High Resolution Ambient MS Imaging of Biological Samples by Desorption Electro-Flow Focussing Ionization.

In this study, we examine the suitability of desorption electro-flow focusing ionization (DEFFI) for mass spectrometry imaging (MSI) of biological tissue. We also compare the performance of desorption electrospray ionization (DESI) with and without the flow focusing setup. The main potential advantages of applying the flow focusing mechanism in DESI is its rotationally symmetric electrospray jet, higher intensity, more controllable parameters, and better portability due to the robustness of the sprayer. The parameters for DEFFI have therefore been thoroughly optimized, primarily for spatial resolution but also for intensity. Once the parameters have been optimized, DEFFI produces similar images to the existing DESI. MS images for mouse brain samples, acquired at a nominal pixel size of 50 µm, are comparable for both DESI setups, albeit the new sprayer design yields better sensitivity. Furthermore, the two methods are compared with regard to spectral intensity as well as the area of the desorbed crater on rhodamine-coated slides. Overall, the implementation of a flow focusing mechanism in DESI is shown to be highly suitable for imaging biological tissue and has potential to overcome some of the shortcomings experienced with the current geometrical design of DESI.

Digital inclusion from the perspective of teachers of older adults - expectations, experiences, challenges and supporting measures.

The goal of the study was to diagnose the needs of instructors working in the area of the digital inclusion of persons who are excluded, at risk of exclusion, marginalized, and discriminated against in terms of using new technologies. The research focused on the phenomenon of the digital divide as seen from the perspective of digital literacy educators of older adults. The study was conducted in 2019 in Poland, using a qualitative research methodology (a structured in-depth interview) and interpretative paradigm. The respondents were 8 specialists, educators of older adults, representing different types of institutions dealing with the digital divide: a activity center, a public library, a nursing home, an NGO, and a University of the Third Age. Triangulation of the results led to several important conclusions regarding to the expectations, experiences, challenges and postulated supporting actions related to digital inclusion. Based on the results gathered, we have noticed that educators readily share their didactic and organizational experience. The respondents were open to the development of their own teaching competences, and recognized the role of lifelong learning. They often highlighted that the digital education of older adults is only one of many additional activities. The activities to improve the digital literacy of older adults are implemented as part of their non-formal education (i.e. it is carried out by educators holding no formal qualifications). For this reason, the teachers expect content-related and methodological support most of all, as well as the promotion of the idea of lifelong education (including digital literacy development) in society.

Correction to: Effect of the Neurofeedback-EEG Training During Physical Exercise on the Range of Mental Work Performance and Individual Physiological Parameters in Swimmers.

The original version of the article unfortunately contained an error in the co-author details such as family name and e-mail address.

Effect of the Neurofeedback-EEG Training During Physical Exercise on the Range of Mental Work Performance and Individual Physiological Parameters in Swimmers.

The aim of the study was to demonstrate the effects of the Neurofeedback-EEG training during physical exercise on the improvements in mental work performance and physiological parameters. The study examined seven swimmers based on the following anthropometric measurements: body height, body mass and body composition. The Kraepelin's work curve test, EEG and EMG during physical exercise were also performed. The athletes followed 20 Neurofeedback-EEG training sessions on the swimming ergometer for 4 months. Most mean indices of partial measures of the work curve were significantly modified (p < 0.05) following the Neurofeedback-EEG training. Mean level of maximal oxygen uptake in study participants was over 55 ml/kg/min, with statistically significant differences documented between the first and the second measurements. No significant differences were found in the fatigue rate between the measurements 1 and 2. The improved mental work performance following the Neurofeedback-EEG training facilitates optimization of psychomotor activities.

Rapid evaporative ionization mass spectrometry imaging platform for direct mapping from bulk tissue and bacterial growth media.

