Cortisol. Almost always cortisol. I say this to patients more than almost anything else. And I say it having lived it myself, years of high-output clinical work, late nights, early mornings, and the particular exhaustion of lying in bed completely depleted but unable to actually fall asleep. Tired but wired. It is a real physiological state, and it has a name: hypothalamic-pituitary-adrenal (HPA) axis dysregulation. It is not insomnia in the traditional sense. And treating it like insomnia is why so many high-functioning people stay stuck.
The design that gets broken
Under normal physiology, cortisol follows a clean circadian arc. It peaks sharply in the early morning, the cortisol awakening response, to initiate alertness and mobilize energy for the day. Then it declines steadily, reaching its lowest point around midnight, allowing melatonin to rise and sleep to begin. That is the design. Elegant, functional, precise.
Chronic stress breaks it. When the HPA axis is running in overdrive for weeks or months, which is the baseline state for most high-achieving professionals, physicians included, cortisol stops following that arc. Evening levels stay elevated precisely when they should be at their lowest. And elevated evening cortisol directly suppresses melatonin production. The pineal gland cannot initiate the sleep cascade when cortisol signaling is still active. The body is stuck in alert mode regardless of how exhausted it feels.
A meta-analysis pooling 20 studies across more than 800 participants confirmed that chronic insomnia is associated with significantly elevated 24-hour cortisol, most pronounced in the evening hours. Researchers describe a self-reinforcing loop: Poor sleep activates the HPA axis, which elevates cortisol, which further impairs sleep, which further activates the HPA axis. It compounds nightly.
What standard sleep advice misses
Most behavioral sleep interventions, consistent bedtime, no screens, cool dark room, no caffeine after noon, are genuinely useful and I recommend them. But they address the environment of sleep, not the neuroendocrine driver of sleeplessness. For patients with HPA dysregulation, behavioral changes are working against a biological current. They help at the margins. They do not fix the underlying problem.
This is why I see patients who have done everything right, the sleep hygiene is immaculate, and they still cannot fall asleep before midnight and wake up at 3 a.m. with their mind racing. That is not a pillow problem. That is a cortisol problem.
What I actually do clinically
First step is measurement. I use Dried Urine Test for Comprehensive Hormones (DUTCH) testing, dried urine collected at multiple points across the day, to map the actual cortisol curve. Not just a single morning serum cortisol, which tells you almost nothing about the rhythm. I want to see the shape: where it peaks, where it should drop and does not, what the metabolites look like. You cannot treat what you have not measured accurately.
From there the protocol is individualized, but typically includes phosphatidylserine for evening cortisol blunting, one of the more consistently studied interventions, ashwagandha KSM-66 extract which has multiple randomized controlled trials (RCTs) behind it for cortisol reduction, and a structured wind-down sequence timed to that specific patient’s cortisol curve rather than generic advice.
I also address morning light anchoring, 10 to 20 minutes of bright light exposure within 30 minutes of waking sets the circadian clock with precision and directly determines melatonin onset time that evening. Most patients have never been told this. And for temperature: A warm bath or far-infrared session 60 to 90 minutes before bed triggers the post-heating core temperature drop the body uses as a biological sleep onset signal.
Melatonin supplements, for most of these patients, are nearly useless as a standalone intervention. They add melatonin into an environment where cortisol is still actively blocking the receptor signal. It is like putting a bandage on a broken pipe.
The question physicians need to ask
When a high-functioning patient comes in reporting poor sleep, the question is not just “tell me about your sleep hygiene.” It is “what does your evening look like, physiologically?” When did you last feel genuinely relaxed before bed? Not distracted. Relaxed. For many of my patients, the honest answer is years. That answer tells me more than any questionnaire. And it tells me where to start.
Shiv K. Goel is a board-certified internal medicine and functional medicine physician based in San Antonio, Texas, focused on integrative and root-cause approaches to health and longevity. He is the founder of Prime Vitality, a holistic wellness clinic, and TimeVitality.ai, an AI-driven platform for advanced health analysis. His clinical and educational work is also shared at drshivgoel.com.
Dr. Goel completed his internal medicine residency at Mount Sinai School of Medicine in New York and previously served as an assistant professor at Texas Tech University Health Science Center and as medical director at Methodist Specialty and Transplant Hospital and Metropolitan Methodist Hospital in San Antonio. He has served as a principal investigator at Mount Sinai Queens Hospital Medical Center and at V.M.M.C. and Safdarjung Hospital in New Delhi, with publications in the Canadian Journal of Cardiology and presentations at the American Thoracic Society International Conference.
He regularly publishes thought leadership on LinkedIn, Medium, and Substack, and hosts the Vitality Matrix with Dr. Goel channel on YouTube. He is currently writing Healing the Split Reconnecting Body Mind and Spirit in Modern Medicine.
