October 13, 2020

The Physiology of Stress and its Impact on Sleep

The Physiology of Stress and its Impact on Sleep

The Constant State of Fight or Flight

Stress has a very useful biological function, in that it alerts us to and helps us avoid potential danger. It causes us to physically tense up, stay awake for longer periods of time, and generally be more on edge to be able to defend ourselves in the event that a danger does eventually present itself.

What isn’t so useful is experiencing this same stress reaction from everyday, non-life-threatening events, like every time your boss messages you after hours, or when you’re assigned a new project at 4:50 PM on a Friday. 

Yet, thanks to constant availability and willingness to accommodate extra work becoming more and more expected by employers everywhere, compounded by the world’s shift to remote, messaging-reliant work amidst COVID-19, more people are experiencing this type of non-dangerous, everyday stress than ever before.

“Non-dangerous”, of course, only means that it’s not as immediately life-threatening as the types of stresses our ancestors faced, such as being chased by a predator. Over time, however, as detailed below, these everyday stresses can be just as dangerous to our physical and mental health–especially as it relates to sleep.

How does stress affect us?

Stressed out man with hands covering face

As innocent as such instances may seem in the moment, thinking about that meeting you have tomorrow or that snarky message you received from your co-worker after work hours can produce in your body a quick burst of something called “acute stress”.

According to the American Psychological Association, or APA, this kind of stress is similar to what you would experience after having to slam on your breaks to avoid rear-ending someone, in that it increases your heart rate, causes stronger contractions of the heart muscle (“my heart was pumping!”), and releases a witch’s brew of stress hormones throughout your body, including adrenaline, noradrenaline, and cortisol–which increase such things as energy and alertness.

Acute stress also causes you to tighten your muscles as if you were bracing yourself for a physical impact, breathe faster and experience shortness of breath, feel butterflies in your stomach, and all sorts of other negative effects terrible for your short-term and long-term health. 

While these effects can be less noticeable during the day when you’re tending to other tasks, they’re often most noticeable when you’re trying to relax, which is why one of the first things to take a hit as a result of heightened stress levels is good sleep.

What is “good” sleep?

Baby sleeping with stuffed animal

The beauty of good sleep is that you know when you got it. You hop out of bed with ease, experience sustained energy levels and minimal anxiety throughout the day, maintain a calmer and less emotional demeanor, and generally feel great all the way until your head hits the pillow again.

From a more scientific standpoint, as explained by the National Institute of Neurological Disorders and Stroke, these benefits are the result of spending enough time in each of the four stages of sleep, which include:

  • Stage 1: You can think of this stage as entering into the theatre of sleep, wherein your heartbeat, breathing, eye moments, muscles, and brain waves begin to relax. 
  • Stage 2: This stage is similar to the preview before the movie. You experience further relaxation across your body, a drop in temperature, and your eyes stop moving altogether. 
  • Stage 3: With the movie about to begin, your heartbeat, breathing, and brain waves slow to their lowest levels during this stage of sleep. You’re also the most difficult to awaken during this stage. This is where you reap the majority of physical restorative benefits of sleep, in part due to the increased release of growth hormone. 
  • REM:  If Stage 3 is the movie itself, REM sleep is the bonus scene after the movie is finished. Taking place about an hour and a half after falling asleep, REM is where you experience dreaming, temporary paralysis of your limbs (to prevent you from acting out your dreams in real life), and increased consolidation of memory. REM becomes more and more precious as you age, as you spend less and less time in it the older you become.

It takes your body about 90 minutes to successfully cycle through all of these stages, and for most people to feel like they got a good sleep, according to the world’s leading elite sport sleep coach Nick Littehales, they require 5 full cycles–or 7 hours and 30 minutes–of sleep.

In most cases, 5 full cycles allow your body enough time to restore physically and mentally, consolidate memories from the day, and wake up feeling ready to tackle a new day–all necessary things for a productive and happy life.

However, stress can not only take away from your ability to benefit from each of these stages as much as you should, but it can significantly prolong, or even stop you from being able to fall asleep in the first place.

How does stress affect our ability to get good sleep?

For your body to be able to enter into and sustain good sleep, it has to be relaxed. This doesn’t just mean physically, as in a comfy mattress and pillow, but also mentally.

If you’re laying in bed wondering how you’re going to have enough time to prepare for that impromptu meeting tomorrow, or if that extra assignment you handed in an hour before you went to bed will satisfy your boss, you’re causing all sorts of stress-induced effects–ranging from hormonal to physical–to take place inside your body (like those described above), all of which prolong your ability to fall asleep.

It’s also not like these effects suddenly stop after finally falling asleep. Even after forcing some shuteye, stress can deter you from reaching deeper, more restorative stages of sleep, resulting in insomnia, in some cases.

This explains why even if you manage to get an acceptable amount of time in the sack, you can still wake up feeling terrible–because you spent the majority of your time in more shallow, less-restorative stages of sleep.

Getting good sleep in a fast-paced, post-COVID world

Man with sticky notes on face

During a time where it can feel like many things are out of your control, reducing stress levels, and getting better sleep starts with understanding what you can control, namely, your schedule.

With many companies moving to a remote workforce amidst the COVID-19 pandemic and all of the extended communication implications that come with that, it’s more important than ever to set aside enough time to allow you to ‘cool down’ and ‘warm up’ in the evenings and mornings.

In the evenings, stop looking at your devices (this includes phones, laptops, and even TVs) at least 90 minutes before bedtime to allow you enough time to process the day’s events. You can even use this time to jot down anything that’s stressing you out, helping you to fall asleep with less on your mind. 

You should aim to keep your phone out of your bedroom, lest you risk having a notification wake you up in the middle of the night or a late-night message sending your thoughts spiraling.

Even upon waking, you should allow yourself 90 minutes (or 60 if that’s all you can manage) to shake off any sleep inertia, make breakfast, exercise, get some sunlight, listen to a podcast, and generally do anything else that specifically helps you warm up your body to be able to tackle the day ahead as productively as possible.

Sleep quality is more important than ever

With remote workforces and socially-distanced communication not going anywhere any time soon, implementing these types of warm-up and cool-down buffer zones is a way to maintain control of your time, reduce stress levels, and sleep better as a result.

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