According to researchers, sleep deprivation can lead to buildup of certain proteins in the brain.
If you’re among the elderly population, the lack of good night’s sleep might lead to more than just tiredness during the next day.
Despite it being common for the elderly to get a good night’s sleep, which includes sleep deprivation and frequent waking up during the night, this seems to indicate that they are more prone to Alzheimer’s disease.
According to researchers at the Washington University School of Medicine in St. Louis, elderly people that spend less time in the so-called slow-wave sleep (the phase of the sleep process that is needed to rest), have shown an increased buildup of a brain protein that was called tau – and is connected with Alzheimer’s disease.
Dr. Brendan Lucey, an assistant professor of neurology, director of the Washington University Sleep Medicine Center, and the lead author of the study, said: “Our project is the first to show an association between slow-wave sleep and tau in very early Alzheimer’s disease.”
This protein, tau, has been shown to form tangles in certain parts of the brain that are crucial for memory. With the progression of Alzheimer’s disease, the protein tau and another one – amyloid beta also spread on other parts of the brain. However, the brain has its own natural way of disposing of these proteins.
Dr. Alex Dimitriu – a double board-certified in psychiatry and sleep medicine and the founder of Menlo park Psychiatry & Sleep Medicine said: “Research shows that during sleep the brain can shrink substantially as it clears built-up toxins, tau, and amyloid among them.”
Study Conclusions | Sleep deprivation and Alzheimer's
In order to gain confirmation for the link between deep sleep and Alzheimer’s, the study had put 119 elderly people aged 60+ under observation, and the subjects had none to very mild cognitive deterioration during their stay at their homes.
Each of them had a portable brain-wave monitor and a movement tracker that were used during the one-week study. As per the study, they had to keep track of their nightly sleep sessions and daytime naps.
Lucey said: “During sleep, the brain cycles through different stages, and slow-wave sleep is one of them. It’s necessary to have good-quality sleep and is thought to be important for preserving memory.”
Another thing that was put under observation was the amyloid beta and tau levels within the brain, as well as the spinal fluid of each participant in the study.
When age, gender, and movement during sleep were taken into account, the study determined that slow-wave sleep resulted in an increase of tau protein in the brain, as well as a higher ratio of tau to amyloid beta in the participants’ spinal fluid.
How Sleep deprivation is detrimental to our health?
The National Sleep Foundation has stated that sleep initiates certain processes in our brains that have a beneficial impact on our memory, and something as seemingly unimportant as a loss of half night’s sleep can have detrimental effects on our brains’ functions.
Dimitriu stated that this might be due to the way our brains’ waste-disposal system works, i.e., it’s mostly active during our slow-wave sleep, a phase of the deep sleep that occurs during the first half of the night.
He further elaborated: “When people lack deep or slow-wave sleep, they can have elevated levels of tau and amyloid beta. Older people with dementia are often known to have a symptom called ‘sundowning,’ where mental processes and awareness diminish as the day wears on.”
According to a CDC report, between 29 to 44 percent of people in the United States get less than the required amount of sleep (7 to 8 hours) during the night.
Increased risk of disease
Loss of sleep can lead to increased risk of health issues, and some of them can be life-threatening.
Dimitriu said: “Sleep is essential to forming memory and creating new room for learning to occur. People who are sleep deprived are more prone to worsening depression or lack of adequate response to treatment for it. Aside from a buildup of toxins, insufficient sleep can also affect mood, memory, metabolism, and the immune system.”
Some of the effects on our health include:
- Obesity – Lack of sleep has been connected to lower levels of leptin, which is a hormone that tells the person that they had enough food. Lack of sleep may also lead to increased levels of ghrelin, a hormone that induces hunger.
- Increased risk of diabetes – A study on short-term sleep restriction has revealed that the otherwise healthy participants had a lower capacity to process glucose when their sleep cycle was reduced to four hours per night, as opposed to when they were allowed to sleep for up to 12 hours.
- High blood pressure or heart disease – Another research has shown that spending less than six hours per day sleeping can lead or increase high blood pressure. This could help link lack of sleep with heart diseases or strokes.
Elderly and sleep deprivation conclusion
The newly conducted research has shown that people that get less than the recommended amount of sleep can show signs of higher levels of tau protein – which is connected with decreased cognitive capabilities and Alzheimer’s disease.
Almost 44 percent of U.S. citizens sleep for a shorter time than the recommended seven to eight hours per day.
Although previous research has found a connection to sleep deprivation and changes to the brain that lead to Alzheimer’s disease, this is the first one that targets slow-wave sleep and the increase of tau protein levels.
While it affects memory, lack of sleep may also lead to other health issues like obesity, diabetes, heart disease, or even stroke.