Table 1.
Literature review of seasonal effects on sleep.
| Author | Methods | Population/topic | Overall N/duration | Finding(s) | ||
|---|---|---|---|---|---|---|
| Sleep duration | Sleep onset/bedtime | Sleep offset/wake time | ||||
| Allebrandt et al.28 | Observational/survey | European adults/chronotype measurement | N = 9765/variable depending on sub cohort | Evening types show seasonal variability, morning types do not | NA | NA |
| Monsivais et al.34 | In situ/call detail records (CDRs) | Subscribers to Telecommunication company in a Southern European country/effects on seasons and day length on sleep duration. | N = ~1 million/12 months | Increased in winter compared to summer, larger seasonal variability in sleep duration for southern vs northern cities | NA | NA |
| Stothard et al.73 | Observational/actigraphy/light sensor/melatonin | physically active adults/circadian effects while camping | N = 5*, 14**/ *2 weeks in winter, **1 week in summer | 2.5 h longer sleep duration during camping, both seasons | Electric environment: NA. Camping, marginally earlier melatonin offset in winter than summer | Electric environment: NA. Camping, later melatonin offset in winter than summer |
| de la Iglesia et al.74 | In situ/actigraphy/sleep diaries | Neighboring hunter and gatherers; one with access to electricity/effects of electricity and season on sleep. | N = 44/7 days in summer or winter | Increased in winter compared to summer for both. Shorter duration for electricity access. | Sleep onset later in electricity; no effect of season | Sleep offset/rise time later in summer collapsed across community. No effect of electricity |
| Wehr et al.77 | Laboratory/light sensor/melatonin/survey | Males/assessing artificial light on melatonin production | N = 21/48 h awake in summer and winter for 1 year. Participants were recruited across 4 years | no difference in self-reported sleep; no effect of light exposure on melatonin. | NA | NA |
| Adamsson et al.78 | Observational/light sensor/melatonin | Swedish office workers/seasonal variations in melatonin and cortisol | N = 15/3 days per month across 1 year |
Study findings: (note; no sleep effects reported) Amount and time of day of light exposure vary seasonally with access to electricity. Light exposure was highest in summer and lowest in winter. In addition, peak melatonin production was highest in winter. |
||
| Honma et al.79 | laboratory/PSG/self-report/physiology | 20–28 yr old males in experimental living facility/ test circadian biomarkers | N = 10/4 days; once per season | No difference | Earlier onset in winter than summer | Earlier offset in winter than summer |
| Yetish et al.82 | In situ/actigraphy | Three preindustrial societies/natural sleep without electricity. | N = 72/8 to 28 days, summer and winter | Increased in winter compared to summer. | Earlier in winter than summer. | Slightly earlier in winter than summer |
| Thorleifsdottir et al.85 | Observational/sleep diary | children and adolesents/sleep habits | N = 668 children/10 years | shorter sleep in spring than in winter under age 5; similar effect age 5–10 (weekends only). Suggested due to social and school factors. | earlier bedtimes in winter than in spring under age 10 during weekdays. Ages 6–10 and 16–19 show same on weekends | later wake-up times in winter than in spring under age 10. age 16–19 show similar effects on weekends |
| Obradovich et al.57 | Survey/meteorological data | USA/effect of nighttime temperature and climate change on sleep. | N = 765 K/9 years | Increased percentage of nights of insufficient sleep on anomalously warm nights; summer is the only significant season. effects of temp on sleep are higher in age 65+ and low socioeconomic status. | NA | NA |
| Cepeda et al.58 | Observational/wearable | Middle age (50–64 yr), young elderly (65–74 yr), Old-elderly (75 + yr) | N = 1116/7 days with data collection spanning 5 years | 31 min more of sleep in winter; middle age only. For the differences in middle age; 49% explained variance is due to temp changes. 5% due to light. | NA | NA |
| Friborg et al.84 | Observational/self-report | Adults from Ghana and Norway/sunlight differences in sleep; ghana = 0.3 h between summer and winter, Norway = 11.7 | N = 330/1 week in summer and winter | No difference | Ghana: no difference. Norway: weekday bedtime 12 min later in summer vs winter (but not weekend) | Ghana: no difference. Norway: weekday 32 min later in summer compared to winter (but not weekend) |
| Hjorth et al.83 | Observational/actigraphy/sleep diary | 8–11-year-old Danish children; relationship between season, sleep and physical activity. | N = 730/7 days in spring, winter, fall | 2% (12 min) more sleep in winter relative to spring, no difference between fall and winter. | NA | NA |
| O Connell et al.80 |
observational/actigraphy*/ self-report**/meteorological * for activity ** for sleep |
adults in UK/monitor physical activity, sedentary behavior, and sleep in all four seasons | N = 46/7 days sleep diary for 4 seasons | No significant differences | NA | NA |
| Lehnkering & Siegmund81 | observational/actigraphy / self-report | Medical students/chronotype, season, and sex effects | N = 34/ 15 days in spring and autumn. | 18 mins more in autumn relative to spring | No effect | No effect |
| Webb & Ades91 | laboratory/PSG/meteorological | Naval aviation trainees/effects of barometric pressure on sleep | N = 547/9 months | NA | Significant Increase or decrease from the mean barometric pressure increased sleep onset (earlier fall asleep time), but no control for daylight length, or season. | NA |
| Crowley et al.92 | Experimental/objective/ wearables | Adult employees/increase wellness | N = 510/1 year | Mixed: continuous monthly increase of sleep, both from fall into winter and winter into spring, likely due to experimental intervention rather than the season. | NA | NA |
| Robbins et al.87 | Observational/“Sleep Cycle” app: sleep duration, quality, location, demographics | Sleep Cycle app users in New York City, aged 14–85 | N = 160,963 (2,161,067 nights of data)/4 years. | Age 14–18 sleep the most during summer. Age 18–25 sleep more in winter and less during summer. Age 26–65 sleep more in autumn/winter than in spring/summer. Age 65–84 males slept longest in winter/autumn, females slept longest in autumn and shortest in spring. | NA | NA |
| Hashizaki et al.88 | Observational/contactless biomotion sensor via radio waves | Japanese biomotion sensor users between aged 20 and 79 | N = 1856 (691,161 nights of data)/3 years. | NA | Stable across year | Significantly varies; later in winter, earlier in summer. Especially apparent on weekends |
| Carskadon, M. & Acebo, C.86 | Parental survey | Survey to parent about children age 9–12 | N = 1680 | More parents report children sleep longer in winter than in fall or spring. | NA | NA |