Physical Work Capacity Research Articles

904Physical fitness across the life-course and the metabolic syndrome in mid-adulthood

Abstract Background Low physical fitness, including muscular strength and cardiorespiratory fitness (CRF), is a risk factor for the metabolic syndrome (MetS). However, it is unknown how physical fitness at different life stages contributes to the development of MetS. Methods Included were 783 Childhood Determinants of Adult Health Study participants who between 1985 and 2019 had measures of physical fitness (muscular strength: dominant grip strength; CRF: 1.6km run or physical work capacity at 170 beats per minute) at three life stages (childhood=7–15 years, young-adulthood=26–36 years, mid-adulthood=36–49 years) and had their MetS status assessed using the harmonised definition in mid-adulthood. The Bayesian relevant life-course exposure model, a novel statistical analytic technique, quantified associations between physical fitness at each life stage with MetS and estimated the maximum accumulated effect of physical fitness across the life-course. Results The contribution of muscular strength at each life stage with MetS in mid-adulthood was equal (childhood=36%, young-adulthood=31%, mid-adulthood=33%), whereas for CRF the greatest contribution was from childhood and mid-adulthood (childhood=41%, young-adulthood=20%, mid-adulthood=39%). A one standard deviation increase in cumulative physical fitness across the life-course was associated with 36–55% reduced odds of MetS (muscular strength: OR = 0.64, 95%Credible Interval=0.40,0.95; CRF: OR = 0.45, 95%Credible Interval=0.30,0.64). Conclusions As physical fitness at each life stage was associated with MetS in mid-adulthood, strategies aimed at increasing both childhood and adult physical fitness levels could improve future health. Key messages Increased participation in both aerobic and muscle-strengthening activities, beginning in childhood and extending into adulthood, could be encouraged to help prevent MetS.

РОЗУМОВА ПРАЦЕЗДАТНІСТЬ У РІЗНІ ВІКОВІ ПЕРІОДИ ЗАЛЕЖНО ВІД РЕЖИМУ РУХОВОЇ АКТИВНОСТІ

РОЗУМОВА ПРАЦЕЗДАТНІСТЬ У РІЗНІ ВІКОВІ ПЕРІОДИ ЗАЛЕЖНО ВІД РЕЖИМУ РУХОВОЇ АКТИВНОСТІ

Ollie Jay: managing heat, improving health

Ollie Jay: managing heat, improving health

A Model for Estimating the Physical Work Capacity Based on Anthropometric Components and Body Composition: A Pilot Study Based on Measuring the Maximum Oxygen Consumption on Direct Method

A Model for Estimating the Physical Work Capacity Based on Anthropometric Components and Body Composition: A Pilot Study Based on Measuring the Maximum Oxygen Consumption on Direct Method

NORMATIVE FRAMEWORK FOR CONTROL AND OPTIMIZATION OF THE PHYSICAL DEVELOPMENT AND SPECIFIC WORKING CAPACITY OF 17-19-YEAR-OLD HANDBALL PLAYERS

The purpose of this study is to reveal the average level and variability of the signs of physical development and specific working capacity of 17-19-year-old Bulgarian handball players and, on this basis, to develop an up-to-date norm framework for control and optimization of sports training in the studied age group. The object of the study is the characteristics of physical development, specific physical fitness, technical and tactical skills, and some mental characteristics. The research was done among 115 handball players between the age of 17 and 19 from the top 10 teams, participating in the national championship for juniors under 19 years old. Anthropometric measurements and sports-pedagogical testing were conducted for the needs of the study with a total of 34 indicators for establishing the level of physical development, specific physical and technical-tactical preparation and some mental characteristics and qualities of the handball players of the studied age group. The following research methods were applied to solve the purpose and tasks of the research: review study and theoretical analysis of the specialized literature, anthropometry, manual dynamometry, sports-pedagogical testing and ascertaining psychological experiment. Frequency analysis and descriptive statistics, sigma estimation method, and index method were used for mathematical-statistical data analysis. The applied approach allowed developing normative tables for evaluation of the results of each competitor or team, based on which, person or team optimization models could be developed, revealing both strengths and weaknesses in their preparation.

