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- š§¬ The changing night sky is affecting your biology
š§¬ The changing night sky is affecting your biology
This week on the Sleepstack Newsletter:
ā¢ š¾ Why our relationship with the night sky has changed forever
ā¢ š What does a true dark sky actually look like?
ā¢ š¦ The price we are paying for mankindās conquest of the night
š It takes an earthquake for Los Angeles to see the night sky
January 17, 1994 approximately 4:30am - the magnitude 6.7 Northridge Earthquake struck Los Angeles, causing major blackouts in the surrounding areas.
Within the next few hours, the reports start coming in: strange alien lights, sinister movement in the darkness, a āgiant silvery cloudā looming over the cityā¦ Spooked Los Angeles residents were anxiously calling the Griffith National Laboratory, and even 911, in the early hours of the morning.
The cause for their worry? The Milky Way.
Los Angelesā light pollution in 1908 (left) and 2017 (right). (UCLA)
Once upon a time we knew the stars by name. Now? Weāve reached the point where we canāt recognise our own galaxy - instead we mistake it for a strange, alien sight!
š Hereās what the stars should actually look like
It turns out that light pollution is far more pervasive than I realised. The Bortle Scale is one way of measuring sky brightness at night.
Check out this clip to see how the night sky changes as you go down the scale:
š Light pollution imbalances sleep hormones and genetic regulation
This 2020 review was published in the leading scientific journal Nature.
The paper reviewed a database of published scientific literature on the effects of artificial lighting at night (ALAN) across organisms and ecological communities. Some pretty clear patterns started to emerge:
The most consistent factor across species? Hormone levels (mostly the āsleep hormoneā melatonin). They were āconsistently and markedly reduced across all studies includedā.
The most unpredictable factor? Gene expression, which āvaried markedly in effect sizesā.
The effects on gene activity are concerning, but most worrying is that ALAN is pretty much guaranteed to disrupt sleep hormones. Not only are falling melatonin levels are a driving factor behind deteriorating sleep quality, but it turns out that melatonin receptors are found throughout the body. The consequences? A drop in melatonin levels affects us at the cellular-level and is linked to accelerated aging, immunological compromise and metabolic disorders.
A recent study found that nearly three-quarters of people in the workplace report poor sleep quality, yet harsher, brighter LEDs continue to be installed in office environments. Insomnia cases spiked during pandemic lockdowns - alongside time spent indoors exposed to artificial light. Is all of this really a surprise?
ā”ļø Recommendation zone
Actionable insight: wind down the lights to prevent melatonin suppression
Nearly a quarter of the global land area already lies under artificially light-polluted night-time skies. Iām increasingly convinced that reducing evening exposure to artificial lighting inside our homes is the first line of defence against poor sleep quality.
Preventing melatonin suppression enables you to fall asleep quicker and sleep deeper - and who doesnāt want that!
Iāve found that winding down the lights + switching to lamps at least an hour before bed has consistently helped me fall asleep much quicker.
Try something new: visit a Dark Sky Place
A number of places are protected for their dark skies. Dark Sky International vets true dark sky locations.
If you have some time this week, consider checking out your nearest Dark Sky Place.
Thatās all for this week!
Weāll be back in your inbox on Saturday,
Kevin
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