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Smarter Sleeping for Data Scientists

Published by SuperDataScience Team

Monday Feb 03, 2020

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Welcome Data Scientists to this post on smarter sleeping! We are here to guide you through the current research on the effects of sleep on cognitive behaviours associated with office/screen? work.

We will be discussing interesting topics including the concept of an ideal amount of sleep, whether naps are a beneficial way to combat dips in productivity, and if there is an optimal time of day to be catching those zzz’s.

There are numerous topics under discussion when considering how sleep can affect you in the workplace, and for us Data Scientists, it is important not only to think about the effect sleep has on our mind and body, but the impact of increased screen time on our focus, health, and happiness.

We have broken the research in this post down to key topics, making it easier for you to navigate throughout:

Additionally, we’ve looked into some bonus concepts such as why some people appear to be more productive and alert at night (Night Owls v Morning Larks), and as to whether sleep can/should be broken down into parts (i.e duo/poly phasic sleep cycles). 

How do computers affect our cognitive responses?

It may come as no surprise that extended time working at a screen has shown a strong correlation with increased mental fatigue alongside ocular and orthopaedic complaints. Mental fatigue is a term which has been coined to define the effect on our brains after considerable stress from prolonged cognitive demand.

Sound familiar? If you’ve ever felt “burnt out” or mentally frazzled from many unbroken hours of work, you’ll understand this term all too well.

Mental fatigue not only affects your concentration and productivity, but has been shown to impair physical ability, too. While screen work may not sound as tiring as manual labour, jobs requiring focus and high levels of cognition are, in fact, highly energy consuming. This is important when considering how best to recharge the brain through smarter sleeping, consolidating memories and supporting learning.

Electronic devices emit an artificial blue light which has been shown to have a significant effect, decreasing the release of the sleep-inducing hormone, melatonin. Lack of melatonin delays the onset of sleepiness and can also affect quality and quantity of sleep. 

Another factor to consider regarding prolonged exposure to electronic devices is the blink response. It has been reported that people blink less (up to 66%) after long periods focusing on screen displays. Importantly, this decrease in blink frequency has been linked to an increase ocular irritation and incidences of dry eye.

But, what does all this mean for those embarking on careers in Data Science?

The good news is that there are various means to prevent the physiological impact of excessive screen time.

Yep, you guessed it, take regular breaks, carry out frequent eye exercises (like the 20/20/20 rule), have a walk to stimulate blood flow, and correctly position your equipment to minimise physical strain. 

Other great additions include antiglare and blue light filters and apps which remind people to take regular breaks. 

Take-aways:
  • Excessive screen exposure has been shown to negatively affect how our brains function.
  • Measures can be taken to limit these negative effects, including light filters and reminder apps.
  • Physical health can be affected by mental fatigue induced by screens, remembering to keep active will help you avoid sleep deprivation.

Is there an ideal amount of sleep?

We’ve all felt it. That grogginess after a terrible night’s sleep where you felt you barely caught any shut-eye. We lose focus, become slow and sluggish.

But then again, what about when we sleep too much? Same thing happens, right? Our bodies just don’t seem to function as well when we don’t hit that perfect amount of sleep.

What is this Goldilocks amount, and is it the same for all of us?

A recent study involving over 600,000 adults (age range from 18-65+) looked into productivity loss versus hours of sleep. They found that the overwhelming optimum amount of sleep was 8 hours in terms of productivity and happiness.

Interestingly, the researchers reported a U-shaped correlation between sleep amount and loss of productivity. Essentially, excessive sleep and lack of sleep affected participants the same way: reduced cognition and less ability to focus at work.

Does this mean there is an ideal amount to be aiming for?

To support this research, the National Sleep Foundation states that there is evidence linking too little (<6 hours) and too much (>10 hours) sleep with cases of heart disease and obesity.

Similar findings were reported from a joint consensus by the American Academy of Sleep. They concluded that adults should be sleeping 7 hours or more to promote optimal health. With the following important statements:

  • 7 hours or less sleep was associated with health issues such as diabetes, hypertension, heart disease, and stroke.
  • 9 hours or more may be appropriate for young adults, those recovering from sleep debt, or those suffering from ill-health.
  • It is uncertain if sleeping more than 9 hours a night has an associated health risk.

It would seem that there is strong evidence to support the fact that we are not so different when it comes to how much sleep we should be aiming for.

Yes, some people may feel “OK” after continuously sleeping 5 hours or less a night, but the overwhelming consensus suggests it to be an unhealthy practice, having cascading effects on health over time.

You may be saying right about now: this all sounds reasonable but what if my sleep quality is poor and I am finding my sleep disturbed and broken?

Sleep quality over quantity is something much harder to measure, and therefore study.

