Interest in sleep among personal trainers and fitness enthusiasts has soared over the last 5 years or so. The release of Matthew Walker's pop-science book "Why We Sleep" also increased knowledge and interest in the area of sleep among the general public. Sleep is important, and people having
knowledge of that is good, but are there downsides?
Yes, there are.
Firstly, Matthew Walker has received no shortage of criticism in relation to
Why We Sleep. The book contains
blatant factual errors, along with instances that near the territory of
research misconduct. The book also leaves the reader feeling like they are doomed if they can't sleep 8-9 hours per night.
Walker writes ‘There are many ways in which a lack of sufficient sleep will kill you’, and it would be no surprise if you were left worrying about your impending doom as you lay in bed at night knowing you are only going to get 5 hours of sleep.
The purpose of this essay is not to tear Walker to shreds, as the book is, on the whole, a good book. The neuroscience of sleep is discussed at an appropriate level for a general readership, and if nothing else, people paying attention to their
sleep hygiene is a good thing in many cases.
When considering books like Why We Sleep, we should try to position the narrative within the broader social, cultural, and technological
context. Those of you in the health and fitness community likely worry about health more than the average person. We often adopt an approach to life in which we try to control as many variables as possible, sometimes with little purpose. This is supported by new technologies that enable the tracking of various physiological parameters, including sleep, even by those who have little understanding of how to interpret that data.
You wake up in the morning, look at your smart watch, and you are given a score of "34%" for the day. Apparently, you are very under-recovered and did not sleep well. This was not your assessment based on how you feel, but rather that of the app you use. If
you didn't feel tired or lacking in concentration or drive for the day, this may just push you in that direction.
This is not my conjecture. This is supported by studies on
placebo sleep. When people are 1) informed about the harms of insufficient sleep, and 2) told they had insufficient / poor quality sleep, this has the effect of reducing their functioning. The power of the mind and all that.
This is even more important to keep in mind for those of you who have sleep restrictions beyond your control. Whether you are a new mother, surgeon on call, nurse on nights, or chronic insomniac, there may be variables in your life that stop you from being able to get a night of sleep that is sufficient in quantity
or quality. Worrying about your sleep, along with the other stressors in your life, may actually make your health even worse, as you are now riddled with anxiety and have expectations of poor performance, wellbeing, and health.
If you want to track your sleep and find the data useful, be my guest. Just make sure that you know what you are interpreting, and why. Missing out on sleep every now and then really isn't that big a deal. I've had all nighters before some of my hardest exams and done very well; short term, we can handle a lot of stress. Long term, well, all nighters on the daily wouldn't be so wise!
Similarly, if you feel well despite not sleeping as much as others seem to require, don't worry much about it. If you are an elite athlete, yes, try to bump it up and see if you can improve further, but for the vast majority of us, we will be just fine with
"good enough" rather than "optimal" sleep.
Finally, as the author of this essay, I should state my own bias. I mostly don't sleep as much as I "should". The claims I have made in this essay all
support my preferred reality, i.e. one in which sleep doesn't matter. To summarise my position; sleep is important for health, and 6-7 hours is probably enough for most people to do well, with higher amounts likely adding some extra benefit (7-8), or even more for those in high-performance sport (9+).
As I say to myself... Slept poorly last night? No factor. Get on with your day. Forget about it. You will be fine.