Grip strength performance from 9431 participants of the GenoFit study: normative data and associated factors

Weak grip strength is a strong predictor of multiple adverse health outcomes and an integral diagnostic component of sarcopenia. However, the limited availability of normative data for certain populations impedes the interpretation of grip performance across adulthood. This study aimed to establish normative data and low grip strength thresholds in a large adult population, and to examine associations between grip strength and clinically relevant health variables. A total of 9431 adults aged between 18 and 92 years participated in this study (mean age: 44.8 ± 13.4 years; 57% females). Grip strength, body composition, and cardiorespiratory (CR) fitness were assessed using hand dynamometry, dual-energy x-ray absorptiometry and physical work capacity tests, respectively. Low grip strength was established according to criteria of the European Working Group on Sarcopenia in Older People. Normative data and t-scores, stratified by sex and age groups, are presented. Grip performance was associated with lean mass, skeletal muscle index (SMI), fat mass, CR fitness, bone mineral density (BMD), android/gynoid ratio, disease prevalence and physical activity levels (all p < 0.001) after controlling for multiple potential confounders. Individuals with weak grip strength had lower lean mass, SMI, CR fitness (all p < 0.001) and BMD (p = 0.001), and higher disease prevalence (p < 0.001), compared to healthy controls, although sex-specific differences were observed. Grip strength has practical screening utility across a range of health domains. The normative data and grip strength thresholds established in this study can guide the clinical interpretation of grip performance and facilitate timely therapeutic strategies targeting sarcopenia.

Effect of intake of Vitrum vitamin-mineral complex in combination with adaptogens on immune status and physical work capacity in highly skilled student athletes

Purpose of the study: to study the effect of Vitrum in combination with adaptogens on immunological reactivity and physical performance in athletes under conditions of intense training.Materials and methods: 4 groups of athletes, 10 people in each, went through a cycle of intensive training according to a specially developed methodology. Group I took Vitrum, group II — Vitrum + Eleutherococcus extract, group III — Vitrum + ginseng tincture. Group IV — ascorbic acid and was used as a control. Blood for analysis was taken from the cubital vein before and after 28 days of drug administration. Indicators of immunological reactivity were determined by modern laboratory methods. Physical performance was determined by the index of the Harvard step test (IHST) and the PWC170 test.Results: the use of Vitrum in combination with adaptogens promotes a significant increase in the parameters of humoral (increase in IgA by 32–40 %, IgM by 28–43 %, IgG by 9–14 %) and cellular (increasing the completeness of phagocytosis by 9–37 % immunity.Conclusion: intake of Vitrum in combination with adaptogens was accompanied by a significant increase in nonspecific immunity and increased the level of fitness.

Differentiation of Physical Loads in Female Students of Different Motor Ages

Purpose: To develop and evaluate the impact of a program of sectional recreational aerobics classes, taking into account the differentiation of physical loads in female students of different motor ages.&#x0D; Materials and Methods. Participants: In the ascertaining experiment, 145 second-year female students were examined, in the formative experiment – 42 female students.&#x0D; The following indicators were measured: biological age (years) using V. P. Voitenko’s method (1991), motor age (years) and the general level of physical conditions (points), heart rate (bpm), heart rate recovery time after 20 squats in 30 s (min, s), the level of physical health (points), physical activity index (c. u.), the level of general physical working capacity (PWC170, kgm ∙ min-1); VO2 max (ml ∙ kg ∙ min-1) – maximal oxygen consumption. The level of motor qualities development: 2,000 m run (min, s), 4×9 m shuttle run (s), standing long jump (cm), sit-ups in 1 min (times), push-ups (times), seated forward bend (cm).&#x0D; Results. The study developed and tested an experimental program of recreational aerobics classes, taking into account a differentiated approach to dosing physical loads in female students of different motor ages. Data factorization revealed a rational combination of means for developing motor qualities: strength endurance – 15.88%, dynamic strength – 12.86%, speed and strength endurance – 8.72%, static endurance – 17.87%, flexibility – 12.69%, speed abilities – 14.66%, and coordination abilities – 17.32%. The study found a moderate negative correlation between motor age and the level of physical health (r = -0.68 at p &lt; 0.01). Three levels of motor age with respect to the levels of physical health were identified.&#x0D; Conclusions. Taking into account female students’ motor age during recreational aerobics classes ensures optimal motor activity and increases the level of physical fitness.

