Nature and Sleep

Spending time in the natural world can normalize our inner “body clock” also known as our circadian rhythm. Attuned to environmental cues like sunlight, temperature, and seasonal changes, our circadian rhythm regulates many physiological processes, including when to sleep and when to eat.

Artificial light and electronic devices like computers and televisions give our bodies false cues that have nothing to do with the natural order of things and disrupt our circadian rhythm, which a growing body of research has linked to many mental and physical health problems.

Sleep issues are an obvious casualty, as is false hunger leading to overweight and obesity. Circadian rhythm disruption has also been implicated in high blood pressure and heart disease, cognitive dysfunction, neurological problems like Parkinson’s disease, asthma, autoimmune illness, and mental health issues like depression, seasonal affective disorder (SAD) and bipolar disorder.

A recent University of Colorado study was the first to do a controlled experiment outside the laboratory to assess how humans adapted to camping in the Rocky Mountains without any electronics or sources of artificial light.

Melatonin is a hormone the body produces in response to the darkness that makes us sleepy. This study compared melatonin production as well as the length of time spent sleeping in healthy, young adults in their homes versus when they were up in the mountains camping without any artificial light sources, both midwinter and midsummer.

What the researchers found was not surprising: without artificial light, melatonin production began earlier and earlier as the participants adjusted to the natural environment, and sleep duration was longer. Comparing winter and summer, melatonin production began earlier and people slept longer in the winter (an average of more than 14 hours compared to about 10 hours in the summer).

However, the study demonstrated how, in a natural environment, people sleep much more than when stimulated by artificial light, and also how quickly circadian rhythms were normalized once artificial light sources were removed.

What can we glean from this study? Probably that we would do well to turn off electronics and lights earlier, especially during the winter months, to be more in harmony with our natural environment and its light-dark cycles. If this means we get tired and go to bed earlier, and sleep more, that may be all to the good.

We might also feel the call of the wild and want to try camping out under the stars ourselves.  This poem by Mary Oliver is further inducement:

 

Sleeping in the Forest

I thought the earth remembered me,

she took me back so tenderly,

arranging her dark skirts, her pockets

full of lichens and seeds.

I slept as never before, a stone on the river bed,

nothing between me and the white fires of the stars

but my thoughts and they floated light as moths

among the branches of the perfect trees.

All night I heard the small kingdoms

breathing around me, the insects,

and the birds who do their work in the darkness.

All night I rose and fell as if in water,

grappling with a luminous doom. By morning

I had vanished at least a dozen times

into something better.

 

References:

Stothard ER. Circadian entrainment to the natural light-dark cycle across seasons and the weekend. Current Biology. February 2017;27(4):508-513.

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