For middle-aged and older adults, 7 hours of sleep may be the ideal nightly amount for optimum mental and cognitive health, according to a new analysis published in the journal Nature Aging.
Numerous studies have found a link between sleep and various aspects of health, including outcomes that are especially relevant to people with diabetes. Not getting enough sleep is linked to a higher risk of developing type 2 diabetes, while good sleep is linked to lower risks for diabetes, high blood pressure, and obesity. Better sleep is also linked to lower blood glucose levels after breakfast and lower overall calorie consumption, while a shorter sleep duration has been shown to cause weight gain in a clinical setting. Not getting enough sleep has also been linked to a higher risk of developing dementia in the future, while getting enough sleep may limit cognitive decline in the early stages of Alzheimer’s disease. Of course, many people have problems falling or staying asleep, but there may be ways to improve your sleep quality such as spending more time outside during the day.
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For the latest analysis, researchers at the University of Cambridge in England looked at data from participants in a large general health study called the UK Biobank. The included participants — about 500,000 — were mostly of European descent (94% identified as white) and ranged in age from 38 to 73. Brain imaging and genetic data were available for about 40,000 of these participants, as noted in a news release on the study.
Sleep “sweet spot” for mental and cognitive health
Looking at range of factors related to brain health — including measures of cognitive performance, brain structure, and indicators of mental health — the researchers examined how these factors were related to participants’ self-reported sleep habits. They found that both insufficient and excessive sleep were linked to poorer cognitive health over time, but that there appeared to be a “sweet spot” for optimum cognitive and mental health of 7 hours of sleep per night. Participants who got more or less than 7 hours of sleep each night were more likely to report experiencing symptoms of depression or anxiety.
The researchers also found, through complex statistical modeling, that genetic mechanisms and brain structural changes may explain the relationship between sleep duration and cognitive and mental health — in other words, why more sleep isn’t always better for the brain. Greater structural changes were seen over time in participants who got either less or more than 7 hours of sleep, on average.
“Getting a good night’s sleep is important at all stages of life, but particularly as we age,” said study author Barbara Sahakian, DSc, a professor of psychiatry at the University of Cambridge, in the news release. “Finding ways to improve sleep for older people could be crucial to helping them maintain good mental health and well-being and avoiding cognitive decline, particularly for patients with psychiatric disorders and dementias.”
Want to learn more about sleeping well with diabetes? Read “Getting the Sleep You Need,” “Eating for Better Sleep” and “Feeling Fatigued: Here’s How to Fight It.”