However, with the (albeit still-limited) knowledge of what the brain is doing in various stages of sleep, we can gather information on how to use this to improve sleep quality. For instance, by avoiding the disruption of certain sleep stages, we can enhance the housekeeping functions such as memory creation.

There are apps in use which monitor the sleeper’s breathing patterns and deduce which cycle of sleep they are currently in. With this data, the person is woken up within a time window of their preferred alarm, catching them in their lighter stage of sleep.

The purpose is to avoid wrenching sleepers from deep sleep and possibly affecting the capability of the brain to organise and process information as we sleep.

Though, not on the topic of how much sleep to get, it may be useful to bear in mind that it also matters when (and how) we are being woken up. This leads us on to our next piece of research, is there an ideal time of night (or day) to sleep?

What are the take-aways:
  • 8 hours is considered the optimal amount of sleep.
  • Less than 8 hours has been linked to increased risk of diabetes and heart conditions.
  • There are excellent sleep apps to aid maximising the perfect sleep-wake cycle.

When is the best time to sleep?

For certain employees, sleeping times are limited to fit around the working day, typically at night, synchronising with the natural circadian rhythm of the body.

However, more people nowadays are able to work flexibly round the clock, meaning they can experiment with finding the sleep pattern to suit them best.

We’ve looked into a particular study comparing lethargy between morning (early risers) and evening (night owls) type people. They found that evening types were:

  • Significantly more prone to feeling drowsy in the day, requiring naps (70% needing naps compared to 45% from morning groups).
  • More likely to be oversleeping (2 hours more) at weekends, with poorer sleep quality.
  • More reliant on caffeine.
  • Performing worse at school: a huge 46% had attention problems (compared to 11%).

The effect of night shift sleeping patterns was investigated over a period of 3 weeks. It was found that when sleep, activity, and meals were out of sync with the body’s natural circadian rhythm, metabolic rates decreased dramatically. Equating to a weight gain of about 4.5kg over a year.

It is widely reported that workers are cognitively and physically sluggish on the night shift due to poorer quality and quantity of sleep. Another investigation, this time involving physicians found that those on the night shift averaged nearly 3 hours less sleep than those on regular daytime schedules.

Additionally, they were about 25% slower to carry out routine tasks, more likely to make mistakes, and significantly sleepier and less happy when working nights.

Perhaps unsurprisingly, sleep deprivation has been linked to an increase also in depression and anxiety. This may be attributed to lack of good quality sleep, inhibition of natural bodily cues such as melatonin release, and social pressures, to name a few.

It’d seem then that there is a definite benefit to sleeping in line with our natural circadian rhythm in terms of performance at work and health. It is apparent through experimental study that the natural way is best. Catching those golden night hours has been proven to be beneficial for both our wellbeing and happiness.

However, for those working the night shift, it’s not all bad news: there are measures advised to help trick the body with artificial zeitgebers to induce better sleep. Many of the negative results from studies on nocturnal work derive from a lack of long and undisturbed daytime sleep.

So if you’re finding yourself more comfortable working late into the night, there are indeed means to ensure you don’t fall victim to any undesired health outcomes. In fact, it has been postulated that sleeping anywhere between the hours of sunset and noon the following day will be enough to avoid health risks.

Similarly, making sure you get enough sunlight and are conscious of your body’s responses to light exposure (remember the apps for light filtering) will help you keep in control of fatigue.

What are the take-aways:
  • Sleeping during the night is more natural for your body, and will help you avoid health risks.
  • Night shift workers can use strategies to combat under-sleeping.
  • Sleeping anywhere between sunset and noon will help your body feel happy and healthy.

Are naps beneficial or harmful?

Is there anything more blissful than the perfect daytime nap? Naps are routine for many people; those on varying work schedules or for that extra boost before a late night, but are they really beneficial for us and could there be a dark side to them?

Firstly let’s be clear on the types of napping:

  • Planned naps: Involves sleeping when you are not yet tired, but as a precautionary means to evading onset sleepiness in the evening.
  • Emergency napping: Occurring when fatigue hits suddenly. Useful for combatting dangerous levels of drowsiness when driving, or operating heavy machinery.
  • Habitual napping: Taking naps at the same time each day. Typically after lunch for adults, and very common for babies and young children.

What are the advantages of napping?

Naps restore our alertness, particularly for those requiring an “emergency” nap for functions such as driving or on long shifts at work.

They are performance enhancers, with a proven record of reducing mistakes: a NASA study revealed that a 40 minute nap reduced performance lapses by 34% and there was a whopping 50% decrease in sleepiness for the napping group in comparison to the control.

There are psychological advantages too: naps elevate your mood, aiding your ability to regulate emotion, tolerate frustration and reduce irritation and impulsiveness.

OK great, so naps for the win… when should I be napping to reap these rewards?

An associate professor from the University of California, Dr Mednick has reported the best time to nap is roughly 7 hours after waking. This is in order to perfectly balance the REM and deep parts of sleep, leaving you less groggy.

