Sleep Deprivation: How Long Can Humans Stay Awake?

The longest documented voluntary wakefulness is 11 days 25 minutes (Randy Gardner, 1965). However, severe cognitive and perceptual impairments emerge much earlier:

• 3–4 days: Hallucinations, delusions, psychosis-like symptoms.
• Extreme cases: Sleep deprivation can be fatal.

Chronic sleep loss also increases risks of accidents, metabolic dysfunction, cardiovascular disease, and immune impairment.