Good sleeping habits reduce the risk of cancer and heart failure and help you maintain healthy body weight. You have also probably heard that sleep has a relationship with Alzheimer's and dementia.
Yes, a good night's sleep is vital for human health. But how much sleep defines good? Does the right amount of sleep vary by age? What does the latest research say about sleep and cognitive decline?
An all-encompassing study
Led by scientists at Cambridge University, results from a recent study involving almost half a million subjects (38 to 73 years old) offers new insights. There's good news for the I-need-less-than-8-hours-of-sleep crowd with one caveat: age.
The study looked at sleep patterns, mental health, and wellbeing and included brain imaging and genetic data for nearly 40,000 subjects.
Too little sleep, too much sleep
The scientists concluded that seven hours of sleep was optimal for brain health. In comparison, sleeping too much or too little may be a risk factor for age-related cognitive decline. The study added to evidence that links disruptions to slow-wave — deep — sleep with Alzheimer's.
Getting a good night's sleep is important at all stages of life, but particularly as we age. Finding ways to improve sleep for older people could be crucial to helping them maintain good mental health and wellbeing and avoiding cognitive decline, particularly for patients with psychiatric disorders and dementias. —Professor Barbara Sahakian, University of Cambridge
Analysis of the data also found that too little or too much sleep negatively affected
- Visual attention
- Memory
- Problem-solving and processing speed
- Depression and anxiety
- Overall wellbeing
The researchers say the findings suggest that insufficient or excessive sleep duration may be a risk factor for cognitive decline in ageing. This is supported by previous studies that have reported a link between sleep duration and the risk of developing Alzheimer’s disease and dementia, in which cognitive decline is a hallmark symptom. —Cambridge University
