Sleep deprivation may be both a symptom and a cause of cognitive decline associated with aging, but you can take steps to improve your sleep and long-term brain health.

Lack of sleep negatively affects several key aspects:

Brain aging: Lack of sleep in midlife is linked to cognitive decline and accelerated brain aging.

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

Declining skin health: Lack of rest raises 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 age

As we age, sleep patterns tend to change. This process begins in midlife 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 sleep earlier and wake earlier. They also have more difficulty falling asleep. Overall, they get fewer hours of sleep per night, making them less likely to achieve the recommended 7 to 9 hours.

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

Reasons for these changes:

Some sleep changes may result from natural brain changes. However, 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 lack of sleep lead to cognitive decline?

Sleep deprivation affects brain efficiency. Not getting enough quality 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 by getting enough sleep. While some older adults may think that cognitive decline is due to irreversible aging, some changes may actually result from not getting enough quality sleep.

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

Sleep researchers believe that chronic lack of sleep may negatively affect brain health in the long term, increasing the risk of mild cognitive impairment and severe neurodegenerative diseases such as Alzheimer's.

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

One study of more than 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 following 20 years.

Another study tracking more than 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 following 4 years.

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

Sleep disturbance is a relevant factor; one study of 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 midlife and for older adults to help prevent this vicious cycle.

Importance of sleep for your brain

During sleep, your brain performs many functions important for overall cognitive health. Here are two key benefits of sleep for 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 highly efficient at removing these proteins during sleep, especially during deep sleep.

People with impaired glymphatic function are more prone to dementia. Those with insufficient or poor sleep cannot efficiently remove these abnormal proteins at 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.

Over 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 quality sleep may help reduce this inflammation and lower these risks.

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