While the conventional wisdom suggests aiming for 7–9 hours of sleep per night, scientists now stress that the quality of rest may be even more crucial.
According to new research, poor or fragmented sleep in older adults may interfere with the brain's ability to eliminate waste, potentially increasing the risk of neurological disorders like Alzheimer’s.
Sleep Needs Vary by Age and Gender
Though most adults function well within the 7–9 hour range, the optimal amount of sleep depends on age, individual biology, and even hormonal changes.
Newborns need up to 17 hours per day, while older adults over 65 may function well with slightly less.
Experts also note gender-based differences. Women, especially during pregnancy, menstruation, and menopause, often experience disrupted sleep.
Although women tend to sleep slightly more than men, they also report higher rates of insomnia.
“If you wake up feeling tired despite long hours of sleep, something may be wrong,” said Dr. Rafael Pelayo, a sleep specialist at Stanford University. “It’s like leaving your favorite restaurant still hungry.”
The Brain's Nightly Detox Process
A key discovery from the University of Hong Kong (HKU) shows that insufficient sleep disrupts the glymphatic system—a brain-wide network responsible for clearing toxins.
Led by Professor Tatia M.C. Lee, researchers studied 72 older adults using functional MRI and sleep tracking.
Their findings confirmed that poor sleep quality impairs glymphatic function, weakening memory and potentially contributing to disorders such as Alzheimer’s, Parkinson’s, and epilepsy.
“Maintaining efficient glymphatic activity appears crucial for promoting healthy aging,” said Professor Lee. “Sleep quality, brain activity, and detox function are tightly interwoven.”
When to Seek Help
Consistent fatigue, irritability, and difficulty concentrating may signal insufficient rest. Experts recommend consulting a physician if one regularly feels unrefreshed despite adequate sleep duration.
Long-term sleep deprivation has been associated with cardiovascular problems, weakened immunity, depression, and cognitive decline.
In conclusion, while sleep needs vary, high-quality rest is universally essential. Researchers urge individuals to listen to their bodies and seek professional help when necessary to safeguard long-term brain health.
