Cortisol and Insomnia

Insomnia is a big problem today and most of it has to do with cortisol. Though one in 10 American adults suffer from chronic insomnia, we do not have the answers to the most fundamental questions about the affliction. There are few treatments for insomnia. Researchers at the University of Colorado Boulder took a group of people for one week and without their electrical devices and living with only natural light. During their week in the wilderness, the campers were exposed only to sunlight and the glow of a campfire. All personal electronic devices and any form of artificial light including flashlights were banned for the entire week.

The rising and setting of the sun directly impact our circadian rhythms. Natural daylight impacts the function of every cell in our bodies. Sunlight dictates when our bodies prepare for sleep and when we prepare for wakefulness. In a modern world, these strong biological forces are thrown out of whack. Electrical lighting did not become the norm until the 1930’s. Before the 20th century our sleeping, waking, and working patterns were based solely on available daylight and the rising and setting time of the sun. We are hardwired to live our lives in sync with the rising and setting of the sun and the waxing and waning of the moon. Today, we are short-circuiting our circadian rhythms and living out of sync. The epidemic of sleep disorders in modern society is a direct reflection of our disconnection from nature.

At the end of the week in the wilderness, the researchers recorded the timing of participants’ circadian clocks in the laboratory by measuring the presence of the hormone melatonin. The release of melatonin is one way that our bodies signal the onset of our biological nighttime. As we have learned, melatonin is greatly affected by cortisol. If cortisol does not come down, melatonin levels do not decrease properly. Every one of the participants normalized their circadian clocks compared to the start of the study. This has big implications for insomnia. If you are someone who suffers from insomnia or is inclined to be a night owl, the researchers suggest that you seek more exposure to natural sunlight in the morning and midday to reset your biological clock. Exposure to natural light throughout the day will result in normal cortisol secretion and nudge your internal clock to synchronize with the natural circadian rhythms. This is just touching the surface of the physiology of natural light, and if you take away one thing from this post, be sure you get natural sunlight each and every morning.