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Results for “work intensity”

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At least 19 recordsLinked to original sources

PubMed1997

[Work intensity during working hours and different types of care done by special nursing home workers].

This study was done to estimated work intensity during working hours and different types of care to obtain basic data for making a care program. The subjects were care workers in good health (n = 8, 24-45 years) who worked in a special nursing home. The estimated maximal oxygen intake level, which is the maximal aerobic capacity, of each subject was assessed as normal to very good. The energy expenditure was 1787 +/- 534kcal during working hours. The work intensity was 0.061 +/- 0.011kcal/kg/min, 2.7 +/- 0.7RMR, 98 +/- 6beats/min, and 30.3 +/- 2.0% VO2max. Among the duties assessed for work intensity, bathing had the highest intensity, followed by transferring, changing diapers, feeding, and dressing. The work intensity of bathing was 0.081 +/- 0.31kcal/kg/min, 3.9 +/- 1.0RMR, and 40.0 +/- 6.1 VO2 max, which was significantly higher than feeding, dressing, and transferring(p < 0.05). Care giving at the time of bathing was significantly longer than the other care types (p < 0.05). Feeding and transferring by inexperienced care workers were significantly low intensity (p < 0.05). Work intensity of care was at high levels within the maximal permissible level in which fatigue doesn't make an appearance during working hours and in five types of care. Furthermore, care work intensity increased according to a decrease in the ADL level among the elderly. It is concluded that when making a care program, it is important to consider the ADL level of the elderly, work intensity and the amount of care-giving time, not only to maintain the health of care workers, but, also, to give superior quality care to the elderly.

Activities of Daily Living↗

PubMed2001

Determining the maximum acceptable work duration for high-intensity work.

The aim of this study was to determine the maximum acceptable work duration (MAWD) for high-intensity work. Thirty young individuals participated in this study. Their maximum oxygen uptake (VO2max) and maximum work rate (MWR) were assessed first. Each subject then performed two cycling tests (60% and 70% MWR) on two separate days. Oxygen uptake and heart rate data were collected throughout the test. The results indicate that the MAWD in the 60% MWR test (18.8 min) was about threefold greater than the MAWD in the 70% MWR test (6.5 min). The MAWD was inversely correlated with the relative workload indices: relative oxygen uptake (RVO2; r = -0.82, P < 0.001) and relative heart rate (RHR; r = -0.79, P < 0.001). The RVO2 was defined as the elevation in oxygen uptake from the resting level as a percentage of the difference between maximum and resting oxygen uptake. The RHR was defined as the elevation in heart rate from the resting level as a percentage of the difference between maximum and restingheart rate. Furthermore, more than 80% of the variations were explained by the exponential decrease regression model for predicting MAWD using the above two variables. The findings of this study can provide useful information for the design of high-intensity jobs.

Adult↗

PubMedDate not supplied

Issues of work intensity, pace, and sustainability in relation to work context and nutritional status.

This article raises issues about work intensity, pace, and sustainability during physical activity, focusing attention on the nature of work in labor-intensive societies, the management of exertion in habitual tasks, and the health and broad socioeconomic correlates of alternative ways to regulate work patterns. At the heart of this review are concerns to document human adaptability (in terms of the physical and behavioral management of heavy work) and to renew debate regarding the conceptualization and measurement of work intensity (variously evaluated in absolute or relative terms, as indexed by oxygen consumption, energy expenditure, percentage maximal work capacity, heart rate elevation, time and motion indicators, or physiological cost). Three questions are examined: Is heavy work primarily a matter of time or energy intensity? How is heavy work habitually sustained? What is the bigger picture relating work performance to work context and to nutritional or health status? It is argued that many arduous activities, such as carrying loads, demand endurance over time rather than intensive effort per unit time, and that work pace management lies in regulating both the rate of work and the time in rest during physical activity. Furthermore, strategies that maximize long-term endurance (adopted by "tortoises") and those that maximize short-term productivity (adopted by "hares") are appropriate to different work contexts (e.g., a subsistence or wage-labor economy) and suit individuals with different health status and ability. Thus, work intensity is an important aspect of the links between physical activity, health, productivity, and society, as noted in literature reviewing objectives for sustainable development and public health messages for disease risk management. These areas of scholarship are underresearched, partly because consensus has been slow in agreeing on which are the best measures of work pace and work intensity for use in field situations, and which are the most meaningful thresholds for evaluating absolute or relative effort across a range of populations.

