Hypoxic Test Research Articles

INTERVAL HYPOXIC HYPEROXIC TREATMENT IN THE REHABILITATION OF POST-COVID-19 PATIENTS

The aim of the study is to reveal the main pathogenetic mechanisms of the effectiveness of interval hypoxic hyperoxic treatment in the rehabilitation of post-COVID-19 patients.
 Materials and Methods. Hypo-Oxy, hypoxic therapy device produced by Oxyterra (Russia) was used to generate a hypoxic mixture with different oxygen content. Hypoxic periods followed the hyperoxic ones (30 % O2). To determine individual sensitivity to hypoxia, patients underwent a hypoxic test, the results of which were used to select the optimal oxygen content in the hypoxic mixture, the duration of hypoxic effects and the number of sessions. The authors determined the parameters of the functional respiratory system, oxygen regimen, lipid peroxidation, antioxidant system, exhaled air condensate and coagulation system. Statistical processing was carried out in accordance with the rules of mathematical statistics using Microsoft Excel and Statistica 6.0 for Windows. When conducting parametric analysis, paired and unpaired Student's t-tests were used. All numerical data were presented as the arithmetic mean and standard error of the mean (M±m). Differences were considered statistically significant at p<0.05. 
 Results. Interval hypoxic hyperoxic treatment has proven to be an effective way to rehabilitate post-COVID-19 patients (medium severity). After hypoxic therapy, there was a decrease in respiratory, circulatory, hemic and tissue hypoxia, and an improvement in the parameters of the prooxidant and antioxidant systems. Hypoxic therapy had a normalizing effect on the hemostasis system: platelet count in the blood increased (p<0.05) (it was low before hypoxic therapy). Activated partial thromboplastin time, international normalized ratio, and antithrombin III content also increased. Prothrombin index, fibrinogen and D-dimer content in the blood serum showed a decreased risk of thrombosis. 
 Conclusion. The conducted studies have proven the high efficiency of interval hypoxic hyperoxic treatment in the rehabilitation of post-COVID-19 patients.

The functioning of the respiratory system of primary school students under the influence of health and sports tourism activities

The article deals with the actual problem of the functioning of the respiratory system of elementary school students under the influence of health and sports tourism activities. Goal. Investigate the specifics of the impact of health and sports tourism on the functioning of the respiratory system of children of primary school age. Methods. Analysis of scientific and methodical literature, pedagogical, physiological methods, methods of mathematical statistics. Results. The study consisted of ascertaining (63 students of 2nd - 4th grades) and formative (40 students of 3rd - 4th grades) experiments. The main distinguishing feature of the means of health and sports tourism is the purpose of their use in the process of physical education: improving health and obtaining pleasure from motor activity within the framework of physical recreation and achieving sports results, respectively. During the ascertaining experiment, it was determined that the respiratory system of children of primary school age is characterized by reduced values of lung volumes and unsatisfactory indicators of hypoxic tests. During the formative experiment, it was found that children engaged in health tourism showed more significant increases in respiratory system indicators compared to those engaged in sports tourism, namely: the vital capacity of the lungs – by 17.50 ml; Stange test – for 0.20 s; Genchi's test – for 0.30 s. It should be added that more children in the experimental group compared to children in the control group improved the values of the Stange test by 15% and the Genchi test by 10%. Conclusions. the use of means of health tourism in the physical education of younger schoolchildren significantly contributes to the development and functioning of their respiratory system. The child's breathing function can be significantly developed and improved not only during the natural age-related development of the body, but also due to cumulative adaptations to physical exertion. Means of health tourism, used in the framework of physical recreation, have great potential for optimizing the development of the respiratory system of children of primary school age.

ERS International Congress 2022: highlights from the Paediatrics Assembly.

