Lights of your life

Amid dark winter nights, James Moore reveals some illuminating secrets about the incredible number of ways light and darkness can impact our health... from weight loss to our libido

LUNAR EFFECT:

The next full moon is on January 25, so take note of how it impacts your slumber. Research shows we spend less time in deep sleep and, on average, snooze for 20 minutes less overall on a night when the phenomenon occurs.

Other research has linked moonlight to more unusual dreams. Oddly, a Leeds University study found visits to the doctor increase around the period of the full moon. Studies also show hospital admissions go up and even asthma attacks get worse.

SAUCY SPOTLIGHT:

Exposure to bright lights can actually improve men’s sex lives, according to scientists. Researchers at Italy’s University of Siena found men with a low libido saw their levels of the hormone testosterone rise when they used light boxes in the morning for half an hour.

But scientists have also discovered being exposed to too much light at night could interfere with women’s fertility levels.

WINTER BLUES:

Less sunlight in winter has been associated with seasonal affective disorder (SAD), which involves low mood, feeling lethargic and eating carb-filled foods.

It’s thought lack of light interferes with the sleep hormone melatonin and feel-good hormone serotonin. If you think you’re affected, talk to your GP.

VIT OF ALL LIGHT:

When sunlight hits skin it helps our bodies make vitamin D, which helps with things such as bone health. But in winter we don’t get enough, leaving many of us lacking.

You can also get some vitamin D from foods such as mushrooms and eggs, though it’s tricky to absorb as much as you need this way. The NHS recommends that everyone takes a vitamin D supplement between October and April. See nhs.uk.

NIGHTMARE:

Artificial light from things such as street lamps and smartphones at night can play havoc with the human body clock and the control of blood sugar levels.

This can raise the risk of developing diabetes by more than a quarter, says a study in China. Studies have also linked too much light at night to raising the risk of obesity as well as breast, prostate and bowel cancer and heart disease, while, of course, also disrupting our sleep.

COLOUR CODED:

A more recent phenomenon is the problems caused by so-called blue light, which tricks the body into thinking it’s daytime.

Red light, the sort you get from candlelight, appears to have a less damaging effect (though never leave a candle burning at night).

Blue light has been linked to causing premature ageing of the skin and damaging vision, especially if looking at devices in the dark. Interestingly, there’s little evidence that reading in poor light damages your peepers.

Stop using your phone a couple of hours before bedtime and leave devices outside the room in which you are going to sleep.

DARK THINKERS:

Want to make a good decision? It might be worth doing it in the dark.

A study by the University of Toronto found people tend to think more clearly when the lights are off as they are less emotional.

But light could be important during the day for brain performance, according to Michigan State University researchers in the US. Some of the studies by the university show that sitting next to a window boosts productivity.

Bright light therapy has also been found to help ease symptoms of dementia.

DIMMER AND SLIMMER:

If you want to lose weight, you might want to dim the lights.

Researchers have found that low lighting makes people slow the rate at which they eat, making them feel fuller so they don’t overindulge.

A study at Cornell University in the US found darker dining areas led to an average of 175 fewer calories being consumed at a meal.