Cardiovascular Load Research Articles

Workload Measurement Using the Cardiovascular Load Method and Defense Research Agency Workload Scale

Workload is a collection of tasks set to be completed within a specific time. The workload can be broken down into "qualitative" (too much or too little) or "quantitative" (too much or too little), which occurs when people are unable to complete tasks or if they do not utilize the abilities they have in achieving a particular job. This study aimed to determine the workload of workers engaged in the sale of fresh or cut chicken meat. Cardiovascular Load is an estimate to determine the classification of workload based on the increase in work pulse compared to the maximum heart rate. The Defense Research Agency Workload Scale (DRAWS) method is a multidimensional technique that involves participants through subjective questions and assessments consisting of four workload dimensions: input demand, central demand, output demand, and time pressure. The results showed that the workload pulse using Cardiovascular Load, the level of fatigue based on workload obtained at the chicken slaughter station by worker 1 was 44.77%, and worker 2 was 41.11% with the category of improvement needed. At the chicken cleaning station, worker 1 was 44.13%, and worker 2 was 47.43%, with the category of needed improvement. At the chicken cutting station, worker 1 was 43.73%, and worker 2 was 45.85%, with the category of needed improvement. The study's DRAWS method results showed that at the chicken slaughtering station, worker 1 was 84.25%, and worker 2 was 87.05% with the overload category. At the chicken cleaning station, worker 1 was 86.75%, and worker 2 was 84.20% with the overload category. At the chicken cutting station, worker 1 was 85.75%, and worker 2 was 81.30%, with the overload category. This means that six respondents felt a high mental burden, so improvements are needed to reduce the impact of the cognitive workload of workers. The upgrades provided include the provision of chairs around the work area, especially at the chicken slaughtering station, so that workers can sit and rest for a moment to reduce the physical workload experienced by workers.

The chronobiology of human heart failure: clinical implications and therapeutic opportunities.

Circadian variation in cardiovascular and metabolic dynamics arises from interactions between intrinsic rhythms and extrinsic cues. By anticipating and accommodating adaptation to awakening and activity, their synthesis maintains homeostasis and maximizes efficiency, flexibility, and resilience. The dyssynchrony of cardiovascular load and energetic capacity arising from attenuation or loss of such rhythms is strongly associated with incident heart failure (HF). Once established, molecular, neurohormonal, and metabolic rhythms are frequently misaligned with each other and with extrinsic cycles, contributing to HF progression and adverse outcomes. Realignment of biological rhythms via lifestyle interventions, chronotherapy, and time-tailored autonomic modulation represents an appealing potential strategy for improving HF-related morbidity and mortality.

Primary and secondary allostatic processes in the context of high-stress work: A multigroup moderation from the English longitudinal study of ageing

Evidence suggests that chronic cortisol excess may precede the development of an allostatic load, and that this association may be influenced by the level of work stress. This study aims to investigate the associations between hair cortisol concentration and the development of systemic allostatic load cross-sectionally and at a lag of four years, stratified by level of effort-reward imbalance.The sample consisted of respondents from the English Longitudinal Study of Ageing (ELSA) who were in employment with hair cortisol measurements at baseline (wave 6), and allostatic load markers at baseline and follow-up (wave 8; n=411; 64 % female). Hair cortisol was used as a measure of total cortisol expression over the preceding two months. Allostatic load was modelled as a count-based index using nine markers; three per system, across the immune, metabolic and cardiovascular systems. This model was then grouped by a median-cut effort reward-imbalance scale (0.83) and regression pathways were compared between groups using a series of Chi-Squared tests of difference.Results provide evidence that higher hair cortisol concentrations predict an increase in immune and cardiovascular allostatic load cross-sectionally, and a metabolic allostatic load at a lag of four years. These pathways were found in the high effort-reward imbalance group, but not in the low effort-reward imbalance group. There were also significant differences found between groups for hair cortisol concentration as a predictor of concurrent immune and cardiovascular allostatic loadFindings may indicate a novel temporality to the accumulation of an allostatic load, and that the “tipping point” between allostasis and allostatic load may lie within the ability of the HPA axis to regulate the cardiovascular system concurrently, with longitudinal consequences for metabolic syndrome indicators.

