Humans Need the Natural Day and Night Cycle

Our Biological Clocks Help Keep Us Healthy

In fewer than 100 years, humans have radically altered our nighttime environment, putting our health at risk. Due to the rapid growth of artificial light at night, most of us spend our nights bathed in light. But basking in all this light at night is not natural and it may be taking a serious toll on our health. We are only just beginning to understand the negative consequences of this swift change in our environment. A growing body of scientific research suggests that artificial light at night can have lasting adverse effects on human health.  The American Medical Association tells us:

“The power to artificially override the natural cycle of light and dark is a recent event and represents a manmade self-experiment.”

Humans evolved with the rhythms of the natural light-dark cycle of bright days and dark nights. Before the advent of artificial lighting, we spent our evenings in relative darkness. Like most life on Earth, humans adhere to a circadian rhythm — our master clock, which is crucial for our overall health. It interacts with our body systems, changes our hormone levels and even modifies our genetic code. Natural light helps keep our clock in tune with Earth’s 24-hour cycle.

When our master clock is out of sync with the day-night cycle, it’s called circadian disruption. Altering or interrupting our normal circadian rhythm can put us at risk for physiological and behavioral impacts. Shift work almost always causes circadian disruption because it puts the internal body clock at odds with the shift schedule.

Circadian disruption may increase our risk of obesity, diabetes, mood disorders, reproductive problems and cancers. Numerous studies have linked working the night shift and exposure to light at night to increased risks for breast and prostate cancers and other health problems. Circadian disruption can affect our natural sleep patterns, too. A good night’s sleep helps reduce weight gain, stress, depression and the onset of diabetes.

We don’t know why light at night appears to be so bad for us. But we do know that exposure to light at night – even if it’s dim – can suppress the body’s natural production of melatonin, a hormone that is important for our health including regulating our sleep-wake cycle, metabolism and immune system.

Learn more about artificial light and its affect on your health

The DUCC Creation Justice Team invites you to read and discuss the gorgeously written and critically acclaimed The End of Night by Paul Bogard. The book is available in print and electronic form from The Saugatuck-Douglas District Library.  If all copies are checked-out, request a copy through the library’s inter-loan network. The book is also available as an audiobook, narrated by the author. It is also available from your favorite booksellers in stores or online.

On November 2, at 6:30 pm, we will gather at the DUCC Friendship Hall, 56 Wall Street, to discuss the book and explore local and national efforts to reduce excessive, damaging and dangerous lighting in our community. This event is free and open to the public, but seating is limited, so please sign up to help us with our planning.

You can register for this event here.

Following CDC recommendations, facemasks are requested for all participants while indoors, regardless of vaccination status.

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