Rapid evaporative ionization mass spectrometry (REIMS) technology allows real time intraoperative tissue classification and the characterization and identification of microorganisms. In order to create spectral libraries for training the classification models, reference data need to be acquired in large quantities as classification accuracy generally improves as a function of number of training samples. In this study, we present an automated high-throughput method for collecting REIMS data from heterogeneous organic tissue. The underlying instrumentation consists of a 2D stage with an additional high-precision z-axis actuator that is equipped with an electrosurgical diathermy-based sampling probe. The approach was validated using samples of human liver with metastases and bacterial strains, cultured on solid medium, belonging to the species P. aeruginosa, B. subtilis, and S. aureus. For both sample types, spatially resolved spectral information was obtained that resulted in clearly distinguishable multivariate clustering between the healthy/cancerous liver tissues and between the bacterial species.

[Glucuronidation of antitumour therapeutics--detoxification, mechanism of resistance or prodrug formation?]. / Glukuronidacja leków przeciwnowotworowych--detoksyfikacja, mechanizm opornosci czy sposób na forme proleku?

The physiological role of phase I and II of xenobiotic biotransformations is their detoxification and better excretion outside the organism. UDP-glucuronosyltransferases (UGTs) being the enzymes of phase II metabolism catalyse the conjugation of glucuronic acid to the lipophilic substrate by its specific nucleophilic group. UGT isoenzymes of various substrate specificities and different expression profiles in selected tissues belong to the large UGT superfamily. Usually, glucuronidation is the detoxification process, but sometimes (morphine, tamoxifen) glucuronides express biological activity higher than or comparable to the native compound. The level of UGT gene expression is individual for patients, because of their genetic status as well as epigenetic conditions. Also, xenobiotics are able to modulate UGT level and gene expression by the interaction with nuclear receptors. Moreover, one can find a lower level of UGT in the tumour compared to normal tissue, which results in the protection against deactivation of the drug and in the promotion of its selective activity in tumor tissue. On the other hand, UGT activity is considered as the possible cause of resistance to chemotherapy. Metabolism by hepatic and intestinal UGT isoenzymes is responsible for the "first-pass effect", whereas acquired resistance consists in the induction of UGT gene expression by the chemotherapeutic or its metabolite. Moreover, UGT induction can be associated with the induction of membrane transporters, particularly proteins of the ABC family, responsible for drug excretion outside the cell. The above resistance effects can be fortified by the overexpression of selected UGT isoenzymes sometimes observed in specific types of tumours. It is also considered that many advanced tumours are characterized by a higher level of ß-glucuronidase. This enzyme has a chance to be the molecular target of directed antitumour therapy, as it catalyses ß-glucuronide hydrolysis, leading to active aglycones.

Effect of rest duration between sets on fatigue and recovery after short intense plyometric exercise.

Plyometric training is characterized by high-intensity exercise which is performed in short term efforts divided into sets. The purpose of the present study was twofold: first, to investigate the effects of three distinct plyometric exercise protocols, each with varying work-to-rest ratios, on muscle fatigue and recovery using an incline-plane training machine; and second, to assess the relationship between changes in lower limb muscle strength and power and the biochemical response to the three exercise variants employed. Forty-five adult males were randomly divided into 3 groups (n = 15) performing an exercise of 60 rebounds on an incline-plane training machine. The G0 group performed continuous exercise, while the G45 and G90 groups completed 4 sets of 15 repetitions, each set lasting 45 s with 45 s rest in G45 (work-to-rest ratio of 1:1) and 90 s rest in G90 (1:2 ratio). Changes in muscle torques of knee extensors and flexors, as well as blood lactate (LA) and ammonia levels, were assessed before and every 5 min for 30 min after completing the workout. The results showed significantly higher (p < 0.001) average power across all jumps generated during intermittent compared to continuous exercise. The greatest decrease in knee extensor strength immediately post-exercise was recorded in group G0 and the least in G90. The post-exercise time course of LA changes followed a similar pattern in all groups, while the longer the interval between sets, the faster LA returned to baseline. Intermittent exercise had a more favourable effect on muscle energy metabolism and recovery than continuous exercise, and the work-to-rest ratio of 1:2 in plyometric exercises was sufficient rest time to allow the continuation of exercise in subsequent sets at similar intensity.

