What The Latest Sleep Science Can Teach Us
"Sleep science" sounds like an obscure low-fi band from Portland, but it's an area of science that has huge medical and societal implications. Sleep, after all, is a crucial part of our functioning; why we sleep (to conserve energy, consolidate memories, repair muscles, or some odd combination we haven't yet discovered) remains an open question, and the relationship between sleep and health, both mental and physical, is constantly revealed to be complex and multi-faceted.
March 17 was World Sleep Day, a celebration of sleep science and how far we're pushing the boundaries on research, so it's time for a deep dive into the latest science of sleep.
A review of the field from Beth Israel in February revealed that we're doing better than we ever have in uncovering sleep's secrets. We have new neuroscientific tools, laser lights that can turn targeted cells "off and on," and a huge range of new ideas about medications, natural hormonal rhythms, sleep disorders, and how sleep may feed into some of humanity's worst illnesses. However, since every solution seems to raise about 15 new questions, it remains an exciting and pretty puzzling area of study. Here's what's going on in sleep at the moment, and why you need to pay attention.
Your Sleep Tracker May Not Be Making Things Better
According to my fitness tracker, last night's sleep was of poor quality which probably explains why I'm so tired. Doesn't help but #nowUknow— Christian Thibodeau (@gorfchris) November 21, 2016
The introduction of sleep monitors on things like fitness trackers seemed like it was going to revolutionize the world of sleep, but a new study from February urges caution. People who are trying to gather data about their sleep and apply it to making their rest more calming or extensive, the researchers noted, may actually be shooting themselves in the foot.
The problem is twofold. Sometimes sleep trackers can create unreachable goals that perpetuate anxiety about "the perfect sleep:" if you only sleep "well" according to its standards if you get eight hours a night of deep slumber, for instance. Anxiety about the quality of your sleep will, as anybody who's tried to force themselves to sleep before an early start, always end in disrupting sleep entirely. The other issue is that trackers can be inaccurate, and that their inaccuracies can reinforce personal beliefs about poor sleep: you're more likely to believe you've had a bad night's slumber (and to feel correspondingly bad) if your sleep tracker tells you so, even if empirically you had no issues in the night at all. Trying to shift your sleep habits is therefore, according to the scientists, best done with professional help, not just with a potentially inaccurate tracker.
How We Sleep When We're Young Can Affect How We Act As Adults
The latest science on sleep and age has revealed that it doesn't matter how old you are: if you sleep poorly at any age, you're impacting on your future health. Infants, for instance, show a decided need to nap, and a University of Arizona study of small children found that napping for at least 30 minutes after learning a new thing was linked to remembering it better the next day. It's important, though, that they sleep for long enough to reach one of the deepest phases, which is associated with memory consolidation even in adults. Memory wasn't the only issue, though. Another study that looked at slightly older kids, aged from 3 to 7, found that if they slept poorly during those formative years, they were more likely to have behavioral issues as they entered later stages of childhood, indicating that sleeping when you're in preschool may help with brain development around social interactions.
It continues into your teen years, too. A joint study from the University of York and the University of Pennsylvania looked at the sleep quality of 101 teen boys, and found that if they had poor sleep quality and showed signs of antisocial behavior, they were more likely to commit crimes later in life. Low sleep quality in teens, one of the research's authors said, is often linked to social adversity and home issues, which also add into the likelihood for social issues. It's a poor cocktail and it sometimes ends up pretty nastily.
The Sleep Burden For Parents Is Gender-Divided
One of the most commonly mentioned conversations around sleep in modern life is the parenthood-sleep issue: "you'll never sleep again!" New research indicates, however, that it's much more true for mothers than it is for fathers, and not just when children are babies. It's unclear what precisely lies behind the findings, but the American Academy of Neurology found that in a study of 5,805 people, motherhood and the presence of children in the house was found to severely impact the sleep quality of young women, but to have little to no impact on the sleep of men.
So what's going on? Gendered sleep may be more of an issue as children age; while explicit conversations about feeding babies might lay out rules about equal involvement, mothers may develop bigger domestic responsibilities as children grow up, causing more stress and resulting in lower sleep quality. This is just speculation, though; more work needs to be done to find why the sleep burden among parents is so unevenly distributed.
We Now Know Why You're Sleepy When You're Ill
The mechanisms that make us sleep are mysterious and bizarre; the brains' circadian rhythms, and the "master clock" that regulates them, are one of the biggest areas of study for sleep scientists. Melatonin, one of the most promoted sleep aids, aims to fiddle with the master clock, as do light therapies and other methods. But there are various kinds of sleepiness, and a new bit of science has uncovered the unique role of the immune system in the sleepiness we endure while ill — and how it's helped us survive infections and illness over human history.
After inflammations and infections, the scientists found, the body releases a bunch of immune proteins that have a specific purpose: they set off a molecule called interleukin-1 beta, which has a strong role in the triggering of sleepiness and the depth of sleep. Without these proteins, which are coded into our genes, our response to severe immune system challenges would be less useful; the body couldn't sleep or recuperate effectively. The scientists also discovered that the lack of the proteins did something else worrying. Without them, mice who'd been sleep deprived didn't recover effectively, and didn't respond with sleep to things that activated their immune systems. The proteins, it seems, play a role not only in our recovery sleep but in our healthy sleep in general. When you next feel immensely sleepy when getting over a health problem, thank your immune system for working properly.
A Blind Fish May Help Us Understand Human Sleep
If you imagine the animal contributing most to sleep science, you'd likely conjure up some hibernating mammal, like the bear. And you'd be wrong. Currently, one of the most exciting contributors to our understanding of how sleep works is a variety of fish that lives in caves, is completely blind, and sleeps for only about two hours a day.
How can the fish survive with such immensely tiny qualities of sleep, and could humans develop mechanisms to do the same? Scientists are poking the Pachon cave fish in all kinds of ways to determine how and why they evolved to be such infrequent sleepers, and have discovered that, to survive, they appear to have developed hugely highly attuned sensory inputs, meaning that they're unable to do as humans do and "turn off" their senses to rest. They also sleep in highly randomized ways that seem to respond to how much food's around, whether there are predators, and all kinds of other factors. This suggests, the scientists say, that creatures evolve to need very little sleep because they survive better through constantly being on high alert and adjusting their sleep schedules to food.
How this will shape future super-humans who don't need to sleep is unclear, but it'll likely involve some kind of sensory input fiddling. Personally I'm not in a hurry to switch to a 2-hour night, though you would get a lot more done.