This review has been prepared by the Early Career Members and Chairs of the European Respiratory Society (ERS) Assembly 7: Paediatrics. We here summarise the highlights of the advances in paediatric respiratory research presented at the ERS International Congress 2022. The eight scientific groups of this Assembly cover a wide range of research areas, including respiratory physiology and sleep, asthma and allergy, cystic fibrosis (CF), respiratory infection and immunology, neonatology and intensive care, respiratory epidemiology, bronchology, and lung and airway developmental biology. Specifically, we report on abstracts presented at the congress on the effect of high altitude on sleep, sleep disorders, the hypoxic challenge test, and measurements of ventilation inhomogeneity. We discuss prevention of preschool wheeze and asthma, and new asthma medications. In children with CF, we describe how to monitor the effect of CF transmembrane conductance regulator modulator therapy. We present respiratory manifestations and chronic lung disease associated with common variable immunodeficiency. Furthermore, we discuss how to monitor respiratory function in neonatal and paediatric intensive care units. In respiratory epidemiology, we present the latest news from population-based and clinical cohort studies. We also focus on innovative and interventional procedures for the paediatric airway, such as cryotherapy. Finally, we stress the importance of better understanding the molecular mechanisms underlying normal and abnormal lung development.

Complex Physical Rehabilitation of Women of Reproductive Age with Stage I Hypertensive Heart Disease

Background. Hypertensive heart disease (HD) is a chronic abnormality that affects various systems of the body and is especially unfavorable for women of reproductive age. The purpose of the study was to develop a comprehensive program of physical rehabilitation for young women suffering with stage I hypertensive heart disease at the outpatient stage of rehabilitation and evaluate its effectiveness. Materials and methods. 42 young women with a diagnosis of HD were randomly divided into two groups: one performing traditional physical rehabilitation (control group) and the other following a method based on the Pilates system. Questionnaire, Martinet-Kushelevsky test, modified Romberg test, and Deshin test were performed. Results. Questionnaire and examination for determination of therapeutic tasks in the application of physical rehabilitation show improvement due to the use of the suggested methodology. Indicators of Martinet-Kushelevsky test improved from 2.46 points to 5.48 points (p<0.01) which is better (p<0.05) than in the case of the traditional methodology where they changed from 2.44 to 4.61 (p<0.01). Kotov-Deshin test results show improvement in both groups evenly but the test results of the women of the main group improved from “unsatisfactory” to “good”, and those of the women of the control group improved from “unsatisfactory” to “satisfactory” with significantly better results in the main group (p<0.05). Distribution of the Romberg test results show improvement of vestibular stability in all participants of the main group. Conclusions. The proposed program of complex physical rehabilitation of patients with stage I hypertensive heart disease using the Pilates method proved to be effective. Due to this program, there was a significant decrease in heart rate, systolic and diastolic pressure, an improvement in the response of the cardiovascular system to the Martinet-Kushelevsky functional test as well as in the state of the respiratory and nervous systems, as evidenced primarily by the indicators of hypoxic tests, spirometry, clino- and orthostatic tests, with the Romberg and Deshin methods.

Effects of hypoxia on exercise-induced diaphragm fatigue in healthy males and females.

Following high-intensity, normoxic exercise there is evidence to show that healthy females, on average, exhibit less fatigue of the diaphragm relative to males. In the present study, we combined hypoxia with exercise to test the hypothesis that males and females would develop a similar degree of diaphragm fatigue following cycle exercise at the same relative exercise intensity. Healthy young participants (n=10 male; n=10 female) with a high aerobic capacity (120% predicted) performed two time-to-exhaustion (TTE; ~85% maximum) cycle tests on separate days breathing either a normoxic or hypoxic (FiO2 =0.15) gas mixture. Fatigue of the diaphragm was assessed in response to cervical magnetic stimulation prior to, immediately post-exercise, 10-, 30-, and 60-min post-exercise. Males and females had similar TTE durations in normoxia (males: 690 ± 181 s; females: 852 ± 401 s) and hypoxia (males: 381 ± 160 s; females: 400 ± 176 s) (p > 0.05). Cycling time was significantly shorter in hypoxia versus normoxia in both males and females (p < 0.05) and did not differ on the basis of sex (p > 0.05). Following the hypoxic TTE tests, males and females experienced a similar degree of diaphragm fatigue compared to normoxia as shown by 20%-25% reductions in transdiaphragmatic twitch pressure. This occurred despite the fact that exercise time in hypoxia was substantially shorter relative to normoxia and the cumulative diaphragm work was lower. We also observed that females did not fully recover from diaphragm fatigue in hypoxia, whereas males did (p < 0.05). Sex differences in the rate of diaphragm contractility recovery following exercise in hypoxia might relate to sex-based differences in substrate utilization or diaphragm blood flow.

