Tip/Thought of the Day

Seven Hours of Sleep Is Optimal for Those in Middle to Old Age

Over several posts, we’ve shared the importance of sleep for overall wellness. It not only decreases the risks of all-cause mortality, but it helps reduce inflammation, decreases the risk of heart disease, promotes a healthy weight, allows the body to restore and repair, improves mood and mental function, and many other factors. A new study has shed light that age does play a role in how much sleep is enough. Findings reveal that seven hours of sleep is the optimal amount of sleep for those in middle to old age, and any more (or less) can negatively impact cognitive performance and mental health.

The study was published in Nature Aging, and shared that scientists from the UK and China examined data from nearly 500,000 adults aged 38-73 years from the UK Biobank. The Biobank was started in 2006, and sources share that it “is a large long-term study in the United Kingdom which is investigating the respective contributions of genetic predisposition and environmental exposure to the development of disease.” Participants in the study were asked about their sleeping patterns, mental health and wellbeing, and took part in a series of cognitive tests. Brain imaging and genetic data were available for almost 40,000 of the study participants.

Through the study, the researchers found that excessive or insufficient sleep resulted in diminished:

  • processing speed
  • visual attention
  • memory
  • problem-solving skills

The study explains that insufficient sleep and cognitive decline may be due to the disruption of slow-wave, ‘deep’ sleep. You can read more about the stages of sleep, here. Disruption to this type of sleep has been shown to have a close link with memory consolidation as well as the build-up of amyloid, a protein which can cause ‘tangles’ in the brain characteristic of some forms of dementia, including Alzheimer’s. The findings in this new study support others that show a link between sleep duration and the risk of developing diseases like Alzheimer’s and dementia, which have the well-known symptom of cognitive decline.

People that slept more or less than seven hours were shown to experience more symptoms of anxiety and depression and worse overall wellbeing. This adds to the list of studies that have found that sleep significantly impacts mental health. The reason behind this isn’t clear, but one study of twins found that long sleep actually activated genes related to depressive symptoms. One hypothesis is that long sleep duration is associated with decreased physical activity. Physical activity has been associated with reduced risk of depression by increasing levels of the neurotransmitters dopamine and serotonin, increasing release of endorphins, distracting from stressful stimuli, and improving self-esteem. 

Professor Barbara Sahakian, from Cambridge University’s department of psychiatry, said, “For every hour that you moved away from seven hours you got worse. It’s very clear that the processes that go on in our brain during sleep are very important for maintaining our physical and mental health.”

Getting a good night’s sleep, she added, was important at all stages of life, but particularly as people aged. “I think it is as important as getting exercise.”

The importance of sleep cannot be underestimated. From the improvement in our day-to-day function, mental health, and decreased risk of acute health issues, this study underscores the significance of sleep as we age. To support your health, ensure you maintain healthy sleep habits.











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