A recent study of around 9000 people aged between 50 and 64 found that those who slept for less than six hours a night or for more than eight had worse decision-making abilities and memories. However, the brain power reduction was only reduced for those aged between 65 and 89 if they slept for longer periods of time.
The study which was undertaken by experts based at the University of Warwick, stated that the effects of having too little sleep are well established, however the new study shows that an excess of sleep is able to create similar problems.
Dr Michelle Miller, a researcher, stated that the study results suggested that the amount of sleep we require and its effects on the brain and body changes as we age.
Co-author of the study, Professor Francesco Cappuccio, claimed that getting the correct amount of sleep as an older person may prevent the mental decline that could result in dementia. He stated that sleep was important for good mental and health wellbeing. Obtaining optimised sleep when older may help in the delay of the decline in brain function that is evident with age, and may even slow down or prevent the decline that results in dementia.
Dr Miller stated that six to eight hours of sleep each night is vital for optimum brain function in younger adults. She stated that this was consistent with research done previously as it indicates that six to eight hours each night was optimal for physical health and showed the lowest risk for developing heart disease, stroke, diabetes, hypertension and obesity.
It was found that among older results there was a distinct connection between their cognitive skills and their quality of sleep. Previous research has indicated that obtaining sufficient sleep is vital as the brain cleanses itself whilst the body is asleep and gets rid of the harmful toxins which accumulate during the day.
It is however, less clear why too much sleep would not be good for you. One of the theories is that sleeping for long periods of time reduces the sleep quality, increasing the periods of restless slumber. It has been found that disturbed sleep may shrink the brain, create stress and impair memory. People who have disrupted body clocks, such as mothers who are nursing or staff who work shifts, are vulnerable.
Existing research has linked oversleeping to a range of health problems, such as heart disease and diabetes. However, researchers have stated that the link may be partly due to oversleeping being common among the unemployed and poor, as well as those who suffer from depression, and these groups are more prone to health problems.
The findings of the study were based on data obtained from 4821 females and 3968 males in the English Longitudinal Study of Aging. Their quantity and quality of sleep was logged for a one month period.
Image Credit: David Goehring