You’d think it was uncontroversial that we need eight hours sleep a night. You hear that everywhere you go, but it turns out that it may be a myth.
Canadian research has called this into question, particularly looking at the impact of shorter duration sleep on health. Some nations tend to sleep less than others. So do the countries which sleep less, have poorer health statistics than those who sleep longer?
Researchers collected data on people’s health and their sleep duration from people in 20 different countries, based on the autumnal equinox, September 21, when the length of the day and night is about the same all around the world. They had four different measures of health and wellbeing including mental health, chronic diseases, overall physical health and how people in those countries perceived their own health.
What they found was that within each country, people who were sleeping shorter durations had worse health than those who were sleeping moderate sleep durations. In addition, people within those countries who were sleeping very long sleep durations also had worse health outcomes. That wasn’t because long sleep hurts people’s health, but when people aren’t healthy, they’re often sleeping longer.
If you imagine a graph of people’s sleep in each country, there was a sweet spot for maximum health and wellbeing. As sleep duration gets longer, people’s health tends to get better till it reaches a peak, and then it gets worse again.
That’s where the eight hours a day being a bit of a myth comes in. The sweet spot varied between countries. For example, Japan is a nation of short sleepers on average, yet Japan is one of the healthiest countries on earth with the longest-lived people. Australians sleep longer than Japanese and Australia is less healthy even though it’s also a long-lived nation.
So, for some reason that’s not clear, but may have something to do with culture and expectations, eight hours is not necessarily the perfect sleep duration. There’s a lot else going on.
Other research suggests that what really matters is sleep quality, meaning getting off to sleep quickly and sleeping through and feeling refreshed in the morning. That’s what insomnia therapy is good at delivering.
Researchers also looked at napping times in each country but that didn’t seem to affect the findings.
Further information
Improving Your Sleep – Dr. Norman Swan: myDoctor https://mydr.com.au/sleep/improving-your-sleep/
