Age features of O2 mass transfer regimes in adolescents’ body at rest

The results of complex studies of the quantitative relationship between the stage-by-stage mass transfer of O2 and the efficiency of cardiorespiratory system functioning in relation to its consumption in adolescents’ body under conditions of relative rest are presented. The results obtained show that in adolescents, the modes of mass transfer of O2 in the body and the nature of the respiratory and circulatory systems functioning in relation to its consumption have a number of age-related differences compared with adult men. So, in adolescents, the external respiration system at rest functions less economically than in adults. Each liter of O2 consumed by adolescents is extracted from almost 3 liters more than in adults the amount of air ventilated per minute through the lungs. The volumetric indicators of blood circulation are also higher in adolescents, which may indicate the influence of neuro-humoral rearrangements in the body during the pubertal period. The coefficient of oxygen utilization by tissues from arterial blood in adolescents turned out to be significantly higher, which may characterize a higher tension of tissue metabolic processes.

Adaptive chemoreceptor plasticity and reactivity of the cardio-respiratory system in athletes under hypoxic loads

An exploration of 110 healthy men (not involved in sports and athletes) with the use of hypoxic loads was carried out. It is established that the specifics of the regulation of gas exchange depend on the nature of training loads (aerobic or mixed), which are manifested in the parameters of chemoreflector reactivity, the pattern of external respiration, gas exchange and activity of the autonomic nervous system under hypoxic load. As sports qualifications grow, the mechanisms of intersystem integration of the functions of the cardio-respiratory system are improved, which is manifested in an increase in cardiorespiratory coherence. Key words: athletes, hypoxia, cardiorespiratory system, gas exchange of the body, chemoreceptor reactivity.

Assessing functional state of the body when wearing a reusable protective suit to minimize risks of contagion among medical personnel

Personal protective equipment has become the last line of protection for medical personnel during the pandemic of the new coronavirus infection since it allows minimizing risks of biological contagion. Given the existing staffing shortage, medical workers have to spend from 4 to 12 hours a day in the “red zone” where they necessarily wear personal protective equipment. Protective clothing is known to produce negative effects on functional state of the body and personnel’s working capacities. Assessment of up-to-date protective suits will allow developing recommendations on their suitable application bearing in mind a balance between necessary protection, providing favorable ergonomics, and reducing risks of adverse effects on functional state and working capacities. Our research aim was to hygienically assess health risks for medical workers who had to wear reusable protective suits. Our research object was a reusable suit made from polyether fabric with polyurethane membrane coating and antistatic threads. We performed an experiment aimed at evaluating thermal state of the body, psychophysiological state, and responses by the volunteers’ cardiorespiratory system in laboratory conditions during an 80 hour working shift under controlled microclimate. Participants in the experiment were questioned in order to assess suits’ ergonomics. Heat exchange dynamics and amount of changes in thermal physiological parameters caused by wearing a protective suit determined heat contents of volunteers’ bodies that conformed to optimal standard values. Data on psychophysiological and mental state taken in research dynamics didn’t have any statistically significant changes. Gas exchange indicators naturally grew during the “load” phase; however, there were no significant changes detected in any phase in the research. Hygienic assessment of the thermal state, functional state of the cardiovascular and respiratory systems, and psychophysio-logical indicators confirmed that wearing a protective suit was quite safe and didn’t involve any health risks for volunteers.

The state of cardiorespiratory system in female students with idiopathic arterial hypertension under treadmill training

