Profiles

Johanna Schwarz

Johanna Schwarz

Forskare

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Arbetar vid Stressforskningsinstitutet
Telefon 08-553 789 32
E-post johanna.schwarz@su.se
Besöksadress Frescati Hagväg 16 A
Rum 337
Postadress Stressforskningsinstitutet 106 91 Stockholm

Om mig

Johanna är forskare vid Stressforskningsinstitutet, Stockholms Universitet och tog sin doktorsexamen 2012 vid institutionen för psykologi vid universitetet i Regensburg, Tyskland. Johannas huvudforskningsområden handlar om åldersskillnader på sömn samt effekter av sömnbrist på dagstidsfunktion (kognitiva funktioner & emotionell reglering) och stresskänslighet hos unga och äldre vuxna.

Publikationer

I urval från Stockholms universitets publikationsdatabas
  • Karin Schraml, Johanna Schwarz, Aleksander Perski.
  • 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.

  • 2018. Torbjörn Åkerstedt (et al.). Journal of Sleep Research 27 (4)

    Bedtime is frequently delayed by many factors in life, and a homeostatic response to the delay may compensate partly for increased time awake and shortened sleep. Because sleep becomes shorter with age and women complain of disturbed sleep more often than men, age and sex differences in the homeostatic response to a delayed bedtime may modify the homeostatic response. The purpose of the present study was to investigate the effect of late-night short-sleep (3 h with awakening at about 07:00 hours) on in-home recorded sleep in men and women in two age groups (20-30 and 65-75 years). Results (N = 59) showed that late-night short-sleep was associated with an increase in percentage of N3 sleep and a decrease in percentage of rapid eye movement sleep, as well as decreases in several measures of sleep discontinuity and rapid eye movement density. Men showed a smaller decrease in percentage of rapid eye movement sleep than women in response to late-night short-sleep, as did older individuals of both sexes compared with younger. Older men showed a weaker percentage of N3 sleep in response to late-night short-sleep than younger men. In general, men showed a greater percentage of rapid eye movement sleep and a lower percentage of N3 sleep than women, and older individuals showed a lower percentage of N3 sleep than younger. In particular, older men showed very low levels of percentage of N3 sleep. We conclude that older males show less of a homeostatic response to late-night short-sleep. This may be an indication of impaired capacity for recovery in older men. Future studies should investigate if this pattern can be linked to gender-associated differences in morbidity and mortality.

Visa alla publikationer av Johanna Schwarz vid Stockholms universitet

Senast uppdaterad: 18 januari 2019

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