Development and validation of the predicted heat strain model

Abstract Eight laboratories participated in a concerted research project on the assessment of hot working conditions. The objectives were, among others, to co-ordinate the work of the main European research teams in the field of thermal factors and to improve the methods available to assess the risks of heat disorders at the workplace, and in particular the "Required Sweat Rate" model as presented in International Standard ISO 7933 Standard (1989). The scientific bases of this standard were thoroughly reviewed and a revised model, called "Predicted Heat Strain" (PHS), was developed. This model was then used to predict the minute by minute sweat rates and rectal temperatures during 909 laboratory and field experiments collected from the partners. The Pearson correlation coefficients between observed and predicted values were equal to 0.76 and 0.66 for laboratory experiments and 0.74 and 0.59 for field experiments, respectively, for the sweat rates and the rectal temperatures. The change in sweat rate with time was predicted more accurately by the PHS model than by the required sweat rate model. This suggests that the PHS model would provide an improved basis upon which to determine allowable exposure times from the predicted heat strain in terms of dehydration and increased core temperature

A ‘heart rate’-based model (PHSHR) for predicting personal heat stress in dynamic working environments

The parameter of human body metabolic rates has been popularly used for the prediction of human heat stress in hot environments. However, most modules use the fixed and estimated metabolic heat production. The aim of this study is to develop the prediction of personal heat stress in dynamic working environments. Based on the framework of the predicted heat stress (PHS) model in ISO 7933, a heart-rate based PHSHR model has been developed using the time-based heart rate index, which is suitable for prediction in situations where metabolic rates are dynamic and there are inter-individual variations. The infinitesimal time unit Δti, has been introduced into the new PHSHR model and all the terms used in the PHS model related to metabolic rates are thus redefined as the function of real-time heart rates. The PHSHR has been validated under 8 experimental combined temperature-humidity conditions in a well-controlled climate chamber. The feature of the PHSHR model is being able to calculate dynamic changes in body metabolism with exposure time. It will be useful to the identification of potential risks of individual workers so to establish an occupational working environment health and safety protection mechanism by means of simultaneous monitoring of workers’ heart rates at the personal levels, using advanced sensor technology

Human Factor and Energy Efficiency in Buildings: Motivating End-Users Behavioural Change

Energy efficiency in buildings does not only rely on efficient technical solutions and design of the building features, but is also highly dependent on how occupants decide to set their comfort criteria, as well as on their energy-related and environmental lifestyles. In this perspective, raising user awareness among occupants by training them to adopt a more “green” and energy-friendly behaviour has become a crucial aspect for reaching energy efficiency goals in buildings. Motivating occupants to change their behaviour can become a challenging task, especially if they are expected to internalize and adopt the new behaviour on a long term. This means that information and feedback provided to the occupants must be stimulating, easy to understand, and easy to adopt in the daily routine. In this context, first methodological progresses are here presented within an European project, designed to raise user awareness, reduce energy consumptions and improve health and IEQ conditions in different typologies of demonstration case studies by providing combined feedback on energy, indoor environmental quality, and health. In particular, this paper presents one out of five MOBISTYLE demonstration testbeds – a residence hotel - located in central Turin (IT). In detail, this paper describes the setup of a tailored engagement campaign for hotel apartments and the reception area. Based on selected monitored variables, user-friendly feedback was defined to provide the users with real-time information on energy use and environmental quality, as well as guidance on how to save energy and optimize consumption profiles while creating an acceptably comfortable and healthy indoor environment

Effect of permissive dehydration on induction and decay of heat acclimation, and temperate exercise performance

