Endocrinology
Cortisol: The Stress Hormone Double-Edged Sword
Cortisol is essential for survival but chronically elevated levels damage your health. Understanding the cortisol curve and how to optimize stress response.
Reference: Morning: 6-23 µg/dL; Evening: < 50% of morning µg/dL
Key Takeaway
Cortisol follows a natural daily rhythm - highest in the morning to wake you, lowest at night for sleep. Chronic stress flattens this curve, leading to fatigue and sleep disruption.
What is Cortisol?
Cortisol is your body's primary stress hormone, produced by the adrenal glands. It's essential for:
- Blood sugar regulation: Releases glucose from the liver
- Blood pressure control: Maintains vascular tone
- Immune modulation: Suppresses inflammation (acute)
- Sleep-wake cycle: Cortisol awakens you; melatonin puts you to sleep
The Healthy Cortisol Curve
A healthy cortisol pattern follows a predictable rhythm:
- 6-8 AM: Peak levels (wake you up)
- Noon: Approximately 50% of peak
- 4-6 PM: Lower, preparing for evening
- 10 PM - 2 AM: Lowest levels (allow deep sleep)
- High cortisol: Anxiety, insomnia, belly fat storage, high blood pressure
- Low cortisol: Fatigue (especially morning), difficulty handling stress, salt cravings
- Flattened curve: Afternoon energy crashes, wired but tired at night
Cortisol and Other Biomarkers
- High cortisol + high blood sugar: Stress-induced metabolic dysfunction
- Low cortisol + low DHEA: Adrenal exhaustion pattern
- High cortisol + [low melatonin]: Sleep-wake cycle disruption
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