Age-related trends of physical activity and work capacity among men and women in an open urban population

Aim. To establish parameters of physical activity (PA) and work capacity among men and women in an open population of Western Siberia city, depending on age.Material and methods. Cross-sectional epidemiological studies were carried out among open male and female population of a middle-urbanized city of Western Siberia (Tyumen). Representative samples of 1000 people aged 25-64 years (250 people in each life decade) were analyzed. PA and work capacity were determined according to the WHO MONICA-psychosocial questionnaire “Awareness and Attitude towards Health”.Results. Age-related trends among young men of middle urbanized Western Siberia city were manifested by PA increase during the last year (in 25-34 yearage group — in 20,9%, in the general population — in 13,8% (p=0,0205)). During the last year, a decrease and an increase in work capacity was revealed in young women (33,6%) and young men (17,5%), respectively. Age-related trends among middle-aged people of both sexes were manifested by low self-esteem — in men by the sixth decade of life (0,6% vs 8,9%, p=0,0002), in women — by the fifth decade of life (3,4% vs 8,2%, p=0,0442). In men, with a decrease in PA and work capacity during the last year, an increase in outdoor activities was revealed (15,8% vs 27,7%, p=0,0020).Conclusion. Since the promotion of physical literacy should be among the state priorities, the presented data can serve as the basis for planning populationbased preventive measures, intended for working-age men and women in middleurbanized Siberian cities.

Effect of year-round training on parameters of heart rate variability, central hemodynamics and physical working capacity in short-distance swimmers

Dynamic examination of athletes is of great interest for sports medicine specialists, as it allows measuring changes in athletes’ functional state in parallel with increasing athletic performance in a one-year training cycle. The aim of the work is to assess dynamic changes in parameters of heart rate variability, central hemodynamics and physical performance in short-distance swimmers during preparatory and competitive periods of the training process. Materials and methods. The swimmers (n = 94) qualified from the second-class sport qualification to Master of Sports of International Class were examined during the preparatory and competitive periods of the training process. Short ECG recordings of 5 minutes were used for the heart rate variability (HRV) analysis according to the International Standard. Results. In the preparatory period, the autonomic equilibrium index had a mean value of 3.104 ± 0.494 1/s2, and in the competitive period – 2.459 ± 0.248 1/s2 (P = 0.295). The initial distribution of athletes depending on the value of autonomic tone, according to the classification proposed by R. M. Bayevskiy, had the following ratio in the preparatory period: 75.0 % / 20.0 % / 5.0 %, vagotonic, normotonic and sympathotonic individuals, respectively, statistically significantly indicating the prevalence of athletes with vagotonia over normotonic individuals (P = 0.0005). In the competitive period, this ratio was 60.0 % / 40.0 % / 0 %. The central hemodynamic indices showed a downward trend as evidenced by a decrease in the cardiac index from 2.954 ± 0.126·l·min-1·m-2 to 2.862 ± 0.088 l‧min-1‧m-2 (Р = 0.510), although these values matched to the eukinetic circulatory type (CT) during both training periods. However, the ratio of hypokinetic, eukinetic and hyperkinetic CT in the preparatory period was 45.0 % / 45.0 % / 10 0 %, and in competitive period – 45.0 % / 55.0 % / 0 %, respectively. The mean value of physical working capacity (PWC170/kg) in the preparatory period was 15.54 ± 0.66 kgm·min-1·kg-1, and in the competitive period it was 18.09 ± 0.53 kgm·min-1·kg-1, making an increase of 16.41 % (Р = 0.0001). The functional state index (FSI) increased significantly by 25.08 % from 5.558 ± 0.322 r. u. to 6.952 ± 0.272 r. u. (Р = 0.00001). The correlation analysis during the preparatory period showed a significant positive correlation between Mo and PWC170/kg (r = 0.46, P = 0.040), ARI and CI (r = 0.50, P = 0.026), IARP and CI (r = 0.53, P = 0.017), stress-index and SI (r = 0.52, P = 0.019) and negative – between Mo and CI (r = -0.56, P = 0.009). In the competitive period, the general tendency of correlation interaction was remained, as evidenced by revealed positive relationships between Mo and FSI (r = 0.53, P = 0.017), ARI and SI (r = 0.51, P = 0.020). Conclusions. Short-distance swimmers in the competitive period had significantly higher level of physical working capacity (by 16.4 %), the functional state index (by 25.1 %), as well as parasympathetic tone of ANS in comparison with the preparatory period. The above-mentioned hemodynamic changes and autonomic balance indicators were associated with the increase in athletic performance: 4 (20 %) swimmers qualified for the title of Master of Sports of Ukraine, 2 (10 %) swimmers – for Candidate Master of Sports, and 2 (10 %) swimmers – for first-class sport qualification.

