It doesn’t matter if you average 8 hours of sleep or if you’re just six and a half years old. That largely depends on new research conducted by scientists from the University of Victoria and the University of British Columbia in Canada.
This study suggests that cultural norms significantly influence sleep needs, indicating that instead of adhering to the universal eight-hour guideline, recommendations should be customized to fit specific countries.
“Sleep is influenced by more than biology alone. It is shaped by cultural expectations, work schedules, climate, light exposure, social standards, and various other aspects,” noted Dr. Christine Ou, an assistant professor at the Victoria School of Nursing, in an interview with BBC Science Focus. “What is deemed ‘good’ sleep in one culture may feel excessive or insufficient in another.”
The OU team studied sleep patterns and health data from nearly 5,000 individuals who participated in an online survey across 20 countries, including regions from North America, South America, Europe, Asia, and Africa.
Combining this data with findings from 14 prior studies, researchers investigated the connections between life expectancy, heart disease rates, obesity, diabetes, and the hours individuals slept.
The findings revealed that sleep durations varied significantly across the 20 countries studied. French respondents had the longest sleep, averaging 7 hours and 52 minutes per night, while Japanese participants reported the least, with an average of 6 hours and 18 minutes.
The global average for sleep was found to be 7 hours and 15 minutes. Participants from the UK reported an average of 7 hours and 33 minutes, whereas those from the US averaged 7 hours and 2 minutes.
Interestingly, the OU team made some notable discoveries. They found no universal “ideal” amount of sleep that correlated positively with health across all countries. In fact, there was no evidence to suggest that individuals in countries with shorter sleep durations experienced worse health than those in nations where longer sleep is standard.
However, a consistent trend emerged. When asked for their ideal sleep duration for optimal health, participants from Costa Rica suggested an average of 8 hours and 3 minutes while those from Korea indicated 7 hours and 16 minutes. In every country, most respondents felt their desired target was about 1 hour to 1 hour and 40 minutes longer than what they typically achieved.
Those who maintained sleep patterns that aligned closely with their country’s cultural norms were generally healthier. For instance, in the US, sleeping around 7 hours and 2 minutes nightly correlated with better health outcomes.
“Our research revealed that when sleep aligns with cultural norms, individuals tend to be healthier,” said OU. “Understanding the cultural context allows for a focus on what genuinely supports health rather than fixating on a specific number.”
Throughout every country examined, significant deviations from culturally accepted sleep norms were linked to worsening health outcomes, whether those deviations meant sleeping too little or too much.
The threshold for excessive sleep where health outcomes began to decline varied, highest in the UK at over 10 hours and lowest in the US at 8 hours and 13 minutes.
Sleep psychologist Dr. Daljinder Chalmers from Kiel University remarked in BBC Science Focus, “Sleep is complex, and there is no evidence to suggest that everyone needs to sleep eight hours a day.”
Dr. Chalmers, who was not involved in the study, noted that in countries where sleep durations are shorter, people might take more naps during the day or have different sleeping habits altogether.
She continued, “When analyzing sleep and health, you must consider cultural factors.”
The researchers controlled for variables such as nutrition, wealth, inequality, and geography, but it’s essential to note this was an observational study and could not establish direct cause-and-effect relationships between sleep and health outcomes.
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About our experts
Dr. Christine Ou is an assistant professor at the Faculty of Nursing at the University of Victoria in Canada. Having begun her career as a registered pediatric nurse, she focuses on sleep and psychosocial health in families with young children through her research programs. Dr. Ou is also a member of Canada’s Active Perinatal Mental Health Joint Committee and recognized as a public scholar and rising star in applied science at the University of British Columbia.
Dr. Daljinder Chalmers is a lecturer in health psychology at Kiel University specializing in sleep. She boasts extensive experience in academia, public service, and the NHS. Dr. Chalmers holds a Bachelor of Science in Psychology from Bedfordshire University, a Master of Science in Health Psychology from Derby University, and a PhD from the University of Portsmouth.
Source: www.sciencefocus.com
