in Cheap Thoughts

Cheap Thoughts: Melatonin – why do we need it?

I’ve been eyeing that Zeo sleep monitor for the past few months and enjoying the sleep tips they post on their blog and Facebook page. Recently Zeo shared a post from an ABC Action News story about how electronic gadgets are stealing sleep. Seems looking at a lighted screen right before bed delays the production of melatonin, the hormone that is produced when darkness falls to make us sleep. As a blogger who does quite a bit of his writing near bedtime, this was of interest to me.

The other day I was considering how quickly I feel sleepy at nightfall when I’m out camping. Out in the dark woods, it could be 7 PM but my body thinks its 11 PM. Then I remembered the story about how light affects sleepiness and I assumed it was that lack of light which was causing my drowsiness.

The camping scenario got me thinking again, though, about how I feel the need to be more aware of my surroundings when I’m sleeping at a campsite, not less aware. I supposed it was much the same for my ancient ancestors of the stone age and well beyond that.

A lot of hungry predators roam after dark. In … uh, light of that, why did man evolve the faculty to produce melatonin at nightfall to bring about sleep? How does this built-in automatic shutdown actually benefit us? Certainly in our brightly-lit modern lives we have control of light and darkness, so the value isn’t as clear today. But even in the distant past when danger lurked around the clock, how did shutting down at sundown make us safer?