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What does sleep affect? (Hint: Everything!)

Published about 2 years ago • 4 min read

Reading time: 4 – 5 min

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In last week's tip I suggested that a reasonable first step for improving our sleep is setting and adhering to a consistent bedtime, and I concluded the tip by offering a few questions to get you thinking about your current sleep schedule.

Have you spent some time reflecting on those questions and perhaps even started making small changes to your sleep-preparation habits? Excellent, if so!

If not, why not?

That's not a beratement or rhetorical question but a serious inquiry. Whether you get the recommended 7–9 hours of sleep per night or regularly fall short, improving your sleep (quality, quantity, or both) is likely to profoundly affect your mental, emotional, and physical health.

Seriously.

Matthew Walker, PhD, professor at UC Berkeley (and former professor at Harvard), and one of the world's leading neuroscientists and sleep experts puts it this way in Why We Sleep:

"The physical and mental impairments caused by one night of bad sleep dwarf those caused by an equivalent absence of food or exercise. It is difficult to imagine any other state—natural or medically manipulated—that affords a more powerful redressing of physical and mental health at every level of analysis.
Based on a rich, new scientific understanding of sleep, we no longer have to ask what sleep is good for. Instead, we are now forced to wonder whether there are any biological functions that do not benefit by a good night’s sleep. So far, the results of thousands of studies insist that no, there aren’t."

Sleep effects & Requirements

If you're into specifics, here are just a few conditions (source: Precision Nutrition) that sleep affects over both the short- and long-term:

  • Mental clarity: Important daily events are "encoded" into long-term memory when we sleep. Too little sleep can cause confusion, impaired judgement, and forgetfulness as well as reduced alertness and concentration (which coffee/caffeine really just covers up rather than "fixes").
  • Emotional & Central Nervous System (CNS) control: Various hormones and neurotransmitters (chemical substances that transmit nerve impulses across synapses) are refreshed during sleep. Related downsides to getting too little sleep can include low mood, impaired regulation of emotions, reduced tolerance to stress, increased risk of depression, decreased reaction time, and lower physical endurance.
  • Immune health: Not getting enough sleep can cause a decline in T-cells and an increase in systemic inflammation which can subsequently cause a higher vulnerability to viruses and bacteria (i.e. increased risk of illness) and an increased risk of developing cardiovascular disease.
  • Metabolic health: Along with decreased emotional regulation (from above) which can disrupt appetite and feelings of satiety and subsequently cause increased caloric intake and unwanted weight gain, poor sleep can affect insulin tolerance (and thus blood sugar levels) and increase the risk of developing type 2 diabetes.

If none of that scares you into working to improve your sleep, let's check back in with Matthew Walker:

“When communicating science to the general public in lectures or writing, I’m always wary of bombarding an audience with never-ending mortality and morbidity statistics, lest they themselves lose the will to live in front of me. It is hard not to do so with such compelling masses of studies in the field of sleep deprivation. Often, however, a single astonishing result is all people need to apprehend the point. For cardiovascular health, I believe that finding comes from a ‘global experiment’ in which 1.5 billion people are forced to reduce their sleep by one hour or less for a single night each year. It is very likely that you have been part of this experiment, otherwise known as daylight savings time.
In the Northern Hemisphere, the switch to daylight savings time in March results in most people losing an hour of sleep opportunity. Should you tabulate millions of daily hospital records, as researchers have done, you discover that this seemingly trivial sleep reduction comes with a frightening spike in heart attacks the following day. Impressively, it works both ways. In the autumn within the Northern Hemisphere, when the clocks move forward and we gain an hour of sleep opportunity time, rates of heart attacks plummet the day after. A similar rise-and-fall relationship can be seen with the number of traffic accidents, proving that the brain, by way of attention lapses and micro-sleeps, is just as sensitive as the heart to very small perturbations of sleep. Most people think nothing of losing an hour of sleep for a single night, believing it to be trivial and inconsequential. It is anything but.”

And the last but certainly not least Walker quote that I'll add to this tip is to convince you otherwise in case you think you can function just fine while getting less than the (minimum) 7 hours of sleep that most reputable sources suggest is necessary for adults:

“It is far, far more likely that you will be struck by lightning (the lifetime odds being 1 in 12,000) than being truly capable of surviving on insufficient sleep thanks to a rare gene.”

(If you wondered about the "99.9917%" reference from last week's tip, this is where the math comes from. One divided by 12,000 is .000083, or .0083%. And that's the probability of you being struck by lightning at some point in your life. The probability of your being able to function optimally on fewer than 7 hours of sleep per night is actually less than that.)

Putting it into practice

OK, so all of that is fine and good—or poor and terrible depending on your current sleep quality and quantity. But what should you do about it?

The answer isn't, "Start staying in bed for 9 hours per day immediately or else!" That's likely to be unsustainable if it's not your current habit. And because of your current circadian rhythm—which you've likely been messing with for a long time and which I'll discuss more next week—it's also unlikely to cause your sleep duration to increase significantly. Instead, as Aesop suggests, take a "little by little does the trick" approach to improving your sleep.

First, head back to last week's tip and answer (or re-answer) the questions I posed at the end. So that your body can more easily adjust to a new schedule, add just 15–60 minutes to your current sleep duration when determining when you need to go to bed. You can always add more time later.

Now that you know when you need to be in bed to get the sleep you need or, at least, to get closer to that mark, set a "get ready for bed" alarm, and start your pre-bedtime routine when it goes off. And, finally, take a deep breath when you climb into bed while reminding yourself that you're working on a new routine and it's OK if you don't fall asleep right away.

Next week I'll offer one more tip (before moving on to other topics) which, along with adhering to a consistent bedtime, could potentially be the most impactful strategy for improving your sleep over the long-term. If you intentionally work to implement these two strategies, you'll be getting more and better sleep in no time.

Until next week,
Ryan

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