Short-term physical exercise impacts on the human holobiont obtained by a randomised intervention study

BackgroundHuman well-being has been linked to the composition and functional capacity of the intestinal microbiota. As regular exercise is known to improve human health, it is not surprising that exercise was previously described to positively modulate the gut microbiota, too. However, most previous studies mainly focused on either elite athletes or animal models. Thus, we conducted a randomised intervention study that focused on the effects of different types of training (endurance and strength) in previously physically inactive, healthy adults in comparison to controls that did not perform regular exercise. Overall study duration was ten weeks including six weeks of intervention period. In addition to 16S rRNA gene amplicon sequencing of longitudinally sampled faecal material of participants (six time points), detailed body composition measurements and analysis of blood samples (at baseline and after the intervention) were performed to obtain overall physiological changes within the intervention period. Activity tracker devices (wrist-band wearables) provided activity status and sleeping patterns of participants as well as exercise intensity and heart measurements.ResultsDifferent biometric responses between endurance and strength activities were identified, such as a significant increase of lymphocytes and decrease of mean corpuscular haemoglobin concentration (MCHC) only within the strength intervention group. In the endurance group, we observed a significant reduction in hip circumference and an increase in physical working capacity (PWC). Though a large variation of microbiota changes were observed between individuals of the same group, we did not find specific collective alterations in the endurance nor the strength groups, arguing for microbiome variations specific to individuals, and therefore, were not captured in our analysis.ConclusionsWe could show that different types of exercise have distinct but moderate effects on the overall physiology of humans and very distinct microbial changes in the gut. The observed overall changes during the intervention highlight the importance of physical activity on well-being. Future studies should investigate the effect of exercise on a longer timescale, investigate different training intensities and consider high-resolution shotgun metagenomics technology.Trial registrationDRKS, DRKS00015873. Registered 12 December 2018; Retrospectively registered.

A Brief Review of Swimming Endurance and Chronic Stress Model for Evaluation of Adaptogenic activity

Stress is the disturbed homeostatic condition of the organism, and it is represented by non-specific response of the body to any demand imposed on it. Stress brings various changes in physiological condition of the organism, but various mechanism of the body will counteract to maintain homeostasis. In some situations, body’s adaptation to stress is like reward, which is responsible for improvement of body’s performance beyond its capacity. However if organism suffer strong acute or chronic stress, body is unable to maintain homeostasis. Under this condition, various types of diseases and disorders will develop, and even it may lead to death, if it is not managed at proper time. Hazardous stressful situation can be managed by using antistress agent or adaptogen. These agents improve physical and mental working capacity in severe stress circumstances. In different screening models for evaluation of adoptogenic activity, animals are challenged with acute or chronic stress conditions. Various stimulating, stress protective, tonic responses and biochemical markers were measured in evaluation of adoptogenic activity in these animal models.

Evaluation of orphan diseases global burden.

Orphan diseases is a significant socio-economic burden for both global and Russian health care systems. The global burden of disease metrics introduced by WHO, such as DALY, QALY, HALE, can be a useful tool for building economic models and prognoses, as well as medicine funding distribution. However, it is very difficult to standardize a heterogeneous group of rare diseases and it is difficult to talk about the cost-effective treatment options search, in cases where patients with an orphan disease may have only one pathogenetic therapy option. Much work needs to be done to find optimal treatment options and establish the standards of care necessary to maintain physical health, work capacity and quality of life.