Agriculture↗

PubMed1981

Standardization of work intensity for evaluation of exercise-induced bronchoconstriction.

Reactivity of airways to 6 min of graded intensity treadmill work was studied in nine asthmatic and 15 non-asthmatic subjects. After performing a progressive VO2 max treadmill test, each subject completed five 6-min exercise tests at selected intensities: 40, 60, 80, and 100% VO2 max; and at 80% of VO2 max predicted from heartrate. Pulmonary function measures recorded after exercise demonstrated a direct relationship between work intensity and exercise induced bronchoconstriction (EIB) for both groups, with the asthmatics showing their lowest values at 80% VO2 max. Heartrate-set work intensities produced a wide range of aerobic demand, thus significantly increasing the variability of the EIB response recorded.

Adult↗

PubMed1986

Mechanical efficiency of pure positive and pure negative work with special reference to the work intensity.

The mechanical efficiencies of pure positive (eta) and pure negative (eta-) work were investigated on a special "sledge ergometer" with 25 and 36 subjects, respectively. The work intensities varied in positive work between 40% and 90% and in negative work from 30% to 120% of the maximum concentric exercise. In 54 exercises of positive work, eta was 17.1% +/- 2.2%, and its value correlated negatively with the work intensity (r = 0.367, P less than 0.01) and with the average knee angular velocity, omega+ (r = 0.359, P less than 0.01). In 103 eccentric exercises, eta- was on the average 80.2% +/- 31.8%, correlating positively with the work intensity (r = 0.396, P less than 0.01). Both inter- and intrasubject variations were large (32%-163%). The integrated electrical activity (IEMG) of the leg extensor muscles increased with an increase of work intensity both in the positive and in the negative work situations. Less efficient MU recruitment in higher positive work rates is suggested to be the reason for the decrease in eta, whereas better stiffness regulation via increased preactivation is speculated to cause high values of eta- in higher work intensities in eccentric exercise.

Biomechanical Phenomena↗

PubMed1997

The relationship between electromyography and work intensity revisited: a brief review with references to lacticacidosis and hyperammonia.

The aim of this investigation was to re-evaluate the relationship between electromyography and work intensity during incremental work in light of highly discrepant literature. Trained male subjects participated in the study (n = 14). Each subject completed a VO2max test on a cycle ergometer. Tests started at a power output of 60 Watts with a 30 Watt.4 min-1 work increment. Each test was terminated at exhaustion. Blood was collected at the end of each work intensity for lactate and ammonia analysis. EMG were recorded from the vastus lateralis, rectus femoris and vastus medialis using pre-amplified surface electrodes. EMG were collected at each intensity over a period of 60 cycle revolutions. EMG signals were analyzed using integration and EMG spectral analysis. Gas exchange variables were recorded on-line for each test (15 second interval). Ammonia and lactate threshold points were surpassed at the same absolute work intensity (200 Watts) which was equivalent to 64-69% VO2max. When a linear model was applied to the iEMG data, coefficients of determination achieved were greater than those obtained when an exponential model was used for the vastus lateralis and medialis. Gradients of regression lines fitted to iEMG data at pre- and post-lactate/ammonia threshold work intensities were not different. Alternatively, the iEMG-work intensity relationship for the rectus femoris muscle tended to be curvilinear. Significant increases in iEMG were observed at post-lactate/ammonia threshold work intensities for the rectus femoris reflecting increases in fatigue and type II motor unit recruitment at these intensities. In general, median frequency of the EMG power spectrum function were unchanged during incremental work, although highly individualistic results were observed between some subjects and muscles. Grouped median frequency values were insensitive to changes in recruitment, metabolite accumulation and fatigue associated with the increases in work intensity. Consequently, the usefulness of EMG spectral analysis during incremental work was questioned.

