It’s another hot summer evening, and the oppressive heat makes getting comfortable an impossibility. Yes, no matter how much you toss and turn, sleep refuses to descend. And yet throughout the sweltering night, you can’t bring yourself to remove the covers. So why are you so reluctant to take off the blanket?
We’ve all been there in those humid evenings when it’s too warm to sleep. No amount of counting sheep or relaxing whale noises can send you off to dreamland. And the answer seems simple – just remove the cover and you won’t be as warm. But this presents another dilemma that makes sleeping difficult.
Yes, many of us don’t feel right unless at least a part of ourselves is concealed during sleep. So instead, we poke a single leg out of the edge of the blanket to cool down, without overexposing ourselves. Or flop our arms over the top of the quilt to combat the rising heat.
However, it doesn’t take long for us to withdraw back under the blankets like a cloth-shelled turtle. It’s a paradox; we seek to be free of our blankets but can’t seem to let them go. Well, experts have researched the cause of this phenomena, and they came to an interesting conclusion.
Actually, they came up with two explanations for this common behavior. And they both offer an insight into not only how our bodies react during slumber, but also how our minds operate. But first, it’s important to note that the dependency on bed covers is quite a modern trapping.
So bedsheets have been around for a long time in human history, but they’ve not always been readily accessible. Take the ancient Egyptians, for example, who used covers made from linen. Now, they would have been especially luxurious for the time, which also meant they were reserved almost exclusively for the upper echelons.
Between acquiring the material for the sheets, and the craftsmanship it took to weave them, bed clothes were a hot commodity. And the ancient Egyptians weren’t the only advanced civilizations to take advantage of bed coverings, either. Yes, the Roman Empire employed them too, albeit made from a more commonly available source – wool.
Now, historians have noted that European weavers during medieval times had blankets made of cotton. But the story remained the same. Indeed, the comfort the bed sheets provided weren’t for the likes of the lower classes. In fact, it wasn’t until the medieval times had ended, and the early modern period began in Europe, that blankets became more accessible.
Yes, craftsmen began to produce comfortable items more readily, but not enough for widespread distribution. Indeed, whereas bedsheets weren’t reserved for the rich, the middle classes still had to work hard to get their hands on them. Funnily enough, a bed was a good indication of how wealthy the head of the household was.
And the importance of beds is reflected by blankets and bed clothes appearing in the wills of the departed. They were worth a significant amount – as much as a third of a family’s wealth. Actually, Virginia Tech historian Roger Ekirch has revealed that a bed was a household’s pride and joy.
You see, Ekirch is no stranger to writing about sleep, and he shared his expertise with Atlas Obscura in 2017. He said, “The bed, throughout Western Europe at this time, was the most expensive item in the house. It was the first major item that a newly married couple, if they had the wherewithal, would invest in.”
So what did the lower classes do while the upper ones swaddled themselves in comfy sheets? Well, they had to find warmth where they could, and that usually meant sharing body heat. Livestock owners would commonly nestle in among their animals, while families would share beds to stave off the cold.
These days, of course, bed cover production is ample and most people have some form of blanket. In fact, research suggests that the majority of cultures around the world use bed clothes, regardless of climate. At least, that’s what Emory University’s Melissa Melby and Carol Worthman reported in a 2002 study.
Now, Melby and Worthman’s research is about what the people of many cultures sleep on – and under – across the globe. And the pair considered this topic a “largely overlooked” font of information on anthropology, as they explained in the paper. Their findings certainly shed some light on the previously murky subject.
Yes, the researchers’ studies were informative, especially when it came to cultures living in hot climates around the equator. For they found that only foraging nomads – people who travel and live off the land – don’t tend to use bed blankets. However, most others do cover up when they sleep, using linen usually crafted from local materials.
With that in mind, there must be some reason why such behavior became so commonplace across the world. As we touched upon before, there are two reasons – one is physical and the other is a more complicated psychological explanation. And the former revolves around our body temperature and how it changes when sleep approaches.
To begin with, you need to know that a human’s body heat is largely self-regulating. That means it adjusts itself to the surrounding temperature in various different ways. And it’s why we shiver when we’re cold and sweat when we’re hot. Also, it’s one of the things that separates warm-blooded beings like us from cold-blooded creatures.
For instance, reptiles have to adjust their behavior and seek out sources of heat or cold. Humans don’t have the same requirements, but our temperature regulation process does change when we sleep. Or to be more precise, it starts to shift slightly prior to our established sleeping patterns – that is, our bedtime.
You see, at lower body temperatures tiredness starts to overtake, so our temperature regulation takes that into account. As a result, anywhere between an hour and an hour-and-a-half before we turn in for the night, our body temperature drops by a few degrees. And researchers have discovered this is biology’s way of giving us a better night’s sleep.
Yes, they tested the theory during a 2008 study called Skin Deep: Enhanced Sleep Depth by Cutaneous Temperature Manipulation. In layman’s terms, they were making people slightly colder using skin-tight suits to see how it affected sleeping quality. And the results revealed that people who were cooler slept more soundly.
In addition, the experts noticed another detail – lower temperatures coincided with the release of a hormone called melatonin. It’s a sleep-inducing hormone that makes us drowsier. And even once you’ve drifted off, your resting body goes through more changes. A few hours into your sleep cycle, you experience phases of rapid eye movement.
