By Chris Mitchell
I have this app (oh, how I dislike using that word!) to lower the brightness of the laptop screen, in tune with the daylight outside.
The idea is to cut back on artificial light that might mess up sleep patterns.
Too much artificial blue light is supposedly the culprit.
That’s the light that illuminates flat-screen TVs, mobile phones, and computer screens.
There is even a market for blue-blocking spectacles for those poor blighters whose work means they have to stare at a laptop for hours on end.
All this has found its way into the serious scientific literature and even a not-so-serious nature notes column.
Melatonin and sleep
Too much blue light in the evening is considered bad because it suppresses the secretion of melatonin – a hormone that induces sleep.
A systematic review of the literature can be found here.
It all comes down to what you can trust, what to believe.
When searching the internet for information, it’s regarded as good practice to seek out three independent sources, and if they are all in agreement, it’s likely to be true.
It reminds me of what the Bellman said, from The Hunting of the Snark:
“Just the place for a Snark! I have said it twice:
That alone should encourage the crew.
Just the place for a Snark! I have said it thrice:
What I tell you three times is true.”
But at the end of last year, those thrice-told warnings of blue light suddenly turned out to be a little shaky.
Blue light (at a wavelength of 460 nanometers) is particularly good at stimulating the non-visual light-sensitive cells in the retina, which entrain the circadian rhythm.
On this basis, artificial blue light has been demonised as a disrupter of sleep patterns. But a study last December by research workers at Manchester University (using mice) suggests that we may have got it all wrong.
Blue light is what we are exposed to naturally at twilight, with the implication that it is the yellow light of midday (together with high intensities) that we should avoid as we prepare for sleep .
Midges and ticks
Sleep? I should be so lucky.
The garden is going frantic; the gardener is going frantic: up before six while Janet prepares breakfast – any excuse to disappear from the kitchen armed with a bucket and fork to weed the carrots before sunrise, before the dreaded root-fly sniffs out the chemicals on the leaf surface, except that by 6am, the sun is already up, and so I have to be quick at pulling out the chickweed and replacing the cover.
And then there is all that sorrel and rampant grass, and nettles that appear to grow by the inch by the hour, and the Canadian salmonberry that I once planted in desperation for a windbreak 30 years ago and have spent the last 20 years regretting, trying in vain to stop it swallowing-up the entire garden, including and especially the onion bed.
Flies everywhere; buzzing round my head as I try and turn the compost; clegs landing on my sweating forearms as I scythe down the salmonberry; midges up my nose and in my ears and landing deliberately on my eyelids – deliberately, and biting them – deliberately.
And ticks, always ticks, which land and embed themselves behind the knee within minutes of my brushing through the long grass to scythe down the salmonberry yet again, even though I’m wearing trousers tucked tight inside my socks.
Solstice: no proper darkness; hardly any sleep.
Keep meaning to buy some blackout blinds for the bedroom skylights. Expensive.
Perhaps a black silk eye pad would be just as good.
Dawn chorus at 4am. I thought I’d come to terms with the chaffinch, except the one that has chosen the electric transmission line as its favourite perch, just opposite our bedroom skylight.
All the while, Janet has been sitting calmly with her tablet, bathed in its blue light, trying to find herbal remedies for high blood pressure and lack of sleep, and has come up with green tea and hawthorn tea.
But I’m not having it.
At least the nights are drawing in, and as Bob Dylan once said, “It’s not dark yet but it’s getting there.”