How Much Sleep Do I Need?

Everyone is different when it comes to sleep. Some people need much more than others. Well, it now turns out that 7 hours may be the ideal amount of sleep for people in their middle age and upwards, with too little or too much sleep associated with poorer cognitive performance and mental health, according to a new British study from the University of Cambridge and Fudan University.

Sleep plays an important role in enabling cognitive function and maintaining good psychological health. It also helps keep the brain healthy by removing waste products. As we get older, we often see alterations in our sleep patterns, including difficulty falling asleep and staying asleep, and decreased quantity and quality of sleep. It is thought that these sleep disturbances may contribute to cognitive decline and psychiatric disorders in older adults.

In a new study published in Nature Aging, scientists from the UK and China examined data from nearly 500,000 adults aged 38-73 years from the UK Biobank. Participants were asked about their sleeping patterns, mental health, and took part in a series of cognitive tests. Brain imaging and genetic data were available for almost 40,000 of the study participants.

The team found that both insufficient and excessive sleep duration were associated with impaired cognitive performance, such as processing speed, visual attention, memory, and problem-solving skills. Seven hours of sleep per night was the optimal amount of sleep for cognitive performance, but also for good mental health, with people experiencing more symptoms of anxiety and depression and worse overall wellbeing if they reported sleeping for longer or shorter durations.

The researchers say one possible reason for the association between insufficient sleep and cognitive decline may be due to the disruption of slow-wave 'deep' sleep. Disruption to this type of sleep has been shown to have a close link with memory consolidation.

The team also found a link between the amount of sleep and differences in the structure of brain regions involved in cognitive processing and memory, again with greater changes associated with greater than or less than seven hours of sleep.

Having a consistent seven hours' sleep each night, without too much fluctuation in duration, was also important to cognitive performance and good mental health and wellbeing. Previous studies have also shown that interrupted sleep patterns are associated with increased inflammation, indicating a susceptibility to age-related diseases in older adults.

The findings suggest that insufficient or excessive sleep duration may be a risk factor for cognitive decline in aging. 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.

"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,” said study investigator Professor Barbara Sahakian with the Department of Psychiatry at the University of Cambridge, UK.

New Advice on Aspirin and Heart Disease Prevention

The recommendations are changing for aspirin use in older adults. For adults, who have no history of cardiovascular disease or stroke, low-dose aspirin is not recommended for prevention of heart attack or stroke, particularly for adults with a higher risk for bleeding. In consultation with their physician, select middle-aged adults may benefit from low-dose aspirin therapy if they are at high risk for heart attack or stroke due to risk factors such as smoking, hypertension, type 2 diabetes, high cholesterol or significant family history.

The new recommendations are from the U.S. Preventive Services Task Force (USPSTF), an independent, volunteer panel of medical experts focused on improving the health of people nationwide by making evidence-based recommendations. “If you are already taking low-dose aspirin because you have had a heart attack, stroke or stenting or you have a history of atrial fibrillation, continue to take it as directed by your physician. This new guidance about low-dose aspirin does not apply to your situation. Do not stop taking aspirin without first talking with your doctor,” said Dr. Donald M. Lloyd-Jones, who is with the American Heart Association.

The new guidance on the use of low-dose aspirin strictly applies to adults who have not had a cardiovascular event or any heart disease diagnosis. Currently, the evidence shows that low-dose aspirin is not appropriate to prevent a first heart attack or stroke in most people. Due to the blood-thinning effects of aspirin, research continues to indicate that for most adults the risk of bleeding may be greater than the number of heart attacks or strokes actually prevented.

“Various research studies over the past two decades indicate more than 80% of all cardiovascular events may be prevented by healthy lifestyle changes and management of known risk factors with medication when needed. Eating healthy foods and beverages, regular physical activity and not smoking are key,” said Dr. Lloyd-Jones, who is also the chair of the department of preventive medicine at Northwestern University’s Feinberg School of Medicine in Chicago, Illinois.

The scientific evidence continues to confirm healthy lifestyle habits and effectively managing blood pressure and cholesterol are the top ways to prevent a first heart attack or stroke, not low-dose aspirin, according to Dr. Lloyd-Jones The new USPSTF guidance now aligns with American Heart Association’s 2019 primary prevention guideline.

John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com.