Biomedical subjects

Torbjorn Akerstedt

Publications and source records attributed to Torbjorn Akerstedt.

7 recordsLinked to original sources

PubMed2006

Transport and industrial safety, how are they affected by sleepiness and sleep restriction?

This review shows that impaired/shortened sleep is a major cause of accidents in industry and transport. The reason is either sleep pathology, voluntary (non-pathological) sleep reduction, or activity during the circadian low. Night or morning work is a prominent factor with regard to the latter two. However, the link between sleep restriction (or shift work) and safety is much better established in the transport industry than in other industrial areas. The reason is that driving a vehicle is a task with continuous demand for attention and immediate punishment for lapses, whereas industrial work in most cases does not have the same demands. Still, there are effects and the consequences may be far-reaching.

Accidents, Traffic↗

PubMed2006

Influence of flexibility and variability of working hours on health and well-being.

Flexible working hours can have several meanings and can be arranged in a number of ways to suit the worker and/or employer. Two aspects of "flexible" arrangement of working hours were considered: one more subjected to company control and decision (variability) and one more connected to individual discretion and autonomy (flexibility). The aim of the study was to analyze these two dimensions in relation to health and well-being, taking into consideration the interaction with some relevant background variables related to demographics plus working and social conditions. The dataset of the Third European Survey on working conditions, conducted in 2000 and involving 21,505 workers, was used. Nineteen health disorders and four psycho-social conditions were tested by means of multiple logistic regression analysis, in which mutually adjusted odds ratios were calculated for age, gender, marital status, number of children, occupation, mode of employment, shift work, night work, time pressure, mental and physical workload, job satisfaction, and participation in work organization. The flexibility and variability of working hours appeared inversely related to health and psycho-social well-being: the most favorable effects were associated with higher flexibility and lower variability. The analysis of the interactions with the twelve intervening variables showed that physical work, age, and flexibility are the three most important factors affecting health and well-being. Flexibility resulted as the most important factor to influence work satisfaction; the second to affect family and social commitment and the ability to do the same job when 60 years old, as well as trauma, overall fatigue, irritability, and headache; and the third to influence heart disease, stomachache, anxiety, injury, and the feeling that health being at risk because of work. Variability was the third most important factor influencing family and social commitments. Moreover, shift and night work confirmed to have a significant influence on sleep, digestive and cardiovascular troubles, as well and health and safety at work. Time pressure also showed a relevant influence, both on individual stress and social life. Therefore, suitable arrangements of flexible working time, aimed at supporting workers' coping strategies, appear to have a clear beneficial effect on worker health and well-being, with positive consequences also at the company and social level, as evidenced by the higher "feeling to be able to work until 60 years of age".

Adult↗

PubMed2005

Fatigue, sleepiness, and performance in simulated versus real driving conditions.

STUDY OBJECTIVES: To determine whether real-life driving would produce different effects from those obtained in a driving simulator on fatigue, performances and sleepiness. DESIGN: Cross-over study involving real driving (1200 km) or simulated driving after controlled habitual sleep (8 hours) or restricted sleep (2 hours). SETTING: Sleep laboratory and open French Highway. PARTICIPANTS: Twelve healthy men (mean age +/- SD = 21.1 +/- 1.6 years, range 19-24 years, mean yearly driving distance +/- SD = 6563 +/- 1950 miles) free of sleep disorders. MEASUREMENTS: Self-rated fatigue and sleepiness, simple reaction time before and after each session, number of inappropriate line crossings from the driving simulator and from video-recordings of real driving. RESULTS: Line crossings were more frequent in the driving simulator than in real driving (P < .001) and were increased by sleep deprivation in both conditions. Reaction times (10% slowest) were slower during simulated driving (P = .004) and sleep deprivation (P = .004). Subjects had higher sleepiness scores in the driving simulator (P = .016) and in the sleep restricted condition (P = .001). Fatigue increased over time (P = .011) and with sleep deprivation (P = .000) but was similar in both driving conditions. CONCLUSIONS: Fatigue can be equally studied in real and simulated environments but reaction time and self-evaluation of sleepiness are more affected in a simulated environment. Real driving and driving simulators are comparable for measuring line crossings but the effects are of higher amplitude in the simulated condition. Driving simulator may need to be calibrated against real driving in various condition.

Adult↗

PubMed2004

Flexible working hours, health, and well-being in Europe: some considerations from a SALTSA project.

