This two-part article will seek to explore the often mysterious experience of sleep as well as it’s implications on work and how these two opposing forces effectively influence and interact with one another. The first part of this article will strive to unpack what sleep is and why we do it.

First, sleep is a challenging and complex experience to clearly define and interpret, yet it impacts us all on a very deep and intimate level: across our life, work, and play.

We understand that sleep consists of a reduced level of activity, typical posture, reduced responsiveness to the external environment, and as a state that is easily reversed (as opposed to coma or hibernation). In addition, scientists have now defined sleep through the changes in brain wave activity and our physiology (Healthy Sleep Harvard Medical School, 2007). However, once we generally define sleep, we are still left wondering: Why? Why do we sleep? What’s the reason? Could our time be better spent doing something else, something more productive?! The short, yet ambiguous, answer to these questions is: sleep is vital to our proper and healthy functioning, and without it, we would not survive. Yet, this answer really isn’t enough. Therefore, I will highlight a few of the common theories as to why we sleep that have been compiled by Healthy Sleep Harvard Medical School (2007):

  • The Inactivity Theory suggests that sleep was an evolved and adapted function that allowed us to stay out of harms way at times when we would be particularly vulnerable. However, this theory can be quickly challenged in saying that conscious stillness would be much more effective in maintaining safety and reducing vulnerability than unconscious stillness (sleep).
  • The Energy Conservation Theory describes sleep as a method to reduce an individual’s energy demands and use, particularly during times where it would be inefficient to search for food.
  • The Restoration Theory expresses that sleep is a means through which our body can restore and recover for the experiences of wakefulness. This theory is supported through research highlighting that the body’s primary restorative functions often happen most or exclusively during sleep.
  • The Brain Plasticity Theory explains that sleep and consequently brain plasticity play a vital role in brain development as well as learning and memory, across the lifespan.

Thus, we can see the various considerations and theories behind why we sleep, and how it has developed to support our healthy functioning and ability to successfully navigate our life and environment.

Moreover, it is important to highlight some examples as to why we sleep and its potential purpose, benefit, and consequences for understanding sleep deprivation. Also outlined by Healthy Sleep Harvard Medical School (2007) are the following examples:

First, sleep is linked to memory and learning. Sleep provides the brain with an opportunity to refine and improve upon skills, abilities, and memories that were initiated and learned during waking hours. Second, sleep is linked to greater health and wellness, where good sleep can reduce the risk of cardiovascular disease (hypertension and stroke), diabetes, and obesity. Third, sleep has been linked to higher levels of safety in navigating work and life (Healthy Sleep Harvard Medical School, 2007).

Alternatively, sleep deprivation can lead to increases in fatigue related mistakes and injuries, as well as increasing the risk of a motor vehicle accidents. For example, one study showed an 160% increase in accidents by physicians after working 24+ hour shifts (Healthy Sleep Harvard Medical School, 2007). In addition, sleep deprivation leads to focus, attention, and vigilance issues, and we lose our ability to coordinate information, access previously learned information, and effectively make decisions. This is highlighted by the numerous severe accidents over the last 50 years where sleep deprivation has been ruled as a contributing factor, including: the Nuclear Accident at Three Mile Island, Nuclear Meltdown at Chernobyl, Exxon Valdez Oil Spill, and the Challenger Space Shuttle Explosion (Healthy Sleep Harvard Medical School, 2007). As such, the links between sleep, sleep deprivation, and performance are clear.

Stay tuned for the next segment of this article, where we will further explore the linkage between sleep, sleep deprivation, and work.

Article by Aaron Telnes
Registered Psychologist
Calgary Career Counselling

Healthy Sleep. Harvard Medical School (2007, December 18). Why We Sleep. Retrieved from: