How Much Sleep You Need and the Health Risks of Too Little Sleep

Summary This article explains the health effects of insufficient or irregular sleep and provides recommended sleep durations for adults and adolescents based on established guidance.

Why sleep matters

• Sleep supports brain function, mood, memory, learning, and mental well-being.
• Regular, consistent sleep also supports metabolic and immune health.

Recommended sleep duration

• Adults: 7–9 hours per night.
• Adolescents: 8–10 hours per night.
• The American Academy of Sleep Medicine recommends aiming for at least 7 hours of consistent sleep per night to stay healthy and reduce health risks.

Effects of insufficient or irregular sleep

• Cognitive and performance effects

  • Attention lapses and reduced vigilance.
  • Impaired memory and reduced learning capacity.
  • Depressed mood, which can negatively affect academic or work performance.
  • Acute and chronic sleep deprivation both produce these effects.

• Physical health risks

  • Increased risk for obesity.
  • Increased risk for diabetes.
  • Increased risk for heart problems.
  • Negative impacts on metabolic and immune health.

• Population considerations

  • Some groups may be at higher risk for sleep disorders and the consequences of insufficient sleep (for example, transgender students have been identified as a group at higher risk).

Practical guidance

• Prioritize consistent nightly sleep that meets the recommended duration for your age group.
• For students and others preparing for high-demand cognitive tasks (for example, exams), getting a good night’s sleep is the best way to maximize performance.

Conclusion Consistent, sufficient sleep is essential for cognitive function, emotional well-being, and metabolic and immune health. Adults should generally aim for 7–9 hours nightly and adolescents for 8–10 hours; at least 7 hours per night is recommended to reduce health risks. Regular insufficient or irregular sleep increases risks for attention problems, mood disturbances, impaired learning and memory, and cardiometabolic conditions such as obesity, diabetes, and heart disease.