The project brought together researchers from 9 EU-Countries and resulted in a number of actions, in particular the following: (a) There is an urgent need of defining the concept of flexible working hours, since it has been used in many different and even counterintuitive ways; the most obvious distinction is where the influence over the working hours lies, that is between the "company-based flexibility" and the "individual-oriented flexibility"; (b) The review of the Legislation in force in the 15 European countries shows that the regulation of working times is quite extensive and covers (Council Directive 93/104/EC) almost all the various arrangements of working hours (i.e., part-time, overtime, shift, and night work), but fails to provide for flexibility; (c) According to the data of the Third EU Survey on Working Conditions, longer and "irregular" working hours are in general linked to lower levels of health and well-being; moreover, low (individual) flexibility and high variability of working hours (i.e., company-based flexibility) were consistently associated with poor health and well-being, while low variability combined with high autonomy showed positive effects; (d) Six substudies from different countries demonstrated that flexible working hours vary according to country, economic sector, social status, and gender; overtime is the most frequent form of company-based flexibility but has negative effects on stress, sleep, and social and mental health; individual flexibility alleviates the negative effects of the company-based flexibility on subjective health, safety, and social well-being; (e) The literature review was able to list more than 1,000 references, but it was striking that most of these documents were mainly argumentative with very little empirical data. Thus, one may conclude that there is a large-scale intervention ongoing in our society with almost completely unknown and uncontrolled effects. Consequently, there is a strong need for systematic research and well-controlled actions in order to examine in detail what flexible working hours are considered, what and where are their positive effects, in particular, as concerns autonomy, and what regulation seem most reasonable.

Adolescent↗

PubMed2003

Fatigue, sleep restriction, and performance in automobile drivers: a controlled study in a natural environment.

OBJECTIVES: To test the neurobehavioral consequences of sleep restriction combined with fatigue from long-distance driving (1000 Km/600 miles). DESIGN: Counterbalanced study involving 3 experimental conditions: laboratory after controlled habitual sleep (8.5 hours), driving after controlled habitual sleep (8.5 hours) (Road 1), and driving after reduced sleep (2 hours) (Road 2). SETTING: Sleep laboratory and open French highway. PARTICIPANTS: 10 male participants (mean age 22 years, range 18-24 years, mean driving distance per year 15000 Km/9000 miles) free of sleep disorders. MEASUREMENTS: Simple reaction time, prospective self-assessment of performance, and instantaneous fatigue and sleepiness ratings measured at 2-hour intervals. RESULTS: A two-way repeated ANOVA with time of day and condition indicated a significant main effect for time of day (p < 0.05). The interaction between the two factors (condition * time of day) was also significant (p < 0.05). The effects of time of day were significant only in the condition of driving after sleep restriction, (p < 0.05). Under sleep restriction, some drivers presented an increase of 650 milliseconds compared to the laboratory condition, representing an increase of 23 meters in breaking distance at a speed of 75 miles per hour. Correlation analyses showed a significant linear correlation between self-assessment and reaction time in the laboratory condition (r = -0.58, p < 0.01) but not in the road conditions. Self-ratings during the breaks showed a significant increase in instantaneous self-rated fatigue and sleepiness between Road 1 and Road 2 conditions (Wilcoxon's test, Z = - 6.47, p < 0.0001 and Z = - 6.26, p < 0.0001). CONCLUSIONS: Sleep restriction combined with fatigue significantly affects reaction time. The lack of correspondence between reaction time and prospective self-evaluation of performance suggests that self-monitoring in real conditions is poorly reliable.

Adolescent↗

PubMed2002

Awakening from sleep.

Awakening is a crucial event for the organism. The transition from sleep to waking implies physiological processes which lead to a new behavioural state. Spontaneous awakenings have varying features which may change as a function of several factors. The latter include intrasleep architecture, circadian phase, time awake, age, or disordered sleep. Despite its clear theoretical and clinical importance, the topic of awakening (in humans) has received little attention so far. This contribution focuses on major issues which relate to awakening from both basic (experimental) and clinical research. Recent knowledge on neurophysiological mechanisms is reported. The experimental data which provide in the human suggestions on the regulation of awakening are discussed, mainly those concerning sleep architecture and homeostatic/circadian factors also in a life-span perspective, since age is a powerful factor which may influence awakening. Clinical contributions will examine two main sleep disorders: insomnia and hypersomnia. Daytime functioning is shown in insomniac patients and compared to other pathologies like sleep apnea. A final section evokes links between some types of night waking and psychological factors.

Adrenocorticotropic Hormone↗

PubMed2002

Work organisation and unintentional sleep: results from the WOLF study.

BACKGROUND: Falling asleep at work is receiving increasing attention as a cause of work accidents. AIMS: To investigate which variables (related to work, lifestyle, or background) are related to the tendency to fall asleep unintentionally, either during work hours, or during leisure time. METHODS: 5589 individuals (76% response rate) responded to a questionnaire. A multiple logistic regression analysis of the cross sectional data was used to estimate the risk of falling asleep. RESULTS: The prevalence for falling asleep unintentionally at least once a month was 7.0% during work hours and 23.1% during leisure time. The risk of unintentional sleep at work was related to disturbed sleep, having shift work, and higher socioeconomic group. Being older, being a woman, and being a smoker were associated with a reduced risk of unintentionally falling asleep at work. Work demands, decision latitude at work, physical load, sedentary work, solitary work, extra work, and overtime work were not related to falling asleep at work. Removing "disturbed sleep" as a predictor did not change the odds ratios of the other predictors in any significant way. With respect to falling asleep during leisure time, disturbed sleep, snoring, high work demands, being a smoker, not exercising, and higher age (>45 years) became risk indicators. CONCLUSION: The risk of involuntary sleep at work is increased in connection with disturbed sleep but also with night work, socioeconomic group, low age, being a male, and being a non-smoker.

Accidents, Occupational↗