Is there anything worse?

Long, warm summer nights can mean bouts of sleeplessness for many of us, but do you actually suffer with insomnia? While struggling to doze off is frustrating, doctors will only diagnose insomnia when an inability to sleep affects you during the day, as my colleague Alison Bough previously reported. Now, scientists believe they have determined what causes insomnia. Researchers from Duke University in South Carolina say that the condition may be actually be a survival skill that's been left over from hunter-gatherer times. While observing a tribe of modern hunter-gatherers from Hadza people in northern Tanzania, they noticed that the members of the tribe rarely sleep at the same time to ensure that there is always at least one person keeping watch for potential danger. This suggests that our ancestors behaved similarly and had irregular sleeping patterns. "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," Charlie Nunn, co-author of the report, told the Evening Standard. Having trouble sleeping? Try this hack to send you straight to the land of nod.