Purpose: It has been suggested that dehydration is an independent stimulus for heat 32 acclimation (HA), possibly through influencing fluid-regulation mechanisms and increasing 33 plasma volume (PV) expansion. There is also some evidence that HA may be ergogenic in 34 temperate conditions and that this may be linked to PV expansion. We investigated: i) the 35 influence of dehydration on the time-course of acquisition and decay of HA; ii) whether 36 dehydration augmented any ergogenic benefits in temperate conditions, particularly those related to PV expansion. Methods: Eight males (VO2max: 56.9(7.2) mL·kg-1 ·min-1 37 ) undertook 38 two HA programmes (balanced cross-over design), once drinking to maintain euhydration 39 (HAEu) and once with restricted fluid-intake (HADe). Days 1, 6, 11 and 18 were 60 min exercise- 40 heat stress tests (HST [40°C; 50%RH]), days 2-5 and 7-10 were 90 min, isothermal-strain 41 (Tre~38.5°C), exercise-heat sessions. Performance parameters (VO2max, lactate threshold, 42 efficiency, peak power output [PPO]) were determined pre and post HA by graded exercise test 43 (22°C; 55 %RH). Results: During isothermal-strain sessions hypohydration was achieved in 44 HADe and euhydration maintained in HAEu (average body mass loss -2.71(0.82)% vs. - 45 0.56(0.73)%, P<0.001), but aldosterone concentration, power output and cardiovascular strain 46 were unaffected by dehydration. HA was evident on day 6 (reduced end-exercise Tre [- 0.30°C(0.27)] and exercise heart rate [-12(15) beats.min-1 47 ], increased PV [+7.2(6.4)%] and sweat-loss [+0.25(0.22) L.hr-1 48 ], P<0.05) with some further adaptations on day 11 (further reduced end-exercise Tre [-0.25(0.19)°C] and exercise heart rate [-3(9) beats.min-1 49 ], P<0.05). 50 These adaptations were not notably affected by dehydration and were generally maintained 7- 51 days post HA. Performance parameters were unchanged, apart from increased PPO (+16(20) 52 W, irrespective of condition). Conclusions: When thermal-strain is matched, permissive 53 dehydration which induces a mild, transient, hypohydration does not affect the acquisition and 54 decay of HA, or endurance performance parameters. Irrespective of hydration, trained 55 individuals require >5 days to optimise HA

Musculoskeletal Disorders among Cosmetologists

A cross-sectional study was performed to investigate the relationships between physical, psychosocial, and individual characteristics and different endpoints of low back, neck, shoulder, hand/wrist and knee musculoskeletal complaints among cosmetologists in Athens, Greece. The study population consisted of 95 female and seven male beauty therapists (response rate 90%) with a mean age and duration of employment of 38 and 16 years, respectively. Neck pain was the most prevalent musculoskeletal complaint, reported by 58% of the subjects, while hand/wrist and low back complaints resulted more frequently in self-reported consequences (chronicity, care seeking and absenteeism). Significant relationships were found between self-reported physical risk factors like prolonged sitting, use of vibrating tools, reaching far and awkward body postures and the occurrence of musculoskeletal disorders at various body sites. Among psychosocial variables co-worker support and skill discretion seem to be the most important reflecting organizational problems and cognitive-behavioral aspects. The study results also suggest that effective intervention strategies most likely have to take into account both ergonomic improvements and organizational aspects

The development of an intervention programme to reduce whole-body vibration exposure at work induced by a change in behaviour: a study protocol

<p>Abstract</p> <p>Background</p> <p>Whole body vibration (WBV) exposure at work is common and studies found evidence that this exposure might cause low back pain (LBP). A recent review concluded there is a lack of evidence of effective strategies to reduce WBV exposure. Most research in this field is focussed on the technical implications, although changing behaviour towards WBV exposure might be promising as well. Therefore, we developed an intervention programme to reduce WBV exposure in a population of drivers with the emphasis on a change in behaviour of driver and employer. The hypothesis is that an effective reduction in WBV exposure, in time, will lead to a reduction in LBP as WBV exposure is a proxy for an increased risk of LBP.</p> <p>Methods/Design</p> <p>The intervention programme was developed specifically for the drivers of vibrating vehicles and their employers. The intervention programme will be based on the most important determinants of WBV exposure as track conditions, driving speed, quality of the seat, etc. By increasing knowledge and skills towards changing these determinants, the attitude, social influence and self-efficacy (ASE) of both drivers and employers will be affected having an effect on the level of exposure. We used the well-known ASE model to develop an intervention programme aiming at a change or the intention to change behaviour towards WBV exposure. The developed programme consists of: individual health surveillance, an information brochure, an informative presentation and a report of the performed field measurements.</p> <p>Discussion</p> <p>The study protocol described is advantageous as the intervention program actively tries to change behaviour towards WBV exposure. The near future will show if this intervention program is effective by showing a decrease in WBV exposure.</p

