It just seems like some people can get by on less sleep than the recommended 8 hours. Granted, that ability may be forced upon them due to circumstances like, say, early parenthood. Bear in mind, this isn’t the same as a morning person, who’s just the kind of person who’s all pep and unicorns early in the morning, every morning – I’m not talking about them. I’m talking about those who are perfectly functional while running on 4-6 hours of sleep. You know people like this, but I’m not one of them. I need one of these.
Here’s the thing, though: what is it with their brains? Is it different in some way than those of us who need 8 hours, and anything less can only be amended by coffee or threats of physical harm? An article recently published in Brain and Behavior wants to find out what kind of connections there are in short-sleepers’ brains using fMRI while they’re relaxed. What’s lighting up in the brains of 839 subjects who were part of a larger project regarding neural connections?
The study examined subjects who reported an average daily sleep of duration of 6.82 hours (+/- 1.15 hours), but range from 2.5 (WHAT!?!?!) to 12 (sweet) hours – this is actual sleep, not just staying in bed. Anyone who sleeps less than 6 hours is considered a short-sleeper, while everyone else is ‘conventional’. The Pittsburgh Sleep Quality Index (PSQI; Buysse et al. 1989) to determine how well subjects slept or felt restful; it contains questions as “During the past month, how often have you had trouble staying awake while driving, eating meals, or engaging in social activity?” Like a lot of psychological tests, it can’t possibly account for every variable – it’s not like the PSQI asks each subject how many dreadfully boring people they know, but anyway.
One thing they also considered was, because the subjects had to be relaxed but alert (this is a thing) was that the fMRI may have weird readings if the subjects’ heads moved (I’m guessing nodding off?), so they had to take that as a variable.
So what did we learn? Turns out that brains of the subjects who reported shorter sleep duration had increased connectivity in some parts of the brain dedicated to the senses, but decreases in, among other places, the caudate nucleus and the putamen. That ought to be a concern, since these are both involved in learning.
The authors suggest that this may explain why people who say they don’t need a lot of sleep and say that they’re alright in the day need environmental stimulation. Plants, daylight, music – that seems like it would have to do with the parts of their brains that light up anyway. When you don’t have a lot of environmental stimulation, like let’s say working in a cubicle or getting or head scanned in an fMRI, you’ll have difficulties staying awake. However, the authors do warn that “the findings of this study should not be generalized beyond self-reports of sleep duration.” There’s some issues that still persist regarding how valid self-reports really are, but one could just measure it themselves. What a job that would be.
I realize that sleep is rather important to us, and that this is a Monday post. Allow me to help you feel a little more fulfilled with something that should feel…cathartic, I should say. You’re welcome.
Featured article: Curtis JB, Williams PG, Jones CR, Anderson JS. (2016) Sleep duration and resting fMRI functional connectivity: Examination of short sleepers with and without perceived daytime function. Brain and Behavior. doi: 10.1002/brb3.576
Featured image credit: Wikimedia Commons/Flickr (CC-BY-20, author: Koji Horaguchi)