Little darlin’, it’s been a long, cold, lonely winter — and stepping outside on a cloudy or overcast day might be the answer to getting a good night’s sleep.
A new study published in the Journal of Pineal Research found soaking up even a little bit of sun can help improve a person’s sleep pattern.
Researchers from the University of Washington used wrist monitors to measure the sleep patterns and light exposure of 507 undergraduate students around the clock from 2015 to 2018.
The data showed that while the young adults logged nearly the same amount of sleep on a daily basis, they did report going to bed 35 minutes later and waking up 27 minutes later, on average, during the winter compared to summer school days.
The findings shocked the researchers, who had not anticipated the impact of winter’s early sunrises and sunsets.
“We were expecting that in the summer, students would be up later due to all the light that’s available during that season,” senior study author Horacio de la Iglesia said in a university news release.
Humans follow a natural circadian clock that runs close to a 24-hour cycle. The process — which guides our energy levels and directly influences our sleep schedules — is affected by environmental stimuli such as light exposure.
“If you do not get enough exposure to light during the day when the sun is out, that ‘delays’ your clock and pushes back the onset of sleep at night,” de la Iglesia noted.
The students’ circadian cycles were running up to 40 minutes later in winter than summer.
“Light during the day — especially in the morning — advances your clock, so you get tired earlier in the evening, but light exposure late in the day or early night will delay your clock, pushing back the time that you will feel tired,” de la Iglesia explained.
“Ultimately, the time that you fall asleep is a result of the push and pull between these opposite effects of light exposure at different times of the day.”
Morning light seems to have a bigger impact on sleep than evening light, with every hour of daytime light pushing the students’ circadian phases up by half an hour. Evening light (even artificial from lamps or screens) only delays circadian phases by about 15 minutes, the study found.
The benefits of daylight persisted even on cloudy or overcast days as any bout of natural light was found to be more impactful than artificial light.
“Many of us live in cities and towns with lots of artificial light and lifestyles that keep us indoors during the day,” de la Iglesia concluded. “What this study shows is that we need to get out — even for a little while and especially in the morning — to get that natural light exposure. In the evening, minimize screen time and artificial lighting to help us fall asleep.”
Around the country, 70% of adults report they obtain insufficient sleep at least one night a month, while 11% report lackluster sleep every night, according to the American Sleep Apnea Association.
Sleep struggles can have detrimental effects on your physical and mental health. Fortunately, California researchers believe they have devised a foolproof three-step formula to turn sluggishness into a refreshed morning feeling.