Aclarubicin: contemporary insights into its mechanism of action, toxicity, pharmacokinetics, and clinical standing.

Aclarubicin (aclacinomycin A) is one of the anthracycline antineoplastic antibiotics with a multifaceted mechanism of antitumor activity. As a second-generation drug, it offers several advantages compared to standard anthracycline drugs such as doxorubicin or daunorubicin, which could position it as a potential blockbuster drug in antitumor therapy. Key mechanisms of action for aclarubicin include the inhibition of both types of topoisomerases, suppression of tumor invasion processes, generation of reactive oxygen species, inhibition of chymotrypsin-like activity, influence on cisplatin degradation, and inhibition of angiogenesis. Therefore, aclarubicin appears to be an ideal candidate for antitumor therapy. However, despite initial interest in its clinical applications, only a limited number of high-quality trials have been conducted thus far. Aclarubicin has primarily been evaluated as an induction therapy in acute myeloid and lymphoblastic leukemia. Studies have indicated that aclarubicin may hold significant promise for combination therapies with other anticancer drugs, although further research is needed to confirm its potential. This paper provides an in-depth exploration of aclarubicin's diverse mechanisms of action, its pharmacokinetics, potential toxicity, and the clinical trials in which it has been investigated.

Changes of Anaerobic Power and Lactate Concentration following Intense Glycolytic Efforts in Elite and Sub-Elite 400-meter Sprinters.

400-m races are based on anaerobic energy metabolism, they induce significant muscle fatigue, muscle fiber damage, and high blood lactate (LA) concentration. Despite extensive research on sprint training, our understanding of the training process that leads to world-class sprint performance is rather limited. This study aimed to determine differences in LA concentration and anaerobic power using jumping tests after an intense glycolytic effort in a group of elite and sub-elite 400-m runners. One hundred thirty male runners were divided into two groups: elite (n = 66, body mass = 73.4 ± 7.8 kg, body height = 182.1 ± 6.2 cm, age = 20.8 ± 4.0 y) running the 400-m dash below 50 s and sub-elite (n = 64, body mass = 72.0 ± 7.1 kg, body height = 182.1 ± 5.2 cm, age = 20.8 ± 4.0 y) with a 400-m personal best above 50 s. The power of the countermovement and the sequential squat jumps was measured in two sets after a warm-up, followed by two intermittent 30-s Wingate tests. LA concentration was measured eight times. It was observed that elite athletes achieved significantly higher power in both types of jumps. The maximum post-exercise LA concentration was significantly lower in the sub-elite group after the 3rd, the 6th, the 9th, and the 20th min after the cessation of two Wingate tests (p < 0.001). The rate of LA accumulation after exercise and the rate of LA utilization did not differ between the groups. It can be concluded that elite and non-elite runners differ in higher LA production but not in LA utilization. Anaerobic power and LA concentration seem to differentiate between 400 elite and sub-elite performance.

Anaerobic Variables As Specific Determinants of Functional Classification in Wheelchair Basketball.

Every parasport is currently encouraged to consider evidence-based classification to develop their respective classification system. Therefore, the aims of this study were to: (1) assess the relationship between trunk function and anaerobic power determining proficiency in wheelchair basketball, and (2) define "natural classes" in wheelchair basketball based on anaerobic power. Fifty-nine elite players (representing five national teams) were divided into four main functional classes: Group 1 (n=17), Group 2 (n=14), Group 3 (n=16), Group 4 (n=12). They performed the 6x10s Anaerobic Power Test using an arm crank ergometer. Average values of mean power, peak power, relative mean power, relative peak power, and power decrement were calculated for the 6x10s and 3x10s tests. The Spearman's correlation matrix revealed significant correlations between classes and values recorded in the 6x10s test. This confirmation between anaerobic power and players' classification endorses the division of players into different classes. Furthermore, cluster analysis (with fair quality) divided players into two "natural classes". The first resulting class was mainly formed of participants from Group 1 (71%). An important complement to this research could be to consider wheelchair acceleration and the volume of trunk action in wheelchair basketball classification.