Annotation. One of the most widespread pathogenic condition, among young women, is idiopathic arterial hypertension which significantly worsen the life condition, learning abilities and in future can lead to the development of arterial hypertension, ischemic heart disease, complicate course of the pregnancy and delivery. The aim of the research was to examine the functional state of cardiorespiratory system in female students of 1-3rd year of high school with the signs of idiopathic arterial hypertension under the fixed stress- test. The main group consisted of 32 female students of 1-3rd year of high school with idiopathic arterial hypertension. The control group was formed from almost healthy female students from the same years of study. The treadmill (Biomedical Systems), due to Bruce protocol, was used for estimating the level of tolerance to physical pressure. To assess the degree of reliability of the results of the study used a variational-statistical method of analysis of the results using a package of statistical programs Statistica V. 10 (USA) and the recommendations of O. Yu. Rebrova (2002). Under the treadmill test it was revealed the decrease of tolerance to physical pressure in female students from the main group on 31,24% (р<0,05), in comparison to the MET numbers got in the control group (37,11±2,16) ml/kg/min. Under stress-test reliable increase of heart rate in control group was observed after 6-8 minutes of training, in female students from control group the same reaction was observed after 3-5 min of training without its further increase. The increase of SBP in the main group at the peak of training was (20,88±3,12)%, in the control group – this index was completely higher (27,88±3,36)% (р<0,01). After the finishing of the stress test in the female students of the main group the duration of their heart rhythm and arterial pressure reviving was (9,85±1,22) min., that overcame the result got in control group (6,24±0,67) min. Thus, the treadmill test allows exactly reveal the level of cardiorespiratory system adaptation to physical pressure, aerobic capacity in young women with the signs of idiopathic arterial hypertension.

High-intensity resistance exercise is not as effective as traditional high-intensity interval exercise for increasing the cardiorespiratory response and energy expenditure in recreationally active subjects

Purpose Traditional high-intensity interval exercise (HIIE) highly stimulates the cardiorespiratory system and increases energy expenditure (EE) during exercise. High-intensity resistance exercise (HIRE) has become more popular in recreationally active subjects. The physiological responses to HIRE performed with light or moderate load is currently largely unknown. Here, we examined the effect of the type of interval exercise [HIRE at 40% (HIRE40) and 60% (HIRE60) 1-RM vs. traditional HIIE] on the cardiorespiratory response and EE during and after exercise. Methods Fifteen recreationally active adults randomly completed traditional HIIE on an ergocyle, HIRE40 and HIRE60. The sessions consisted of two sets of ten 30-s intervals (power at 100% VO2max during HIIE; maximal number of repetitions for 10 different free-weight exercises during HIRE40 and HIRE60) separated by 30-s active recovery periods. Gas exchange, heart rate (HR) and EE were assessed during and after exercise. Results VO2mean, VO2peak, HRmean, the time spent above 90% VO2max and HRmax, and aerobic EE were lower in both HIRE sessions compared with HIIE (P < 0.05). Anaerobic glycolytic contribution to total exercise EE was higher in HIRE40 and HIRE60 compared with HIIE (P < 0.001). EE from excess post-exercise oxygen consumption (EPOC) was similar after the three sessions. Overall, similar cardiorespiratory responses and EE were found in HIRE40 and HIRE60. Conclusions HIRE is not as effective as HIIE for increasing the cardiorespiratory response and EE during exercise, while EPOC remains similar in HIRE and HIIE. These parameters are not substantially different between HIRE40 and HIRE60.

Passive leg cycling increases activity of the cardiorespiratory system in people with tetraplegia

Individuals with cervical spinal cord injury (SCI) are at an increased risk for cardiovascular disease. Exercise is well-established for preventing cardiovascular disease, however, there are limited straightforward and safe exercise approaches for increasing the activity of the cardiorespiratory system after cervical SCI. The objective of this study was to investigate the cardiorespiratory response to passive leg cycling in people with cervical SCI. Beat-by-beat blood pressure, heart rate, and cerebral blood flow were measured before and throughout 10 minutes of cycling in 11 people with SCI. Femoral artery flow-mediated dilation was also assessed before and immediately after passive cycling. Safety was monitored throughout all study visits. Passive cycling elevated systolic blood pressure (5±2 mmHg), mean arterial pressure (5±3 mmHg), stroke volume (2.4±0.8 mL), heart rate (2±1 beats/min) and cardiac output (0.3±0.07 L/min; all p<0.05). Minute ventilation (0.67±0.23 L/min), tidal volume (70±30 mL) and end-tidal PO2 (2.6±1.23 mmHg) also increased (all p<0.05). Endothelial function was improved immediately after exercise (1.62±0.13%, p<0.01). Passive cycling resulted in one incidence of autonomic dysreflexia. Therefore, passive leg cycling increased the activity of the cardiorespiratory system, improved endothelial function, indicating it may be a beneficial exercise intervention for the cardiovascular and respiratory systems in people with cervical SCI. Novelty: ● Passive leg cycling increases the activity of the cardiorespiratory system and improves markers of cardiovascular health in cervical SCI. ● Passive leg cycling exercise is an effective, low-cost, practical, alternative exercise modality for people with cervical SCI.

