Newsletter #170

Newsletter #170: Sleep & Cognitive Performance 🧠💤

Good morning, humanOS friends! This week, we took a look at some recent studies examining how aspects of sleep affect your brain function (something that I am all too aware of today, as I write these words 😣).

We know, of course, that sleep loss impairs pretty much every aspect of cognition, including memory, learning, attention, executive function, and so on. And unfortunately, sleep complaints are highly prevalent: about 40% of US workers report symptoms of insomnia. This obviously has an impact on individual health and performance, but it may also have pretty serious public health implications. For example, we know that sleep deprivation increases risk of car crashes- drivers who reported fewer than 4 hours of sleep were found to have 15.1 times greater odds of being responsible for a car wreck, similar to the increase in risk associated with drunk driving. So this is something that, on some level, affects every single one of us!

To learn more, scroll on down 👇🏼

This Week’s Research Highlights

👨‍💻 Even losing a relatively small amount of sleep may impair focus and productivity at work.

Researchers analyzed diary data on sleep characteristics and cognitive performance from a sample of 130 US workers at an IT firm. The scientists were specifically interested in participants’ daily experience of cognitive interference, meaning the intrusion of off-task and distracting thoughts. They found that on days after the subjects got less sleep or poorer sleep quality than what was typical for them, they reported more cognitive interference. And this effect was evident even when the sleep loss was quite miniscule - sleeping just 16 minutes less than usual was associated with an additional point on the cognitive interference scale the following day. Subjects also appeared to have worse sleep after days in which they reported struggling with distracting thoughts, suggesting a potential bidirectional relationship between cognitive interference and aspects of sleep.

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Summary: Researchers analyzed data from 130 US workers and found that sleeping just 16 minutes less than usual was associated with an additional point on the cognitive interference scale the following day. The study also suggests a potential bidirectional relationship between cognitive interference and aspects of sleep.

🩺 Extended work shifts affect cognitive performance of medical residents - potentially putting patients at risk.

Researchers analyzed data from 294 resident-physicians. These residents worked either extended-duration work rosters (meaning they would work 24+ hours every third or fourth shift), or a rapid cycling work roster (most shifts were limited to 16 consecutive hours). The researchers found that residents working the extended shifts experienced significantly more attentional failures (6.8 ± 1.0) compared with counterparts doing the shorter shifts (2.9 ± 0.7), and such attentional failures in turn were associated with serious medical errors. This finding mirrors the results from a study last year, which found that very high sleep-related impairment was associated with 97% greater odds of self-reported clinically significant medical errors among physicians.

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Summary: This study found that medical residents who worked extended shifts (24+ hours every third or fourth shift) experienced significantly more attentional failures and were at greater risk of making serious medical errors. The study highlights the importance of limiting work hours to prevent fatigue-related errors.

🌤️ Chronotype has a significant impact on what time of day our brains at their best.

Researchers in Germany examined how individual differences in circadian rhythms, or chronotype, modulate daily brain physiology and cognition in human subjects. They recruited 32 individuals who were either habitual early risers or night owls, and had them perform motor learning and cognitive tasks in two randomly assigned sessions at the same time in the morning and evening while recording electroencephalography (EEG). This meant that every individual was being tested and monitored during their circadian-preferred and non-preferred time. Sure enough, the researchers found that motor learning and cognitive performance was significantly better at each individuals’ preferred time. This improved performance was accompanied by a number of basic physiological differences in the brains of the subjects, such as enhanced cortical excitability and plasticity, at the times that corresponded with their respective chronotype.

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Summary: This study conducted in Germany found that an individual's chronotype, or circadian rhythm, has a significant impact on their cognitive and motor performance. The study found that performance was significantly better at an individual's preferred time, and this was accompanied by physiological differences in the brain at that time.

Random Trivia Question of the Week

🤔 What creature sleeps the most in the animal kingdom?

🥱 Answer

Podcasts We Loved This Week

Sara C. Mednick: Dreams - the next frontier for advertising? Via Sleep Junkies Podcast.

Diane Griffin: How long do viruses hang out in your body? Via Science Friday.

Products We Are Enjoying

Silk sleep mask

This sleep mask is super soft and fully adjustable, ensuring a comfortable fit without pressing too hard on your face or your eyeballs. It’s also huge, like almost ridiculously big, so it can block out all light even if you’re wearing it pretty loosely. Plenty of color options too!

humanOS Catalog Feature of the Week

Thanks for reading, and see y'all next week! ☕

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