The Impact of Body Composition and Physical Fitness on Parasympathetic Reactivation in Firefighters

Objective: Firefighting involves aerobic and anaerobic physical activities that cause heart rates to rise from submaximal to above maximal levels. These varying demands can occur with each call firefighters respond to during their shift, imposing both acute and cumulative cardiovascular loads. Heart rate is commonly used to measure cardiovascular responses during disasters, emergencies, firefighting, and firefighting simulations. There is substantial evidence suggesting that heart rate recovery (HRR) parameters are associated with body composition and aerobic fitness. Therefore, the primary aim of this study is to determine the relationship between body composition, physical fitness, and HRR parameters in firefighters. Method: This cross-sectional descriptive study was conducted among firefighters working in a metropolitan municipality. Using the G-Power 3.1 program, seventy-four firefighters (age = 32.61 ± 8.9 years, height = 1.76 ± 0.6 cm, weight = 83.9 ± 13 kg) volunteered to participate in this study. Body mass index (BMI), waist circumference (WC), and body fat percentage (BFP) were recorded for each subject. To determine aerobic fitness (VO2max), each participant performed a submaximal exercise test on a treadmill. HRR was calculated as the difference between peak heart rates post-exercise (HRmax) and heart rates at the first and second minutes of the recovery phase, recorded as HRR1 and HRR2, respectively. Results: The mean VO2max and BMI of the participants were 48.32 ± 9.18 ml/kg/min and 27.10 ± 3.49 kg/m², respectively. No significant relationship was found between the HRR1 and HRR2 parameters and the variables of BMI, WC, and BFP in firefighters (p>0.05). However, positive significant relationships were detected between HRR1 and HRR2 and VO2max (p<0.05). A statistically significant negative relationship was found between VO2max and the variables of BMI, WC, BFP, and weight (p<0.05). These findings indicate that higher aerobic capacity is associated with better heart rate recovery and lower body fat percentage. Conclusion: The results of this study demonstrate that cardiovascular autonomic function is significantly related to maximum aerobic fitness. However, no measure of body composition appears to affect the overall HRR response of the firefighters. This research provides important insights into how the aerobic capacity of firefighters affects their heart rate recovery responses. These findings offer a crucial foundation for improving the physical fitness levels and maintaining the cardiovascular health of firefighters.

Shift Work System Analysis of Store Employee Fatigue Using the Subjective Self Rating Test and Independent Sample T Test Methods (Case of Sports Station Plaza Surabaya)

This study analyzed the initial symptoms of fatigue and measured the level of fatigue with the subjective self rating test method as the subjective method, the CVL (Cardiovascular Load) method as the objective, and the independent sample t test at the Plaza Surabaya sports station. shop. Shift work in the workshop has the potential to pose health risks in the form of fatigue due to differences in physical workload experienced in each shift. Sports Station Plaza Surabaya outlets face work activity problems that are at risk of ergonomics, with several worker complaints due to work shifts that only do rotating shifts per month and unclear employee jobdesk placements. The Subjective Self Rating Test method is used to identify early symptoms of employee fatigue by filling out a questionnaire, the CVL method is used to measure pulse to obtain the level of physical workload fatigue experienced by employees. While the independent sample t test test is to find out whether there is a significant difference in the level of shift fatigue at the Sports Station Plaza Surabaya store. get the highest classification value in shift 1, for the independent t test test method get a significance value of 0.01 which means there is a significant difference in the level of worker fatigue in shift 1 and shift 2.

