For those with trouble going to sleep at night and waking up in the morning, a week of camping outdoors might be the solution to the problem. New evidence, reported on August 1 in the publication Current Biology, shows that the human biological clock will synchronize to a midsummer light-dark schedule if the chance to do so is offered.

A week of exposure to both dawn and dusk with nights lit by campfire had the biggest effect on people who had trouble sleeping at night. Under those specific conditions, they quickly reverted back to a schedule similar to those who don’t experience any difficulties sleeping or rising early.

“By increasing our exposure to sunlight and reducing our exposure to electrical lighting at night, we can turn our internal clock and sleep times back and likely make it easier to awaken and be alert in the morning,” says Kenneth Wright of the University of Colorado Boulder.

Wright and his colleagues first studied internal circadian timing in eight people after one week of their regular work, school social activities and chosen sleep schedules with normal exposure to electrical lighting. Those same eight people were then taken on a Colorado camping trip with nothing but sunlight and campfire for night time lighting. They were not allow to take flashlights or smartphones on the trip. However, they were allowed to choose their own sleeping schedule.

What the study showed was that a typical, modern environment results in a 2-hour delay of the natural circadian clock, indicated by fluctuations in the hormone melatonin. Most of the people participating planned to stay away until after midnight and wake at 8 am. After a week of exposure to natural lighting, their circadian clocks shifted back by 2 hours. Their sleep schedules changed as a result, even though the number of hours spent sleeping stayed about the same.

These findings could explain an observed paradox in brain arousal, researchers are saying. In the modern world, melatonin levels had a tendency to decrease to daytime levels about 2 hours after we wake up. What this means is that our biological night is extending past our wake times, which contributes to many people feeling excessively sleepy not long after waking up in the morning. Exposure to natural light results in the melatonin decrease occurring during the last hour of sleep, which results in brain arousal occurring earlier and helps people feel more alert in the morning.

“Our findings suggest that people can have earlier bed and wake times, more conducive to their school and work schedules, if they were to increase their exposure to sunlight during the day and decrease their exposure to electrical lighting at night,” Wright says.