Commentary: How much sleep do you need? Forget the eight‑hour rule

Commentary

Estimates of optimal sleep duration are based on averages, and the average person does not exist, say these professors.

If we define optimal sleep as the amount linked to the best health, many large studies suggest the sweet spot may be less than eight hours. (Photo: iStock/AleksandarGeorgiev)

27 Aug 2026 05:58AM

GUILDFORD, England: For decades, the answer to “how much sleep does an adult need?” has been simple: eight hours. The idea dates back to the mid-19th century when the notion of eight hours of work, eight for recreation and eight for sleep first took hold.But growing evidence suggests that eight hours may not be the ideal amount of sleep for everyone, as a new narrative review in Brain Medicine reminds us.To find out how much people naturally sleep, researchers have studied hunter-gatherer communities whose lifestyles are closer to those of our ancestors and who have little or no access to artificial light.In one early study, researchers found that people in Tanzania, Namibia and Bolivia slept for between 5.7 and 7.1 hours a night. These short sleep durations can’t be attributed to traffic noise, social media use or too much artificial light at night.