Sleep By Matthew Walkerrar - Why We

Chronic lack of sleep is a key risk factor for Alzheimer’s disease as it prevents the brain from clearing toxic amyloid proteins.

Just one night of four hours of sleep can reduce natural killer (NK) cells —which fight cancer—by up to 70%.

Sleep loss keeps the "fight-or-flight" system in overdrive, leading to higher blood pressure and increased risks of heart attack and stroke. Why We Sleep by Matthew Walkerrar

Occurs primarily in the first half of the night. It serves as a "sensory blackout," during which the brain moves information from short-term to long-term storage and clears out "mental trash".

Matthew Walker’s Why We Sleep argues that sleep is a critical biological necessity, not a luxury, influencing every major system in the body and brain. Walker, a professor of neuroscience, emphasizes that routinely getting less than 7–9 hours of sleep leads to severe cognitive impairment and life-threatening health risks. Chronic lack of sleep is a key risk

Sleep is not a uniform state but a complex cycle of two main stages that serve distinct functions:

Short sleep makes fat cells less responsive to insulin, which can lead to pre-diabetic blood sugar levels within just one week of moderate deprivation. Occurs primarily in the first half of the night

Walker highlights that missing even a small amount of sleep can have "dire" consequences: