89. Sleep: The Missing Link in Health, Hormones, and Longevity with Dr. Kirk Parsley

From Navy SEAL to Sleep Expert

At just 17 years old, Dr. Kirk Parsley joined the U.S. Navy, determined to test his toughness in the world’s most elite fighting force. What he didn’t expect was that his greatest battle wouldn’t be fought in combat, it would be waged in the medical field, against a system that misunderstood what true health really means.

After years as a Navy SEAL and later as the physician for the West Coast SEAL teams, Dr. Parsley noticed a disturbing trend: the toughest warriors on earth were breaking down. They were strong, fit, and disciplined — yet they were exhausted, inflamed, moody, and losing their edge. The common thread? Chronic sleep deprivation.

The Sleep Crisis No One Talks About

Dr. Parsley discovered that nearly every SEAL he treated was relying on sleep aids like Ambien to cope with years of disrupted rest. The problem? These drugs don’t promote real sleep — they create pharmaceutical amnesia. While users might feel like they’re sleeping, their brains are robbed of the deep and REM cycles responsible for recovery, hormone balance, memory, and emotional regulation.

When he began helping his team wean off these medications and restore natural sleep through nutrition, supplementation, and lifestyle, the results were astonishing. Testosterone tripled, inflammation plummeted, and mood and performance returned.

Sleep, he realized, wasn’t just one piece of health, it was the foundation of every system in the body.

Why Sleep Impacts Everything

In this conversation, Dr. Parsley and Susan dive deep into how sleep affects:

  • Hormones: Sleep regulates cortisol, testosterone, estrogen, and thyroid function.
  • Brain Health: Deep sleep activates the glymphatic system, which detoxifies the brain and clears amyloid plaque linked to Alzheimer’s and cognitive decline.
  • Stress and Aging: Sleep deprivation accelerates aging, mimics the effects of chronic stress, and can make you biologically years older.
  • Metabolism: Poor sleep drives insulin resistance, inflammation, and cravings, making weight management nearly impossible.

The Bottom Line

Sleep is not a luxury, it’s your body’s most powerful healing and performance tool. Whether you’re an elite athlete, a high-achieving entrepreneur, or simply trying to feel better in your daily life, optimizing your sleep is the most effective way to improve your energy, mood, focus, and longevity.

As Dr. Parsley says, “All of health sits on the foundation of sleep.”

To learn more about Dr. Parsley’s work and his natural sleep support formulas, visit docparsley.com.

P.S. Stay tuned for part 2 on sleep next week with Chris Winters!

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Learn more about our guest Dr.Kirk Parsley:

Kirk Parsley completed SEAL training at the age of 19 and served as a 60-gunner on SEAL Team Five in Coronado, California. He left the SEAL community in 1994 to pursue a college education. Later, he re-entered the US Navy to attend the military’s medical school in Bethesda, Maryland, where he was commissioned as a Navy Officer in 2000.

After completing medical school, internship, and residency, Kirk returned to the SEAL teams as the physician for the West Coast SEAL teams. Kirk was tasked with helping the world’s most elite warriors optimize and maintain their performance after eight years of sustained combat. It was during this period that he noticed a significant gap between “healthcare” and true “health optimization.”

Kirk was forced to delve into extensive alternative medical literature, synthesizing and applying it effectively and practically to ensure the SEALs could perform at their peak 365 days a year. Performance and fitness are related components of a SEAL’s ability, but they are not synonymous.

Due to the limitations and restrictions of medical interventions available in austere environments with limited medical support, Kirk had to develop plans that relied minimally on pharmaceuticals, supplements, or gadgets. His unparalleled success led him to become a sought-after medical human performance expert, not only for Navy SEALs but also for various military special forces commands. He parlayed this experience into private consulting for professional sports teams, international corporations, law enforcement, first responders, the Department of Justice, entrepreneurs, and executives.

Dr. Parsley has collaborated with numerous elite performers, achieving remarkable results in optimizing their physical, cognitive, and emotional performance. His philosophy is straightforward: our bodies are built on a 100,000+ year-old model, and we perform best by emulating the lifestyle we evolved to live, as closely as possible, striving to approximate the health metrics of our 25-30 year-old selves (the physiologic peak of most humans). Kirk firmly believes that 80% of health is derived from focusing on Sleep, Nutrition, Exercise, and Stress mitigation, with a strong emphasis on Sleep.


Kirk is certified in Hyperbaric Medicine, Anti-Aging Medicine, Hormone Replacement Therapy, and is currently pursuing national certification in Psychedelic Medicine Therapies. He dedicates a significant portion of his time to advising non-profit organizations that support the SEAL community and providing healthcare guidance and treatment to veterans. Operating his practice and supplement business from Austin, Texas, Kirk is an avid outdoorsman and fitness enthusiast. When he’s not working or working out, you can usually find him in nature, or enhancing his medical skills or knowledge–is some far off place.

Learn More about Kate King:

Kate brings nearly two decades of experience as a licensed psychotherapist and board certified art therapist, combined with her work as a Radiant Life coach to the table. She is also the multi-award-winning author of three powerful self-help psychology books. Kate’s work integrates epigenetics through a relational, behavioral, and intergenerational family trauma lens. She also incorporates brain and nervous system science with psychology, spirituality, and creativity for a dynamic approach to deep inner work and personal healing.

Learn More about Susan Robbins:

Susan is a retired law enforcement officer and an accomplished Certified Epigenetic Human Performance Coach with a diverse and extensive background in wellness. She began her wellness career in 2015 as a holistic health and stress management coach. Her passion for helping others led her to expand her expertise into epigenetics in 2019, where she discovered the missing piece of the health optimization puzzle: Personalized health.

As a Certified Integrative Nutrition Health Coach, Certified Level 2 Apeiron Zoh Epigenetic Human Performance Coach (DNA), and Certified PH360 Coach through Precision Health Alliance, Susan has developed a unique approach to health and wellness through completely personalized health. She is the proud recipient of the 2023 Precision Health Alliance Coach of the Year award. Susan works with clients to elevate their health and overall quality of life by understanding their unique needs based on their genetic makeup, taking out the guesswork, and getting results.

Their Synergy

Susan and Kate come from two very different, but perfectly complementary, worlds in the health and wellness space. Together, their synergy is magnetic. Think: science meets soul, strategy meets intuition, real talk meets radical transformation.

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