Winter’s long nights might be gloomy, but it’s not all bad. In fact, it’s vital for our health.
Most of us despair a little about the extra darkness this time of year brings, whether that’s due to having less time outdoors, the dreaded winter blues or Seasonal Affective Disorder.
While it’s hard not to associate diminishing daylight with a sense of gloom, it’s worth remembering that darkness also plays a crucial part in keeping us healthy.
Most people rely on a framework for the day, regulating when we eat, work, rest and play.
Sleeping at night isn’t just logical though – we’re biologically programmed to want to sleep when it’s dark.
“Darkness is an absolute prerequisite for good sleep,” says independent sleep expert Dr Neil Stanley. “Our bodies are designed to work according to light/dark cycles – in the morning, it takes just four minutes of daylight to tell our bodies it’s daytime. At night-time, the minute it starts going dark, we begin to release the hormone melatonin, which is the signal to the body that it’s time to go to sleep.”
This regulation means our bodies have enough time to regenerate and recharge, keeping us tip-top for action, physically and mentally, during waking hours.
Poor sleep doesn’t just make us feel groggy and less able to concentrate, it affects health in the short and long-term.
Lack of quality sleep is linked with a suppressed immune system, so if you’re sleeping badly and catching every cold going, that could be why. Research has also found that melatonin plays a role in helping fight cancer. In fact, studies have suggested that sleeping in total darkness may be a factor in preventing cancer, and also in the effectiveness of certain treatments.
Melatonin is at the centre of it all, and one of the best things we can do is ban screens from the bedroom.
“We know from recent work that things like computers, TVs and mobile phones fluoresce in blue light, and blue light is what tells us it’s daytime,” explains Dr Stanley. “Things that fluoresce blue actually stop the production of melatonin. So while it might be naturally dark, if you’re looking at a computer, TV or smartphone, you’re actually going to be stopping that melatonin. The advice is to get rid of the screens at least 45 minutes before lights out.”
Obesity rates are rising, and so too is our addiction to technology, and it seems the two things could be linked – not only because our reliance on screens means we spend less time moving and more time sat on our bums, but also because melatonin could play a significant role in our metabolisms.
A study by London’s Institute of Cancer Research published earlier this year found women who sleep in a bedroom with enough light to see across the room at night have bigger waistlines. The link was still apparent even when other factors were taken into account. It’s too early to fully explain the results, but a recent study found melatonin injections helped reduce obesity and weight-related diabetes in rats. Scientists believe the principles apply to humans too, and that increased use of melatonin-blocking screens could be contributing to our increasing weight.