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- Sjödin, Fredrik, 1978-
(författare)
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Noise in the preschool : health and preventive measures
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on noise recordings and health evaluations carried out at preschools in the northern part of Sweden. Sound level recordings were made on individuals and by use of stationary devices in dining rooms and play halls. Health evaluations were based on ratings by use of questionnaires and by analyses of cortisol.The average equivalent individual noise exposure was 71 dB(A). The average equivalent noise levels in the dining room and playing halls were 64 dB(A). The hearing loss of the employees was significantly higher for the frequencies tested than in an unexposed control group. Symptoms of tinnitus were reported among 31% of the employees. Noise annoyance was rated as somewhat to very annoying, and the voices of the children were the most annoying noise source. The dB(A) level and fluctuations of the noise exposure were significantly correlated with the number of children per department. Stress and energy output were pronounced among the employees. About 30% of the staff experienced strong burnout syndromes. Mental recovery was low as indicated by noise fatigue and high levels of stress after work. Increased cortisol levels during work were associated with higher number of children present at the department.An essential finding of the thesis was that noise and noise sources may impair the pedagogic work, thereby increasing the work load of employees. It is concluded that noise exposure in the preschool, isolated or in combination with other stressors, plays a fundamental role in the building up of acute as well as long term stress. An intervention study implementing six acoustical and seven organizational measures was tested, aimed to improve the noise situation in the departments. Acoustical measures improved the noise situation as well as the rated noise experiences better than the organizational measures.
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| 2. |
- Lowden, Arne, 1957-
(författare)
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Jet lag and shiftwork : their effects on sleep & sleepiness
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the studies was to describe the detailed sleep/wake patterns before, during, and after a period of work that forces individuals to deviate from their normal sleep/wake pattern. Possible countermeasures to experienced problems was evaluated in intervention designs. Measures of sleep included activity monitoring, sleep and wake diaries and questionnaires. Also performance measures during work were obtained.It was found that in connection to both a westbound and an eastbound flight almost all subjects adapted to local bed times on layover. This increased the wake span during outward and homeward flight days to between 21-28 hours. During flight days napping was found to be very common, especially during flights. Sleep efficiency dropped below 90% during layover in both flight directions, disturbed by awakenings, and gradually returned to normal across four recovery days. Sleepiness symptoms increased during layover, peaked to encompass 25% of the return flight day and gradually decreased across recovery days. The eastbound flight was shown to contain more sleep difficulties and to be more dependent on nap sleep.A possible countermeasure to jet lag was tested in an intervention study, letting crews retain their home-base sleep/wake pattern on layover after westward flight. This reduced jet lag symptoms and sleepiness on layover but not at home. Another intervention was evaluated when a group of shift workers changed from rotating three shift (8-hour) to a 12-hour shift schedule. The data showed that quick changes (8h rest) in the 8-hour schedule increased sleep problems and fatigue. Health, perceived accident risk or reaction time performance was not negatively affected; alertness improved and subjective recovery time after night work decreased in the 12-hour schedule. It was concluded that the change was positive in most respects, possibly due to shorter sequences of work days, longer sequences of consecutive days off, and the elimination of quick changes.A detailed analysis of morning work including use of polysomnography (EEG) showed that preceding sleep was reduced to 5 hours and 12 minutes. Subjective ratings demonstrated that morning work was associated with more apprehension of difficulties in awakening and insufficient sleep.The present studies demonstrate that sleep related problems are frequent for both shift workers and air crew. The particular characteristic of each work schedule pose different problems, either it involves night work, quick changes, early morning work, time zone crossings or long work hours. The studies further demonstrate that a change of either work hours or sleep strategies can decrease some of these problems.
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| 3. |
- van den Berg, Johannes, 1962-
(författare)
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Indicators and predictors of sleepiness
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sleep is a basic need as important as physical fitness and good nutrition. Without enough sleep, we will create a sleep debt and experience sleepiness. Sleepiness can be defined as the inability to stay awake, a condition that has become a health problem in our 24-hour-7-day-a-week society. Estimates suggest that up to one-third of the population suffers from excessive sleepiness. Among other interactions, sleepiness affects our performance, increasing the risk of being involved in accidents. A considerable portion of work related accidents and injuries are related to sleepiness resulting in large costs for the individuals and society. Professional drivers are one example of workers who are at risk of sleepiness related accidents. Up to 40% of heavy truck accidents could be related to sleepiness. A better knowledge about reliable indicators and predictors of sleepiness is important in preventing sleepiness related accidents.This thesis investigates both objective and subjective indicators of sleepiness, how these relate to each other, and how their pattern changes over time. The indicators investigated were electroencephalography, heart rate variability, simple reaction time, head movement, and subjective ratings of sleepiness (Study I-IV). In Study V, a questionnaire study was conducted with professional drivers in northern Sweden. This study mainly deals with predictors of sleepiness. When subjects were sleep deprived both objective and subjective ratings indicated a rapid increase in sleepiness during the first hour of the test followed by a levelling off. This change in pattern was evident for all the indicators except heart rate and heart rate variability. On the other hand, HRV was correlated with the increase of EEG parameters during the post-test sleep period. The changes in pattern of the indicators included in the thesis are analysed in the perspective of temporal patterns and relationships. Of the tested indicators, a subjective rating of sleepiness with CR-10 was considered to be the most reliable indicator of sleepiness. Of the investigated predictors of sleepiness, prior sleep habits were found to be strongly associated to sleepiness and the sleepiness related symptoms while driving. The influences of driving conditions and individual characteristics on sleepiness while driving were lower. A multidisciplinary approach when investigating and implementing indicators and predictors of sleepiness is important. In addition to their actual relations to the development of sleepiness, factors such as technical and practical limitations, work, and individual and situational needs must be taken into account.
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