The length of the nap is a little more complicated. A full cycle of sleep including the REM, deep and light stages lasts around 90 - 110 minutes. It is recommended to grab a snippet of the superficial stages (in the first 20 or so minutes) to feel refreshed and alert.

Diving into deep sleep allows the brain to release compounds which prolong drowsiness, leaving you feeling sleepier and wanting more. Even as little as 10 minutes has been shown to immediately improve cognitive performance and alertness.

However, for those feeling this may be an unsatisfactory amount of sleep, there is evidence to prove that longer naps are also useful and can be necessary in certain situations.

If you’re able to fulfil one complete 90-minute cycle of sleep (try using an app to measure your breathing to wake you in the lighter stage), you’ll wake feeling less groggy, and could potentially be avoiding interrupting the natural restorative functions. However, there is still more research to be undertaken as to the long-term effects of habitual napping for periods of over 20 minutes.

What are the disadvantages of napping?

The Mayo Clinic recognises sleep inertia as an associated downside of napping. Sleep inertia is the period following disruption of REM sleep where the body has high levels of melatonin present. In essence, if you interrupt your nap in the deep stage, you’ll wake feeling less alert than before.

Sleep paralysis, although more uncommon, is a distressing condition and may also be induced by long naps (more than 90 minutes), and those taken too late in the day due to the potential disruption of sleep patterns.

Incorrect timing or duration of naps can induce feelings of jet-lag or insomnia due to onset wakefulness at night.

In general, there is yet more to be explored on the negative effects of napping. For now, it is advised to:

  • Limit duration for an immediate, refreshing effect.
  • Minimise interruption of deep sleep cycles and release of melatonin.
  • Balance nap timings between nocturnal sleeping to reduce disruption of sleep pattern.

Take-aways:
  • Naps are healthy, useful and essential sometimes.
  • You should carefully time your naps to avoid unwanted sleep deprivation and health effects.
  • Short naps are generally considered better for you.

Now for some more unconventional topics…

Night Owls v Morning Larks

Ever felt like you’re going against the grain with the 9-5 job? Feeling apprehensive as yet again you’re unable to sleep until the early hours of the morning, knowing you’ve got little time to sleep until that alarm sounds…

You may have already identified yourself as a “night owl” in a world governed by morning larks, if not, you may be surprised to find that you’re not alone in this community struggling from socially-imposed jet-lag.

But, what does this mean and is it possible for morning larks and night owls to live harmoniously?

Unfortunately for night owls, subjection to social demands has been shown to result in reduced brain connectivity, reduced attention span, slower reaction time, and an increase in fatigue.

This makes sense since owls are essentially out of sync with their natural sleep cycles and averaging less sleep on average than larks.

There has been lots of stigma over the years for being classified as a night owl as opposed to a lark: Benjamin Franklin was quoted as saying “early to bed and early to rise makes a man healthy, wealthy, and wise”.

Is this really true?

Finally, some good news for the owls: it has been reported that owls are in fact no less wise, wealthy, nor healthy. What is important is that they are able to find patterns to suit them and not fall victim to a toxic relationship with their snooze buttons.

At Southampton University, England, researchers analysed over 600 larks and owls in respect to income, cognition, and health. They found “no evidence” that following Franklin’s advice lead to any associated benefit in these circumstances.

In fact, owls were wealthier overall (and slightly more intellectual).

Can I change to be a lark?

Totally.

Should I?

Jury’s still out.

The brains of larks and owls have been studied and are actually different: owls were found to have a reduction of integrity in white matter in the brain, in areas associated with depression.

If you’re unhappy with your body’s predisposition to stay up late, there are some “sleep hygiene” methods you can try. These include: saying goodbye to caffeine, avoiding lie-ins on weekends, and keeping those pesky smartphones out the bedroom prior to bedtime, check them out here.

In this article there’s mention of a joint study by Universities in Australia and the UK which found that owls going to bed around 3am and waking around 10.30am were successfully able to adjust their sleep schedules 2-3 hours earlier.

Not only were they all successful at sticking to the regime, they actually reported feeling better. Anxiety levels, stress, and depression all decreased significantly. Though, it was commented that some negative feelings were associated with negative social response to owl behaviour, something we need to look at as a society in the future.

On the flip side, if you’re happy with your schedule and are lucky enough to be flexible with work, there are definite benefits to listening to your inner owl. Even some doctors would not condone fighting your natural rhythm.

“If people are left to their naturally preferred times, they feel much better. The mental capacity they have is much broader.” - Oxford biologist, Katharina Wulff.

She even proposed that pushing yourself too far out of your norm can be harmful, again relating to melatonin production and associated insulin and glucose sensitivities.