Physical Activity and Cardiovascular Fitness During Childhood and Adolescence: Association With Retinal Nerve Fibre Layer Thickness in Young Adulthood.

Higher physical working capacity (PWC) at age 17 was associated with thicker peripapillary retinal nerve fiber layer (pRNFL) at age 20, suggesting a mechanistic link between cardiovascular fitness and neuroretinal integrity. Physical activity and cardiovascular fitness have been linked with lower odds of developing glaucoma. We tested the hypothesis that early beneficial effects of physical activity and cardiovascular fitness can be observed by measuring the pRNFL thickness in young healthy adults. The Raine Study is a longitudinal study that has followed a cohort since before their births in 1989-1992. Parent-reported physical activity was collected between 8 and 17 years, and latent class analysis was used to identify the participants' physical activity trajectories. At the 20-year follow-up (participants' mean age=20.1±0.4 y), participants' metabolic equivalent of task-minutes/week was determined using self-reported physical activity data. Participants' PWC was assessed at the 14- and 17-year follow-ups to estimate their level of cardiovascular fitness. An eye examination, which included spectral-domain optical coherence tomography imaging, was conducted at the 20-year follow-up for 1344 participants. Parent-reported or participant-reported physical activity was not associated with pRNFL thickness. However, higher PWC at 17 years was associated with thicker pRNFL globally [by 0.3 µm; 95% confidence interval (CI)=0.2-0.6; P<0.001], superotemporally (by 0.4 µm; 95% CI=0.1-0.7; P=0.013), inferonasally (by 0.7 µm; 95% CI=0.1-0.9; P=0.002), and nasally (by 0.4 µm; 95% CI=0.1-0.7; P=0.006) per 10 Watt increase in PWC. The association between estimated cardiovascular fitness and pRNFL thickness suggests there may be overlapping mechanisms for cardiovascular health and retinal ganglion cell integrity. While the effect sizes were small, it is possible that larger effects and clinically significant associations may arise as we follow this cohort of participants through their later adulthood.

Aerobic fitness as a parameter of importance for labour loss in the heat

ObjectivesTo derive an empirical model for the impact of aerobic fitness (maximal oxygen consumption; V̇O2max in mL∙kg−1∙min−1) on physical work capacity (PWC) in the heat. DesignProspective, repeated measures. MethodsTotal work completed during 1 h of treadmill walking at a fixed heart rate of 130 b∙min−1 was assessed in 19 young adult males across a variety of warm and hot climate types, characterised by wet-bulb globe temperatures (WBGT) ranging from 12 to 40 °C. For data presentation and obtaining initial parameter estimates for modelling, participants were grouped into low (n = 6, 74 trials), moderate (n = 8, 76 trials), and high (n = 5, 29 trials) fitness, with group mean V̇O2max 42, 52, and 64 mL∙kg−1∙min−1, respectively. For the heated conditions (WBGT 18 to 40 °C), we calculated PWC% by expressing total energy expenditure (kJ above resting) in each trial relative to that achieved in a cool reference condition (WBGT = 12 °C = 100% PWC). ResultsThe relative reduction in energy expenditure (PWC%) caused by heat was significantly smaller by up to 16% for the fit participants compared to those with lower aerobic capacity. V̇O2max also modulated the relationship between sweat rate and body temperature changes to increasing WBGT. Including individual V̇O2max data in the PWC prediction model increased the predicting power by 4%. ConclusionsIncorporating individual V̇O2max improved the predictive power of the heat stress index WBGT for Physical Work Capacity in the heat. The largest impact of V̇O2max on PWC was observed at a WBGT between 25 and 35 °C.

