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a post to send you to sleep, or not

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Häggström, Mikael (2014). “Medical gallery of Mikael Häggström

 

Canto: Anything interesting you’ve learned lately?

Jacinta: Well, there’s so much, it’s hard to keep track of it all, before it slides down the slippery slope into a past of fragmented memories.

Canto: A pasta of memories? That’s food for thought. I know you’ve been reading up on sleep, among all your other heavy reading. Tell me.

Jacinta: Yes, I’ve been reading up on feminism and misogyny as you know, which is mostly depressing, but this sciencey but very accessible book, Why we sleep by Matthew Walker, is not so much depressing as worrisome, for those of us whose sleep patterns are all over the place, like mine. He’s a big-time sleep researcher, and what he says about sleep deprivation is all bad – even for a wee bit of it.

Canto: So, those dreams of doing away with sleep, of zapping your brain for a few seconds to provide the instant reinvigoration that sleep takes eight hours of wasteful oblivion to achieve, allowing us that much more time to ruin the biosphere and all, or just to read more books and shit, those dreams are just a waste of sleep?

Jacinta: No zapping will ever replace the complexity of sleep, with all its REMness and non-REMness, let Mr Walker assure you. Sleep is a restorative and builder, which has complexly evolved with the complex evolution of our brains and bodies. And by ‘our’ I don’t just mean humans, but every complex or not-so complex evolved organism. They all sleep.

Canto: Well, there are many questions here. You’ve mentioned REM sleep, which I think has something to do with dreaming – your eyes, presumably under their lids, are rapidly moving about. Why? It doesn’t sound healthy.

Jacinta: They’re responding to brain signals, and it’s perfectly normal. More specifically, they seem to be responding to the brain’s changing visual representations while dreaming. They used electrodes in the brain to discover this – which sounds Frankensteinish but in this case they were patients with epilepsy preparing to have very invasive treatment to stop their seizures. They looked at activity in the medial temporal lobe, a region deep in the brain which includes the hippocampus and amygdala, and is involved in encoding and consolidating memories, and found fairly clear-cut connections between that activity and patients’ eye movements.

Canto: But how could they ‘see’ the eye movements?

Jacinta: Oh god, I don’t know, for now I’m more interested in sleep deprivation, which raises concerns for everything from diabetes to Alzheimer’s. And, although I haven’t measured anything carefully, my guess is that I average 6 to 7 hours’ sleep a night, and I need to amp that up.

Canto: And you’ve recently been diagnosed as pre-diabetic, so do you think more sleep can help with that? It’s usually pretty strongly correlated with diet isn’t it?

Jacinta: Less time sleeping, more time for eating, Walker writes. I’m certainly trying to lose weight, but only by eating less. I think my diet’s not too bad, less wine though. And I suppose if I slept more, which is easier said than done, I wouldn’t eat so much. I’ve found in the past that just reducing the quantity of food I ingest, without changing its make-up – in other words, being more disciplined – can take the weight off quite quickly. The key is to make it life-long.

Canto: More fibre is good, I think. For the microbiome.

Jacinta: So type 2 diabetes is generally about blood sugar levels and their regulation, or lack thereof. In a healthy person, eating a meal adds glucose to the blood, which triggers the hormone insulin, produced in the pancreas, to somehow bring about cellular absorption of the glucose as an energy source. In the case of diabetes, there’s usually a break-down in the cellular response to the insulin signal, I think, and so you become hyperglycaemic – not that this has ever happened to me, so far.

Canto: So how does this relate to lack of sleep, apart from giving you more time to guzzle sugar?

Jacinta: Walker describes a series of studies, independent from each other, in different continents, which found high rates of type 2 diabetes in people who reported sleeping for less than six hours a night on a regular basis. They controlled for other factors such as obesity, alcohol use, smoking etcetera. But of course correlation isn’t causation so they investigated further. They conducted experiments with a bunch of healthy people – no blood glucose problems or signs of diabetes. Firstly, they mildly tortured them – they permitted them only four hours of sleep per night over six straight nights. Then they tested their ability to absorb glucose, and found a 40% reduction in that ability. This would immediately classify them as pre-diabetic, and these studies, I’m assured, have been replicated numerous times.

Canto: That sounds incredible. And these guinea pigs quickly recovered? Or are they now full-blown diabetics? Doesn’t sound like mild torture to me. And do they know why a week’s sleep deprivation had such a dramatic effect?

Jacinta: Ha, well, Walker doesn’t mention the afterlife of the experimental subjects, but I’m assuming normality came bounding back after they recovered their sleep. As to the mechanism of action, Walker describes two options – sleep loss may have blocked the release of insulin by the pancreas, providing no signal for cell absorption to take place, or it may have interfered with the released insulin’s message to the cells. And though it seems that sleep loss probably had an effect on both, it was clear from biopsies taken from subjects that it was the latter, the cells’ lack of response to insulin, their ‘refusal’ to take up the blood glucose, that was the principal problem.

Canto: Just looking at the Sleep Foundation website, and they seem to get things the other way round, that diabetics are suffering from sleep loss. I must say, that, off the top of my head, I’d find being pre-diabetic easier to manage than my sleep behaviour. I mean, I can imagine changing my diet and exercise habits easily enough, but my sleep habits not so much. How do you turn off your brain?

Jacinta: Well, Mr Walker has some suggestions on that, which we’ll explore next time. And by the way, there seems to be tons of videos and websites providing knowledge and advice on the issue, which always makes me feel superfluous to requirements as a human being…

Canto: Well, try not to lose sleep over it.

References

Why we sleep, by Matthew Walker, 2017

https://www.sciencealert.com/scientists-have-worked-out-why-your-eyes-move-when-you-re-dreaming

https://en.wikipedia.org/wiki/Sleep_deprivation

https://www.sleepfoundation.org/physical-health/lack-of-sleep-and-diabetes

 

Written by stewart henderson

November 7, 2021 at 3:56 pm