Workload analysis using energy expenditure and the work posture evaluation approach with brief method at PT XYZ

Abstract PT XYZ is a company operating in the tire retreading sector on JL. Medan-Banda Aceh, Cot Seurani Village, Muara Batu District, Aceh Utara. Retreading truck tires is carried out through several processes such as inspection, grating, repairing, gluing tire, installing tire treads, installing wheels and rings, cooking tires and finishing. The vulcanization process which is carried out manually and repeatedly makes workers easily fatigued, making them vulnerable to injury and the risk of Musculoskeletal Disorders (MSDs). This research aims to calculate the workload of PT XYZ workers. PT XYZ to determine the level of worker fatigue using the Energy Expenditure approach and assessing worker work posture using the BRIEF method to assess work postures that cause complaints of pain in workers’ body parts. Researchers measured the resting pulse and working pulse of 8 workers, then classified the Cardiovascular Load (%CVL) and Energy Expenditure workload levels of the workers and assessed work posture using the BRIEF worksheet. The results of calculating the worker’s workload obtained an average %CVL value of 57.92%, the average result of the worker’s Energy Expenditure was 6,8048 Kcal/8 hours with very heavy work criteria. The average BRIEF work posture value is 3.28 in the high risk category. The suggestions given regarding the problem of workers who easily experience fatigue, high workloads and unergonomic work postures are to increase the number of workers, add benchrest jacks at each work station, add a table with wheels and rings and add chairs for finishing workers, lighten the work and reduce excessive bending activities for tire retreading workers.

Possibilities of backward walking application in the rehabilitation of patients with gonarthrosis: review

INTRODUCTION. Osteoarthritis of the knee joint or gonarthrosis (GA) is one of the most common joint pathologies. The medical and social significance of GA is associated with its high prevalence and a significant percentage of premature disability and a significant deterioration in the quality of life due to persistent pain syndrome. Modern treatment of patients with GA includes a combination of pharmacological and non-pharmacological methods; physical therapy is the leading method of non-drug therapy. By now, a number of studies have been conducted to research the effectiveness of backward walking (BW) in people with GA. AIM. Analysis of scientific data on the possibilities of using BW in the rehabilitation of patients with GA. MATERIALS AND METHODS. A systematic search of literary sources by keywords was carried out: “backward walking”, “gonarthrosis”, “knee osteoarthritis”, “knee joint”, “rehabilitation”, “physical therapy”. DISCUSSION. Recently, backward locomotion is increasingly used in medicine. Kinetic and kinematic analysis during BW showed a number of advantages over the usual method of movement, which can be successfully used for rehabilitation of patients with GA. BW is associated with less overload on knee joints. It is also one of the few natural ways of strengthening the quadriceps. It prevents excessive stretching of the anterior cruciate ligament and improves the stability of the knee joint. BW leads to a more cardiovascular and respiratory load and a more significant aerobic and anaerobic capacity of the organism compared with forward walking at similar parameters of physical activity. CONCLUSION. There is evidence that adding BW to conventional physiotherapy treatment may further reduce pain, functional disability and improve the strength of the quadriceps muscles.

Cardiovascular Demand Differences Between Male and Female US Marine Recruits During Progressive Loaded Hikes.

Schram, B, Orr, R, Niederberger, B, Givens, A, Bernards, J, and Kelly, KR. Cardiovascular demand differences between male and female US Marine recruits during progressive loaded hikes. J Strength Cond Res 38(8): e454-e458, 2024-Despite having to carry the same occupational load, female soldiers tend to be lighter than male soldiers. The aim of this study was to determine the differences in cardiovascular load between female and male US Marine recruits during progressive load carriage hikes. United States Marine Corps recruits (565 male recruits; 364 female recruits) completed 6 loaded hikes over 6 weeks (1: 10 kg, 30 minutes; 2: 10 kg, 45 minutes; 3: 15 kg, 30 minutes, 4: 15 kg, 45 minutes; 5: 20 kg, 30 minutes; 6: 20 kg, 45 minutes) during which cardiovascular response was measured. Average heart rate (HRavg), HR maximum (HRmax), and pace were measured via a wrist-worn physiological monitor. Independent sample t -tests were conducted to compare between sexes, with significance set at 0.008 after adjusting for multiple comparisons. The average female recruit had significantly lower body mass (BM) compared with the average male recruit ( p < 0.001) and thus carried a significantly heavier relative load. (10 kg ∼17%, 15 kg ∼25%, 20 kg ∼33%, p < 0.001). There were no significant differences in pace in any hike, and no significant differences were found in HRavg or HRmax when comparing female and male Marines during Hike 1. For female Marines, HRavg was significantly higher compared with male Marines during Hike 2 (+6.5 b·min -1 , p < 0.001) and Hike 3 (+7.4 b·min -1 , p < 0.001), and both HRavg and HRmax were significantly higher in Hike 4 (+11.9 b·min -1 , +8.4 b·min -1 , p < 0.001), Hike 5 (+7.7 b·min -1 , +7.9 b·min -1 , p < 0.001), and Hike 6 (+6.9 b·min -1 , +7.1 b·min -1 , p < 0.001), respectively. Female Marines endured greater cardiovascular demand compared with male Marines during load carriage events when carrying loads greater than 15 kg (∼25% BM).

