The Power of Rest

Why sleep alone is not enough–and how to reset your body

Should You Light the Night?

Light Is a Drug

White Lit Nights

 

themeroom.blogspot.com
 

White Nights – romance and adventure. These are times where the barriers of fatigue and tradition can be broken. We are afflicted by longing and piqued by possibility. If dreams can occur at night, so may their unexpected fulfillments.

Yet what if white nights, filled with the light of love and literature, make you fat?

That is a conclusion from a large British project known as the “Breakthrough Generations Study.” It’s real interest was teasing apart causes of cancer. Since obesity is part of that picture, they looked at body clocks and light.

And found what animal and human studies generally find – don’t mess with your inner time. You – and the rest of your community – will probably be sorry you did.

The Study

About 113,000 people were surveyed. One question they were asked was whether in their bedtime room could they:

Read

See across the room though not read

See a hand

Not even see their hand in front of him.

All measures of obesity increased with increasing light exposure at night. All of them.

Then the authors tried to control for other obvious causes of obesity – sleep duration (if you sleep less, you weigh more,) alcohol intake (which adds calories and interrupts sleep far more than people know,) physical activity (which everyone hopes will help control community obesity,) and smoking (not just models smoke to control weight.) The numbers still moved the same way – more light at night, more weight.

Does That Mean Cutting Light at Night Will Cause Me to Lose Weight?

No. That’s not known – and will be hard to prove. Just as it is difficult to prove that giving people more sleep time will get them to lose weight – or even stabilize our normally increasing girth. There are lots more variables that affect weight besides body clocks and light. But people get deeper, better sleep with less light at night.

Why Are Small Amounts of Light Important?

Light resets body clocks. Time rules life.

In experiment after experiment, disrupted body clocks cause increased weight. It’s not just animal studies; ask shift workers. Disrupting body clocks also has nasty effects on heart disease, stroke, probably cancer rates, depression, anxiety, irritability, memory, productivity – among many other things. Body clocks are not just about weight.

Light is a powerful, encompassing drug.

One to which we are exquisitely sensitive. With your eyes closed, you can appreciate a third of a light unit, called a lux.

A bright summer day can produce 50,000, even 100,000 lux. Relatively dark rooms still may have 100-200 lux.

How Might Light Change Weight?

Resetting clocks is certainly part of it. Not just the precision of our timing, the very nature of our timing changes with light. The inflection point is usually about 90 minutes before we awake. Light before that time phase delays us – makes our inner day longer; light after that time makes our inner day shorter.

Ever experience jet lag? If you have, you begin to see how this stuff works.

Light also disrupts sleep. People who sleep less usually get hungrier, particularly for sugar.

And small amounts of light for just seconds can provoke melatonin turn-off. Melatonin is the hormone of darkness. It's production really gets going when it’s dark and we’re asleep.

Little bits of sleep stop it cold. It takes a while to come back.

What Are Sources of Light at Night?

Pretty much anything powered by electricity.

Certainly it includes lamps. But there are lights attached to televisions and table telephones; lights sneaking through the corners of curtains; lights from smoke detectors.

And then there are the bright, blue tinged lights of cellphones.

As many working people and students take their cellphones to bed with them, and answer them at night, the bright lights of phones and pads can do more than wake them up.

Those lights can shut down melatonin production quickly. They may also reset the inner clocks that make us morning or evening types.

And most of us won’t have a clue.

What Can Be Done to Control Light?

Plenty. There’s the quick solution at a few dollars cost: a night mask.

Night masks cover the eye at night. They do more than block out light. The small pressure over the eye orbits may, according to researcher Roger Cole, create a reflex that provokes sleepiness. Night masks also are a behavioral cue to rest and sleep.

For room sized solutions, black out drapes work fairly well. They darken the night more than most any blinds that are presently manufactured.

Yet the most effective strategy may simply be turning off electrical devices. Not smoke detectors. Not emergency personnel’s cell phones.

But the electrical devices that continue to beep and light the night. Taking the television cord out of its socket may save a little bit on electricity, conserve power, and help you stay asleep.

If it also keeps you from gaining weight, what’s so bad?

Some white nights may remain treasured memories of romantic encounters and major life transitions. But light is a drug. Light resets much of the body’s information systems.

And you want those systems to work for you all the time – keeping you whole, letting your body regenerate accurately and creatively.

Humans are born to sleep at night. We sleep deeper and more effectively with less light.

It’s the way we’re built – and it pays to use your body the way it’s built.

Night and day.

 

Matthew Edlund, M.D. researches rest, sleep, performance, and public health; he is the author of Healthy Without Health Insurance and The Power of Rest.

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