PECULIARITIES OF PULMONARY VENTILATION RESPONSE TO DOSED HYPOXIA IN ELDERLY PEOPLE WITH IMPAIRED GLUCOSE TOLERANCE.

The aim: To determine the peculiarities of the response of pulmonary ventilation to hypoxia in elderly people with impaired glucose tolerance. Materials and methods: Forty-three elderly people were examined, including 20 patients with impaired glucose tolerance and 23 healthy individuals with preserved glucose tolerance. Fasting plasma glucose and insulin concentrations were determined, and the HOMA-IR insulin resistance index was calculated. Under conditions of normoxia and during a dosed hypoxic test (12% oxygen, duration 20 min), blood saturation and lung ventilation parameters were monitored. Results: Under conditions of normoxia, the indicators of lung ventilation function did not differ between the groups of elderly people with impaired and preserved glucose tolerance. Under conditions of hypoxia, elderly people with impaired glucose tolerance had a less significant increase in ventilation, despite the development of more severe arterial hypoxemia. This leads to a decrease in the ventilatory response to hypoxia in case of impaired carbohydrate metabolism. Conclusions: In people with impaired glucose tolerance, a less significant ventilatory response to hypoxia is combined with more pronounced insulin resistance.

Steady-state chemoreflex drive captures ventilatory acclimatization during incremental ascent to high altitude: Effect of acetazolamide.

Ventilatory acclimatization (VA) is important to maintain adequate oxygenation with ascent to high altitude (HA). Transient hypoxic ventilatory response tests lack feasibility and fail to capture the integrated steady-state responses to chronic hypoxic exposure in HA fieldwork. We recently characterized a novel index of steady-state respiratory chemoreflex drive (SSCD), accounting for integrated contributions from central and peripheral respiratory chemoreceptors during steady-state breathing at prevailing chemostimuli. Acetazolamide is often utilized during ascent for prevention or treatment of altitude-related illnesses, eliciting metabolic acidosis and stimulating respiratory chemoreceptors. To determine if SSCD reflects VA during ascent to HA, we characterized SSCD in 25 lowlanders during incremental ascent to 4240 m over 7 days. We subsequently compared two separate subgroups: no acetazolamide (NAz; n= 14) and those taking an oral prophylactic dose of acetazolamide (Az; 125 mg BID; n= 11). At 1130/1400 m (day zero) and 4240 m (day seven), steady-state measurements of resting ventilation (V̇I ; L/min), pressure of end-tidal (PET )CO2 (Torr), and peripheral oxygen saturation (SpO2 ; %) were measured. A stimulus index (SI; PET CO2 /SpO2 ) was calculated, and SSCD was calculated by indexing V̇I against SI. We found that (a) both V̇I and SSCD increased with ascent to 4240 m (day seven; V̇I : +39%, p< 0.0001, Hedges' g= 1.52; SSCD: +56.%, p< 0.0001, Hedges' g= 1.65), (b) and these responses were larger in the Az versus NAz subgroup (V̇I : p= 0.02, Hedges' g= 1.04; SSCD: p= 0.02, Hedges' g= 1.05). The SSCD metric may have utility in assessing VA during prolonged stays at altitude, providing a feasible alternative to transient chemoreflex tests.

Testing the hypoxia tolerance and hypoxic performance of fishes: A two-tier screening approach

With regional hypoxic episodes in the world’s oceans becoming more severe and more frequent, a valuable management need will be a screening protocol to characterize the full diversity of hypoxic robustness among fishes (defined here as their tolerance and performance). Yet, high-throughput screening protocols to deal with the almost 33,000 fish species have the potential to trade off convenience with the information depth normally provided with comprehensive but more time-consuming phenotyping protocols. As a solution, we propose a two-tier testing approach, one that combines a simple, rapid, cost-effective, and well-established hypoxia challenge test (a measure of hypoxic tolerance) with an individual-based hypoxic performance test that defines maximum aerobic capacity over a wide range of ambient water oxygen levels (a hypoxic performance curve). The later test would be performed on selected indicator species identified from the tolerance screening test. Here we describe the two methodological approaches for this two-tier approach using some existing data to illustrate the potential for their applications in marine science.

