The surprising link between bedtime and dementia

  • Alzheimer’s disease, a common form of dementia, is one of the diseases top ten The leading causes of death in the United States.
  • New research suggests that time spent in bed and time spent sleeping may influence dementia risk.
  • People between the ages of 60 and 74 were most affected.
  • Previous research has also highlighted the role of sleep quality in memory and dementia.

Sleep can affect physical and mental health and is linked to heart disease, stroke, depression and obesity.

new study Posted on September 21 in Journal of the American Geriatrics Society Offer more ideas about sleep’s role in dementia.

Researchers in China, Sweden and the United Kingdom studied sleep data for 1,982 Chinese individuals with an average age of 70 – none of whom had symptoms of dementia at the start of the study.

After an average of 3.7 years, 97 participants (5%) were diagnosed with dementia according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).

Those affected mainly ranged in age from 60 to 74. Men were also more likely to be affected, which contrasts with what many other dementia researchers have found previously.

“In most studies, women are known to be at twice the risk of developing dementia than men. It is unusual for this study to find the opposite,” shared Dr. Alex DemetriouBoard Certified in Psychiatry and Sleep Medicine and Founder of Menlo Park Psychiatry and Sleep Medicine BrainfoodMD.

The study found that spending more time in bed (TIB) was associated with a significantly increased risk of dementia. Those who had been in bed for more than 8 hours were more likely to have cognitive decline during the Mini Mental State Examination (MMSE) – a test used to measure cognitive impairment.

So why do seniors need to spend more time in bed?

“As we get older, we see a fragmentation of sleep states,” Dr. Michael Breus, a sleep specialist and clinical psychologist, told Healthline. This means “we don’t seem to get the same kind of physical sleep restoration (stages 3/4) as we did when we were younger.”

As such, “it is possible that people with poor sleep quality may need more sleep time to compensate,” Dimitriou added.

Dr. explained. Carl W. BasilPh.D., Caitlin Tynan Doyle, Professor of Neurology at Columbia University College of Physicians and Surgeons.

Depression (which the elderly suffer from) greater dangerExplain that it can make sleeping difficult. “But there are also many other medical conditions (such as heart disease or diabetes) and medications being taken for them that can increase fatigue and sleep requirements.”

The researchers also highlighted the time individuals go to sleep as a critical contributing factor. The early midnight hours were considered the most dangerous. The research paper stated that “every hour before bed [before 10 pm] It was associated with a 25% increased risk of dementia.”

The study authors hypothesized that earlier bedtimes could be driven by a disturbed circadian rhythm.

The parts of the brain responsible for managing sleep begin to change as we age. Dr. said. David RabinMD, a neuroscientist, board-certified psychiatrist, and co-founder of Apollo Neuro, a wearable for stress relief.

And age-related factors, such as having to use the bathroom frequently during the night, “also affect our quality and sound sleep,” Rabin said. Cumulative sleep deprivation “leads to a change in the structures of the brain that regulate daily cycles.”

Demetriou mentioned that there are other influences that may play a role.

“People with early stages of dementia are likely to experience early brain fatigue during the day, which causes them to fall asleep earlier,” he said. “Sunset” is a well-known effect in older people who are prone to dementia, as they can become disoriented and disoriented in the evening. “

Study limitations to consider

One major drawback of the research is that TIB does not necessarily reflect time spent asleep. Scientists note that sleep duration is a critical factor in cognitive health and dementia risk.

Breus stated that a longer TIB could indicate an underlying sleep problem, such as insomnia, which “can affect this situation and make it worse.”

modern Canadian study It also highlighted that those suffering from insomnia were more likely to have memory loss.

Furthermore, TIB does not consider a person’s sleep quality – which is also important in cognition and dementia. For example, not getting enough deep sleep can greatly affect memory (more on this later).

There is one last consideration to take into account.

“This study, like many other similar studies, are association studies, and therefore do not show cause and effect,” Bazil explained.

“So it is never clear whether the observed association (in this case, short or long periods in bed or the time of onset of sleep) actually causes dementia, or is it indirectly related to it,” he added.

Memory loss is one of the main signs of dementia. At all stages of life, Basil explained, “we know that good sleep is required for many, if not all, types of memory.”

So what happens when you are in hibernation? With regard to memory, two main actions take place.

The first is the processing and “storage” of memories.

“Short-term memory is initially stored in the hippocampus when it reaches the brain, which is the area where information is stored for short-term remembering and use,” Rabin explained.

“When we sleep, information is passed from the hippocampus to the higher cortical structures of the brain that allow it to become a long-term memory and integrate with previous memories,” he continued.

Rabin revealed that this process is called memory reconsolidation — and is particularly affected by poor REM sleep or short sleep duration.

Second, sleep is when our brains get rid of harmful toxins that can affect memory over time.

“When the brain is active during the day, it produces a lot of what we call ‘reactive oxygen species,’ or inflammatory waste products,” Rabin said. “When the brain is asleep and able to recover, especially in deep sleep and rapid eye movement sleep states, [it] It detoxifies and removes inflammatory waste products.”

The buildup of toxins eventually increases stress on the brain and prevents it from reconsolidating the memory.

“In short, the quality of sleep, as much as the quantity of sleep, may be important,” Demetriou said.

This study monitored the onset of dementia in older individuals – the period when symptoms are most likely to develop in life.

Symptoms of dementia, such as Alzheimer’s disease, are often present [among people] In their 60s, although early onset in their 40s or 50s may occur,” Dr. Sandra PetersenSenior Vice President of Health and Wellness at Pegasus Senior Living, with Healthline.

And she continued: “Dementia is a ‘comprehensive’ term for a group of diseases, the most prevalent of which is Alzheimer’s disease, where gradual changes occur in the brain.

Petersen explained that common signs and symptoms of dementia are:

  • Persistent and widespread difficulty with memory, cognition and the ability to perform daily tasks
  • loss of focus
  • Inability to pay attention
  • Loss of language skills
  • Decreased visual perception
  • Loss of problem solving skills
  • Weak logic and judgment

risk factors for dementia

While this new study (among others) reveals that sleep is a risk factor for dementia, it is not the only one involved.

“Researchers have looked at a number of potential causes of dementia,” Petersen said. We don’t know for sure, but it’s likely a combination of factors that contribute to [its] evolution and progress.

She revealed that scientists assume that dementia may arise from:

  • Inflammation – caused by lack of sleep, poor diet, lack of exercise, and other unhealthy habits
  • Abnormal tau proteins in the brain
  • Genetics
  • Untreated and prolonged depression
  • Inability of the brain to use insulin properly

Sleep has long been associated with dementia. Lack of sleep is thought to increase the risk, while people with dementia often struggle to get a proper, restful night of rest.

This study did not explore some important aspects of sleep, such as quality. However, it does highlight the relationship between dementia, TIB and bedtime – elements that the research paper notes are “not well understood” and “seldom explored,” respectively.

More research is required on how TIB and sleep times affect the onset of dementia.

But, until then, the study authors said their findings “indicate the need to monitor cognitive function in older adults who report prolonged bedtime and advanced sleep timing.”