Support for the development of physical education in higher education institutions is the responsibility of the state to the future of the country

The paper considers the problem of today is a bad attitude to physical education in higher education. The health of every citizen is the main slogan of the country's policy. The human body is the only complex biological system that constantly interacts with environmental conditions. Health is a state of physical, moral, psycho- emotional, social, intellectual and harmonious development. Health is a reserve of organ capacity that needs to be improved during regular exercise training and a healthy lifestyle. Physical culture and sports are part of the general culture. As a safeguard, it helps to get rid of the negative aspects of life that hinder the development of the individual in a harmonious relationship with society. The level of physical activity of the country's population, by age, is below the minimum allowable. Hypodynamia is one of the leading causes of death and disability. The strategy for the development of physical culture, recommendation for the development of physical education and sports among students are state documents. They are developed with the participation of the specialists and sent for implementation to institutions. The help to direct forces to a new positive, responsible attitude ti physical training, physical working capacity of our future experts, heads, citizens of the country. The statistics provided in the documents finally prove that the crisis has reached significant proportions and may lead to negative consequences for Ukrainians and their future. Many factors and conditions can change the attitude of young people to physical culture and sports to a positive vision. The main thing is for young people to know that all the measures aimed at them have been implemented.

PERBEDAAN KAPASITAS KERJA FISIK PEKERJA NON PRODUKSI, WEAVING, DAN SPINNING PABRIK TEKSTIL BANDUNG

Workers of PT. Grandtex is divided into three different divisions; nonproduction division, weaving division, and spinning division. These workers have different activities, job processes, and work environments, especially in the cotton dust exposure rate. Exposure to cotton dust can influence physical working capacity. This study aimed to find out physical working capacity differences between workers of nonproduction division, weaving division, and spinning division. A comparative analytic survey study is conducted on 112 subjects, which consists of 32 nonproduction division workers, 40 weaving division workers, and 40 spinning division workers. Subjects are picked by the stratified random sampling method. Physical working capacity measured by using an anaerobic capacity parameter (V̇O2 max)with the Astrand-Rhyming chair test. The homogeneity of the result is tested by the Levene test and the normality is tested by Kolmogorov-Smirnov. To find out the differences, those data are analyzed by one-way ANOVA test (p&lt;0,05) and followed by Duncan test to measure how big the differences are. The result of data analyzed with ANOVA indicated that there is a significant difference in physical working capacity (V̇O2 max)(p=0,000) among workers of nonproduction, weaving, and spinning division. This result was also followed by Duncan’s test suggesting thatthe physical working capacity (V̇O2 max) of nonproduction workers are bigger than weaving production workers and also bigger than spinning workers (35,78 ± 7,27 vs 31,50 ± 7,59 vs 28,03 ± 5,92 ml/kg BW/minute). From this study, we can conclude that the physical working capacity (V̇O2 max) of nonproduction workers is better than weaving and spinning division workers.

Personal protective equipment for Health care workers donning for COVID-19 areas: Walking a tight rope between safety and comfort!

Dear Editor, Coronavirus disease-2019 (COVID-19) pandemic has infected more than 180 million cases worldwide. The frontline healthcare workers (HCWs) battling the disease need to don into personal protective equipment (PPE) to protect themselves from the infection.[1] An N95 respirator is a protective mask designed to achieve an efficient filtration (block at least 95% of particles >0.3 μm in size). Its incorrect use could compromise its protective effect and may even increase the risk of infection.[23] This is especially important for anesthesiologists who are frequently involved in aerosol-generating procedures like noninvasive ventilation, tracheal intubation or extubation. The most important consideration for the effectiveness of a mask is its fit on the HCWs face and its filtration efficacy. A tightly fit mask may lead to discomfort, claustrophobia, pressure on the face and difficulty in breathing.[1] Previous studies have observed that the HCW's compliance with use of N95 mask and the recommended PPE is generally poor because the respirators reduce the maximal physical work capacity by increasing the inspiratory resistance, expiratory resistance, and dead space. COVID areas have limited air conditioning and the non-valved masks may become wet with usage earlier due to inability to dissipate humidity. The resistance offered by the non-valved masks during expiration may lead to headache, inability to concentrate, shortness of breath, dizziness, rise in blood pressure, and fatigue due to accumulation of carbon dioxide.[4] This may increase mask handling and increase the risk of infection to the HCW. In addition, non-valved N95 masks may increase the fogging of goggles and face shield and that makes procedures like intubation difficult for HCW especially with a prolonged donning (6–8 h period usually), in the already cumbersome conditions (PPE and aerosol box).[5] The valved variety allows unimpeded exhalation through one-way valve. An exhalation valve in the N95 masks may help to dissipate humidity, heat, and carbon dioxide from the dead space and decrease exhalation resistance. However, an infected person wearing a valved mask may spread the virus to others around him. No previous study has identified the impact of mask type on COVID-19 transmission. A valved N95 mask may be more acceptable for the HCW, but there is a distinct possibility of transmition of the infection to others. This can be minimized by daily screening of the HCWs before coming for duty, maintaining a safe distance from each other and wearing a surgical mask over it. The stress of working in COVID areas with PPE during the present pandemic has already dented the morale of HCWs. We should ensure comfort of the HCWs along with the safety for others. Based on logical thinking a valved mask should be avoided when working in non-COVID or COVID suspect areas. However, in COVID positive areas where prolonged continuous donning in full PPE is required and risk of infection from HCW to others is negligible, valved mask would offer the best balance of breathing comfort and safety to the provider. Centers for disease control and prevention (CDC) also mentions that valve in N95 masks reduces the exhalation resistance and makes it more comfortable to wear without reducing their efficacy in prevention of infection to the HCWs caring for COVID positive patients.[6] Further research could give invaluable insights for clarifying the risks and level of safety associated with the use of either type of devices and in framing appropriate policies regarding the appropriate type of PPE in various circumstances. We would urge the manufacturers to deliberate into mask designs with appropriate certification like 'SITARA' and are universally acceptable to all HCWs in tackling the pandemic of COVID-19. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