Predicting an Athlete’s Physiological and Haematological Response to Live High-Train High Altitude Training Using a Hypoxic Sensitivity Test

Predicting an Athlete’s Physiological and Haematological Response to Live High-Train High Altitude Training Using a Hypoxic Sensitivity Test

Influence of extreme factors on the ratio of cardiointervals in the structure of the cardiocycle

BACKGROUND: The proportion of the golden section, discovered by Pythagoras, is of great importance in the organization of wildlife. Since the golden proportion is one of the criteria for self-organization in living nature, it is natural to assume that this criterion can also be manifested in the work of the heart. The organization of the cardiac cycle is the result of a long evolution of a living organism in the direction of optimizing the structure and functions, ensuring life with minimal energy consumption. However, in clinical medicine and physiological research, until recently, this approach has hardly been used, and there are only a few reports in the literature on the effectiveness of this method.&#x0D; AIM: To study the sensitivity of indicators of the symmetry analysis of the cardiocycle in accordance with the methodology of the golden section to physical exertion, hypoxic and temperature effects for an integral assessment of the functional state of the heart. For the geometric analysis of the ECG, the ratios of the main parameters were used to assess their compliance with the criteria of the golden section.&#x0D; MATERIALS AND METHODS: Geometric analysis of ECG interval intervals according to the principles of the golden section in healthy individuals exposed to debilitating physical activity, hypoxia, combined hyperthermia or low temperatures. In the course of the work, the results of a study of 252 male volunteers aged 2035 years were analyzed, of which 46 people underwent an exhaustive exercise test, 113 a hypoxic test, 34 a combined hyperthermia tolerance test, and 69 a moderate cooling tolerance test.&#x0D; RESULTS: the use of a geometric analysis of cardiocycles at rest, during exercise, as well as moderate exposure to typical adverse environmental factors (hypoxia, high or low temperatures) showed the fundamental possibility of assessing the dynamics of the functional state in young practically healthy individuals. The indicators characterizing the activity of the processes of regulation of myocardial work at the extracardiac and intracardiac levels were more dynamic. The indicator of symmetry analysis, which characterizes the level of myocardial homeostasis, energy processes and contractility, to a greater extent reflects unfavorable prognostic characteristics in terms of failure of myocardial adaptation. It has been established that for practically healthy individuals (in the normal state of activity, without external influences), the 1st class of the functional state occurs in 83% of cases, hemodynamic stress is noted in 16% of the subjects, hemodynamic inadequacy in 1%.&#x0D; CONCLUSIONS: The deviations from the ideal proportion of the golden section identified as a result of adverse external influences remained within acceptable fluctuations, which indicated a fairly perfect functioning of the heart and the cardiovascular system as a whole in the surveyed contingent of young, practically healthy individuals. Proposed by N.V. Dmitrieva (1989) the classification of functional states, based on the assessment of the degree of deviation of the calculated coefficients from the optimal value corresponding to the golden section, is not optimal for healthy young men, which include athletes without signs of sports heart and other myocardial pathology. It does not take into account the sign of the deviation, as a result, for the state of rest, with the predominance of bradycardia, typical for athletes, there is an overdiagnosis of tense hemodynamics. At the same time, the work of the heart during short-term intense physical exertion, which naturally causes pronounced sympathicotonia, can be unreasonably characterized as a premorbid or pathological condition.

Exercise and hypoxia unmask pulmonary vascular disease and right ventricular dysfunction in a 10- to 12-week-old swine model of neonatal oxidative injury.