Epicardial Adipose Tissue and Cardiovascular Risk Assessment in Ultra-Marathon Runners: A Pilot Study.

Epicardial adipose tissue (EAT) volume is associated with cardiovascular disease (CVD). Data regarding the influence of extremely intensive training on CVD are scarce. We compared EAT volume among ultra-marathon runners and in the sedentary control group, and assessed the correlations between EAT and risk factors of coronary artery disease (CAD). EAT volume around three main coronary vessels and right ventricle (RV) was measured in 30 healthy amateur ultrarunners and 9 sex- and age-matched sedentary controls using cardiac magnetic resonance. In addition, body composition, lipid profile, interleukin-6 (IL-6) plasma concentration, and intima-media thickness (IMT) were measured as well. The EAT volume was lower in all measured locations in the ultrarunners' group compared to control group (p < 0.001 for all). Ultrarunners had lower BMI and fat percentage (FAT%) and more favorable lipid profile compared to the control group (p < 0.05 for all). Ultrarunners had lower rate of pathologically high levels of plasma IL-6 (>1 pg/mL) compared to the control group (17% vs. 56%, p < 0.05). IMT was similar in both groups. In the ultrarunners' group, there was a positive correlation between EAT surrounding left anterior descending artery, circumflex artery, and RV and FAT%, and between EAT around circumflex artery and LDL and non-HDL cholesterol (p < 0.05 for all). In summary, extremely intensive training may decrease the risk of cardiovascular events in adult population of amateur athletes by reducing the amount and pro-inflammatory activity of EAT. However, more research is needed to draw firm conclusions regarding the anti- and pro-inflammatory effects of intensive training.

Alterations in Circulating MicroRNAs and the Relation of MicroRNAs to Maximal Oxygen Consumption and Intima-Media Thickness in Ultra-Marathon Runners.

The impact of long-term training on cardiovascular disease (CVD) is not clear. Carotid intima-media thickness (CIMT) test is recommended as a useful measure to diagnose the early stages of atherosclerosis. MicroRNAs (miRNAs) are altered due to endurance exercise and can be promising biomarkers of pathophysiological changes. We aimed to evaluate the association of circulating miRNAs with physical fitness and markers of atherosclerosis in ultra-marathon runners. Ultra-marathon runners had 28-fold upregulation of miR-125a-5p expressions compared to control individuals (p = 0.002), whereas let-7e and miR-126 did not differ statistically between ultra-marathon runners and controls. In the ultra-marathon runners' group, negative correlations were observed between VO2max/kg and relative expression of miR-125a-5p and miR-126 (r = -0.402, p = 0.028; r = -0.438, p = 0.032, respectively). Positive correlations were observed between CIMT and miR-125a-5p and miR-126 (r = 0.388, p = 0.050; r = 0.504, p = 0.023, respectively) in ultra-marathon runners. Individuals with the highest quartile of VO2max/kg had 23-fold lower miR-126 expression in comparison to subgroups with lower VO2max/kg (p = 0.017). Our results may indicate that both miRNAs may serve as a biomarker for early pathological changes leading to atherosclerosis burden in athletes. Furthermore, the association between miRNAs and traditional risk factors for CVD indicate a possible use of these molecules as early biomarkers of future cardiovascular health.

An Untargeted Metabolomics Approach to Investigate the Metabolic Effect of Beetroot Juice Supplementation in Fencers-A Preliminary Study.

