A new study challenges the long-held belief that eight hours of sleep per night is essential for everyone. Researchers analyzing data from approximately 500,000 participants in the UK Biobank project found that the optimal sleep duration for slower biological ageing lies between 6.4 and 7.8 hours per night.
Key Findings on Sleep and Ageing
The study, published in Nature, compared self-reported sleep habits with markers of biological ageing across multiple body systems, including the brain, lungs, liver, immune system, and skin. Those sleeping within the 6.4 to 7.8 hour range showed slower ageing compared to those sleeping significantly more or less.
Risks of Insufficient Sleep
Getting fewer than six hours of sleep per night was strongly associated with an increased risk of health problems such as heart failure, type 2 diabetes, anxiety, and depression.
Risks of Excessive Sleep
On the other hand, sleeping more than eight hours was linked to conditions including major depressive disorder, bipolar disorder, schizophrenia, ADHD, and alcohol dependency. The findings suggest that too much sleep may also be detrimental to health.
Gender Differences
The researchers observed a slight difference between men and women. Women appeared to benefit most from around 6.48 hours of sleep, while men showed optimal results at 6.42 hours. This aligns with previous research indicating that women may need slightly more sleep than men.
Limitations and Considerations
The study relied on self-reported sleep data, which may be subject to memory errors or estimation inaccuracies. Additionally, individual sleep needs vary based on factors such as age, sex, and existing health conditions.
Importance of Sleep Regularity
Another study published in Sleep highlighted that sleep regularity—maintaining consistent bed and wake times—may be a stronger predictor of overall mortality risk than total sleep duration. This suggests that a consistent sleep schedule could be more crucial than simply hitting a specific number of hours.
While focusing on sleep duration is common, experts emphasize that establishing a reliable routine may be the key to better health and longevity.
