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MindBrain

The new science of alertness will help you perk up during that midday slump

By
Sonya Collins
Sonya Collins
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By
Sonya Collins
Sonya Collins
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April 27, 2022, 3:00 PM ET
woman at work drinking coffee
Working from home can affect your alertness.d3sign—Getty Images

Has the aftermath of the pandemic made a permanent work-from-homer out of you? Or have you recently been thrust back under the bright fluorescents of an office you hadn’t seen in a couple years? These new ways (or returning to the old ones) might have you thinking about how you can stay “on” during an entire workday—whatever form it may take.

“As a culture, we are struggling with a lot of challenges related to overwork, incredible amounts of pressure, and Zoom fatigue,” says Eric Zhou, PhD, a psychologist and assistant professor in the Division of Sleep Medicine at Harvard Medical School. “People are trying to find ways to prop themselves up as they confront the modern-day challenges of 2022.”

While there’s no escaping the need for sufficient sleep each night, research offers a few strategies that can help you stay more alert during the workday.

Start the day with a song

The ideal way to wake up is from light sleep. When you are yanked from deep sleep, it’s harder to get going, and you’re more likely to stumble around feeling groggy. This phenomenon, called sleep inertia, can affect your critical decision-making skills and brain performance even several hours later. 

While it’s unlikely you can time your slumber so that you’re in a light sleep when the alarm goes off, new research finds that you can choose an alarm tone that’s more likely to coax you into an alert, bushy-tailed state rather than that of the walking dead.

A group of Australian researchers evaluated people’s thinking skills after waking up to various alarm tones. They found that the ideal alarm tone to promote alertness upon waking was one with a melody you can sing or hum along to. When they dug further into the weeds, they found that among tuneful alarm tones, the most effective ones were in the key of C5 and played at a pace of about 100 to 120 beats a minute. They even created a tune that fits the bill. Other studies suggest that when you just set a pop song that you like as your alarm tone, you’re likely to arise more alert.

Let the sunshine in

After you’re up and moving, open your curtains or shades. And keep that sunshine flowing in your workspace too. 

You’ve probably heard that the blue glow from your phone can keep you up at night. That’s because your screen produces short-wavelength light. The sun also produces this short-wave light, but it’s this specific type—not all light—that tells your brain it’s time to be up and alert. 

Light-sensitive proteins in your eyes called melanopsin send a wakeup call to your brain based on the light they take in. They are most sensitive to that short-wavelength light on the blue spectrum, which includes your phone and the sun. 

Until now, guidelines on the best illumination schemes for day and night haven’t taken melanopsin into account. But recent research in PLOS Biology sheds new light on the topic. 

According to the study, you should get as much of your daytime indoor light as possible from the sun. Supplement that with short-wavelength white light. Think fluorescent bulbs, which glow white with a blue hue, rather than incandescent bulbs that skew yellow. 

“Structure your work environment so that you get as much full-spectrum light during the day as possible,” Zhou says. “That includes not only direct sources of light but also surfaces that reflect light. This light tells your brain it’s time to be awake.” 

It’s just as important that you tone down that light as the day comes to a close, so you can sleep well tonight and be alert again tomorrow. Three hours before bed, the lighting should be yellow, not white. It ought to be a whopping 25 times dimmer than full daylight. Of course, that’s impossible for most mere mortals to measure. But the science recommends 250 lumens at eye level in the day and just 10 in the final hours of the evening. For sleep, your bedroom should be as dark as possible, with no more than a single lumen of yellow light shining in the space. To get a sense of lumens, check out the back of a lightbulb package the next time you pick up bulbs.

The ‘coffee nap’ 

Even under the glare of fluorescent lights, that afternoon slump can hit hard. If you feel a nap coming on but it’s too early to knock off for the day, make it a coffee nap. 

A handful of studies have shown that a quick cup of coffee—don’t sip it, sling it back—followed by a nap of about 20 minutes is a more effective way to restore alertness than either a nap or coffee alone. It may sound counterintuitive, but there’s science to back this up. 

As your brain plugs away at work, it burns sugar for energy and builds up a substance called adenosine. This molecule fits like a key into designated receptors in your brain. As you run low on stored sugar and high on adenosine, you get sleepy. While you sleep, your brain clears out the adenosine. What else might fit into those empty receptors? Caffeine. That’s right. These particular receptors are like a lock that you can open with two different keys.

A cup of coffee takes about 20 minutes to work its way through your gut, into your bloodstream, and into your brain. So during a coffee nap, your brain clears out the adenosine and makes room for caffeine to move in.  

You may prefer a 40-minute nap instead, but it’s not advisable. The longer you sleep past 20 minutes, the deeper you’ll sleep and the groggier you’ll feel on the other side. 

Of course, there is no coffee nap restful enough (nor a tune peppy enough, nor light bright enough) to maintain the focus of a person who just needs a good night’s sleep, Zhou says. 

“None of this matters if you’re not consistently, and I stress consistently, getting the amount of sleep that your unique body needs.” 

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By Sonya Collins
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