Circadian Rhythms

Circadian Rhythms

Articles tagged with "Circadian Rhythms".

E-Readers with Light Disrupt Sleep and Circadian Rhythms More Than Paper Books

Tags: E-Readers, Blue Light, Sleep Disruption, Circadian Rhythms

October 22, 2025

Do Light-Emitting E-Readers Disrupt Sleep More Than Traditional Paper Books?

Yes, significantly. Research demonstrates that using light-emitting e-readers before bedtime disrupts sleep and circadian rhythms much more than reading traditional paper books. Studies show that people using backlit e-readers take longer to fall asleep, experience reduced REM sleep, have delayed melatonin onset, and feel less alert the following morning compared to those reading paper books. The blue-enriched light from e-reader screens suppresses melatonin production and delays circadian timing, creating a cascade of sleep disruption that extends into the next day.

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The Cortisol Awakening Response: Your Body's Natural Morning Alarm System

Tags: Cortisol Awakening Response, Morning Cortisol, Stress Hormones, Circadian Rhythms

October 22, 2025

What Happens to Your Stress Hormones When You Wake Up Each Morning?

Your cortisol levels surge dramatically by 50-75% within the first 30 minutes of waking in what’s called the Cortisol Awakening Response (CAR), serving as your body’s natural alarm system that prepares you for the day ahead. This remarkable physiological response represents one of the largest hormonal changes in the human body, mobilizing energy, enhancing alertness, and coordinating multiple systems to transition from sleep to active wakefulness. The CAR is so consistent and important that it serves as a key marker of circadian health, stress resilience, and overall physiological function.

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Your Brain's Master Clock: How the Suprachiasmatic Nucleus Controls Circadian Rhythms

Tags: Circadian Rhythms, Suprachiasmatic Nucleus, Biological Clock, Sleep Timing

October 22, 2025

What Controls Your Body’s Internal Clock and Sleep-Wake Cycle?

The suprachiasmatic nucleus (SCN), a tiny cluster of about 20,000 neurons in your brain’s hypothalamus, serves as your body’s master circadian clock. This landmark transplantation research definitively proved that the SCN determines circadian period by showing that when researchers transplanted SCN tissue from one animal to another, the recipient adopted the donor’s circadian rhythm pattern. This small but mighty brain region coordinates all biological rhythms throughout your body, from sleep-wake cycles to hormone release and body temperature fluctuations.

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