In today's episode, Haylie Pomroy sits down with Dr. David Systrom, a pulmonary and critical care physician at Mass General Brigham and Assistant Professor at Harvard Medical School, to explore the science behind exercise intolerance in ME/CFS and long COVID.

Dr. Systrom breaks down the invasive cardiopulmonary exercise test (CPET) and what it reveals about blood flow, oxygen extraction, and mitochondrial dysfunction in patients who have been told their tests are normal. He explains why dysautonomia, small fiber neuropathy, and acquired mitochondrial dysfunction may be driving the fatigue, post-exertional malaise, and wide-ranging symptoms these patients experience every day.

He also shares details on two active clinical trials at Brigham and Women's Hospital, including the LYFT trial testing low-dose naltrexone, Pyridostigmine (Mestinon), and the combination of both, as well as a muscle biopsy study designed to understand the role of the mitochondrion in post-exertional malaise.

If you or someone you love has been dismissed, misdiagnosed, or left without answers, tune in to Fast Metabolism Matters

Dr. David Systrom is a physician at Brigham and Women's Hospital. He is also an assistant professor of medicine at Harvard Medical School. He received his medical degree from Dartmouth Medical School. He then completed a residency in internal medicine at Emory University Hospital, followed by a fellowship in internal medicine at Massachusetts General Hospital. He is board-certified in internal medicine and pulmonary disease. An active investigator and director of the Massachusetts General Hospital Cardiopulmonary laboratory, Dr. Systrom regularly publishes research examining pulmonary hypertension, pulmonary vascular disease, right heart failure, and thromboembolic disease. He has authored over 130 peer-reviewed publications, has received funding from the National Institutes of Health and the American Heart Association, and has been named to the annual list of the Best Doctors in America. Dr. Systrom is a member of the American Thoracic Society, the American Heart Association and the American Physiological Society. He has special expertise in the pathophysiology of exercise intolerance in ME/CFS and Long Covid and is conducting clinical trials investigating the same

Haylie Pomroy, Founder and CEO of The Haylie Pomroy Group, is a leading health strategist specializing in metabolism, weight loss, and integrative wellness. With over 25 years of experience, she has worked with top medical institutions and high-profile clients, developing targeted programs and supplements rooted in the "Food is Medicine" philosophy. Inspired by her own autoimmune journey, she combines expertise in nutrition, biochemistry, and patient advocacy to help others reclaim their health. She is a New York Times bestselling author of The Fast Metabolism Diet.

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In today's episode, Haylie Pomroy sits down with Dr. Theoharis Theoharides — Professor of Clinical Immunology and Executive Director of the Center for Excellence in Neuroinflammation Research — to dig into a topic that's finally getting the attention it deserves: multiple chemical sensitivity (MCS) and its deep connection to mast cell activation.

Dr. Theoharides explains what actually happens in the immune system when the body is exposed to everyday chemicals — from perfume and jet fuel to formaldehyde in clothing and mycotoxins in food. He walks through the biology of mast cells, why stress dramatically lowers your chemical reaction threshold, and why so many patients go undiagnosed or are dismissed as "just sensitive."

Haylie brings her own personal experience with chemical sensitivity and autoimmune disease to the conversation, making this one of the most candid and clinically rich discussions we've had on the show. Whether you've been told your symptoms are in your head, or you've quietly suspected that your environment is making you sick, this episode is for you.

Tune in to Fast Metabolism Matters — and finally get the science to back up what your body has been telling you all along.

