Kourtney Gordon, MS, RD/LD, CEDS-C
April 28, 2025
She shared with me, “They told me I’m fine; I just have an athletic heart.”
Those words couldn’t be further from the truth.
Throughout my years of working with athletes across various age groups, I often encounter the phrase, “My doctor said my heart is fine; I just have an ‘athletic’ heart.” This statement can be misleading and potentially dangerous, especially for individuals who may not be fueling their bodies adequately in relation to their activity levels. Bradycardia, or a low heart rate, is a common complication linked to Anorexia Nervosa, other eating disorders, and Relative Energy Deficiency in Sport (RED-S), where body systems are disrupted due to restricted or inadequate nutrition.
Introduced by the International Olympic Committee in 2014, RED-S addresses the rising need to identify Low Energy Availability (LEA) in both female and male athletes. While many clinicians are familiar with the Female Athlete Triad—characterized by low energy availability, amenorrhea (loss of menstrual cycle), and bone loss—RED-S encompasses a broader spectrum of male and female athletes facing physical and performance declines due to low energy availability to multiple systems in the body.
Bradycardia is characterized by a heart rate below 60 bpm, often accompanied by symptoms such as dizziness, shortness of breath, fatigue, and sometimes chest pain or syncope. In a well-nourished athlete, the term “athlete heart” may refer to the lower heart rate resulting from regular training and conditioning, as the physiological adaptations make the heart more efficient. This efficiency allows for a lower heart rate during activity. These individuals are typically fueling adequately and meeting both metabolic and activity needs.
However, when someone is experiencing LEA —whether deliberately or due to insufficient intake to meet the body’s demands—the clinical picture can change dramatically. Bradycardia may no longer be a result of an “athletic” heart but may be from an “under fueled” heart. Insufficient caloric intake fails to meet the energy required for exercise and sport, leading to heart rates dropping into the 30s and 40s, which warrants further investigation. Typically, this low heart rate, or bradycardia, will appear to speed up (tachycardic) when activity begins. This is not indicative of a strong heart but rather a “starved” heart. In such cases, RED-S should be considered, prompting inquiries into recent weight changes, menstrual cycle patterns (for females), and detailed nutrition intake, including fueling habits such as quantity, timing, and frequency.
With over 90% of adolescent athletes reported to experience bradycardia, it raises the question of how many of these cases developed due to Low Energy Availability (LEA) or even more severe conditions like Relative Energy Deficiency in Sport (RED-S). It is crucial for everyone involved with athletes, including athletic trainers and coaches, to be trained in recognizing these risks. It is entirely appropriate to treat bradycardia as an “injury” and ask an athlete to take a break, just like any other physical injury. Both conditions can lead to serious consequences if they are not properly identified, assessed, addressed, and rehabilitated.
As a community, we can improve the care we provide to our athletes by becoming more curious and exploring nutritional and metabolic health when bradycardia is identified, rather than hastily labeling it as an “athletic heart.” This could inadvertently reinforce a potentially life-threatening condition. Let’s do better…
Resources:
Bradycardia: How Low is Too Low?: Bradycardia & Eating Disorders
Gibson & Written by Dennis Gibson
Health Myths of the Female Athlete: Myth 4: Bradycardia
Gaudiani
Relative Energy Deficiency in Sport (RED-S) | British Journal of Sports Medicine
PDF + Supplementary Material · https://doi.org/10.1136/bjsports-2014-094559