Acidosis, Lactic↗

PubMed2004

Why is work intensity associated with heavy alcohol use among adolescents?

PURPOSE: To examine and explain the relationship between work intensity (number of hours worked per week) and heavy alcohol use among adolescents. METHODS: Analyses were conducted with two waves of in-home interview data provided by a representative sample of adolescents who participated in the National Longitudinal Study of Adolescent Health. Multinomial logistic regression analyses were conducted to determine whether a higher level of work intensity at Wave 1 predicted a higher level of past-year heavy drinking approximately 1 year later at Wave 2, and the degree to which the relationship between work intensity and heavy drinking persisted after adjusting for demographic characteristics, alcohol use before Wave 1, and psychosocial risk and protective factors in family, school, and peer-individual domains. RESULTS: Higher levels of work intensity at Wave 1 (11-20 or more than 20 hours/week) were predictive of heavy drinking at Wave 2. However, these effects were substantially attenuated after adjusting for demographic characteristics and prior alcohol use. Risk and protective factors such as school commitment, friends' drinking, and delinquency also partially explained the effects of work intensity and background variables on heavy drinking, suggesting that these factors may act as confounders and/or mediators. CONCLUSIONS: This study suggests that working more than 10 h/week increases the likelihood of heavy alcohol use among adolescents, and that the effect of work intensity is largely, but not completely attributable to demographic characteristics (e.g., age, race/ethnicity, personal income), prior alcohol use, and family, school, and peer-individual factors.

Adolescent↗

PubMed1997

[Bases of the integral indicator in the determination of the category of work intensity].

Physiologic and clinical examination of mental workers (19 occupational groups) helped to justify and calculate integral parameter evaluating the work intensity, to determine 6 categories of work intensity. Physiologic and clinical data prove that higher integral parameter of work intensity (category of work intensity) correlates with higher degree of strain at work and higher share of the diseased individuals. The results help to improve classification of hygienic criteria for evaluation of work conditions, in particular the work intensity.

Adult↗

PubMed2006

Payer type has little effect on operative rate and surgeons' work intensity.

Does health-care payer type affect the rate of operative treatment and surgeons' work intensity for patients with orthopaedic conditions? We analyzed the clinical and financial data collected during 6 consecutive years (1999-2004) for a group practice of 40 orthopaedic surgeons. We examined the rate of operative treatment and surgeons' work intensity (total physician's work Resource-based Relative Value System units) by diagnosis, patient age, and payer type. The eight payer types were: capitation health maintenance organization, health maintenance organization, preferred provider organization, indemnity, self-pay, Workers' Compensation, Medicaid, and Medicare. There were 230,306 patients with 526 unique primary diagnoses. Diagnosis accounted for most of the variability in operative rates and surgeons' work intensity. After adjusting for differences attributable to diagnosis, payer type had little effect on the rate of operative treatment and surgeons' work intensity.

Adult↗

PubMed2005

The heart rate increase at the onset of high-work intensity exercise is accelerated by central blood volume loading.

