There’s a new medicine on Tiree. It’s free. It’s all around us (during the day, anyway). It makes us sleep like babies and wake up full of energy. It stops us feeling depressed. But, like all medicines, there’s a downside, if we don’t use it properly. It can keep us awake at night, and even encourage the growth of cancer. And some of our new gadgets are messing up our brains. Tiree is famous for it. Light.
As well as affecting our skin, light has extraordinary powers over the inside working of the body. It was only in 1995 that scientists found that the eye sends a signal to the control centre of the brain which tells us what time of day it is. This control centre (the pineal gland) pumps out a hormone called melatonin at night, making us sleepy.
Light, especially blue light, cuts production down, so we wake up and feel lively. Our sex drive is also higher (one reason why sunshine holidays are so popular!). Researchers found that if you put residents of an old peoples’ home into bright light (equivalent to outdoors on a cloudy day) for an hour in the morning, they cheer up. Students shown bright blue light did better in their tests than those exposed to green light.
On Tiree we sleep less in the summer and more in the winter. But as we age, the eye becomes less transparent (think cataracts) and we need more light to have the same effect. But this control centre, which tells us when to go to sleep and when to wake up, can also be upset by quite dim light – from a computer screen, iPad or television. Even normal room lighting in the evening (200 lux) has a big effect on melatonin production and the brain can detect levels down to 1 lux (full moonlight). And new energy saving bulbs produce more blue light than the old bulbs.
So, dimming the lights well before bedtime and using red lights if we have to get up, will help you sleep. Some people have even recommended using amber goggles in the evening to calm the brain. Shift workers (like doctors!) are exposed to light at night, messing up their sleep-wake rhythm and this makes them (us) more likely to have heart attacks, diabetes and strokes. Breast cancer in particular is more common in shift workers.
In a nutshell, I think that means– sit out in the sun every morning and turn off your screens at 9pm. Sounds like good advice to me!