If you find yourself feeling groggy and out of it on Monday morning because you stayed up late and slept in over the weekend, a few days camping might be all you need to reset your biological clock, according to new research from the University of Colorado.
Researchers on the Boulder campus also discovered that without exposure to cell phones, television and other forms of modern electrical lighting, our internal biological timing systems adapt to winter’s long nights.
The results of the two studies, conducted by the sleep and chronobiology lab in CU’s integrative physiology department, were published in the journal Current Biology this month.
This new research expands upon earlier work produced by the lab, which is led by professor Kenneth Wright Jr.
In a 2013 study, Wright and his colleagues found that when people were only exposed to natural light during a summer camping trip, the body’s internal clock aligned more closely with the patterns of the sun.
That first study compelled the researchers to keep digging. They wanted to find out more about how the body’s internal timing system responds to different lengths of natural light exposure and how quickly the body would adapt when it’s not exposed to as much artificial light.
To try to answer these questions, they conducted two more camping studies.
In the first study, researchers sent five people on a six-day winter backpacking trip, during which they were only exposed to natural light — sunlight, moonlight and campfires. Researchers also studied the campers for six days prior to the camping trip, when they were maintaining their normal schedules.
The scientists measured melatonin, a hormone that signals to your body when it’s time to sleep or wake up, to assess how the campers’ biological timing systems shifted while they were camping.
On average, their bodies began to release melatonin 2.6 hours earlier while camping than when they were exposed to modern electrical lighting. In other words, their “biological night” started earlier when they were only exposed to natural light, said Ellen Stothard, a CU graduate student and one of the study’s lead authors.
The winter campers also had a longer biological night when compared to the summer campers.
“The beginning of the biological night shifted earlier and so it shows that we’re seasonably responsive,” Stothard said.
Other animals, including hamsters and sheep, show biological differences between the summer and winter months. Researchers have assumed this might also be true for humans but had not produced results that supported their suspicions until now.
In the second study, researchers sent nine people on a summer weekend camping trip and had five people spend their weekend in a modern electrical lighting environment. The campers were exposed mostly to natural lighting, but they were also allowed to use flashlights and headlamps.
Researchers compared the effects of the weekend camping trip to their early study of a weeklong camping trip. They found that spending just a weekend camping produced 69 percent of the biological timing shift that a week of camping produced — a weekend camping trip can effectively reset our biological clocks.
Compared to the people who stayed home, the weekend campers went to bed earlier and woke up earlier. In other words, those study participants who stayed home shifted their biological clock later, likely due to social factors.
This may have contributed to social jet lag they felt on Monday, when they needed to wake up earlier for school or work.
“Our findings also show that a weekend of camping prevents the typical weekend circadian and sleep delay, which is an important contributor to the phenomenon of social jet lag,” the researchers wrote in their paper. “Specifically, the weekend phase delay in the modern electrical environment contributes to social jet lag on Monday because there is a mismatch between biological and social timing.”
Exposure to more natural light on the weekend could help people avoid feeling tired and groggy come Monday, Stothard said.
“Just camping can counteract that delay that we impose on ourselves on the weekend,” she said.
There is no optimal sleep schedule for everyone, Stothard said. Issues tend to arise when there is a mismatch between a person’s biological clock and their social obligations and schedule.
To get to sleep and wake up earlier, you don’t necessarily need to go camping, but you can try to create a lighting environment that mimics the one you’d find in nature.
“We’re really lucky in Colorado to be able to go camping often,” Stothard said. “But camping is not necessarily a solution for everyone. There are things you can do, including having your morning cup of coffee outside in the sunlight; if you get a break during the day, take a walk outside. We also think that dimming the lights in your house, turning off your computer, your TV, your phone an hour or two before bed — those can all have positive health effects.”
Sarah Kuta: 303-473-1106, kutas@dailycamera.com or twitter.com/sarahkuta
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