Using a water immersion (WI) method, the combined effect of central blood volume (CBV) loading and work intensity on the time course of heart rate (HR) at the onset of upright dynamic exercise was investigated. Seven males cranked a cycle ergometer for 12 min using their un-immersed arms at low-, moderate- and high-work intensities, followed by a 12-min rest. For WI, the pre-exercise resting cardiac output increased by 36%, while HR decreased by 22% [from 76.8 (10.4) to 59.6 (9.8) beats/min]. WI also increased the high-frequency (HF, 0.15-0.40 Hz) component of the HR variability, suggesting an increased vagal activity. During the initial 2 min of the exercise period at low-work intensity, HR increased by 34.9 and 25.8% in the WI and control conditions, respectively. These were 117 and 73% at high-work intensity, indicating more accelerated HR with WI than the control. The plasma norepinephrine concentration increased less during high-work intensity exercise during WI, as compared to exercise during control conditions. In conclusion, the HR increase at the onset of high-work intensity exercise is accelerated by CBV loading but not at low intensity, possibly reflecting vago-sympathetic interaction and reduced baroreflex sensitivity.

Adult↗

PubMed1990

Changes in muscle free carnitine and acetylcarnitine with increasing work intensity in the Thoroughbred horse.

Treadmill exercise in Thoroughbred horses of 2 min duration and increasing intensity resulted in increased formation and accumulation of acetylcarnitine in the working middle gluteal muscle. At high work intensities a plateau in acetylcarnitine formation was reached corresponding to approximately 70% of the total carnitine pool (approx. 30 mmol.kg-1 dry muscle). Formation of acetylcarnitine was mirrored by an equal fall in the free carnitine content, which stabilised, at the highest work intensities, at around 8 mmol.kg-1 dry muscle. Acetylcarnitine and carnitine reached their point of maximum change at a work intensity just below that resulting in the rapid production and accumulation of lactate and glycerol 3-phosphate. It is possible that the formation of acetylcarnitine is important in the regulation of the intramitochondrial acetyl CoA/CoA ratio; equally these changes may represent a blocking mechanism aimed at preventing the transfer of unwanted free fatty acids (as acylcarnitines) into the mitochondria at work intensities where they could contribute little to energy production.

Acetylcarnitine↗

PubMed2003

[Using pulse measurements for physiological regulation of work intensity].

The article covers materials of physiologic evaluation of work intensity through pulse measurements. The authors stress drawbacks of present norms for average shift pulse rate. To evaluate work intensity, the researchers suggest normal value of pulse rate change at the 7th work hour vs at the 2nd hour.

Adult↗

PubMed1976

Effect of three levels of work intensity on performance of a fine motor skill.

The purpose of this study was to investigate the effect of three levels of work intensity on the performance of a fine motor skill during steady-state exercies. Subjects were administered a progressive bicycle ergometer test to exhaustion in order to determine maximum heart rate (HRmax). Following practice sessions on the pursuit rotor, subjects performed 3 different rides on a bicycle ergometer at 60, 75, and 90% of HRmax. The order to test administration was varied randomly in an attempt to control for sequential effects. Analysis of variance with repeated measures was used to determine differences in pursuit rotor performance by days and by levels of work intensity. No confounding of learning was noted. A significant F ratio (p less than .001) between work intensities showed that fine motor performance during steady-state exercise is affected by levels of work intensity.

Adolescent↗

PubMed1989

Cardiorespiratory response to absolute and relative work intensity in untrained men.

Twenty young, untrained men performed two tests on cycle ergometer in order to verify whether the kinetics of the cardiorespiratory reactions exhibit any relation to maximal oxygen uptake (VO2max) in the untrained state. On the 1st day, the subjects exercised at work intensities of 50 and 100 W, the increase as a step function, for periods of 10 min each. The next day, they performed exercise at a relative intensity of 50% VO2max for 10 min. Respiratory frequency, tidal volume, minute ventilation (VE), heart rate (HR), stroke volume (SV), and cardiac output (Q) were measured continuously. The SV was measured by impedance plethysmography. All the cardiorespiratory variables increased rapidly at the onset of both absolute and relative intensity of work, with a faster response for Q than for VE. The increase in absolute intensity of work from 50 to 100 W caused a significantly slower cardiorespiratory reaction than at the beginning of exercise. The SV increased by 20 ml during first 20 s of both absolute and relative intensities of work and then began to decrease after 6 and 4 min of the exercise, respectively. The decrease in SV was associated with an increase in HR and a stable value of Q. Acceleration at the beginning of, and deceleration during recovery from, the relative intensity of work for VE, HR, and Q were well correlated with individual levels of VO2max in the tested men. It is concluded that the kinetics of cardiorespiratory reaction to a constant, relative intensity of work is related to VO2max in untrained men, and that the kinetics probably constitute a physiological feature of an individual.

