However, while the researchers in this study seem to suggest that there is an optimal duration of sleep (between 4, 5 and 6 or 5 hours each night), sleeping on an occasional weekend is unlikely to harm the brain. Seven to eight hours of sleep is recommended for older adults, with 5 to 6 hours being appropriate for their age. However, sleeping less than 5 hours is not recommended. The importance of getting enough sleep is well-documented.
Among the many impacts on health and well-being, lack of good quality sleep is related to cognitive decline and conditions such as dementia. However, a recent study (opens in a new tab) has found that sleeping too much can have a similar negative effect on brain performance. People strive to get a good night's sleep in the hope that they can meet the standard of eight hours of sleep per night. Young adults can sleep 7 to 9 hours as recommended by the National Sleep Foundation, with 6 hours being appropriate.
Overall, the researchers found that sleeping less than 4.5 hours and more than 6.5 hours a night, along with poor quality sleep, was associated with cognitive decline over time. Sleep is vital to good health, but new research indicates that you shouldn't sleep more than 6.5 hours a night. A group that slept eight hours was 12% more likely to die in the six-year period than those who slept seven hours, all else being equal. However, while the researchers in this study seem to suggest that there is an optimal duration of sleep (between 4.5 and 6.5 hours each night), sleeping late from time to time on weekends is unlikely to cause any damage to the brain.
They studied people with short natural family sleep (FNSS), the ability to function fully and who preferred to sleep four to six hours a night. As reported by The Conversation (opens in a new tab), researchers from the University of Washington School of Medicine discovered that sleeping less than 4.5 hours or more than 6.5 hours a night, as well as poor quality sleep, was linked to cognitive decline over time. Dr. Kripke said that previous sleep studies had indicated that both prolonged and short-term sleep led to higher mortality, but no study was large enough to distinguish the difference between seven and eight hours a night.
A study of the sleeping habits of more than a million people over six years seems to debunk the popular idea that eight hours of sleep are required every night for optimal health.