (hemoglobin, hematocrit), and an increase in plasma volume was hypothesized (secondary outcomes). Forty-four either individuals (89 % women) with chronic stress and moderate to high hypnotic suggestibility were randomized to a hypnosis con-dition (20 min relaxation hypnosis; n = 20) or a control condition (20 min documentary; n = 24). Venous blood was drawn before and after the intervention and used to generate a differential hemogram and determine the plasma volume. The relaxation hypnosis led to a significant reduction in erythrocytes (Cohen's d = 0.23) and consequently to a decrease in erythrocyte-related parameters (hemoglobin, d = 0.27; hematocrit, d = 0.37) as well as to a reduction in thrombocytes (d = 0.15) in the hypnosis compared to the control condition. Putatively, this could be the consequence of an increased plasma volume (d = 0.10), estimated by the hematocrit con-centration and body weight. A hypnosis-induced change in leukocyte count could not be confirmed. Thus, a single session of relaxation hypnosis already alters specific blood count parameters. While relaxation-induced vasodilatation might explain these changes, it is still not completely clear how these changes affect our stress response system.

Aim The programme “Join the Healthy Boat” promotes amongst other things a healthy diet in primary school children. In order to evaluate the programme’s effectiveness, this study longitudinally investigated children’s nutrition behaviour. Subject and methods A total of 1564 children (7.1 ± 0.6 years) participated in a cluster-randomised study. Teachers delivered lessons including behavioural contracting and budgeting. Nutritional behaviours of parents and child were assessed via parental report. Anthropometrics were measured on site. Results After one year, children in the intervention group (IG) showed a significant reduction in the consumption of pure juices ( p ≤ 0.001). Soft drink consumption reduced in both groups, although with a trend towards a slightly greater reduction in the IG. Children with fathers of normal weight as well as first graders showed a significant reduction of soft drink consumption in the IG ( p = 0.025 and p = 0.022 respectively). Fruit and vegetable intake increased significantly for first graders ( p = 0.050), children from families with a high parental education level ( p = 0.023), and for children with an overweight father ( p = 0.034). Significant group differences were found for fruit and vegetable intake of children with migration background ( p = 0.01) and children of parents with a high school degree could be observed ( p = 0.019). Conclusion This shows that the programme appeals to a wider range of children, and is therefore more likely to compensate for differences due to origin or other social inequalities, which also shows that active parental involvement is vital for successful interventions.

High prevalence rates of β2-agonist use among athletes in competitive sports makes it tempting to speculate that illegitimate use of β2-agonists boosts performance. However, data regarding the potential performance-enhancing effects of inhaled β2-agonists and its underlying molecular basis are scarce. In total, 24 competitive endurance athletes (12f/12m) participated in a clinical double-blinded balanced four-way block cross-over trial to investigate single versus combined effects of β2-agonists salbutamol (SAL) and formoterol (FOR), to evaluate the potential performance enhancement of SAL (1200 µg, Cyclocaps, Pb Pharma GmbH), FOR (36 µg, Sandoz, HEXAL AG) and SAL + FOR (1200 µg + 36 µg) compared to placebo (PLA, Gelatine capsules containing lactose monohydrate, Pharmacy of the University Hospital Ulm). Measurements included skeletal muscle gene and protein expression, endocrine regulation, urinary/serum β2-agonist concentrations, cardiac markers, cardiopulmonary and lung function testing and the 10-min time trial (TT) performance on a bicycle ergometer as outcome variables. Blood and urine samples were collected pre-, post-, 3 h post- and 24 h post-TT. Mean power output during TT was not different between study arms. Treatment effects regarding lung function (p < 0.001), echocardiographic (left ventricular end-systolic volume p = 0.037; endocardial global longitudinal strain p < 0.001) and metabolic variables (e.g. NR4A2 and ATF3 pathway) were observed without any influence on performance. In female athletes, total serum β2-agonist concentrations for SAL and FOR were higher. Microarray muscle gene analysis showed a treatment effect for target genes in energy metabolism with strongest effect by SAL + FOR (NR4A2; p = 0.001). Of endocrine variables, follicle-stimulating hormone (3 h Post–Post-TT), luteinizing hormone (3 h Post–Pre-TT) and insulin (Post–Pre-TT) concentrations showed a treatment effect (all p < 0.05). No endurance performance-enhancing effect for SAL, FOR or SAL + FOR within the permitted dosages compared to PLA was found despite an acute effect on lung and cardiac function as well as endocrine and metabolic variables in healthy participants. The impact of combined β2-agonists on performance and sex-specific thresholds on the molecular and cardiac level and their potential long-term performance enhancing or health effects have still to be determined. Trial registration: Registered at Eudra CT with the number: 2015-005598-19 (09.12.2015) and DRKS with number DRKS00010574 (16.11.2021, retrospectively registered). • Combined β2-agonist application in threshold doses according to World Anti-Doping Agency (WADA) standards does not result in acute enhanced high-intensity endurance performance in healthy male and female athletes. • Sex-specific thresholds have to be considered as female sex showed significantly higher β2-agonist serum concentrations compared to their male counterparts. • Acute effects on lung function and cardiac variables are observed with presumably no performance-enhancing effects in competitions of short duration, but effects in longer time trials or long-term health effects have to be considered.

