Our amygdala might need this period of processing to reset before the next day.
(It's one thing to be better prepared for looking at distressing photos and another to be prepared for your boss shouting at you in reality, however.) The longer people had felt fear during their dreams, the less their emotion centres were activated when they were shown stressful images. These emotionally charged memories then become the subject of our dreams.Īfter a bad dream, the area of the brain that prepares us for being afraid is more effective, as though the dream trained us for this situation. It is thought that this happens throughout sleep, but it is in the Rapid Eye Movement (REM) stage (just before we awake or as we dip into sleep) that we store our most emotional memories. While we sleep, we organise and file away our memories of the previous day and give our older memories a bit of a dust-off and reshuffle.
Children are particularly susceptible, says Ho, because their brains are still developing. A study looking at schoolchildren aged 10 to 12 in the Gaza strip found that more than half experienced frequent nightmares and on average they occurred on more than four nights per week. People living under regular duress are more likely to have nightmares. Long periods of stress which last months or years and affect whole populations are quite unusual – comparable only to wars in recent history, Ho says – but we know that chronic stress has a significant effect on our cognitive function. But for people who research trauma, the increase in nightmares was no surprise.įor those on the frontline of Covid-19 responses, like those doctors and nurses in Wuhan, 2020 was a period of "chronic stress", says Rachelle Ho, a PhD candidate at McMaster University in Canada. Reports of nightmares among citizens also rose during national lockdowns, with young people, women and people suffering with anxiety or depression the highest risk. Of 114 doctors and 414 nurses working in the Chinese city of Wuhan, who all took part in one study published in January 2021, more than a quarter reported having frequent nightmares. Concerns about lockdowns, loved ones and personal health were suddenly jumbled up with other mundane thoughts, leaving some waking up in confusion.įor people on the frontline, the dreams became nightmares. The effect seems to have been most pronounced in those particularly affected by the virus and in countries with strict lockdown measures. At the height of the pandemic, a strange phenomenon occurred – people started having weird dreams.