A new international study is turning conventional sleep wisdom on its head, revealing that the often-repeated “eight hours of sleep” rule may not be the universal gold standard we thought it was.
Researchers from the University of British Columbia (UBC), in collaboration with institutions worldwide, examined sleep patterns across 20 countries and nearly 5,000 individuals. Their findings? The ideal amount of sleep varies greatly between cultures—and what matters more than the number of hours is how your sleep aligns with your country’s norms.
For example, the average sleep duration in Japan clocks in at just six hours and 18 minutes, while in France, people typically sleep for nearly eight hours. Canada falls somewhere in between, averaging seven hours and 27 minutes. Surprisingly, researchers found no consistent link between less sleep and poorer health outcomes, suggesting that cultural expectations play a crucial role in determining what constitutes “healthy sleep.”
“We’ve long been told to aim for eight hours, but that recommendation might not be right for everyone,” said Dr. Steven Heine, senior author of the study and professor of social and cultural psychology at UBC. “There is no one-size-fits-all amount of sleep.”
The study, published in the Proceedings of the National Academy of Sciences, found that people who sleep closer to their country’s average tend to report better health—even if they sleep significantly more or less than the classic eight hours.
Dr. Christine Ou, lead author and assistant professor at the University of Victoria, emphasized that the “right” amount of sleep may be more about cultural fit than scientific consensus. “People who matched their culture’s norms for sleep duration were generally healthier,” she said.
Even more concerning, the study revealed that people in all 20 countries were sleeping at least one hour less than what was considered optimal for their region. Whether in fast-paced Tokyo or relaxed Paris, modern life appears to be cutting into sleep across the globe.
So what does this mean for you? If your sleep routine aligns with what’s typical in your culture, you’re likely doing just fine—even if it’s fewer than eight hours. The researchers suggest that public health messaging should take cultural differences into account instead of pushing a rigid, universal standard.
The takeaway is simple but profound: sleep is not just a biological need—it’s a cultural experience. And the healthiest rest may not be measured by the clock, but by how well you fit into the rhythm of your community.