Now, rapid eye movement (REM) describes a period of sleep when your eyes dart about beneath your eyelids. According to website Medical News Today, the majority of dreams happen during the REM phase of sleeping. Also, it signifies a change in your body’s ability to regulate heat, as one expert told Atlas Obscura.
That’s right, Dr. Alice Hoagland, director of New York’s Unity Sleep Disorder Center, said, “You almost revert to a more – and this is my word – reptilian form of thermoregulation.” Essentially, we take on traits more associated with cold-blooded reptiles, and can’t warm ourselves up in our sleep.
To make matters worse, even in hot countries, the nights get colder following dawn, while many of us are asleep. So if you’ve ever wondered why you went to bed in oppressive heat and woke up cold, that’s why. Not only has the temperature dropped, but your sleeping self doesn’t shiver to warm up.
So through trial and error, humans have realized that bed coverings are the best way to deal with this obstacle. Thus, even if you sleep without blankets, you can reach over for one when you wake up. However, people are a little more complicated than that, as Hoagland revealed. Yes, there’s another reason we use blankets.
Dr. Hoagland said, “The requirement for blankets takes on two components to it. There’s a behavioral component and a physiological component.” Which brings us to the next reason why you can’t sleep without a cover regardless of temperature. Like the physical reason, this also has its roots in the REM sleep phase.
You see, sleeping bodies release a cocktail of hormones and chemicals that interact with each other. Many of them are called neurotransmitters, which are responsible for sending signals to the brain. And in 2016 neuroscientist Colin Gerber addressed the subject in Forbesand explained what they do. At least, to the best of our current level of understanding.
Gerber said, “There are at least eleven (almost definitely more) neurotransmitters and hormones that play intimate roles in the sleep-wake cycle.” He named GABA, Orexin, Glutamate, Acetylcholine, Norepinephrine, Dopamine, Adenosine, Corticotropin-releasing hormone, Growth hormone-releasing hormone, Cortisol, serotonin and, of course, melatonin. Of course, some of these names are more widely known than others.
For instance, you’ve probably heard the name dopamine before, and maybe even serotonin. The latter is often called the happiness chemical, because it’s responsible for feeling contentment, euphoria and keeping us calm. Decreasing serotonin levels is another physical response our bodies have to REM sleep, which has a psychological effect, too.
You see, people living with anxiety and depression have lower amounts of serotonin in their brain. Essentially, REM sleep makes our slumbering selves less at ease and more prone to panic or anxiety. On the other hand, various studies have revealed that blankets are linked to higher serotonin levels, thus making us happier.
To add to that, the sensation of touch that bedclothes provide play an important role in the process. You might have noticed that Gerber mentioned cortisol in the list of sleep-associated chemicals. Well, it’s a counterpart of sorts to serotonin. Your adrenal gland makes cortisol which controls fear, mood and your fight-or-flight responses.
And touch helps decrease levels of cortisol in the body. Psychology Today reported in 2018 that touch can even alleviate both physical and emotional pain. But why would our bodies react to touch in such a way? To answer that question, you need look no further than what touch is – it’s pressure.
Yes, Deep Pressure Stimulation (DPS) is what experts call pressure on the skin with the intention of healing. In fact, it’s the basis of many treatments such as physiotherapy, chiropractic therapy and massage. On a less clinical note, though, blankets provide a form of touch therapy simply by covering us while we sleep.
Perhaps it’s something to do with what Hoagland calls “pure conditioning.” In other words, it’s behavior we learned as babies that has subconsciously shaped us. She told Atlas Obscura, “Chances are you were raised to always have a blanket on you when you went to sleep. So that’s a version of a transitional object, in a sort of Pavlovian way.”
Now, this is similar to the practice of swaddling, or wrapping babies up firmly in blankets. You see, some people claim that the reassuring pressure makes babies feel protected and calms them down. One theory is that it reminds the infants of their time in the womb.
But Hoagland told Atlas Obscura that she disputes this theory. “I’m very suspicious of anyone who implies that this goes back to the feeling of being in the womb,” she revealed. “I think that’s very far-fetched.” Whatever the cause for the reaction, though, DPS certainly has applications in medical therapy and treatment.
For example, take weighted blankets, which differ from regular bedclothes in both function and accessibility. Although they’re not as affordable as other kinds of bed linen, weighted blankets are heavier, as the name suggests. That’s because they leverage DPS to enhance the calming, comforting effects of bedclothes. Yes, they provide comfortable pressure to create beneficial chemical reactions.
In reality, the extra weight of these covers enhances melatonin and serotonin production while reducing cortisol levels. So who should be using these blankets? They’re really for anyone who wants a better night’s sleep. But it goes without saying that some people will find greater benefit from weighted blankets than others.
Yes, if you’ve got a sleeping disorder such as insomnia, you may want to give weighted blankets a try. Furthermore, studies have shown that they’re a safe and effective treatment for anxiety or sensory disorders. This includes autism, depression, post-traumatic stress disorder, obsessive compulsive disorder and more.
In fact, in 2016 occupational therapist Karen Moore told Collective Evolution that weighted blankets can be invaluable therapy assets. She said, “Weighted blankets are one of our most powerful tools for helping people who are anxious, upset, and possibly on the verge of losing control.” Therefore, let’s hope researchers dedicate more time to sleep studies in the future so we can better understand the fascinating topic.