Lack of sleep may be a symptom of age-related cognitive decline, and even a cause, but you can take steps to improve your sleep and brain health in the long term.

Lack of sleep negatively affects several key areas:

Brain aging: Lack of sleep in middle age is linked to decline in mental abilities and accelerated brain aging.

Impaired cell regeneration: Deep sleep is the primary time when the body secretes growth hormones to repair tissues and cells.

Declining skin health: Lack of rest leads to elevated levels of the stress hormone cortisol, which breaks down collagen responsible for skin elasticity and youthfulness.

Age-related diseases: Chronic insomnia increases the risk of type 2 diabetes, heart disease, and high blood pressure.

Sleep changes with aging

As we age, sleep patterns tend to change. This process begins in middle age and becomes more pronounced with advancing age. Older adults may experience these two changes in their sleep, according to Health website:

1- Different sleep and wake times: Older adults often go to bed earlier and wake up earlier. They also have more difficulty falling asleep. Generally, they get fewer hours of sleep per night, meaning they are less likely to get the recommended 7-9 hours.

2- Decreased sleep quality: Older adults tend to spend less time in the deeper, more restorative sleep stages and wake up more frequently during the night.

Reasons for these changes:

Some sleep changes may be due to natural brain changes. But factors such as medications, chronic pain, and conditions like sleep apnea or restless legs syndrome make sleep more difficult for some older adults.

Short-term: How does sleep deprivation lead to cognitive decline?

Sleep deprivation affects brain function. Not getting enough good-quality sleep can negatively impact:

Concentration and attention.

The ability to form new memories.

Sensory and motor skills.

Emotions.

Impulse control.

Fortunately, these changes can be reversed with adequate sleep. While some older adults may think that cognitive decline is due to irreversible cognitive aging, some changes may actually be due to not getting enough good sleep.

Long-term: How does lack of sleep contribute to cognitive decline with aging?

Sleep researchers believe that chronic sleep deprivation may negatively affect brain health in the long run, increasing the risks of mild cognitive decline and severe neurodegenerative diseases like Alzheimer's.

Here is how not getting enough sleep or not getting good sleep affects your cognitive health in the long term:

One study of over 800,000 women around age 60 found that getting less than 7 hours of sleep per night was associated with a slight increase in the risk of dementia over the next 20 years.

Another study following more than 5,600 older adults found that those with sleep problems on average performed worse on many cognitive tests. Their performance also declined sharply over the next 4 years.

Not getting enough good sleep: Deep sleep stages are particularly beneficial. People who generally feel refreshed and rested after waking are less likely to develop cognitive decline and dementia.

Sleep disturbance is a related factor; one study on people aged mid-30s to late 40s found that those with severe sleep disturbance performed worse on cognitive tests a decade later. Thus, sleep becomes increasingly important in middle age and among older adults to help prevent this vicious cycle.

Importance of sleep for your brain

During sleep, your brain performs many important functions for your overall cognitive health. Here are two main benefits of sleep for your cognitive brain health:

1- Waste clearance

The brain has its own waste clearance system, known as the glymphatic system. This network of fluid-filled channels flushes out toxic proteins during sleep, much like a dishwasher running at night.

Some of these proteins are the same that accumulate in the brains of Alzheimer's patients. The glymphatic system is particularly efficient at clearing these proteins during sleep, especially during deep sleep stages.

People with impaired glymphatic function are at higher risk for dementia. Those with insufficient or poor-quality sleep cannot efficiently clear these abnormal proteins during the night. This may be one reason why sleep deprivation in middle age and beyond increases the later risk of dementia.

2- Anti-inflammatory effects

Getting enough sleep helps reduce inflammation. In people of all ages, chronic sleep deprivation tends to increase inflammation, which can affect the brain.

In the long term, inflammation may increase the risk of neurodegenerative diseases like Alzheimer's.

To a lesser extent, chronic inflammation may also increase the risk of mild cognitive decline with aging. Getting enough good sleep may help lower this inflammation and reduce these risks.

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