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Cut your light at night

MATTHEW EDLUND M.D.
Contributing Columnist
health@lbknews.com

If reading this at night, you might want to dim the lights.

Q: What is the drug everyone is sensitive to?
A: Light. (Some, but not all blind people are exceptions.)

Q: What does it do?
A: Changes body clocks; in the daytime improves mood and creates vitamin D; shifts immunity, increases natural killer cell activity.

So what does light do just before sleep?

Electronic nights
The National Sleep Foundation just surveyed Americans aged 13-64 about their sleep, and the results were not encouraging. Sixty-three percent said they had trouble sleeping many or most nights. This is in accord with the recent CDC study of 75,000 adults, including older individuals, demonstrating more than a third slept less than seven hours on average each night.

Americans are sleepless. Is light at night one of the reasons?

In the NSF survey, a full 95 percent of the population many or most nights was using electronics with light exposure before sleep — either through televisions, computers, cell phones or tablets. This light is often much more powerful than people appreciate. Many sleep docs think night light is unhelpful before sleep because:

1. Late-night light keeps people up and keeps them more alert.

2. Late-night light resets biological clocks to later in the night — making many, particularly adolescents, go to bed later and later.

3. Late-night light turns off melatonin production.

4. People who have more late night light seem to have higher risk of severe disease — one Israeli group found higher rates of breast cancer.

5. Late-night light clearly violates normal body clocks — putting them out of synch and possibly leading to systemic immunological difficulties.

If light is a drug, then how do you properly use it?

Light at night
Though nothing succeeds like excess, too much light, especially sunlight, is problematic. Positively, daytime sunlight increases vitamin D and natural killer cell levels. And despite the risks of increased skin cancers, other tumors may become rarer through exposure to sunlight. One Australian study of prostate cancer, that supposedly controlled for exercise level and other illnesses, found half the expected incidence among men who worked regularly outside.

Yet light at night is a different animal. As shift workers can tell you, changing body clocks causes malfunctions almost everywhere. Shift workers have more heart disease, more strokes, probably more tumors and certainly more mood problems. If light at night can provoke these kinds of problems, why bring them on yourself?

In order to sleep you first need to rest. So if you can:

Make the lights at night dim – especially in the hour before you fall asleep.

1. If possible, turn off electronic devices an hour before you go to bed. The light they pump out will keep you up longer and may well interfere with sleep.

2. Rest before sleep — read, do yoga, put out the clothes you will wear the next day. Get your mind relaxed and focused on things that help you feel calm, rather than rev you up.

3. Take out an eye mask if your light exposure at night is too high to let you rest. We can appreciate a tiny amount of light even through firmly closed eyes. We also have light receptors in our eyes that are non-visual and are used to reset our long-term biological clocks. About half of blind people still appear to have these retinal giant cells that literally place your body in time, allowing your brain to schedule the many physiologic changes of the 24-hour day.

4. Simply recognize that light is a drug. You want to use it during the day. It can alert you, wake you, encourage you.

But you don’t want so much light at night — especially before sleep. Our bodies are built on time. Our times for required rest are decreed by our planet’s motion around the sun.

Darkness has its uses, after all.

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2 Responses for “Cut your light at night”

  1. Herb says:

    I agree with Richard. I’ve found that blue blocking glasses work really well for fixing circadian sleep problems. I review several brands of sleep glasses on my blog: http://www.lighttherapyreviews.net/amber-sleep-glasses-reviews/

  2. Richard L. Hansller says:

    There is a simple fix to this problem. It is mainly the blue component in whitee light that causes the broblem. Glasses that block blue light are available ona website http://www.lowbluelights.com.

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