A scientist has revealed why we often wake up at 3am and think about every decision we've ever made.
We've all been there, you bolt up in your bed and catastrophise everything, from our relationships and work, to that thing someone said to you at school 10 years ago.
Well, it seems that there is a very good reason behind it.
In a post on The Conversation, Greg Murray, a psychology researcher explained that it's incredibly common.
He said: "In a normal night's sleep, our neurobiology reaches a turning point around 3 or 4am.
"Core body temperature starts to rise, sleep drive is reducing (because we've had a chunk of sleep), secretion of melatonin (the sleep hormone) has peaked, and levels of cortisol (a stress hormone) are increasing as the body prepares to launch us into the day.
"Remarkably, all this activity happens independent of cues from the environment such as dawn light - nature decided long ago that sunrise and sunset are so important that they must be predicted (hence the circadian system).
"We actually wake up many times each night, and light sleep is more common in the second half of the night. When sleep is going well for us, we are simply unaware of these awakenings.
"But add a bit of stress and there is a good chance that waking will become a fully self-aware state."
The past year, Greg says, has also taken its toll on people, and affected our shut eye.
He added: "Not surprisingly, there is evidence the pandemic is a sleep-disturbing stressor. So if you're experiencing 3am wakings at the moment, you're definitely not alone."
And this often culminates in us staying awake and thinking our whole lives over. But why?
Greg said: "Around this time in the sleep cycle, we're at our lowest ebb physically and cognitively.
"From nature's viewpoint, this is meant to be a time of physical and emotional recovery, so it's understandable that our internal resources are low.
"But we also lack other resources in the middle of the night - social connections, cultural assets, all the coping skills of an adult are unavailable at this time.
"With none of our human skills and capital, we are left alone in the dark with our thoughts.
"So the mind is partly right when it concludes the problems it's generated are unsolvable - at 3am, most problems literally would be.
"The truth is, our mind isn't really looking for a solution at 3am. We might think we are problem-solving by mentally working over issues at this hour, but this isn't really problem-solving; it's problem-solving's evil twin - worry."
If you're struggling with this, though, Greg does have some words of advice.
He said: "I bring my attention to my senses, specifically the sound of my breath. When I notice thoughts arising, I gently bring my attention back to the sound of breathing (pro tip: earplugs help you hear the breath and get out of your head).
"Sometimes this meditation works. Sometimes it doesn't. If I'm still caught in negative thinking after 15 or 20 minutes, I follow the advice from cognitive behavioural therapy, and get up, turn on dim light and read."
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Topics: Science, World News, Interesting, Sleep