When it comes to dreams, it can often feel as though there’s no rhyme or reason to how our brains operate when we go to sleep. Dreams can feel cathartic, disturbing, interesting, exciting and even neutral—and many times we forget we even had them. But it turns out that temperature can have a major impact on how we dream and potentially what emotions our dreams elicit.
In 2018, Dr. Neil Stanley of the British Sleep Society and European Sleep Research Society claimed that a cooler bedroom, ideally a temperature between 60.8 – 64.4 degrees Fahrenheit (16–18 degrees Celsius), can help sleepers get a more restful sleep and even avoid nightmares, according to this article from the Liverpool Echo.
Dr. Stanley also explained that, “REM sleep occurs during either very light stage, or deep stage of sleep, both of which can be brought on by your sleep being disturbed by the ambient temperature. It’s during the REM phase of sleep when brain-waves behave similarly to being awake. This is the time nightmares typically occur.”
A very recent study makes the connection between temperature and dreams much more explicit and both supports and complicates Dr. Stanley’s explanation. Using genetically engineered mice, a group of Swiss neuroscientists studied how changes in temperature affect sleep and, in particular, dreaming. Basically, the study pin-pointed specific neurons, called melanin-concentrating hormone neurons, that exist within the hypothalamus and increase REM sleep when the body is in an environment with a comfortable temperature.
While dreaming is important for processing the information of the day, the brain and body prioritize survival when attempting to sleep in a place that is too hot or too cold. As this Medical Daily article explains, “REM sleep places a lot of physical demands on the human body. The brain of a person in REM sleep, which can account for up to 25 percent of an adult’s sleep cycle, eats up almost as much energy as when it’s awake.” But an even more energy-sapping function of our bodies is thermoregulation, and when our brains are faced with the question of which to focus on, it chooses thermoregulation.
The Swiss study both confirms and complicates the notion that hot temperatures produce nightmares—because being too hot may, in fact, cause us to skip dreaming altogether as our bodies preserve energy and use it to cool down. It also means that a comfortable and slightly cozy temperature could facilitate healthier dreaming. This study marks a huge breakthrough in sleep science, "Our discovery of these neurons has major implications for the control of REM sleep," says Schmidt. "It shows that the amount and timing of REM sleep are finely tuned with our immediate environment when we do not need to thermoregulate. It also confirms how dream sleep and the loss of thermoregulation are tightly integrated."
Ultimately, this breakthrough emphasizes the importance of environmental temperatures during sleep. In order to promote consistency in dreaming and deeper sleep, it’s essential to provide the body and mind with a well-regulated sleeping space. For RSA’s, it adds to the value proposition of cooling (and heating) technologies in sleep products and for consumers, it should put climate control higher on the list of priorities when furnishing their ideal sleeping space.
This article originally appeared in Sleep Retailer eNews on June 27, 2019.
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