Prematurely born young adults who experienced neonatal oxidative injury (NOI) of the lungs have increased incidence of cardiovascular disease. Here, we investigated the long‐term effects of NOI on cardiopulmonary function in piglets at the age of 10–12 weeks. To induce NOI, term‐born piglets (1.81 ± 0.06 kg) were exposed to hypoxia (10–12% FiO2), within 2 days after birth, and maintained for 4 weeks or until symptoms of heart failure developed (range 16–28 days), while SHAM piglets were normoxia raised. Following recovery (>5 weeks), NOI piglets were surgically instrumented to measure haemodynamics during hypoxic challenge testing (HCT) and exercise with modulation of the nitric‐oxide system. During exercise, NOI piglets showed a normal increase in cardiac index, but an exaggerated increase in pulmonary artery pressure and a blunted increase in left atrial pressure – suggesting left atrial under‐filling – consistent with an elevated pulmonary vascular resistance (PVR), which correlated with the duration of hypoxia exposure. Moreover, hypoxia duration correlated inversely with stroke volume (SV) during exercise. Nitric oxide synthase inhibition and HCT resulted in an exaggerated increase in PVR, while the PVR reduction by phosphodiesterase‐5 inhibition was enhanced in NOI compared to SHAM piglets. Finally, within the NOI piglet group, prolonged duration of hypoxia was associated with a better maintenance of SV during HCT, likely due to the increase in RV mass. In conclusion, duration of neonatal hypoxia appears an important determinant of alterations in cardiopulmonary function that persist further into life. These changes encompass both pulmonary vascular and cardiac responses to hypoxia and exercise. Key points Children who suffered from neonatal oxidative injury, such as very preterm born infants, have increased risk of cardiopulmonary disease later in life.Risk stratification requires knowledge of the mechanistic underpinning and the time course of progression into cardiopulmonary disease.Exercise and hypoxic challenge testing showed that 10‐ to 12‐week‐old swine that previously experienced neonatal oxidative injury had increased pulmonary vascular resistance and nitric oxide dependency.Duration of neonatal oxidative injury was a determinant of structural and functional cardiopulmonary remodelling later in life.Remodelling of the right ventricle, as a result of prolonged neonatal oxidative injury, resulted in worse performance during exercise, but enabled better performance during the hypoxic challenge test.Increased nitric oxide dependency together with age‐ or comorbidity‐related endothelial dysfunction may contribute to predisposition to pulmonary hypertension later in life.

Design, synthesis and anti-hypoxia activity of HPN derivatives containing lipophilic long chains.

To design and synthesize long-chain substituted 2-[(4'-hydroxyethoxy) phenyl]-4,4,5,5-tetramethyl-2-imidazoline-1-oxyl 3-oxide (HPN) derivatives with enhanced anti-hypoxic activity. HPN derivatives 1, 3, 5 containing lipophilic long chains were synthesized via the alkylation of HPN with 6-bromohexan-1-ol, ethyl 6-bromohexanoate or 6-bromohexane, respectively using acetonitrile as the solvent and K 2CO 3 as the acid-binding agent at 60 ℃. Derivative 2 was synthesized via hydrolysis reactions of derivative 1 in the NaOH/CH 3OH/H 2O system. Using dichloromethane as the solvent and N, N'-diisopropylcarbodiimide as the dehydrating agent, HPN underwent esterification with hexanoic acid to obtain derivative 4. The structures of derivatives 1-5 were characterized by infrared spectroscopy, electron paramagnetic resonance and high resolution mass spectrometry. The purities of derivatives were detected by high performance liquid chromatography, and the lipid solubilities of derivatives were evaluated by calculating the oil-water partition coefficients (log P). Anti-hypoxia activities of HPN and its long-chain lipophilic derivatives 1-5 were evaluated using normobaric hypoxia test and acute decompression hypoxia test. The structures of the derivatives were confirmed by infrared spectroscopy, electron paramagnetic resonance and high resolution mass spectroscopy. The yields of target derivatives were all above 92%, and the purities were all above 96%. The log P values of derivatives 1-5 were 2.78, 2.00, 2.04, 2.88 and 3.10, which were higher than that of HPN (0.97). Derivatives 1-5 significantly prolonged the survival time of mice at the dose of 0.3 mmol/kg in normobaric hypoxic test and reduced the mortality rate of acute decompression hypoxic mice to 60%, 70%, 60%, 70% and 40%, respectively. The synthesis of derivatives 1-5 is convenient, and the yield is high. The synthesized derivatives especially derivative 5 show anti-hypoxic activity similar to or better than HPN at lower doses.

Diagnostic value of functional tests in determining the condition of the cardiorespiratory system