Unfortunately we don’t have a definitive answer of whether you should change your clock. If you’re feeling good working into the late hours of the night, it’s very possible you’re an owl and scientists would back you to embrace that. However, if you’re having to conform to social pressure and be up by 7am, there are means by which you can adjust your schedule and perhaps even benefit from a boost in morale.

Our take-aways:

  • An owl schedule isn’t inherently worse for our health, it is the imposed societal demand.
  • Owls can change their spots and become larks should they need.
  • The early bird is no better off than the night owl.

Taking us to our last topic…

What is polyphasic sleeping?

You may have heard the term before, or could hazard a guess at it. Polyphasic sleeping has been around since, well, since we started sleeping! It is the practice of sleeping in multiple periods throughout the day/night and has been employed by people such as solo sailor, Ellen MacArthur.

There are various sleep schedules according to the Polyphasic Society, with the favourite involving a longer “core” sleep (around 90 minutes) supported by shorter (20 minute) naps during the day.

The length of the core sleep and supporting naps vary across the board, but in general, sleepers are averaging from 2 to 7 hours of sleep per day.

Advocates claim that polyphasic sleepers are able to maximise time spent in REM and deep sleep. This is due to the body’s increased fatigue, meaning it will default to skipping lighter, reportedly “unnecessary” stages and shortcut you to the stages believed to be beneficial.

Should I try it out?

“No”, says Dr. Alon Avidan, director of the University of California LA Sleep Disorders Centre. He states that there is “very little data” demonstrating that polyphasic sleep has any advantage whatsoever.

Moreover, this practice typically leaves participants well below the required minimum time spent asleep per day, leading to increased risk of chronic conditions related to the disruption of hormone levels and spikes in blood sugars, such as diabetes.

It is also yet to be investigated whether we can just discard certain sleep stages and label them unnecessary. Likely, they are beneficial and avoiding them may cause undesired consequences to the endocrine system and metabolic function.

But, didn’t we used to be biphasic sleepers?

In a sense, yes. During the times of hunter-gatherers, many were adjusting sleep for survival and environmental needs. While it served a purpose back then, it is still contentious whether this practice is harmful, with many doctors claiming it to be ill-advised over long periods of time.

Some take-aways:

  • Polyphasic sleeping can be essential and should be carefully monitored.
  • It is ill-advised for long periods of time, with known associated health risks such as diabetes.
  • There is some interesting research to be done regarding “unnecessary” stages of sleep to be done before conclusive advice can be given on polyphasic sleeping.

Of course, when taking the findings from this article into consideration, it is vital to remember the limitations of qualitative research, namely the indetermination of causality and the simplicity of analysis affecting the ability to distinguish confounding variables.


References:
  • Gingerich SB, Seaverson ELD, Anderson DR., Association Between Sleep and Productivity Loss Among 598 676 Employees From Multiple Industries., Sage Journals (2018).
  • Samuele M. Marcora, Walter Staiano, and Victoria Manning,
  • Mental fatigue impairs physical performance in humans, Journal of Applied Physiology (2009).
  • Jatinder Bali, Naveen Neeraj1 , Renu Thakur Bali, Computer vision syndrome: A review, Journal of Clinical Ophthalmology and Research ,(2014).
  • The National Sleep Foundation, https://www.sleepfoundation.org/
  • The impact social media and proximity of digital screens is having on our eyes: https://bausch.co.uk/news/blink-rate
  • Flavia Giannotti Flavia Cortesi Teresa Sebastiani Salvatore Ottaviano, Circadian Preference, Sleep and Daytime Behaviour in Adolescence, Journal of Sleep Research, (2002).
  • Smith-Coggins R1, Rosekind MR, Hurd S, Buccino KR, Relationship of day versus night sleep to physician performance and mood, US National Library of Medicine, (1994).
  • Buxton OM1, Cain SW, O'Connor SP, Porter JH, Duffy JF, Wang W, Czeisler CA, Shea SA, Adverse metabolic consequences in humans of prolonged sleep restriction combined with circadian disruption, Sci Transl Med, (2012).
  • The NASA Studies on Napping
    https://priceonomics.com/the-nasa-studies-on-napping/ 
  • How long is the ideal nap?
    https://www.medicalnewstoday.com/articles/326803.php 
  • The Short-Term Benefits of Brief and Long Naps Following Nocturnal Sleep Restriction 
    https://academic.oup.com/sleep/article/24/3/293/2750008 
  • https://www.nhs.uk/conditions/sleep-paralysis/ 
  • https://time.com/5063665/what-is-polyphasic-sleep/ 
  • https://www.newscientist.com/article/dn24292-first-physical-evidence-of-why-youre-an-owl-or-a-lark/#.VRVvALrdRBX 
  • https://www.fastcompany.com/3046391/morning-people-vs-night-people-9-insights-backed-by-science 
  • https://www.livescience.com/64779-night-owls-brain-connectivity.html 


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