Rancang Bangun Alat Angkut Bahan Baku Guna Meningkatkan Efektivitas Material Handling dengan Pendekatan Ergonomi

PT Candi Jaya Amerta is a company engaged in the food sector and produces various types of traditional crackers, such as shrimp crackers, fish crackers, and other variations. The process of manually transporting flour raw materials at PT CJA takes a long time so that it can reduce the effectiveness of material handling. In this study, the design of an ergonomic raw material transport tool was carried out with the aim of reducing the level of fatigue in workers and speeding up the process of moving raw materials. the method used is the anthropometric method. the results of collecting anhtropometric data on workers are used to design the tool. the cardiovascular load method is used to measure the level of fatigue of workers based on the pulse rate of workers. the dimensions of the tool have a height of 114cm, width of 80cm, length of 125cm, and tool reach of 88cm. the percentage of worker fatigue is known with % CVL before using the tool design. worker 1 = 72.5%, worker 2 = 61.22% then there is a decrease in fatigue levels after using the tool design to %CVL worker 1 = 43%, worker 2 = 26%.

Sustainable Measurement of Mental and Physical Workloads of Transjakarta Bus Drivers

The number of accidents in the Transjakarta mode of transportation is increasing from year to year. Accidents can occur dueto the driver’s workload which is not ideal so that it affects the driver’s negligence while driving. Therefore, this study aims to investigate the workload experienced by Transjakarta bus drivers using a comprehensive approach that includes questionnaires, pulse measurement, and analytical methods such as NASA-TLX, Cardiovascular Load, Correlation Test. The process of collecting data using the NASA Task Load Index method involving 30 samples of Transjakarta bus drivers was used which was divided into two stages, namely Paired Comparison and Event Scoring. The Cardiovascular Load method was used from calculating the Max Pulse Rate data, calculating %CVL which ends with identifying the results of the average %CVL. The result shows by using the NASA-TLX (mental load) and Cardiovascular Load - CVL (physical load) analysis methods was be used as a source of data that was go through acorrelation test and tested using Minitab software. The results obtained from the NASA-TLX method show that the mental load was quite high with an average value of 70.8%. The CVL result shows that the highest percentage of fatigue level was achieved at value of 27.59%. In addition, Correlation Test Results of %CVL and WWL showed that the correlation between %CVL and WWL was achieved at value of -0.197 and the P-Value was 0.296. It is found that the results of an inverse relationship were found between %CVL and WWL.

Implications of Heat Stress-induced Metabolic Alterations for Endurance Training.

Inducing a heat-acclimated phenotype via repeated heat stress improves exercise capacity and reduces athletes̓ risk of hyperthermia and heat illness. Given the increased number of international sporting events hosted in countries with warmer climates, heat acclimation strategies are increasingly popular among endurance athletes to optimize performance in hot environments. At the tissue level, completing endurance exercise under heat stress may augment endurance training adaptation, including mitochondrial and cardiovascular remodeling due to increased perturbations to cellular homeostasis as a consequence of metabolic and cardiovascular load, and this may improve endurance training adaptation and subsequent performance. This review provides an up-to-date overview of the metabolic impact of heat stress during endurance exercise, including proposed underlying mechanisms of altered substrate utilization. Against this metabolic backdrop, the current literature highlighting the role of heat stress in augmenting training adaptation and subsequent endurance performance will be presented with practical implications and opportunities for future research.

