Chances are, your mother always told you that you needed to get enough sleep. You know this…
...What you probably don’t know, and what you have not thought about trying to quantify, is how much your lack of sleep is costing you. In fact, isn’t it kind of weird how little we really know about how we spend about a third of our lives? I’ve recently conducted some rather alarming research.
It started when I began considering messing with my sleep patterns in order to improve my productivity – something like the Uberman Cycle. In preparation for this, I began looking at the impact of chronic sleep deprivation.
In one study (Van Dongen et al, 2003), subjects were restricted to varying hours of sleep per night over a 14 day period. The results are worth quoting at length:
chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days resulted in significant cumulative, dose-dependent deficits in cognitive performance on all tasks […] since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation, it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults
This is jaw-dropping: If you sleep six hours a night for two weeks, you’ll perform at the same level someone who hasn’t slept for two days straight! Surely that’s hyperbole?
This is where the next key conclusion comes in:
Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign.
Crucially, people are not aware of the drop in performance due to chronic fatigue. As another, similar study (Belenky et al. 2002) affirms, the body is able to adapt:
In mild to moderate sleep restriction [7 hours and 5 hours per night in this study] this adaptation is sufficient to stabilize performance, although at a reduced level. These adaptive changes are hypothesized to restrict brain operational capacity and to persist for several days after normal sleep duration is restored, delaying recovery.
This is why people don’t notice the drop in performance, it’s due to the stabalization/adaptation that chronic sleep deprivation triggers.
Now granted, both of these studies have pretty small sample sizes (36 and 48 respectively), so we’re not talking about definite conclusions here. However, it certainly fits with what I’ve noticed about my own performance under conditions of chronic fatigue. The denial of there being an issue with a lack of sleep also fits with what I’ve observed – people who habitually get less than 6 hours sleep a night never think it’s a big deal. They say things like, “I can get by on xyz hours”. And that is the crux, yes, you can get by.But how much are you short-changing yourself here? If you are trying to teach yourself something, rapidly get better at something, or generally perform at a high level – you do not want to “get by”.
Which brings me back to this post’s theme: sleep efficiency. The key thing which my research has hammered home to me is that sleep deprivation is much more dangerous than I’ve previously acknowledged. I would often think working is more important than sleeping. But if I’m working on something with my cognitive performance level lower than if I’d had a decent amount of sleep, then the maximum quality of my work will be lessened, and the amount I complete per hour will be reduced.
I am being inefficient.
Clearly, I’ve only scratched the surface in this post. I think I will return to this topic in future posts, since I feel that learning about sleep is important in order to get the most out of life. Sleep is something scientists still don’t fully understand. That said, it is apparent that sleep is more important than society generally believes. If you’ve had any experiences with changing your sleep cycle, please leave a comment. I’ll leave you with this quote from this excellent article.
Rats totally deprived of sleep die in 17 to 20 days: their hair starts falling out, and they become hypermetabolic, burning lots of calories while just standing still.