Just one night of four hours of sleep can reduce natural killer (NK) cells —which fight cancer—by up to 70%.
Walker highlights that missing even a small amount of sleep can have "dire" consequences:
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. Why We Sleep by Matthew Walkerrar
Chronic lack of sleep is a key risk factor for Alzheimer’s disease as it prevents the brain from clearing toxic amyloid proteins.
Sleep loss keeps the "fight-or-flight" system in overdrive, leading to higher blood pressure and increased risks of heart attack and stroke. Just one night of four hours of sleep
Driving while sleep-deprived can be as dangerous as driving drunk; being awake for 22 hours results in the same level of cognitive impairment as legal intoxication. Practical Tips for Better Sleep
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. Sleep loss keeps the "fight-or-flight" system in overdrive,
Sleep is not a uniform state but a complex cycle of two main stages that serve distinct functions:
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