As anyone who has ever had trouble sleeping will know, there is nothing worse than a bad night of kip.
From spending hours tossing and turning with increasing levels of rage, to downing espressos the next day in an attempt to stay awake, insomnia is a particular form of torture.
However, it turns out that having trouble sleeping might actually be an evolutionary advantage, with one group of scientists arguing that insomnia is a survival tool inherited from our ancestors.
The scientists reached this conclusion while studying a tribe of modern hunter-gatherers living in Tanzania, with one of the most surprising findings from their research being that the tribe members rarely slept at the same time.
In fact, the researchers only recorded 18 minutes when all 33 members of the tribe were sleeping simultaneously.
Read more: 10 proven ways to get a great night's sleep
The advantage of this, the scientists concluded, was that the tribe would always have one member who was awake and on the lookout for danger, ensuring the safety of the group at all times.
The researchers, from the Duke University in South Carolina, believe their findings could also explain why our quality of sleep typically gets worse as we get older.
“The idea that there's a benefit to living with grandparents has been around for a while, but this study extends that idea to vigilance during nighttime sleep,” Dr David Samson, co-author of the study, told the Evening Standard.
And the researchers believe their study shows the evolutionary advantage of not getting enough sleep.
“A lot of older people go to doctors complaining that they wake up early and can’t get back to sleep,” Charlie Nunn, another co-author of the study, added.
“But maybe there’s nothing wrong with them. Maybe some of the medical issues we have today could be explained not as disorders, but as a relic of an evolutionary past in which they were beneficial.”
So next time you find yourself counting sheep in the early hours, take comfort in the fact your body probably knows what it’s doing.