Understanding Cortisol (AM): Normal vs Optimal Ranges

?What is Cortisol (AM)?

Cortisol is the primary stress hormone, produced by the adrenal glands in response to physical and psychological stress. It follows a strong diurnal rhythm — highest in the early morning (cortisol awakening response) to mobilise energy for the day, then declining through the afternoon and evening. Morning cortisol (8 AM) is the standard clinical test.

!Why It Matters

Chronic cortisol dysregulation — either chronically elevated from ongoing stress or inappropriately low from adrenal fatigue — affects virtually every body system. High cortisol promotes abdominal fat deposition, insulin resistance, immune suppression, bone loss, and impaired memory. Very low cortisol (Addison's disease or adrenal insufficiency) is a medical emergency.

Reference Ranges

Lab normal ranges may vary between laboratories. Optimal and longevity targets are based on research literature and should be interpreted with your physician.

Symptoms of Imbalance

• Chronically high cortisol: weight gain (especially abdomen), high blood pressure, poor sleep, anxiety, impaired immunity
• Low cortisol: extreme fatigue, dizziness, low blood pressure, salt cravings, nausea

How to Improve Your Levels

• 1Chronic stress management: mindfulness, yoga, adequate sleep — the most effective interventions
• 2Adaptogens: ashwagandha, rhodiola, phosphatidylserine all modestly reduce cortisol
• 3Avoid chronic caloric restriction — it chronically elevates cortisol
• 4High-intensity exercise acutely raises cortisol but reduces baseline when done regularly
• 5Screen for Cushing's syndrome (chronically very high cortisol) if suspected

When to Test

Morning (8–9 AM) test is standard. Fasting is preferred. Salivary cortisol testing throughout the day provides more information about diurnal rhythm.

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