Background. The purpose was to study the nature of changes in the cardiorespiratory system in the case of short-term hypoxemia during functional tests with breath-holding. Materials and methods. The paper presents the results of a survey of school-age children with acute bronchitis with and without obstructive syndrome (60 patients) and a group of healthy children (52 people). Patients underwent pulse oximetry in combination with hypoxic tests for breath-holding with data recording on a computer and performed a Rufier test. Results. The severity of bronchitis in patients in the first days was average on the BSS-ped scale — 7.79 ± 0.19 points. The level of blood oxygen saturation was normal (above 95 %), but there was a difference between the groups: in patients with obstructive syndrome it was 98.60 ± 0.04 %, in the absence of this syndrome — 98.80 ± 0.03 %, which was lower than in the control group — 99.00 ± 0.01 % (p &lt; 0.05). Time of breath-holding did not differ significantly between groups, but there was a slight decrease in saturation after them. There was greater reaction to breath-holding on exhalation. Level of oxygenation in patients with bronchitis achieved by increasing heart rate. Due to the phenomena of relative hypoxemia of peripheral tissues during convalescence, there was a decrease in tolerance to physical loading after the Rufier test. Conclusions. It is established that even in mild forms of acute bronchitis in children, according to functional tests, there is a decrease in gas exchange reserves, especially in the presence of obstructive syndrome. Compensatory mechanisms to maintain blood saturation are based on increasing systemic blood flow due to increased heart rate.

A Strategy to Enhance Confidence in Respiratory Chemoreflex Characterization by Modified Rebreathing

Modelling breath‐by‐breath ventilation (V̇E) in response to carbon dioxide rebreathing in hyperoxic and hypoxic conditions (modified rebreathing) is used to characterize the central and peripheral respiratory chemoreflexes in humans. However, breath‐to‐breath variability produces uncertainty in the estimation of model parameters. We explored whether signal‐averaging of repeated rebreathing trials would improve chemoreflex sensitivity parameter estimation and confidence. Seven healthy males (age: 27±5 years) performed 6 repetitions of modified rebreathing tests in isoxic‐hypoxic (end‐tidal PO2 (PETO2)=50 mmHg) and ‐hyperoxic conditions (PETO2=150 mmHg) over the course of 4 days. End‐tidal PCO2 (PETCO2), PETO2 and V̇E were measured breath‐by‐breath by dual gas analyser and pneumotach. The slope of the V̇E vs PETCO2 relationship above the PETCO2 threshold in the hyperoxic test gave the central chemoreflex sensitivity (L∙min‐1∙mmHg‐1) and the difference in hypoxic versus hyperoxic test slopes provided peripheral chemoreflex sensitivity. Chemoreflex slopes modelled from a single trial versus ensemble‐average of 6 trials were compared by paired t‐test and effect size (Cohen’s d). Breath‐by‐breath data from the 6 trials were aligned to the same starting PETCO2, linearly interpolated to 0.1 mmHg of PETCO2, ensemble‐averaged, and averaged into 0.2 mmHg bins. Central chemoreflex sensitivity did not differ (p=0.94) between single (4.10±2.98 L∙min‐1∙mmHg‐1, 95%CI: 3.82–4.39) versus ensemble‐averaged data (4.13±2.14 L∙min‐1∙mmHg‐1, 95%CI: 3.99–4.27) but the 95%CI was reduced (p=0.031) by 0.29 L∙min‐1∙mmHg‐1 (effect size=1.5) with the ensemble‐averaged approach. Similarly, peripheral chemoreflex sensitivity did not differ (p=0.83) between single (1.69±1.14 L∙min‐1∙mmHg‐1, 95%CI: 1.54–1.84) versus ensemble‐averaged data (1.58±1.32 L∙min‐1∙mmHg‐1, 95%CI: 1.5 –1.66); 95%CI of the ensemble‐averaged data was 0.15 L∙min‐1∙mmHg‐1 lower than a single trial but this was not different (p=0.38; effect size=0.5). Signal averaging of multiple modified rebreathing trials reduces the confidence interval of respiratory chemoreflex sensitivity. This strategy could enhance the ability to detect differences in respiratory chemoreflex control in comparative or interventional studies where modified rebreathing is used.

Contribution of Hypoxic Exercise Testing to Predict High-Altitude Pathology: A Systematic Review.

