The quality of sleep is important for staying healthy. However, so too is the length of time a person sleeps, especially as they age. A night that is too short or, conversely, too long, can have harmful effects on the brain, according to a new scientific study.
Does sleep time impact the brain of seniors?
The researchers wanted to know if the duration of sleep played a role in the brain health of the elderly and in particular in their cognitive performance. Although their study has certain limitations, the scientists made some observations of interest. They recruited 4,417 people aged 65 to 85 across several countries, including the United States, Canada, Australia and Japan. The results, published in the JAMA Neurology, are based on statements from study participants. Researchers have found that too short sleep time is just as bad as too long sleep time. For the authors, too short a sleep duration is less than six hours. It is considered too long when it exceeds 9 hours of sleep. It turns out that this time, too short or too long, is associated with deficits in cognitive performance in the elderly. That’s not all, as scientists have spotted a link between length of sleep, more severe depressive symptoms, and cardiovascular disease. The need to take daytime naps is fatally associated with the quality and duration of nighttime sleep.
The responsible: beta-amyloid
This link can be explained, from a scientific point of view, by a higher amyloid-ß load in an elderly person who sleeps too little. Beta-amyloid is a protein that, when it accumulates, can create amyloid plaques. This agglomerate, which is found in nerve cells, is suspected to be partly responsible for certain neurodegenerative diseases, such as Alzheimer’s disease. The protein would also have a role in the reduction of inter-neuronal communication. As we age, the quality and duration of sleep can undergo changes. However, sleep disorders can be associated with cognition, i.e. memory, language, concentration, perception, etc. In addition, the time of sleep also influences the body mass index, which is more important in people who sleep too much or not enough. It is therefore important to have a healthy sleep, especially to preserve the brain health of seniors.