Adult↗

PubMed2001

Part-time work and hurried adolescence: the links among work intensity, social activities, health behaviors, and substance use.

The present study examines adolescents' part-time work intensity and its relation to participation in various activities as well as substance use. We consider mechanisms articulated in two theoretical perspectives on how high work intensity is associated with substance use: (1) the "time trade-off perspective," and (2) "the precocious development perspective." Nationally representative data were drawn from the "Monitoring the Future" project from 8th, 10th and 12th grade students (overall N approximately 380,000) to address our research questions. Work intensity was found to be linked to more time spent on unstructured social activities, but to less time spent engaged in sports, health behaviors, and school-related activities. Social time use and health behaviors were found to partially mediate the relationship between work hours and substance use. Overall, results provide evidence for a combination of both perspectives.

Adolescent↗

PubMed1999

Shoulder impingement syndrome in relation to shoulder intensive work.

OBJECTIVES: To analyse the risk of shoulder impingement syndrome relative to shoulder intensive work. METHODS: A cross sectional study of a historical cohort of 1591 workers employed between 1986 and 1993 at a slaughterhouse or a chemical factory. Workers not doing tasks in slaughtering or meat processing constituted the reference group. Intensity of shoulder work in meat processing tasks was assessed by video based observations. Information on shoulder disorders was collected by questionnaire and by physical examinations. Impingement syndrome was diagnosed when shoulder symptoms had been present for at least 3 months during the past year and there were signs of subacromial impingement in the corresponding shoulder at physical examination. Shoulder function was assessed at the same occasion with the Constant scoring technique. Prevalence of shoulder impingement syndrome was analysed according to job title and cumulative exposure. RESULTS: Prevalence ratio for shoulder impingement syndrome was 5.27 (95% confidence interval (95% CI), 2.09 to 12.26) among currently working and 7.90 (95% CI, 2.94 to 21.18) among former slaughterhouse workers. Transformed model based prevalence ratios according to years in slaughterhouse work showed an overall association between cumulative exposure and risk for shoulder impingement syndrome. CONCLUSIONS: This study supports the hypothesis that shoulder intensive work is a risk factor for impingement syndrome of the shoulder. Despite the historical cohort design healthy worker selection may have influenced the exposure-response relation found.

Abattoirs↗

PubMed2001

[Regulation of work intensity according to duration, density and pace].

The author describes a method for hygienic regulation of work intensity. The parameters used are "average shift working pace" and "physiologic intensity of work" that summarize three time characteristics of occupational activities--working week duration, density of working time (presence of breaks and pauses within a shift), working pace.

Adolescent↗

PubMed1999

The influence of a nurse practitioner on out of hours work intensity for surgical house officers.

We have prospectively studied the influence of a nurse practitioner service on out of hours work intensity of surgical house officers. Data collection was achieved by prospective audit. The study was set in the surgical wards in a large teaching hospital. The main outcome measures were; 1) the nature and frequency of overnight calls to the nurse practitioner, and 2) the outcome of these calls (doctor not bleeped, telephone advice given by doctor or doctor attended ward). A total of 645 calls were made over the 75 night study period (8.6 calls/night). Two hundred and ninety-six calls were managed by the nurse practitioner alone. This represents a 46% reduction in work intensity for the surgical house officer. This study illustrates the benefits of a nurse practitioner service and also identifies important areas for undergraduate education in preparing medical students for the common problems encountered during the surgical on-call period.

Female↗