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

Sleep deprivation negatively affects several key aspects:

Brain aging: Lack of sleep in midlife is linked to declining mental abilities and accelerated brain aging.

Impaired cell regeneration: Deep sleep is the primary time when the body releases 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 raises 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 midlife and becomes more pronounced with aging. 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 full 7-9 hours of sleep.

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

Causes of these changes:

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

In the short term: How does lack of sleep lead to cognitive decline?

Sleep deprivation affects brain efficiency. Not getting enough good sleep can negatively impact:

Focus and attention.

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 cognitive decline is due to irreversible cognitive aging, some changes may actually be due to not getting enough quality sleep.

In the long term: How does lack of sleep contribute to cognitive decline with aging?

Sleep researchers believe that chronic lack of sleep may negatively affect brain health in the long term, 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 slightly increased risk of dementia over the next 20 years.

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

Not getting enough good sleep: Deep sleep stages are especially 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; a study of people in their 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 midlife and for older adults to help prevent this vicious cycle.

The importance of sleep for your brain

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

1- Waste removal

The brain has its own waste removal 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 ones that accumulate in the brains of Alzheimer's patients. The glymphatic system is particularly efficient at removing these proteins during sleep, especially during deep sleep.

People with impaired glymphatic function are more likely to develop dementia. In those with insufficient or poor sleep, the brain is not able to efficiently remove these abnormal proteins during the night. This may be one reason why lack of sleep in midlife and beyond increases the risk of later 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 such as Alzheimer's.

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

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