Analysis of Employee Work Posture and Physical Workload Using del Riesgo Individual Evalution and Cardio-Vascular Load Methods

The role of humans as workers is still dominant in carrying out the production process, especially activities carried out manually in Material Handling (MMH). Activities carried out using the MMH method are identified as having a high risk if they are not carried out ergonomically and with a good work system, musculoskeletal complaints can occur due to wrong work postures and physical workload. The production process for SME Barokah Tofu in Kendal Regency is still carried out manually by employees who have identified incorrect work postures due to musculoskeletal complaints and physical workload. Therefore, it is necessary to analyze work posture and physical workload of Barokah Tofu employees who have a high risk to reduce musculoskeletal complaints and high physical workload, as well as provide suggestions for improvements to Barokah Tofu. The methods used in this research are ERIN (Evaluation Del Riesgo Individual) and CVL (Cardiovascular Load). Based on the calculation results, it can be concluded that there are 2 activities that have the results of the classification of work posture and physical workload inversely, namely soybean milling and moulding of tofu where work posture has a high risk and physical workload has a low risk, and there are 2 activities that have a work posture classification result. and the physical workload is directly proportional, namely filtering cooking products with low risk and cutting tofu with high risk. Activities that have a high risk require suggestions for improvements, namely simulation of tool design and Standard Operating Procedures (SOP) for the application of ergonomic principles at work.

Analysis of Work Fatigue in Preventing Work Accidents: A Case Study of Human Comfort Pulse Rate in Wood Processing Industry Workers

Work fatigue in workers in companies can trigger work accidents, which can hurt the company’s work and productivity. Work fatigue can easily result in loss of concentration, so fatigue is often the cause of accidents and deaths. Work comfort for workers needs to be prioritized as a culture of health, safety, security, environment, and quality. This study uses a quantitative approach that aims to analyze fatigue through worker human comfort with a pulse rate indicator as a parameter in monitoring the risk of work accidents in wood processing industry workers. The population in this study was 30 heavy equipment operators in the plywood industry with a total sampling technique. Data analysis using SPSS IBM 20. The results of the study showed results of the study showed an average increase in cardiovascular load of 62.73% and peak work fatigue occurred at 11:30 and 15:30 AM. Companies need to pay attention to safety at these risk hours by evaluating the arrangement of rest and production hours.

Total ergonomics approach to analyze work system and propose improvements for increasing worker productivity

UD. TGM is one of SMEs located in Blora, Central of Java. They can produce 60 – 150 pallets of paving block per hour. Based on observations and measurements, the noise level around production machines is above 90 dB and the temperature around UD. TGM reaches 34°C. Those conditions do not match with the regulatory standards by Ministry of Health of Republic Indonesia. In addition, based on NBM questionnaire, there were 10 complaints of very sick, 7 complaints of pain, and 7 complaints of moderate pain. The worker's cardiovascular load was 36.4% (or needed improvement). Based on the REBA assessment informed that a corrective action needs to be taken immediately. This study aims to analyze the work system totally and provide improvement recommendations. We proposed recommendations by total ergonomics approach collaborated with fishbone diagrams, tree diagrams, and PDPC diagrams. The recommendations were UD. TGM need to create a supervisory team, create work instructions, design additional of transportation tools like a hand stacker, replace dirt floors with paving, enlarge air ventilation holes and add roof height. Then, the evaluation of the recommendations by Catia software, the REBA score was reduced from level 3 to level 1 (or low risk).

