There seems to be a heat receptor in the brain that makes you sleepy when temperatures reach a certain level.
- A nap of 10 to 20 minutes between 1 and 3 p.m. lowers the level of stress-related hormones.
- It also improves our alertness and memory.
The summer siesta, especially in the afternoon, is a very popular activity. In a crowded park or in the garden of the family home, a nap in the sun seems like a pleasant moment to live. But it could be that this habit is biological, according to a study published in the journal Current Biology. Researchers at Norhtwesh University found that vinegar flies were pre-programmed to nap in the middle of the day. A previous article in 2020 revealed a brain thermometer that was only active in cold weather.
Flies that don’t stay awake
To reach these conclusions, the scientists used fruit flies. For Marco Gallio, associate professor in neurobiology, this choice of test is relevant. These flies are subjects capable of answering questions like “why do we sleep?” or “what does sleep do for the brain?”. These insects do not try to stay awake, as humans can.
As a result, the researchers discovered that fruit flies were preprogrammed to sleep when the temperature reached 77° Fahrenheit, or 25°C. If these laboratory insects prefer this temperature, it is also the preferential temperature of many human beings.
An “absolute heat” receiver
The scientists also show that the brain of this fly has an “absolute heat” receptor when the temperature goes beyond 25 degrees. They found that the neurons in the brain that receive heat information are part of an overall system that also regulates sleep. This system targets cells that help sleep during the day. As a result, flies sleep during the hottest times of the day.
“People may choose to take an afternoon nap on a hot day, and in some parts of the world it’s a cultural norm, but what do you choose and what is programmed into you? “ Says Gallio. “Of course, it’s not cultured in flies, so there could be a very powerful underlying biological mechanism that’s overlooked in humans.”
