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- Garde, A. H., et al.
(författare)
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Effects of lifestyle factors on concentrations of salivary cortisol in healthy individuals
- 2009
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 69:2, s. 242-250
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Tidskriftsartikel (refereegranskat)abstract
- Objective . Salivary cortisol is widely used in occupational health research. However, many ordinary daily activities can influence the concentrations of cortisol and the interpretation of field studies. The aim of the present study was to evaluate the effect of lifestyle factors on salivary cortisol in everyday settings. Material and methods . Healthy employees participated in one or more sub-studies on the effect of eating a vegetable salad versus protein-rich mid-day meal (n=40), drinking coffee and smoking (n=12), drinking alcohol (n=32), awakening at different times (n=29) and exercising (n=21). Cortisol in saliva was measured by radioimmunoassay (RIA). Results . When eating a mid-day meal, salivary cortisol was increased by 10 % (CI -1 % to 24 %) 1 h after eating compared to before eating in the case of both types of meal. Salivary cortisol increased by 80 % (CI 9 % to 199 %) after exercising compared to before exercise. The relative awakening response was approximately 100 % when using an alarm clock on both work-days and days off. However, the awakening response was 39 % (CI 10 % to 75 %) on a day off with spontaneous awakening. No effects of alcohol, coffee or smoking were observed. Discussion . In field studies, the biological variation in salivary cortisol may be reduced by restricting physical exercise and in collecting pre-meal samples. However, the protein content of food and moderate consumption of alcohol had no effect on concentrations of cortisol. Differences in relative awakening responses on work-days and days off are related to time and mode of awakening.
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| 2. |
- Garde, Anne Helene, et al.
(författare)
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Month-to-month variation in sleep among healthy, Scandinavian daytime workers
- 2014
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 74:6, s. 527-535
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Tidskriftsartikel (refereegranskat)abstract
- Background. The overall purpose of the present study was to attain more insight in month-to-month variation of sleep duration and quality in order to improve design and interpretation of, e.g. epidemiological studies using sleep as outcome. Methods. The study design entailed monthly self-reports from 38 (26 women/12 men) daytime workers, who completed the Karolinska Sleep Diary (KSD) once a month during one year. A subgroup (n = 16) also wore actigraphs on one day every month during a year. Self-reports of bedtime, time of awakening, sleep duration, individual sleep characteristics, disturbed sleep index (DSI, 4 items) and awakening index (AWI, 3 items) were analyzed together with actigraphy-derived measures. Hours of daylight were used to test for circa-annual variation in statistical models adjusted for intake of hypnotics and alcohol, gender, age and within-person variability. Results. Hours of daylight were found to be associated to self-reported bedtime (p = 0.032) and DSI (p = 0.030), thereby indicating a circa-annual variation. Bedtime was delayed by 1.8 min (95% CI: 0.6-2.9 min) per 1 hour increase in length of daylight. Sleep was slightly more disturbed during the winter. Conclusion. Only circa-annual variation in self-reports of bedtime and DSI were observed in a healthy daytime working population, and the effects were small. Therefore potential bias due to circa-annuality in the studied parameters appears to be of limited concern in adult daytime working populations.
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