Waking up to a morning alarm after going to bed late is excruciating, and studies show late nights can also be bad for your health, wellbeing and productivity.
The answer, according to new research, is to go camping for a weekend, which is enough time to restore circadian rhythms to a more natural setting, taking the sting out of early starts.
It’s long been known that exposure to natural daylight can help reset our sleep patterns, but a research team led by chronobiologist Ellen Stothard at the University of Colorado Boulder has uncovered more detail.
In a paper published in Current Biology, Stothard’s team set about discovering how quickly we can reset our sleep patterns, and whether this tactic also works in winter, when days are shorter.
“Late circadian and sleep timing in modern society are associated with negative performance and health outcomes such as morning sleepiness and accidents, reduced work productivity and school performance, substance abuse, mood disorders, diabetes, and obesity,” says co-author Kenneth Wright, also at the University of Colorado Boulder.
“Our findings demonstrate that living in our modern environments contributes to late circadian timing regardless of season, and that a weekend camping trip can reset our clock rapidly.”
By “late circadian timing”, Wright means our tendency to stay up way past sunset, thanks to electrical lighting, and to sleep in later thanks to bedroom blinds that shut out the dawn.
In an earlier study, the same research team found that exposure to a standard summer day/night cycle – roughly 14.5 hours of sunlight, followed by 9.5 hours of night – pushes our biological urge to sleep back a few hours, closer to sunset.
To figure out how quickly this reset can happen, they sent nine healthy participants outdoors for a summer camping weekend, observing their sleeping habits before and after. They compared the results to five participants who spent the weekend at home, in a modern environment.
After the weekend, the researchers recorded each participant’s urge to doze off by measuring their level of melatonin, the hormone that regulates sleep and wakefulness.
In the group that stayed home, sleep and waking occurred between one and 1.5 hours later during the weekend rest period. This resulted in a lag in circadian rhythms during the following week. This delay in sleep, and the resulting lag, didn’t occur among those who went camping.
In other words, after just one weekend, the campers’ circadian rhythms had pulled their biological sleep time back at least an hour, setting them in good stead for the days ahead.
To measure seasonal changes, the team also sent five people on a week-long camping adventure during the Colorado winter, around the time of the shortest day of the year. Campers’ melatonin levels kicked off – and sent them to sleep – around 2.5 hours earlier when relying on daylight rather than electrical light.
“Our findings demonstrate that the human melatonin rhythm adapts to short summer and long winter nights when living in a natural light-dark cycle – something that has been assumed but never demonstrated,” the researchers write.
As well as the hot tip that a weekend camping can reset our circadian rhythms, the findings suggest we’re similar to other animals, in that our natural sleep cycles change with the seasons.
The authors say the research could have applications for innovative building design, too.
“Our findings highlight an opportunity for architectural design to bring in more natural sunlight into the modern built environment and to work with lighting companies to incorporate tunable lighting that would be able to change across the day and night to enhance performance, health, and well-being,” says Wright.
Amy Middleton is a Melbourne-based journalist.
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