How was your sleep last night? And what about the night before that? How about three nights ago? Did you feel relaxed and refreshed each morning after getting the recommended 7-9 hours? Or are you among the growing group of people who don’t get 7+ hours each night? A 2013 Gallup poll showed that a whopping 40% of Americans were getting less than seven hours of sleep per night. However, in 1942 that number was only 11%![i] We’re going the wrong way when it comes to sleep. But is getting less sleep actually a big deal? Well, it makes us dumber, it makes us perform worse at life, and it increases our risk of chronic pain.
Sleep and Cognitive Performance
So let’s first talk about how sleep makes us, well, dumber. In students, it was found that getting one less hour of sleep per night turned the intelligent level of sixth-graders into that of fourth-graders[ii]. Again, that was only ONE HOUR difference per night. What else does deprived sleep do to our mental ability? A lot, and none of it is good[iii]. It decreased our reaction time. Decreased sleep impairs our attention to both hearing and visual stimuli. It decreases both our short-term and long-term memory. Sleep deprivation also impairs our decision-making. Basically, if you need to use your mind on any task, you can pretty much bet that it’ll be worse without adequate sleep.
Sleep and Physical Performance
Not getting enough sleep turns our brains into non-functioning goo, but what does it do to our physical performance? Let’s take a look at a study done on soldiers[iv]. In this study, four groups of soldiers ran simulated combat drills daily for 21 days. One group received seven hours of sleep per night, one got six, another group got five and one poor group only received four hours per night. At the end of 21 days, the group that received seven hours per night was performing at ~90% of their initial performance. That’s not too bad, right? The group with six hours was performing at 55%. Uh oh. The five-hour group was down to 31%!!! And those poor guys getting only four hours? They could only perform at a measly 15%!
What about athletic performance? As expected, a large review showed that (not surprisingly) it decreases with less sleep[v]. Our walking and running endurance both go down. Peak power decreases. Strength during biceps curls, bench press, leg press, and deadlift all decrease. Vertical jump decreases. Again, you can pretty much guarantee that your performance will basically suck if you’re not getting quality sleep. One thing I should mention is that this same review found, for the most part, that one night of decreased sleep isn’t a big deal. It becomes a big deal when decreased sleep is a nightly routine.
Sleep and Pain
At our clinic, we are mostly concerned about pain. You might not think sleep and pain have a big correlation. However, the research is pretty clear that there is a strong association between chronic pain and sleep deprivation. The scariest part is that research has also shown that not getting enough sleep actually PREDICTS new episodes and exacerbations of chronic pain[vi]. If you’re not routinely getting enough sleep, you shouldn’t be surprised by increased pain or even new painful episodes. Why are they related? For one, sleep is when our bodies repair and recover. If you have an injury with tissue damage, you need sleep for your body to repair this tissue. Secondly, pain is closely related to our psychological state. If we don’t get enough sleep, this causes our mind to be stressed, which then causes our nervous system to be more and more sensitive to pain.
Hopefully, between the risk of losing intelligence, the risk of decreased performance and risk of chronic pain, you can realize the importance of sleep. Now, it’s very easy to tell everyone to just “get more sleep.” However, the “how” part can be frustrating. Next month’s article will have lots of tips to help you get the 7-9 hours your body needs. And if you follow these tips, you’ll basically become a super-hero with your improved intelligence, improved athletic performance, and resistance to pain!
Jeff Remsburg, DC, MS, DACRB, Cert MDT
[iii] Neuropsychiatr Dis Treat. 2007 Oct; 3(5): 553–567.
[v] Sports Med. 2015 Feb;45(2):161-86
[vi] J Pain. 2013 Dec; 14(12): 1539–1552.