This study aimed at assessment of the long-term (4 weeks) metabolic effect of a diet with and without beetroot juice supplementation in fencers using the untargeted metabolomics method with the UPLC Q-TOF/MS system to carry out an analysis of urine samples. Ten women and 10 men underwent the cardiovascular fitness VO2max test at baseline-(B) and after two stages of implementation of the dietary recommendations-the first 4 weeks without beetroot juice (D) and the second with 26 g/d of freeze-dried beetroot juice supplementation (D&J). The urine samples were collected one hour after the VO2max test at B and after D and D&J. The meal before the VO2max test after D&J contained beetroot juice, whereas to the meal at B and after D maltodextrin was added. Changes in metabolites and VO2max were significant only for comparison of D versus D&J. During D and D&J, there were no significant changes in the physical activity level, body mass, and body composition. We observed significant changes in tyrosine and tryptophan metabolism, mainly associated with such neurotransmitter's metabolism as: Serotonin, noradrenaline, and adrenaline. Changes in signal intensity of bile acid, AICAR, and 4-Hydroxynonenal (peroxidation of polyunsaturated fatty acids product) were also observed. The obtained results indicate that long-term beetroot juice supplementation induces considerable changes in metabolism.

Factors Related to Cardiac Troponin T Increase after Participation in a 100 Km Ultra-Marathon.

BACKGROUND: Intensive and prolonged exercise leads to a rise of troponin concentration in blood. The mechanism responsible for troponin release during exercise remains ill-defined. The study aim was to search for risk factors of troponin increase after a prolonged endurance competition. METHODS: The study included a group of 18 amateurs, healthy volunteers (median age 41.5 years, interquartile range - IQR 36-53 years, 83% male) who participated in a 100 km running ultra-marathon. Information on demographic characteristics, pre- and post-race heart rate, blood pressure, body composition and glucose, lactate (L), troponin T (hs-TnT) and C reactive protein (hs-CRP) concentration were obtained. Additionally, data on L and glucose levels every 9.2 km and fluid/food intakes during the race were collected. RESULTS: There was a significant hs-TnT increase after the race exceeding upper reference values in 66% of runners (from 5 IQR 3-7 ng/L to 14 IQR 12-26 ng/L, p < 0.0001). None of the baseline parameters predicted a post-race hs-TnT increase. The only factors, correlating with changes of hs-TnT were mean L concentration during the race (rho = 0.52, p = 0.03) and change of hs-CRP concentration (rho = 0.59, p = 0.01). CONCLUSIONS: Participation in a 100 km ultra-marathon leads to a modest, but significant hs-TnT increase in the majority of runners. Among analysed parameters only mean lactate concentration during the race and change in hs-CRP correlated with troponin change.

Acute Effects of a Static Vs. a Dynamic Stretching Warm-up on Repeated-Sprint Performance in Female Handball Players.

This randomized cross-over study examined the effects of typical static and dynamic stretching warm-up protocols on repeated-sprint performance. Thirteen young female handball players performed a 5 min aerobic warm-up followed by one of three stretching protocols for the lower limbs: (1) static stretching, (2) dynamic-ballistic stretching, and (3) no stretching before performing five all-out sprints on a cycle ergometer. Each protocol was performed on a different occasion, separated by 2-3 days. Range of movement (ROM) was also measured before and after the warm-up protocols with a sit-and-reach test. Fixed and random effects of each stretching protocol on repeated sprint performance were estimated with mixed linear modeling and data were evaluated via standardization and magnitude-based inferences. In comparison to no stretching, there were small increases in ROM after dynamic stretching (12.7%, ±0.7%; mean, ±90% confidence limits) and static stretching (19.2%, ±0.9%). There were small increases in the average power across all sprints with dynamic stretching relative to static stretching (3.3%, ±2.4%) and no stretching (3.0%, ±2.4%) and trivial to small increases in the average power in the 1st and 5th trials with dynamic stretching compared to static stretching (3.9%, ±2.6%; 2.6%, ±2.6%, respectively) and no stretching (2.0%, ±2.7%; 4.1%, ±2.8%, respectively). There were also trivial and small decreases in power across all sprints with static relative to dynamic stretching (-1.3%, ±2.8%) and no stretching (-3.5%, ±2.9%). Dynamic stretching improved repeated-sprint performance to a greater extent than static stretching and no stretching.

