The Study
Exercise echocardiography for improved assessment of diastolic filling dynamics
This study looked at how well-trained athletes' hearts work during exercise compared to people who don't train much. It found that athletes' hearts fill with blood better when they're working hard — but we can't say that training made their hearts better, because they were already athletes before the study started.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Athletes' hearts don't beat faster than others during exercise — they fill up with more blood between beats, letting them pump out more blood each time.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 555 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — this means athletes can deliver more oxygen to muscles during intense exercise without speeding up their heart, giving them a major performance edge.
- 2At the same heart rate (140 bpm), athletes had 63% higher stroke volume and 3x faster heart filling than untrained people, even though standard heart tests showed no difference.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Experimental Physiology
Year
2025
Authors
Mads Fischer, T. Bonne, M. B. Klaris, Emil Lenzing, Eric J. Stöhr, J. Bejder, Carsten Lundby, N. B. Nordsborg, Lars Nybo
Related Content
Claims (10)
Endurance athletes have a longer time for blood to fill the heart between beats while at rest, which allows more blood to enter the heart with each cycle, without their heart beating faster than that of non-athletes.
During intense exercise, endurance athletes have faster blood flow in the heart's pumping phase to compensate for less time available for the heart to fill with blood between beats.
During exercise, endurance athletes have a shorter cardiac cycle than non-athletes, with both the time the heart spends pumping blood and the time it spends filling with blood reduced more significantly.
Athletes who train for endurance have a 63% larger increase in the amount of blood their heart pumps per beat during exercise at 140 beats per minute than untrained people, even when their heart rates are the same, due to greater filling of the heart during relaxation.
When exercising at the same heart rate, elite endurance athletes have a 50% higher rate of blood filling the left ventricle of the heart compared to untrained people, a difference caused by training adaptations that are not visible when the heart is at rest.
When heart rate is controlled during exercise, standard echocardiographic measurements such as mitral E-wave velocity, tissue Doppler velocities, and left ventricular twist show no difference between endurance-trained athletes and untrained individuals, meaning these measurements cannot detect the cardiac changes caused by endurance training.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.