Impact on the Quality of Life of an Educational Program for the Prevention of Work-Related Musculoskeletal Disorders: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Work-related musculoskeletal disorders (WMSD) are a major cause for concern in public health and the main causes of sick leave. Treatments for WMSD have given disappointing results; prevention is the best strategy, but results of preventive measures have not been consistent. To the best of our knowledge there are few studies in literature that evaluated the impact of a specific program aimed at preventing WMSD on the quality of life of employed persons.</p> <p>Methods</p> <p>One hundred and one clerical and production workers in a steel trading company were enrolled in an open-label randomized controlled clinical trial (parallel groups) to compare the efficacy of an educational program for primary prevention of WMSD with control intervention. The primary outcome was a change in the physical functioning domain of the quality of life (QL) measured by Medical Outcomes Study Short Form 36 Health Survey (SF-36). The intervention group underwent six consecutive weekly sessions concerning specific orientations for the prevention of WMSD, while the control group received general health education in an identical schedule. The SF-36 and theses Work Limitation Questionnaire (WLQ) were evaluated at weeks zero, five and 26.</p> <p>Results</p> <p>Baseline characteristics of the interventions groups were comparable, and both groups comprised predominantly young healthy individuals. No significant differences in the variation of the SF-36 and WLQ between the groups were observed at weeks five and 26. However, both groups demonstrated improvement in some aspects of SF-36, suggesting that both educational interventions have beneficial impacts on QL.</p> <p>Conclusions</p> <p>A specific educational program aimed at the preventing of WMSD was comparable with general health orientation for the improvement of QL and work capacity in a sample of healthy workers during a six month period.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00981877">NCT00874718</a></p> <p>Trial Registration</p

The (cost-)effectiveness of a lifestyle physical activity intervention in addition to a work style intervention on the recovery from neck and upper limb symptoms in computer workers

BACKGROUND: Neck and upper limb symptoms are frequently reported by computer workers. Work style interventions are most commonly used to reduce work-related neck and upper limb symptoms but lifestyle physical activity interventions are becoming more popular to enhance workers health and reduce work-related symptoms. A combined approach targeting work style and lifestyle physical activity seems promising, but little is known on the effectiveness of such combined interventions. METHODS/DESIGN: The RSI@Work study is a randomised controlled trial that aims to assess the added value of a lifestyle physical activity intervention in addition to a work style intervention to reduce neck and upper limb symptoms in computer workers. Computer workers from seven Dutch companies with frequent or long-term neck and upper limb symptoms in the preceding six months and/or the last two weeks are randomised into three groups: (1) work style group, (2) work style and physical activity group, or (3) control group. The work style intervention consists of six group meetings in a six month period that take place at the workplace, during work time, and under the supervision of a specially trained counsellor. The goal of this intervention is to stimulate workplace adjustment and to improve body posture, the number and quality of breaks and coping behaviour with regard to high work demands. In the combined (work style and physical activity) intervention the additional goal is to increase moderate to heavy physical activity. The control group receives usual care. Primary outcome measures are degree of recovery, pain intensity, disability, number of days with neck and upper limb symptoms, and number of months without neck and upper limb symptoms. Outcome measures will be assessed at baseline and six and 12 months after randomisation. Cost-effectiveness of the group meetings will be assessed using an employer's perspective. DISCUSSION: This study will be one of the first to assess the added value of a lifestyle physical activity intervention in addition to a work style intervention in reducing neck and upper limb symptoms of computer workers. The results of the study are expected in 2007