Altitude travelers are exposed to high-altitude pathologies, which can be potentially serious. Individual susceptibility varies widely and this makes it difficult to predict who will develop these complications. The assessment of physiological adaptations to exercise performed in hypoxia has been proposed to help predict altitude sickness. The purpose of this review is to evaluate the contribution of hypoxic exercise testing, achieved in normobaric conditions, in the prediction of severe high-altitude pathology. We performed a systematic review using the databases PubMed, Science Direct and Embase in October 2021 to collect studies reporting physiological adaptations under hypoxic exercise testing and its interest in predicting high-altitude pathology. Eight studies were eligible, concerning 3558 patients with a mean age of 46.9 years old, and a simulated mean altitude reaching of 5092 m. 597 patients presented an acute mountain sickness during their altitude travels. Three different protocols of hypoxic exercise testing were used. Acute mountain sickness was defined using Hackett’s score or the Lake Louise score. Ventilatory and cardiac responses to hypoxia, desaturation in hypoxia, cerebral oxygenation, core temperature, variation in body mass index and some perceived sensations were the highlighted variables associated with acute mountain sickness. A decision algorithm based on hypoxic exercise tests was proposed by one team. Hypoxic exercise testing provides promising information to help predict altitude complications. Its interest should be confirmed by different teams.

Correlation and spectral analysis of microcirculatory changes in symmetric areas of human head in short-term hypoxic exposure

Purpose. To study the effect of short-term hypoxic exposure on correlation between microcirculatory parameters (MCR) of symmetric areas of the human head. Materials and methods. MCR parameters of 10 healthy male volunteer were measured by laser Doppler flowmetry method. Short-term hypoxic exposure was produced according to the hypoxic test method using the ReOxy Cardio unit (S. A. Aimediq). We assessed the perfusion metrics left and right areas of interest, neurogenic, myogenic, respiratory and cardiac contributors to vascular tone and correlations between baseline parameters and after hypoxic exposure. Results. We revealed the specificity of regional circulation system rearranging induced by hypoxic load. The specificity is caused by functional asymmetry of correlations between different vascular tone contributors in symmetrical head areas. Strong correlation declining under the hypoxic loads between baseline perfusion on left/right was found. The perfusion changes of symmetrical temporal areas under the hypoxic loads correlate negatively with the baseline perfusion of both the same and the opposite side. Conclusion. Short-term hypoxic load rearranges the balance of different vascular tone contributors regulatory role in MCR of symmetric head areas to maintain the sustainable activity of the whole MRC.

Вплив гіпоксичних тренувань на стан легеневої гемодинаміки у хворих похилого віку з хронічним обструктивним захворюванням легень

Abstract. The aim of the study: to find out the effect of hypoxic training on the state of pulmonary hemodynamics in elderly patients with chronic obstructive pulmonary disease (COPD). Materials and research methods. We examined 42 elderly patients with COPD, stage I-II, without exacerbation, groups A and B, that were divided into a group (21 people) wich received interval normobaric hypoxic training and a group (21 people) wich received simulated training. Pulmonary hemodynamics was studied using rheopulmonography and oxygen saturation by pulse oximetry. To assess the body’s resistance to hypoxia, a hypoxic test was performed with inhalation of a hypoxic gas mixture (12 % oxygen and 88 % nitrogen) for 20 min. The course of interval normobaric hypoxic or simulated training consisted of 10 daily sessions. All studies were conducted before training, immediately after the training course, in a month and three months after the training course. Conclusions. In elderly patients with COPD, blood circulation in the lungs is associated with the body’s resistance to hypoxia. The course of hypoxic training improves blood circulation in the lungs in elderly patients with COPD. At the same time, the beneficial effect of hypoxic training preserves for a month. In elderly patients with COPD, the effectiveness of hypoxic training’s influence on blood circulation in the lungs is associated with resistance to hypoxia. At the same time, the greater effectiveness of hypoxic training is observed in patients with lower resistance to hypoxia. Keywords: COPD, old age, pulmonary hemodynamics, hypoxic training.

Evaluation of the Lake Louise Score for Acute Mountain Sickness and Its 2018 Version in a Cohort of 484 Trekkers at High Altitude.

