Why do we have strange dreams when it’s very hot?

From Sunday, July 28, a heat wave has spread throughout France. Sweating, anxiety, insomnia… Your nights are affected. And your dreams too. Dead people come back, fish with multicolored wigs, you turn into a water plant… When the mercury rises, you get the impression that your dream universe is reminiscent of a David Lynch movie. Does increasing temperature affect the content and frequency of dreams?

Split sleep

For sleep doctor Philippe Beaulieu, if we seem to dream more when we’re hot, it’s probably because we remember them more easily. “The brain needs to lower its temperature to sleep. If the heat does not allow it, the sleep becomes more unstable and fragmented, with more regular waking moments,” explains the doctor. However, these waking periods are key moments for remembering your dreams.

In 2014, a team of Inserm researchers found that people who remember their dreams more easily have twice as many waking stages as those who don’t. In a 2017 study published in the journal Frontiers in Human Neuroscience French researchers also showed that big dreamers’ nighttime awakenings lasted an average of two minutes, compared to one minute for small dreamers. So it’s not your brain that’s overheating, it’s you that’s not sleeping well.

The essence of a dream, unaltered by external conditions

Christian Riddell, author of the book Love and sex in your dreams (1) categorical. “Heat doesn’t make you dream more intensely or regularly.” According to the expert, a dream requires everyday elements to convey its message to us through staging, but its frequency or essence does not change due to external conditions. However, if our lifestyle changes due to late bedtimes and alcoholic nights, “a dream can warn us of the dangers of our lifestyle,” notes Christian Riedel.

(1) Love and sex in your dreams By Christian Riedel, Trajectoire Éditions, €22.30.

This article has been updated.