Low Heart Rate in Athletes: When “Fit” Can Signal REDS or an Eating Disorder With Dr. Megan Hellner & Dr. Katherine Hill, MD (AthleatMD)

What does a low heart rate really mean in athletes? When is it a normal adaptation to training, and when is it a sign that something is medically wrong? In this interview, Dr. Marianne Miller speaks with Megan Hellner, RD and Katherine Hill, MD, co-founders of AthleatMD, about one of the most misunderstood issues in athlete health. Together, they unpack how low heart rate, underfueling, and performance pressure can intersect in ways that are often minimized or missed entirely in both sports medicine and eating disorder care. Content Caution This episode includes discussion of eating disorders, Relative Energy Deficiency in Sport (REDS), medical instability, low heart rate, weight loss, body image pressure, and athletic injury. Listener discretion is encouraged. What Is Relative Energy Deficiency in Sport (REDS)? Relative Energy Deficiency in Sport occurs when an athlete’s energy intake does not meet the demands of training, daily functioning, and, for young athletes, growth and development. Dr. Hill explains that REDS can occur with or without an eating disorder and that many athletes develop REDS unintentionally due to intense schedules, high training loads, or lack of accurate nutrition guidance. Although REDS is a relatively new diagnostic framework, its medical consequences are not new. Energy deficiency affects nearly every system in the body, including the heart, bones, hormones, digestion, immune function, and mental health. Importantly, many athletes with REDS do not appear thin, which contributes to how frequently the condition is overlooked. Low Heart Rate in Athletes: Fitness or Medical Red Flag? A low resting heart rate is often praised as evidence of elite fitness, yet this episode challenges that assumption. Dr. Hill and Dr. Hellner explain the difference between mild athletic bradycardia and dangerous cardiac suppression related to undernutrition. They discuss why heart rates in the low 40s or 30s should never be automatically dismissed as “normal for athletes,” particularly when fatigue, injury, missed periods, or hormonal suppression are present. The conversation highlights how REDS and malnutrition can compound athletic adaptations, leading to serious medical risk while athletes are reassured that nothing is wrong. Where Eating Disorder Care and Sports Medicine Fall Short Athletes often exist in a gray area where eating disorder treatment programs and sports medicine settings fail to fully meet their needs. Drs. Hellner and Hill describe how eating disorder programs may underestimate the importance of athletic identity, while sports environments frequently minimize eating disorders and REDS altogether. This disconnect can result in rigid activity bans, delayed diagnosis, or false reassurance that prolongs harm. The episode emphasizes the need for individualized, multidisciplinary decision-making that considers medical stability, psychological safety, and the athlete’s relationship with sport. Body Image Pressure and the Athletic Aesthetic Myth The conversation also explores how appearance-based expectations shape athlete health. Dr. Hellner introduces the concept of the athletic aesthetic myth, which falsely assumes that performance requires a specific body type. Dr. Marianne and her guests discuss how coaching culture, social media trends, and gendered body ideals increase risk for REDS and disordered eating. They also highlight the growing visibility of elite athletes across a wide range of body sizes, challenging the belief that leanness equals success. How AthleatMD Supports Athletes With REDS and Eating Disorders AthleatMD provides virtual medical and nutrition care for athletes across many states, serving competitive, recreational, and former athletes. Dr. Hellner explains how assessment focuses on weight history, growth patterns, labs, training load, injury history, and relationship with food and sport, without assuming intentional restriction. Treatment centers on nutrition restoration, medical stabilization, and education, with approaches tailored to the athlete’s sport, goals, and developmental stage. For many athletes, restoring adequate energy intake improves both health and performance in ways they did not expect. Who This Episode Is For This episode is especially relevant for athletes experiencing fatigue, injury, or declining performance, as well as parents of young athletes, coaches, therapists, dietitians, and medical providers. It is also an important listen for anyone questioning whether “fit” always means healthy in sport. Related Episode Eating Disorders & Athletes: The Pressure to Perform on Apple & Spotify. About Today’s Guests Dr. Megan Hellner and Dr. Katherine Hill are the co-founders of AthleatMD (@athleatmd), a virtual, multidisciplinary practice specializing in medical and nutrition care for athletes with eating disorders and Relative Energy Deficiency in Sport (REDS). Their work focuses on bridging the long-standing gap between sports ...