Objectives:Evidence on the work-related societal impact of long-term health-related consequences following SARS-CoV-2 is emerging. We characterize the modified work ability index (mWAI) of employees 6 to 12 months after an acute infection compared to pre-infection. Methods:Analyses were based on a population-based, multi-center cross-sectional study including employees aged 18-65 years with positive SARS-CoV-2 polymerase chain reaction (tested between October 2020-April 2021 in defined geographic regions in Germany). Prevalences and results of adjusted logistic regression analyses were given. Results:In 9752 employees (mean age 45.6 years, 58% females, response 24%), n = 1217 (13.1%) participants were regarded as having low mWAI compared to pre-infection. Outpatient medical treatment, inpatient treatment, and admission to intensive care during infection were associated with mWAI <15th percentile (P15, each odds ratio [OR] >3.0). Post-COVID symptom clusters most strongly linked to mWAI

BackgroundIt has not yet been conclusively determined whether reduced left ventricular global longitudinal strain (LV GLS) after COVID-19 contributes to a reduction in exercise capacity. Our own studies showed a possible mild myocardial involvement in the form of reduced LV GLS in athletes after COVID-19 compared with healthy athletes. The aims of this prospective follow-up study were to investigate the development of LV GLS over a 3-month period in athletes after COVID-19 and the possible relationship between LV GLS and physical performance.MethodsLV GLS was determined in four-, two-, and three-chamber views and assessed offline by a blinded investigator in 96 recreational athletes (mean age 33.15 ± 12.40 years, 53 male, peak VO2 38.82 ± 11.14 ml/min/kg) at a median of two (t0) and five months (t1) after COVID-19. Cardiopulmonary exercise testing (CPET) was performed on a bicycle ergometer on both examination dates.ResultsLV GLS improved significantly between t0 and t1 (t0 −18.82 ± 2.02 vs. t1 −19.46 ± 2.05, p < 0.001). Echocardiographic and spiroergometric parameters were within the normal clinical reference range. Maximum power increased significantly from t0 to t1 (t0 283.17 ± 83.20 vs. t1 286.24 ± 85.22 Watt, p = 0.009) and there was a trend toward increased peak oxygen uptake (t0 36.82 ± 11.14 vs. t1 38.68 ± 10.26 ml/min/kg, p = 0.069). We found no correlation between LV GLS and performance parameters, except for the respiratory exchange ratio (RER) [ρ −0.316, (−0.501; −0.102), p < 0.050].ConclusionsSignificant improvement in LV GLS approximately five months after COVID-19 may be due to mild myocardial involvement during or shortly after COVID-19, which seems to recover. There was no correlation between LV GLS and performance parameters, except for an inverse correlation of LV GLS and RER, suggesting insufficient exercise intolerance at lower GLS values. Further studies on the development of GLS in athletes or in the general population with moderate and severe disease courses would be informative as well as the comparison of pre-COVID-19 with post-COVID-19 echocardiography to evaluate the effects of COVID-19 on cardiac function.