Scientists debunk myth of universal sleep norm by studying Japanese lifestyle

Tengrinews.kz - Canadian researchers from the University of British Columbia have challenged the widely accepted notion that eight hours of sleep is the gold standard for good health. Their findings, published in the Proceedings of the National Academy of Sciences (PNAS) and cited by Gazeta.ru, suggest that sleep needs vary significantly across cultures.
Analyzing data from 70 countries, the researchers found no consistent link between sleep duration and health outcomes. One striking example is Japan, where people sleep on average 1.5 hours less than the French, yet enjoy one of the highest life expectancies in the world.

“Japan has the highest average life expectancy globally, despite shorter sleep durations,” the study notes.

The research found no direct correlation between national sleep averages and rates of heart disease, diabetes, or obesity. In fact, the “ideal” sleep duration varied across the 20 countries studied. Moreover, individuals whose sleep patterns aligned with cultural norms reported feeling healthier overall.
The scientists suggest that social adaptation—such as alignment with work schedules, public transport, and other societal rhythms—may be more important than a fixed number of sleep hours.
These findings cast doubt on global sleep recommendations and highlight the importance of considering cultural context when evaluating health guidelines.
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