Sleep and Biological Rhythms

Definition of Sleep

• Natural state of rest for body and mind.
• Involves reversible loss of consciousness.
• Takes up about one-third of our lifetime.

Importance of Sleep

• Essential for overall health.

Cultural Influences on Sleep

• Sleep practices vary by culture.
• In the US, infants typically sleep alone.
• Other cultures may practice cosleeping or family beds.

Biological Rhythms

• Periodic physiological fluctuations in the body.
• Controlled by biological clocks.
• Includes annual cycles (e.g., migration) and 24-hour cycles (e.g., sleep/wake cycle).

Circadian Rhythms

• Daily behavioral or physiological cycles.
• Includes sleep/wake cycle, body temperature, blood pressure, blood sugar levels.
• Body temperature fluctuates about 3 degrees Fahrenheit in 24 hours, peaking in the afternoon, lowest between 2 A.M. and 5 A.M.