Changes in Oxidative Stress, Inflammation, and Muscle Damage Markers Following Diet and Beetroot Juice Supplementation in Elite Fencers.

The aim of this study was to assess the impact of diet and active substances in beetroot juice on the parameters of oxidative stress, inflammation, and muscle damage as well as on the maximum rate of oxygen uptake (VO2max) in elite fencers (10 women, 10 men). Athletes during four weeks realized dietary recommendations (ID) and, after that, diet with freeze-dried beetroot juice supplementation (ID&BEET). At baseline and after each stage, fasting antioxidants, biomarkers of oxidative stress, inflammation, and skeletal muscle damage were measured, and a VO2max test was performed. Only after ID&BEET was a significant increase of VO2max observed, and changes of this parameter were negatively related with changes of serum lactate dehydrogenase (∆LDH) activity, as well as with serum ∆ß-carotene and malondialdehyde concentration (∆MDA). Additionally, positive relationships were observed between ∆ß-carotene versus changes of the serum concentration of advanced oxidation protein products (∆AOPP), changes of serum glutathione peroxidase activity (∆GPx3) versus both changes of physical activity level and ∆LDH, as well as erythrocyte glutathione peroxidase activity (∆GPx1) versus ∆LDH. To summarize, we showed that long-term beetroot juice supplementation increases lipid peroxidation, and improvement of VO2max after ID&BEET seems to be dependent on LDH activity, as well as on the serum concentration of MDA and ß-carotene.

The Effect of the Ultra-Marathon Run at a Distance of 100 Kilometers on the Concentration of Selected Adipokines in Adult Men.

Pro-inflammatory adipokines have a multifunctional role in adipogenesis, angiogenesis, glucose homeostasis, and inflammation. The aim of the present study is to evaluate the effect of running a 100 km ultra-marathon on serum levels of two adipokines: resistin and chemerin. Fifteen male participants complete a medical questionnaire and their body composition is assessed. Serum resistin, chemerin, high sensitivity C-reactive protein (hs-CRP), glucose, and lactate levels are measured at baseline and post-race. During-race data on fluid and food consumption and energy expenditure are calculated. There is a higher (p < 0.001) post-race concentration of resistin and hs-CRP compared with resting values, with no change in chemerin levels. There is an inverse correlation of the change in resistin levels with post-run glucose values (r = 0.742, p < 0.001) and a positive correlation between changes in hs-CRP and energy expenditure (r = 0.782, p < 0.001). The present results show the impact of running an ultra-marathon on serum levels of pro-inflammatory markers released by adipose tissue. It is difficult to establish whether these results may be due to the stress of exercise, high energy expenditure or caloric deficit. However, we suggest that an addition of resistin to traditional pro-inflammatory markers (including CRP) may improve the assessment of inflammation in conditions of high-energy expenditure.

Physiological parameters depending on two different types of manual wheelchair propulsion.

OBJECTIVE: The purpose of this study was to compare aerobic parameters in the multistage field test (MFT) in hand rim wheelchair propulsion and lever wheelchair propulsion. METHODS: Twenty-one men performed MFT using two different types of propulsion, i.e., lever and hand rim wheelchair propulsion. The covered distance and physiological variables (oxygen uptake (VO2), minute ventilation (VE), carbon dioxide output (VCO2), respiratory coefficient (RQ), and heart rate (HR)) were observed. Physiological variables were measured with Cosmed K5 system. Kolmogorov-Smirnov test, t-test, Wilcoxon test and effect sizes (ESs) were used to assess differences. Statistical significance was set at p < .05. RESULTS: A significantly longer distance was observed in lever wheelchair propulsion than in hand rim wheelchair propulsion (1,194 and 649 m, respectively). VO2max and RQ were higher in hand rim wheelchair propulsion. All physiological variables for the last (fifth) level of the test in hand rim propulsion were significantly higher than in lever wheelchair propulsion. ES was large for each observed difference. CONCLUSION: The lever wheelchair propulsion movement is less demanding than hand rim wheelchair propulsion and longer distances can be achieved by the user. There is a need to check lever wheelchair propulsion in different types of field tests.