Richalet, Jean-Paul, Chantal Julia, and François J. Lhuissier. Evaluation of the Lake Louise Score for acute mountain sickness and its 2018 version in a cohort of 484 trekkers at high altitude. High Alt Med Biol. 22:353-361, 2021. Background: The Lake Louise Score (LLS) is widely used in field studies and chamber studies for the diagnosis of Acute Mountain Sickness (AMS). This score aggregates symptoms that are nonspecific: headache, gastrointestinal symptoms, fatigue, dizziness and sleep disturbance can be due to a variety of causes unrelated to altitude hypoxia. The objectives of this study were to (1) reevaluate the need for a headache score >0 for the diagnosis of AMS, (2) evaluate the role of sleep disturbances, in relation with other symptoms, (3) evaluate the significance of dizziness. Materials and Methods: We analyzed LLS from 484 trekkers at high altitude. Among them, 212 suffered from moderate AMS (mAMS: 3 ≤ LLS < 6) and 115 from severe AMS (sAMS: LLS ≥ 6). Results: Cluster analysis of AMS revealed three main groups presenting the following symptoms: Group 1 includes 254 subjects who had less than 2 symptoms; Group 2 includes 137 subjects who had fatigue, sleep disturbance, and headache, corresponding to mAMS; Group 3 includes 93 subjects who had headache, fatigue, dizziness and sleep disturbance, corresponding to sAMS. A headache score of zero was found in 25% of mAMS and 5% of sAMS subjects. Only the absence of headache associated with the absence of fatigue was specific of absence of sAMS. In subjects with a dizziness score > 1, end-tidal partial pressure of carbon dioxide during a hypoxic exercise test was lower than that in subjects with a dizziness score < 2. Subjects with high ventilatory response to hypoxia may develop dizziness with high altitude exposure. Conclusion: (1) An isolated headache score > 0 should not be mandatory to define AMS, (2) sleep disruption contributes to the diagnosis of AMS, (3) gastrointestinal symptoms and dizziness are weaker contributors to the LLS, (4) dizziness might be linked to a hyperresponsiveness to hypoxia and not to AMS itself.

Substantiation of Methods for Predicting Success in Artistic Swimming.

To develop a methodology for predicting success in artistic swimming based on a set of morphofunctional indicators and indices, 30 schoolgirls, average age (12.00 ± 0.22), were divided into two groups. Group 1: 15 athletes, training experience 4–5 years. Group 2: 15 schoolgirls without training experience. For each participant, we determined the length and weight of the body, the circumference of the chest, vital lung capacity, and the circumference of the biceps in a tense and at rest. The Erisman index, biceps index, and the ratio of proper and actual vital lung capacity was calculated. Them, we conducted the Stange and Genchi hypoxic tests, and flexibility tests for “Split”, “Crab position”, and “Forward bend”. Prediction was conducted using the Wald test with the calculation of predictive coefficients and their informativeness. A predictive table containing results of functional tests and indices of artistic swimming athletes is developed. It includes nine criteria, which informativeness varied in the range of 395.70–31.98. The content of the prediction consists of evaluating the results, determining the appropriate predictive coefficient, and summing these coefficients before reaching one of the predictive thresholds. The conducted research allowed us to substantiate and develop a method for predicting the success of female athletes with the use of morphofunctional indicators and indices.

Effects of dietary supplementation with filamentous microalgae (Oedocladium sp. or Tribonema ultriculosum) on growth performance, fillet fatty acid composition, skin pigmentation, and immune response of yellow catfish Pelteobagrus fulvidraco

AbstractA 40‐day feeding trial was conducted to investigate the effect of dietary microalgae Oedocladium sp. or Tribonema ultriculosum supplementation on growth performance, fillet fatty acid composition, skin pigmentation, and immune response of yellow catfish Pelteobagrus fulvidraco. Two hundred and seventy experimental fish (51.19 ± 1.17 g) were distributed among nine net cages (2 × 2 × 2 m3) in a randomized design and were fed diets containing 0% (control), 4% Oedocladium meal (Oedocladium), and 5% T. utriculosum meal (Tribonema) to apparent satiation twice a day. After the feeding trial, a hypoxic stress test was conducted to evaluate the effect of dietary microalgal supplementation on fish immune response. Compared to the control, microalgal supplementation did not affect fish growth performance. Dietary supplementation of T. utriculosum significantly increased fillet contents of palmitoleic acid by 100.44% and eicosapentaenoic acid by 12.51%, while the supplementation of Oedocladium meal in diet significantly increased the fish skin ventral lutein content by 61.6%. In addition, dietary Oedocladium or T. utriculosum supplementation significantly increased the plasma total superoxide dismutase activity (before hypoxic stress) and complement component 3 contents (after hypoxic stress). The addition of T. utriculosum meal also significantly increased the plasma immunoglobulin M content regardless of hypoxic stress. These results demonstrated Oedocladium sp. and T. utriculosum can be used to enhance fillet nutritional quality, skin pigmentation, and fish immune response.