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Shine a light on sleep

Sleep. What could go wrong? In my last blog I distilled the science of sleep relying on UC Berkeley neuroscientist Matthew Walker’s research. Today I turn to my favorite science podcaster, Stanford vision scientist Andrew Huberman for research-based protocols to enhance sleep using light.

First, a qualification. I wish there were a silver bullet to fix bad sleep. There is no simple solution to this complicated problem. Good sleep often eludes me. And all kinds of advice and good sleep hygiene tips abound. I’ve tried them all.

Ultimately, I come back to a concept Walker discusses - sleep opportunity time. Basically, give your body the opportunity to sleep, which means a regular sleep schedule. Go to bed at the same time and rise at the same time even on the weekends. Granted, this is not always realistic but often it is. Walker suggests setting an alarm clock for bedtime and hiding the clock from view altogether in the bedroom. And keep the room cool to allow the body temperature to lower by 1 to 3 degrees helping folks fall and stay asleep.

I suggest we view sleep as a practice, unless we have underlying medical problems to be addressed, and approach it with calm and curiosity. Specifically, I find Huberman’s focus on light leads to behavioral practices that are quite easy to do. And it’s gratifyingly not what not to do. How can we harness light to help our sleep time?

Remember the biomechanisms that trigger sleep? Light enters the eyes setting our brain’s internal 24-hour clock. The chemical adenosine builds pressure to sleep from waking up to 12-16 hours later when the urge to sleep overwhelms wakefulness. The hormone melatonin sends the urgent message to the brain – “It’s time to sleep.” Our sleep alternates between slow-wave sleep (NREM) and fast-wave sleep (REM) in ninety-minute cycles.

With these mechanisms in mind, what can we do?

Seek morning light – Go outside within the first hour of awaking. Look towards the morning sun for at least five minutes. Maybe layer this natural light viewing with a morning walk or some other outdoor exercise. If it’s cloudy, extend the time to 20 minutes.

“Waking up” your circadian clock by bathing our eyes with light in the morning impacts alertness. Important – wear no sunglasses or brimmed hats; glasses and contacts are okay.

I walk outside or garden first thing in the morning and drink coffee while greeting the day. Huberman suggests delaying that first cup of coffee for 90 minutes after awakening. This can minimize that early afternoon crash in energy. But I am unwilling to wait.

View natural light at dusk – Go outside at the end of the day and view the sun setting in the sky for five minutes. This tells the body that the day is ending, and night is approaching with sleep not far behind.

Avoid viewing bright light at night. Basically, limit artificial lighting as you can. Your circadian rhythms will thank you. Crucially, skip overhead lights between 10pm and 4am, admittedly impossible for night shift workers.

The rest of us can reduce our exposure to bright light as evening wears on, allowing the sleep pressure to build and the messenger melatonin to send us off to slumber. With ample sleep opportunity time, even middle of the night awakenings can be managed if we’re calm, focus on breathing, and remind ourselves that few things stay the same. Shine a light on your sleep. Happy dreams!


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