Mental Spring Cleaning: The Function of Sleep

Sleep spring clean crop

There’s a lot happening in the Harvey household at the moment. Between the new book I’ve been writing for the last year and a half, the new film we’ve just received development funding for, the new baby who is due to arrive in late July, working to keep the bills paid, and the general hustle and bustle of every day life, just like many of you reading this post, I’ve got a lot to think about. My head space feels rather full.


At times like this it’s easy to tell myself I’m too busy to cook good food, or keep up my regular exercise, or to give in to mental fatigue after a hard day and stay up late watching television. These are all things I’ve been guilty of during busy periods in the past. What usually follows is a deep sense of weariness and an autoimmune flare up where my body becomes sore and inflamed with arthritis. It’s taken me many years to learn that maintaining my healthy habits during times like this is more important than ever and lately, I’ve come to think that sleep is actually the top of the list.


When you think about it, sleep doesn’t really make sense from an evolutionary-survival-of-the-fittest point of view. After all, during sleep we’re unconscious, paralysed and hardly on red alert for wild animals that want to make us their next meal. And yet, we humans spend about one third of our lives asleep. Although biologists have scoured the earth, to date there is no clear evidence of a species that does not need to sleep, so we know sleep must serve some kind of vital need. But why, when it’s so risky, do we spend such a significant part of our lives lying dormant, with our eyes closed, unaware of the world around us?


Thanks to modern research we now know that there are two distinct types of sleep – slow-wave sleep (SWS), known as deep sleep, and rapid eye movement (REM), also called dreaming sleep. Most of the sleeping we do is of the slow wave variety and it’s characterised by large, slow brain waves, relaxed muscles and slow, deep breathing. This type of sleep is considered restorative as it helps your mind and body to recuperate after a long day. The other type of sleep, REM, is not well understood but it is considered so important that some researchers describe it is a third state of consciousness, alongside being awake and being asleep. To an observer, REM is utterly bizarre. A dreamer’s brain becomes highly active while the body’s muscles are paralyzed, and breathing and heart rate become erratic. In a typical night, you’ll switch between REM and SWS about four to six times, with each cycle lasting 90 to 110 minutes.


With all that in mind, although there is a growing understanding of the biochemistry and the neurobiology of sleep, it’s exact function and purpose remains somewhat of a mystery. Researchers are still trying to understand exactly why sleep is restorative and why lack of sleep impairs brain function.


One break through study came from neuroscientist Maiken Nedergaard the University of Rochester in 2013. By peering into the waking and sleeping brains of mice, she discovered that during sleep the brain activates a waste disposal system, clearing out harmful proteins that build up between cells. “You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can’t really do both at the same time,” Nedergaard told BBC News when her research was first published.


Like the lymphatic system, which clears waste from our body, this glymphatic system has been shown to clear waste such as beta-amyloid (a protein associated with Alzheimer’s) from our brain. When our brains don’t have enough time to rest, toxins build up, and neurodegenerative disease may set in. Given that sleep disruption is closely associated with neurodegenerative diseases like Alzheimer’s disease and dementia, it may well be that too many of us have been doing too much entertaining and not enough cleaning up afterwards.


So with my brain choc full of the latest research I’ve been reading for my book, preparing for interviews with scientists, running a household, being the mother of a toddler, preparing for a new baby’s arrival and thinking about our future plans for the next film…. I’m taking myself off to bed. There’s some serious cleaning up that needs to be done if I want to keep all this up.


Of course, when times are really eventful, sleep isn’t always readily available and many of us can succumb to insomnia. If you’d like to read about some of the rather weird (but evidence based) things we do in our house after sunset to reduce the chances of insomnia setting in, check out this post I’ve written about how artificial light can wreck your sleep. You might also be interested in this post about how I learned to get a good night sleep, and this post about why successful people actually get more sleep.

  • Bob

    Extremely interesting blog post, and it's coincidental because I was just thinking about this last night as I was falling asleep. I was thinking that the state of deep sleep and unconsciousness seems to be necessary so that the mind can re-energize and reconnect itself with the universal consciousness that some hypothesize exists and that connects everything. Just a metaphysical theory.

    Thank you for writing this.

    Take care.

  • Ted

    Thanks for this, Shannon. Coincidentally (or is it…?), I just read an article about sleep that supports what you wrote. Just in terms of physical brain health, adequate sleep is necessary to stave off health issues, both physical and cognitive.

    As I proceed on my own journey (cancer), I understand more than ever the importance of prioritizing healthy actions: good nutrition, regular vigorous exercise, psycho-social connections, and sufficient sleep. I now realize (isn't it the way that we need a good kick in the seat of the pants to realize some things?) that if I don't have the time to tend to myself, and my health, I am simply too busy – too unbalanced. In which case, I now know that something of lesser importance must go. One project too many? Gone! A chance for entertainment that might keep me up too late or leave my energy sapped? Erased my calendar! People with energy that saps my own? Avoided or minimized!

    It may sound harsh, but in reality, it isn't. If we do not prioritize for our own health, we cannot tend to others' health, especially our family's. And concurrently, if we realize that we are out of balance, we can also realize that we really should let go of things that we rally don't need in our lives. And letting go can be some of the best therapy in the world!

    Best of balance to you, Shannon.

  • Shannon

    Hi Ted,
    I could not have worded any of this better myself nor could I agree more. Thanks for taking the time to write. If you have any tips on how you manage to actually implement this approach to your health I'd love to hear them. How, for instance, you say 'no' when you have to.
    Wishing you wellness in your journey ahead,

  • Shannon

    Thanks Bob. Lovely to hear from readers.

  • Ted

    "How, for instance, you say 'no' when you have to."

    Pretend as if your life depends on it (and you're really not pretending).

    Busy-ness is a way of running from the quiet things that call to us. Most often we can only hear them if we stop, or at least, slow down.

    Be Peace,

  • Ted


    I've thought about what I wrote in response to your question and realize how arrogant and certain my response appears. That surely wasn't my intent.

    Let me add that for me, at my age (60) and with my illness, tapping into what I really need and want (and don't need/want) in my life is very important. Indeed, I feel like my life (at least, the quality of my life) depends on my being honest with myself, as much as possible. I haven't perfected letting go by any means, but I strive for that. An honest assessment of what is good for me and important to me vs. what isn't, is proving to be very helpful as a first step to saying 'no.'


  • Anna

    HI Ted and Shannon,
    just stumbled over your comment-conversation and just wanted to say thank you for both sharing your opinion in such an authentic and compassionate way. No accusation, no blaming, but interesting pointers shared coming from a place of peace & wanting to help.

    Ted, I really relate with your point of 'running from the quiet things that call to us'. I find it so important to prioritize creating this place of quietness for me for me/my most authentic self to unfold and be empowered.


About the author: Shannon Harvey

Shannon Harvey is a journalist and producer who was diagnosed with an autoimmune disease when she was 24 years old. Although doctors meant well, none could offer her a cause or a cure. Since then Shannon has been researching the latest scientific research linking her mind and body to health outcomes. Nearly 10 years have passed since her diagnosis and today Shannon is well and not taking medication. Shannon has worked as a television, radio and online journalist and producer and has a Master’s degree in Communications. She worked for the ABC and Fairfax before starting her own production company, Elemental Media. Shannon is the director of the feature film The Connection.



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The Connection is a feature documentary and blog about integrating the latest science in mind body medicine into our everyday lives.


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