Kajian Ergonomika Terhadap Penggunaan Mesin Penggoreng Vacuum

Agricultural machine tools with technology can help processes in agriculture so that time is more effective, cost-effective and improves the quality or quality of plants or products, such as vacuum frying which is used to fry fruit chips that are susceptible to hot temperatures so that the taste of fruit chips from vacuum frying will be similar to the original fruit. The use of agricultural tools and machines cannot be separated from K3 and ergonomics. Therefore this research was conducted for the ergonomics of a vacuum fryer in terms of anthropometry, recommended workload, work fatigue, and the physical work environment. This study used a quantitative method supported by literature studies on the ergonomic dimensions of a vacuum fryer or in accordance with the size of the human body. The results showed that the ergonomic dimensions of the tool corresponded to the dimensions of the operator's body in the form of control box height, stove height, frying tube cover height, pressure output height, pressure regulator height, and stirrer lever. The level of operator fatigue is classified as ergonomic because the CVL (Cardiovascular Load) percentage obtained is ≤ 30% so that fatigue does not occur in operating the tool. The recommended workload is classified as ergonomic because the actual load lifted is lower than the RWL calculation results. The temperature measurement is not ergonomic because the temperature exceeds the NAV, while the lighting is classified as ergonomic because it has exceeded the minimum standard value for lighting and the noise measurement is classified as ergonomic because it does not exceed 88 dBA. In operating a vacuum fryer, it can be done in the morning or there is a work station repair so that glare does not occur when using the machine, and when using it, it must be equipped with personal protective equipment (PPE). Keywords: Anthropometry, Ergonomic, Vacuum Fryer

Physiological workload assessment with the help of heart rate and perceived exertion rating on handcart pullers of wholesale trade markets of Delhi.

Background . Handling a heavy load on a handcart is common in the wholesale and retail trade markets in India and many parts of the globe. These carts transport goods between major markets, warehouses and transporters. We assessed the physiological workload among handcart pullers in terms of cardiovascular load (CVL), energy expenditure (EE), heart rate (HR), physiological cost of work and subjective rating of perceived exertion. Methods . Physiological workload was assessed with the help of HR during resting, working (15 minutes) and recovery state with a smart wearable device to extrapolate percentage of CVL, EE and physiological cost of work among handcart pullers. Subjective assessment of exertion was measured with the Borg 5-point rating scale among 35 cart pullers. Data were analysed using Microsoft Excel version 2010. Results . It was found that in handcart-pulling activity, EE was 11.706 kJ/minute, average working HR was 128 beats/minute and physiological cost of work was 89.09 beats/minute with no loads on handcart. This signifies that the activity falls under heavy physiological workload. The average percentage of CVL was found to be 50.5%, which falls under acceptable category for persons with a healthy cardiovascular system. Thirty-one (88.6%) of the participants reported the activity to be moderately heavy, whereas 4 (11.4%) participants mentioned it to be light. Conclusions . Handcart-pulling operation in this study without load on cart was found to be a heavy physiological workload. In real-time situations, the load, road conditions, long duration and traffic congestion is likely to result in a higher range of physiological workload on cart pullers.

Analisis Beban Kerja di Laboratorium Produksi PT. XYZ Dengan Metode CVL dan NASA-TLX

To evaluate the workload, one can consider the combination of physical and mental effort that employees undergo. The quantification of physical workload is accomplished through the utilization of the Cardiovascular Load (%CVL) methodology, whereas the evaluation of mental workload is conducted employing the NASA-TLX methodology. Pulse measurement is employed to gather data on the physical exertion level. Concurrently, the cognitive load was alleviated by administering NASA-TLX surveys to the personnel. The physical workload measurements were acquired from a sample of 12 employees who showed no indications of fatigue. Meanwhile, the measurements of mental workload indicate a substantial level of both elevated and extremely elevated workload One employee was classified as having an extremely heavy workload, while the majority of respondents (11 out of 12) assessed their workload as high. The results suggest that around 33% of employees face a substantial mental workload, underscoring the need for a leadership policy focused on workload reduction.

Sex-Specific Variations in Vitamin D and Vitamin D Binding Protein (Vdbp) and Flipped Pattern of their Association in Preeclamptic Women with Dyslipidemia.

Women with preeclampsia frequently have disorders of calcium metabolism during their pregnancies, including hypocalciuria and low vitamin D levels. The link between fetal sex and vitamin D and vitamin D binding protein levels in pregnancy and preeclampsia is not clear. Present study was designed to explore sex-specific variations in vitamin D and vitamin D binding protein levels in maternal and umbilical cord blood samples for age and gestation matched 20 primigravida normotensive and 20 primigravida with preeclampsia with a singleton pregnancy. Routine investigations, vitamin D binding protein (VDBP), and serum vitamin D in both maternal serum and cord blood were measured in both groups. Association between maternal and cord blood vitamin D levels was highly positive in both cases and control with babies of either sex. This association exhibited sexual dimorphism between cord blood vitamin D and vitamin D binding protein (VDBP) suggesting that the occurrence of pregnancy complications differs according to fetal sex with a higher cardiovascular and metabolic load for the mother in the presence of a male fetus. Vitamin D binding protein (VDBP) measurement along with vitamin D level should be advised in clinical practice for early detection and screening.

Isolated cardiac muscle contracting against a real-time model of systemic and pulmonary cardiovascular loads.

Isolated cardiac tissues allow a direct assessment of cardiac muscle function and enable precise control of experimental loading conditions. However, current experimental methods do not expose isolated tissues to the same contraction pattern and cardiovascular loads naturally experienced by the heart. In this study, we implement a computational model of systemic-pulmonary impedance that is solved in real time and imposed on contracting isolated rat muscle tissues. This systemic-pulmonary model represents the cardiovascular system as a lumped-parameter, closed-loop circuit. The tissues performed force-length work-loop contractions where the model output informed both the shortening and restretch phases of each work-loop. We compared the muscle mechanics and energetics associated with work-loops driven by the systemic-pulmonary model with that of a model-based loading method that only accounts for shortening. We obtained results that show simultaneous changes of afterload and preload or end-diastolic length of the muscle, as compared with the static, user-defined preload as in the conventional loading method. This feature allows assessment of muscle work output, heat output, and efficiency of contraction as functions of end-diastolic length. The results reveal the behavior of cardiac muscle as a pump source to achieve load-dependent work and efficiency outputs over a wider range of loads. This study offers potential applications of the model to investigate cardiac muscle response to hemodynamic coupling between systemic and pulmonary circulations in an in vitro setting.NEW & NOTEWORTHY We present the use of a "closed-loop" model of systemic and pulmonary circulations to apply, for the first time, real-time model-calculated preload and afterload to isolated cardiac muscle preparations. This method extends current experimental protocols where only afterload has been considered. The extension to include preload provides the opportunity to investigate ventricular muscle response to hemodynamic coupling and as a pump source across a wider range of cardiovascular loads.

An Analysis of Physiological Workload on Pure Coconut Oil Production Process

This study aims to analyze the physiological workload in the virgin coconut oil production process based on energy expenditure evaluations and determine rest periods to ensure that work does not require excessive energy. Assessment of workload objectively using pulse indicators and energy consumption (energy cost) observations at the four stages of the virgin coconut oil production process, namely the process of stripping the coconut husk, the process of cutting the coconut shell, the process of grating the coconut and the process of cooking the coconut milk. The energy expenditure of workers in the coconut coir stripping section is 5,138 kcal/min, the coconut shell cutting section is 2,552 kcal/min, the coconut meat grating section is 3,575 kcal/min, and the coconut milk cooking section is 2,885 kcal/min. Hence the coco coir stripping workstation is included in the heavy workload category with an average cardiovascular load value of %CVL of 56%, which means that the work needs to be improved; the recommended work-rest cycle for workers at the coco peeling workstation is 47 minutes. The workstation for cutting coconut shells to cooking coconut milk is included in the category of moderate workload with a value of %CVL ≤33%, still within the recommended workload limit.