An advanced empirical model for quantifying the impact of heat and climate change on human physical work capacity

Occupational heat stress directly hampers physical work capacity (PWC), with large economic consequences for industries and regions vulnerable to global warming. Accurately quantifying PWC is essential for forecasting impacts of different climate change scenarios, but the current state of knowledge is limited, leading to potential underestimations in mild heat, and overestimations in extreme heat. We therefore developed advanced empirical equations for PWC based on 338 work sessions in climatic chambers (low air movement, no solar radiation) spanning mild to extreme heat stress. Equations for PWC are available based on air temperature and humidity, for a suite of heat stress assessment metrics, and mean skin temperature. Our models are highly sensitive to mild heat and to our knowledge are the first to include empirical data across the full range of warm and hot environments possible with future climate change across the world. Using wet bulb globe temperature (WBGT) as an example, we noted 10% reductions in PWC at mild heat stress (WBGT = 18°C) and reductions of 78% in the most extreme conditions (WBGT = 40°C). Of the different heat stress indices available, the heat index was the best predictor of group level PWC (R2 = 0.96) but can only be applied in shaded conditions. The skin temperature, but not internal/core temperature, was a strong predictor of PWC (R2 = 0.88), thermal sensation (R2 = 0.84), and thermal comfort (R2 = 0.73). The models presented apply to occupational workloads and can be used in climate projection models to predict economic and social consequences of climate change.

Physiological criteria for improving labor intensity classification used in occupational risks assessment

The paper focuses on results of substantiating and selecting informative physiological criteria that can be used for assessing and controlling functional state and working conditions category taking into account physical and nervous-emotional loads borne by CNC- machinery operators. Basing on complex physiological and ergonomic studies and retrospective data analysis, we showed that workers from various occupational groups who dealt with physical labor had to face certain strain over a working shift. Such strains, given long-term working experience, could result in neuromuscular system overstrain and occupational diseases occurrence. We substantiated and developed informative physiological criteria that allowed assessing and controlling functional state and working capacity as well as working conditions category taking into account occupational activities. The present research involved using a set of occupational studies, physiological and ergonomic procedures as well as clinical and statistic ones for examining peculiarities related to functional state of workers’ bodies under exposure to occupational factors taking into account specific working tasks and loads. It allowed us to substantiate labor intensity assessment. Our research results revealed that there was a strong correlation between hand muscles endurance to static exertion (decrease in % by the end of a work shift) and working conditions category given local and overall muscular loads borne by workers. This criterion is recommended for control over functional state and working capacity taking into account occupational peculiarities and gender-related differences. It is necessary to accumulate scientific data for confirming a similar correlation between overall physical working capacity (OPWC) and working conditions category. Results obtained via physiological research were used for developing prevention activities for workers.