CLINICAL AND FUNCTIONAL DISORDERS OF CARDIORESPIRATORY SYSTEM IN PATIENTS WITH COVID-19

The goal of the paper is to range information about early and delayed clinical and functional disorders of the respiratory and cardiovascular systems after COVID-19. The review focuses on clinical and functional diagnostic methods (laboratory, instrumental and radiation) of disorders of the cardiovascular and respiratory systems in patients after COVID-19. At the moment, enough data has been accumulated confirming early and aftereffect of COVID-19. The need for further rehabilitation may be caused by the presence and severity of clinical and functional disorders of the respiratory and cardiovascular systems. Key words: coronavirus disease (COVID-19), impaired respiratory function and diffusion lung capacity, acute myocardial injury, electrical myocardium instability. Цель – систематизировать сведения о ранних и отсроченных клинико-функциональных нарушениях дыхательной и сердечно-сосудистой систем после перенесенной коронавирусной инфекции. В обзоре основное внимание уделено клинико-функциональным методам диагностики (лабораторным, инструментальным и лучевым) нарушений сердечно-сосудистой и дыхательной систем у пациентов, перенесших COVID-19. На данный момент накоплено достаточно данных, подтверждающих наличие ранних и отсроченных последствий новой коронавирусной инфекции. Необходимость дальнейшей реабилитации может быть обусловлена наличием и тяжестью клинико-функциональных нарушений со стороны органов дыхания и сердечно-сосудистой системы. Ключевые слова: новая коронавирусная инфекция (COVID-19), нарушения функции внешнего дыхания и диффузионной способности легких, острое повреждение миокарда, электрическая нестабильность миокарда.

Heart and Lung Sound Measurement Using an Esophageal Stethoscope with Adaptive Noise Cancellation

In surgeries where general anesthesia is required, the auscultation of heart and lung sounds is essential to provide information on the patient’s cardiorespiratory system. Heart and lung sounds can be recorded using an esophageal stethoscope; however, there is huge background noise when this device is used in an operating room. In this study, a digital esophageal stethoscope system was designed. A 3D-printed case filled with Polydimethylsiloxane material was designed to hold two electret-type microphones. One of the microphones was placed inside the printed case to collect the heart and lung sound signals coming out from the patient through the esophageal catheter, the other was mounted on the surface of the case to collect the operating room sounds. A developed adaptive noise canceling algorithm was implemented to remove the operating room noise corrupted with the main heart and lung sound signals and the output signal was displayed on software application developed especially for this study. Using the designed case, the noise level of the signal was reduced to some extent, and by adding the adaptive filter, further noise reduction was achieved. The designed system is lightweight and can provide noise-free heart and lung sound signals.

The Effects of Sodium Phosphate Supplementation on the Cardiorespiratory System and Gross Efficiency during Exercise under Hypoxia in Male Cyclists: A Randomized, Placebo-Controlled, Cross-Over Study

The main aim of this study was to evaluate the effects of six days of tri-sodium phosphate (SP) supplementation on the cardiorespiratory system and gross efficiency (GE) during exercise under hypoxia in cyclists. Twenty trained male cyclists received SP (50 mg·kg−1 of fat-free mass/day) or placebo for six days in a randomized, cross-over study, with a three-week washout period between supplementation phases. Before and after each supplementation phase, the subjects performed an incremental exercise test to exhaustion under normobaric hypoxia (FiO2 = 16%, ~2500 m). It was observed that short-term SP supplementation led to a decrease in heart rate, an increase in stroke volume, and an improvement in oxygen pulse (VO2/HR) during low and moderate-intensity exercise under hypoxia. These changes were accompanied by an increase in the serum inorganic phosphate level by 8.7% (p < 0.05). No significant changes were observed in serum calcium levels. GE at a given workload did not change significantly after SP supplementation. These results indicated that SP promotes improvements in the efficiency of the cardiorespiratory system during exercise in a hypoxic environment. Thus, SP supplementation may be beneficial for endurance exercise in hypoxia.