The prevalence of prolonged grief disorder in bereaved individuals following unnatural losses: Systematic review and meta regression analysis.

BACKGROUND: Previous research has indicated that one out of ten naturally bereaved individuals develops prolonged grief disorder (PGD). Less is known about the prevalence of PGD following unnatural deaths, such as accidents, disasters, suicides, or homicides. The aim of this study was to compute the pooled prevalence of PGD and to determine possible causes of its varied estimates. METHODS: A literature search was conducted in PsycINFO, Ovid Medline, PILOTS, Embase, Web of Science, and CINAHL. A meta-analysis using random effects models was performed to calculate the pooled prevalence rate of PGD. Multivariate meta-regression was used to explore heterogeneity among the studies. RESULTS: Twenty-five articles met eligibility criteria. The random-effects pooled prevalence was 49%, 95% CI [33.6, 65.4]. Death of only child, violent killings and non-western study location were associated with a higher PGD prevalence. A longer time since loss and a loss in a natural disaster were associated with a lower PGD prevalence. LIMITATIONS: These findings should be interpreted with caution, because of the heterogeneity in study methodology. CONCLUSIONS: This first meta-analysis of PGD following unnatural losses indicated that nearly half of the bereaved adults experienced PGD. This illustrates the importance of assessing PGD in individuals affected by loss and trauma.

Wheelchair Basketball Competition Heart Rate Profile According to Players' Functional Classification, Tournament Level, Game Type, Game Quarter and Playing Time.

Heart rate is a popular parameter observed in team sports to plan training sessions with regard to load and sport specificity. Wheelchair basketball is an intermittent team game for physically impaired players. The study aim was to define heart rate profile of wheelchair basketball players in terms of their functional classification (category A: 1.0-2.5 points, category B: 3.0-4.5 points), tournament level (championships and friendly games), game type (close, balanced, and unbalanced), game quarter (1st, 2nd, 3rd, and 4th) and playing time (40-59%, 60-79%, and 80-100% in a quarter). Heart rate of 18 wheelchair basketball players was monitored in 22 games in four different tournaments, i.e., European Championships 2017, World Championships 2018, two friendly international tournaments of national teams (2017 and 2018). Heart rate (HRmean, HRpeak, %HRpeak, HRR, and %HRR) was monitored by Polar Team Pro (Kempele, Finland) during playing time on the court. Timeouts, quarter breaks, a half break, time on a bench were not taken into account in HR monitoring. The Kolmogorov-Smirnov test, the Mann-Whitney U test and the Kruskal-Wallis test were used. Fourteen players divided according to the classification into category A and B were included in the final calculations (n = 457 cases). Significantly higher HRmean, %HRpeak, HRpeak, and %HRR were noted among category B players, and higher %HRpeak and %HRR among category A players at the highest tournament level compared to friendly games. There were significant differences in %HRR and the percentage of time spent in HR zone I between the players with different playing time (40-59% versus 60-79%) in category B. No significant differences in HR were noted between four quarters. Among category A players, differences in HR in zone II were observed. Among category B players, statistically significant differences in % HRpeak, the percentage of time spent in HR zones I, II, III, and %HRR between close, balanced and unbalanced games were found. In conclusion, the intermittent nature of wheelchair basketball was confirmed. Monitoring heart rate in a game could be helpful in creating exercises with proper loads for better physical preparation of wheelchair basketball players. High intensity training sessions would be more beneficial in preparing players for game demands.