Understanding Sleep Cycles & Circadian Rhythm

A good night’s sleep is more than a luxury; it’s a critical pillar of your overall health and the foundation of your energy, and productivity.

Circadian rhythm impacts energy
A circadian rhythm is your body’s internal, near-24-hour biological clock, synchronized by environmental cues like light and dark to regulate sleep-wake cycles, hormones, body temperature, and other physiological processes. Controlled by the suprachiasmatic nucleus (SCN) in the brain, this rhythm influences when you feel sleepy or alert, with disruptions from factors like shift work or irregular schedules potentially leading to health issues.
What It Is
Your internal clock: It’s a built-in biological system that keeps your body’s processes synchronized with the day-night cycle.
A ~24-hour cycle: Named “circadian” from the Latin circa diem (about a day), it’s a cycle that repeats roughly every 24 hours.
What It Controls
Your circadian rhythm governs many essential functions, including:
Sleep-wake patterns: The most well-known function, dictating when you feel awake and when you are sleepy.
Hormone release: The production of hormones like melatonin (promotes sleep) and cortisol (increases alertness) fluctuates with your circadian rhythm.
Body temperature: Your core body temperature changes over the course of the day.
Digestion: Eating patterns are also influenced by your internal clock.
How It Works
Light signals: Your eyes detect light (or the absence of it).
SCN receives signals: The suprachiasmatic nucleus (SCN), a group of nerve cells in the brain’s hypothalamus, receives these signals.
Internal responses: The SCN sends signals to other parts of the body to adjust temperature, heart rate, and hormone release.
Hormonal influence: When it gets dark, the SCN triggers the pineal gland to produce melatonin, making you feel sleepy.
Disruptions and Health
Environmental factors: External factors like irregular schedules, shift work, late-night screen time, and travel can disrupt your natural rhythm.
Health risks: An out-of-sync internal clock is linked to various health problems, including obesity, diabetes, depression, and sleep disorders.
How to Support a Healthy Rhythm
Consistent schedule: Maintain a regular sleep and wake-up routine.
Manage light exposure: Expose yourself to natural sunlight during the day and limit bright light exposure in the evening