Profiles

Torbjörn Åkerstedt

Torbjörn Åkerstedt

Professor

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Telephone 08-553 789 28
Email torbjorn.akerstedt@su.se
Visiting address Frescati Hagväg 16 A
Room 320
Postal address Stressforskningsinstitutet 106 91 Stockholm

About me

Torjörn is professor emeritus at Stress Research Institute, where he also leads a research group that focuses on stress, sleep and recovery, in particular on the role of sleep in fatigue regulation. It also includes preventive measures such as stress management, sleep advice and alertness-enhancing measures. His research areas is mainly, sleep regulation, stress and sleep, sleep quality, hours of work and health, sleepiness and security, and the nature of drowsiness.

Publications

A selection from Stockholm University publication database
  • Helena Schiller (et al.).

    Objectives: A 25% reduction of weekly work hours for full-time employees has been shown to improve sleep and alertness and reduce stress during both workdays and days off. The aim of the present study was to investigate how employees use their time during such an intervention: does total workload (paid and non-paid work) decrease, and recovery time increase, when work hours are reduced?

    Methods: Full-time employees within the public sector (N=636; 75% women) were randomized into intervention group and control group. The intervention group (N=370) reduced worktime to 75% with preserved salary during 18 months. Data were collected at baseline, after 9 months and 18 months. Time-use was reported every half hour daily between 06 and 01 a.m. during one week at each data collection. Data were analyzed with multilevel mixed modeling.

    Results: Compared to the control group, the intervention group increased the time spent on domestic work and relaxing hobby activities during workdays when worktime was reduced (p≤0.001). On days off, more time was spent in free-time activities (p=0.003). Total workload decreased (-65 minutes) and time spent in recovery activities increased on workdays (+53 minutes). The pattern of findings was similar in subgroups defined by gender, family status and job situation.

    Conclusions: A worktime reduction of 25% for full-time workers resulted in decreased total workload and an increase of time spent in recovery activities, which is in line with the suggestion that worktime reduction may be beneficial for long-term health and stress.

  • 2018. Torbjörn Åkerstedt (et al.). Frontiers in Psychology 9

    Fatigue is prevalent in the population and usually linked to sleep problems, and both are related to age. However, previous studies have been cross-sectional. The purpose of the present study was to investigate the trajectories of sleep and fatigue across 8 years of aging in a large group (N > 8.000) of individuals. A second purpose was to investigate whether fatigue trajectories would differ between age groups, and whether different trajectories of fatigue would be reflected in a corresponding difference in trajectories for sleep variables. Results from mixed model analyses showed that fatigue decreased across 8 years in all age groups, while sleep problems increased, non-restorative sleep decreased, weekend sleep duration decreased, and weekday sleep duration showed different patterns depending on age. Furthermore, the larger the decrease in fatigue, the larger was the increase in sleep duration across years, the lower was the increase of sleep problems, and the larger was the decrease of non-restorative sleep. The results suggest that aging has positive effects on fatigue and sleep and that these changes are linked.

  • 2018. Anna Anund (et al.). Scandinavian Journal of Work, Environment and Health 44 (1), 88-95

    Objective It is generally believed that professional drivers can manage quite severe fatigue before routine driving performance is affected. In addition, there are results indicating that professional drivers can adapt to prolonged night shifts and may be able to learn to drive without decreased performance under high levels of sleepiness. However, very little research has been conducted to compare professionals and non-professionals when controlling for time driven and time of day.

    Method The aim of this study was to use a driving simulator to investigate whether professional drivers are more resistant to sleep deprivation than non-professional drivers. Differences in the development of sleepiness (self-reported, physiological and behavioral) during driving was investigated in 11 young professional and 15 non-professional drivers.

    Results Professional drivers self-reported significantly lower sleepiness while driving a simulator than nonprofessional drivers. In contradiction, they showed longer blink durations and more line crossings, both of which are indicators of sleepiness. They also drove faster. The reason for the discrepancy in the relation between the different sleepiness indicators for the two groups could be due to more experience to sleepiness among the professional drivers or possibly to the faster speed, which might unconsciously have been used by the professionals to try to counteract sleepiness.

    Conclusion Professional drivers self-reported significantly lower sleepiness while driving a simulator than non-professional drivers. However, they showed longer blink durations and more line crossings, both of which are indicators of sleepiness, and they drove faster.

  • 2018. Anna Miley-Åkerstedt, Jerker Hetta, Torbjorn Åkerstedt. Nature and Science of Sleep 10, 295-301

    Background: The public often seeks rule-of-thumb criteria for good or poor sleep, with a particular emphasis on sleep duration, sleep latency, and the number of awakenings each night. However, very few criteria are available. Aim: The present study sought to identify such criteria. Methods: Whether or not a person has sought medical help for sleep problems was selected as an indicator of poor sleep. The group that was studied constituted a representative sample of the general Swedish population (N=1,128), with a response rate of 72.8%. Results: Logistic regression analysis, with an adjustment for age and gender, showed an increased OR for a weekday sleep duration of <= 6 hour, (OR >2, and for <5 hour: OR >6). For weekend sleep, the value was <= 6 hour (OR >2). For awakenings per night, the critical value was >= 2 (OR >2, and for awakenings: OR >9), and for a sleep latency the critical value was >= 30 minutes (OR >2, and for >= 45 minutes: OR >6). Adding difficulties falling asleep and early morning awakening (considered qualitative because of the reflected difficulty), led to the elimination of all the quantitative variables, except for the number of awakenings. The addition of negative effects on daytime functioning and sleep being a big problem resulted in the elimination of all the other predictors except age. Conclusion: It was concluded that weekday sleep <= 6 hour, >= 2 awakenings/night, and a sleep latency of >= 30 minutes, can function as criteria for poor sleep, but that qualitative sleep variables take over the role of quantitative ones, probably because they represent the integration of quantitative indicators of sleep.

  • 2018. Johanna Schwarz (et al.). Psychoneuroendocrinology 96, 155-165

    Sleep loss and psychosocial stress often co-occur in today’s society, but there is limited knowledge on the combined effects. Therefore, this experimental study investigated whether one night of sleep deprivation affects the response to a psychosocial challenge. A second aim was to examine if older adults, who may be less affected by both sleep deprivation and stress, react differently than young adults. 124 young (18–30 years) and 94 older (60–72 years) healthy adults participated in one of four conditions: i. normal night sleep & Placebo-Trier Social Stress Test (TSST), ii. normal night sleep & Trier Social Stress Test, iii. sleep deprivation & Placebo-TSST, iv. sleep deprivation & TSST. Subjective stress ratings, heart rate variability (HRV), salivary alpha amylase (sAA) and cortisol were measured throughout the protocol. At the baseline pre-stress measurement, salivary cortisol and subjective stress values were higher in sleep deprived than in rested participants. However, the reactivity to and recovery from the TSST was not significantly different after sleep deprivation for any of the outcome measures. Older adults showed higher subjective stress, higher sAA and lower HRV at baseline, indicating increased basal autonomic activity. Cortisol trajectories and HRV slightly differed in older adults compared with younger adults (regardless of the TSST). Moreover, age did not moderate the effect of sleep deprivation. Taken together, the results show increased stress levels after sleep deprivation, but do not confirm the assumption that one night of sleep deprivation increases the responsivity to an acute psychosocial challenge.

Show all publications by Torbjörn Åkerstedt at Stockholm University

Last updated: January 18, 2019

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