Dr. Theoharis Theoharides is a Professor, Vice Chair of Clinical Immunology, and Director at the Institute for Neuro-Immune Medicine-Clearwater, an Adjunct Professor of Immunology at Tufts School of Medicine, where he was a Professor of Pharmacology and Internal Medicine, and also the Director of Molecular Immunopharmacology & Drug Discovery, and Clinical Pharmacologist at the Massachusetts Drug Formulary Commission (1983-2022). He received his BA, MS, MPhil, PhD, and MD degrees and the Winternitz Price in Pathology from Yale University and received a Certificate in Global Leadership from Tufts Fletcher School of Law and Diplomacy and a Fellowship at Harvard Kennedy School of Government. He trained in internal medicine at New England Medical Center, which awarded him the Oliver Smith Award, "recognizing excellence, compassion, and service." Dr. Theoharides has 485 publications (46,491 citations; h-index 106), placing him in the world's top 2% of most cited authors, and he was rated the worldwide expert on mast cells by Expertscape. He was inducted into the Alpha Omega Alpha National Medical Honor Society, the Rare Diseases Hall of Fame, and the World Academy of Sciences.

Website: https://www.drtheoharides.com

LinkedIn: linkedin.com/in/theoharis-theoharides-ms-phd-md-faaaai-67123735

Instagram: https://www.instagram.com/dr.theoharides/

Haylie Pomroy, Founder and CEO of The Haylie Pomroy Group, is a leading health strategist specializing in metabolism, weight loss, and integrative wellness. With over 25 years of experience, she has worked with top medical institutions and high-profile clients, developing targeted programs and supplements rooted in the "Food is Medicine" philosophy. Inspired by her own autoimmune journey, she combines expertise in nutrition, biochemistry, and patient advocacy to help others reclaim their health. She is a New York Times bestselling author of The Fast Metabolism Diet.

Learn more about Haylie Pomroy's approach to wellness through her website: https://hayliepomroy.com

Instagram: https://www.instagram.com/hayliepomroy

Facebook: https://www.facebook.com/hayliepomroy

YouTube: https://www.youtube.com/@hayliepomroy/videos

LinkedIn: https://www.linkedin.com/in/hayliepomroy/

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In today's episode, Haylie Pomroy sits down with Dr. Nancy Klimas, Director of the Institute for Neuro-Immune Medicine at Nova Southeastern University, to map out a practical, clinically grounded starting point for anyone navigating post-viral illness — whether that's long COVID, ME/CFS, post-viral chronic fatigue, or a diagnosis they're still trying to name.

Dr. Klimas walks through how to become a skilled historian of your own health, outlines the three most critical areas to address first: sleep, dysautonomia and the autonomic nervous system, and bioenergetics — the mitochondrial and nutritional foundations that drive energy, inflammation, and immune function.

Perhaps most powerfully, Dr. Klimas closes with a message she gives from every stage and every microphone: these are curable illnesses, not just manageable ones — and the science is closer than most patients have been told.

If you or someone you love is losing traction and can't figure out why, this episode is your roadmap — tune in to Fast Metabolism Matters.

Dr. Nancy Klimas, a clinical immunologist by training, is the director of the Institute for Neuro-Immune Medicine, who has allotted her life to helping other people find cures for their complex illnesses that were once considered helpless. She works with her fellow medical experts in researching and analyzing the deeper causes of such diseases, particularly on the neuro-immunity side, to provide the best option suited for every single case or story they handle.

LinkedIn: https://www.linkedin.com/in/nancy-klimas-49255178/

Instagram: https://instagram.com/nancyklimas

Twitter: https://x.com/ngklimas?s=20

Haylie Pomroy, Founder and CEO of The Haylie Pomroy Group, is a leading health strategist specializing in metabolism, weight loss, and integrative wellness. With over 25 years of experience, she has worked with top medical institutions and high-profile clients, developing targeted programs and supplements rooted in the "Food is Medicine" philosophy. Inspired by her own autoimmune journey, she combines expertise in nutrition, biochemistry, and patient advocacy to help others reclaim their health. She is a New York Times bestselling author of The Fast Metabolism Diet.

Learn more about Haylie Pomroy's approach to wellness through her website: https://hayliepomroy.com

Instagram: https://www.instagram.com/hayliepomroy

Facebook: https://www.facebook.com/hayliepomroy

YouTube: https://www.youtube.com/@hayliepomroy/videos

LinkedIn: https://www.linkedin.com/in/hayliepomroy/

X: https://x.com/hayliepomroy