On social media, athletes often proudly showcase their resting heart rates. In fact, the resting heart rates of athletic individuals differ from those of the non-active population. The average resting heart rate ranges between 50 and 90 beats per minute. Athletes, particularly those in endurance sports, have significantly lower readings. Multiple Tour de France winner and world champion Tadej Pogacar explains in an interview that his lowest recorded heart rate is 37 beats per minute and his resting heart rate is usually around 42–43 on average. This means his resting heart rate is relatively high compared to other athletes. But what is the resting heart rate, and what defines it? How does it change, and what can be inferred from its value?
The resting heart rate is the number of heartbeats per minute that occurs when the body is in a state of complete physical and, ideally, mental rest. In practice, it is usually measured either by a doctor or by the athlete themselves, typically in the morning immediately after waking up while lying down. The measurement is best taken in the morning before getting out of bed or moving around. In this situation, the body’s energy requirements are low, and the heart is working at a baseline level to supply organs and tissues with oxygen and nutrients.
Athlete’s heart
Athletes have a significantly lower resting heart rate than the average person who is less active. There are several reasons for this. The main reason is what is known as the “athlete’s heart.” In the past, even medical professionals considered the athlete’s heart to be a pathological condition and generally attributed it to the negative effects of “too much” exercise. This view has since changed. The athlete’s heart refers to a physiological adaptation of the heart to regular, intense training, particularly in endurance athletes. Due to repeated physical exertion, the heart must maintain an increased cardiac output over extended periods to supply the working muscles with sufficient oxygen. In other words, the heart must be able to pump a greater volume of blood. As an adaptation to physical activity, structural and functional changes occur in the heart. A key change affects the heart’s main left pumping chamber (called the ventricle). In endurance athletes, the volume of this chamber increases in particular. At the same time, the wall of the heart muscle may also thicken moderately. This change is referred to as physiological hypertrophy (hypertrophy = enlargement of tissue due to an increase in cell volume). Due to the larger chamber and stronger muscles, the heart can “eject” more blood per heartbeat, thereby increasing the so-called stroke volume. Because the stroke volume is increased, the heart needs to beat less frequently at rest to pump the same amount of blood and supply the body with sufficient blood. This is why many endurance athletes have a significantly lower resting heart rate than untrained individuals. The athlete’s heart is fundamentally a healthy and reversible adaptation. If intense training is reduced or stopped over an extended period, the structural changes in the heart can regress. However, it is important to distinguish this from pathological heart enlargement (hypertrophic cardiomyopathy), in which the thickening of the heart muscle is not caused by training and may be associated with functional impairments. In the athlete’s heart, on the other hand, heart function remains normal or is even improved. In addition to the athlete’s heart, there are other factors that influence the resting heart rate.
Cardiovascular System – Frank-Starling Mechanism – Nervous System
The central part of the circulatory system functions by the heart pumping blood out into the arteries. The blood flows through the organs and must then return to the heart via the veins to keep the circulatory loop closed. How much blood actually flows back (venous return) is determined by several factors. One of the most important is total blood volume. When there is more fluid in the circulatory system, there is also more blood available to return to the heart. Endurance athletes have a higher blood volume due to an increase in plasma, which plays a supportive role in this process. This greater volume improves venous return to the heart—that is, the amount of blood flowing back to the heart. As a result, the heart fills more fully, can expand further, and subsequently contract more forcefully, much like a spring that is stretched tighter. This mechanism also results in more blood being ejected with each heartbeat, which in turn allows for a lower heart rate. This is described by the so-called Frank-Starling mechanism, which states that the heart’s pumping force automatically adapts to its filling. Simply put: the more blood flows back into the heart and fills the ventricles, the stronger the subsequent heartbeat.
The autonomic nervous system plays an important role in determining the resting heart rate. The resting heart rate results from the interaction between the sympathetic and parasympathetic nervous systems. The sympathetic and parasympathetic nervous systems are the two main components of the autonomic nervous system, which operates automatically, without conscious control. It regulates vital functions such as heart rate, breathing, blood pressure, digestion, and sweating. The sympathetic nervous system is the body’s activation or stress response system. It becomes active during stress, danger, excitement, or physical exertion. Its goal is to prepare the body for action (“fight or flight”). It is also activated by exercise. The parasympathetic nervous system is its counterpart and acts primarily through the vagus nerve, which calms the heart and lowers the pulse. In a relaxed and healthy person, the parasympathetic influence usually predominates at rest, which is why the resting heart rate is lower. In athletic individuals, the influence of the parasympathetic nervous system also predominates at rest. This reduces the frequency of electrical impulses and slows the heart rate.
In short: An athlete’s body adapts to regular physical exertion. Some of these adaptations result in a resting heart rate dropping below 45 beats per minute. The exact resting heart rate is partly determined by genetics. A further decrease in resting heart rate does not indicate an increase in athletic performance.
Literature:
Nanchen D. Resting heart rate: what is normal? Heart. 2018 Jul;104(13):1048-1049. doi: 10.1136/heartjnl-2017-312731. Epub 2018 Jan 30. PMID: 29382691.
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D’Ambrosio P, De Paepe J, Spencer LW, Ohanian M, Janssens K, Mitchell AM, Flannery MD, Bekhuis Y, Pauwels R, Delpire B, Dausin C, Rowe SJ, Van Puyvelde T, Young PE, Soka MJ, Johnson R, Yu C, Morris GM, Robyns T, Lacaze P, Giannoulatou E, Kistler PM, Kalman JM, Heidbuchel H, Willems R, Claessen G, Fatkin D, La Gerche A; Pro@Heart Consortium. Bradycardia in Athletes: Prevalence, Mechanisms, and Risks. Circulation. 2026 Mar 3;153(9):616-630. doi: 10.1161/CIRCULATIONAHA.125.076170. Epub 2025 Dec 18. PMID: 41410046; PMCID: PMC12952486.
Eurosport (2024). El llamativo dato de Tadej Pogacar y sus pulsaciones que evoca al gran Miguel Indurain: De 213 a 37 por la noche. Eurosport.es, aktualisiert am 17. Oktober 2024. Online verfügbar unter https://www.eurosport.es/ciclismo/pulsaciones-pogacar-variaciones-minimas-maximas_sto20046017/story.shtml
Attia, P. (Host). (23. September 2024). Cycling phenom and Tour de France champion Tadej Pogačar reveals his training strategies, on‑bike nutrition, and future aspirations (Episode #318) [Audio podcast episode]. In The Peter Attia Drive. Podcast veröffentlicht auf der Website von Peter Attia. Verfügbar unter https://peterattiamd.com/tadejpogacar/ (abgerufen 2026).
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