Cardiac function after exhaustive open-sea swimming

Area of Science:

• Cardiology
• Sports Medicine
• Exercise Physiology

Background:

• Elite athletes push physiological limits during prolonged endurance events.
• Understanding cardiac adaptations and potential impairments post-exercise is crucial for athlete health.
• Open-sea swimming presents unique physiological demands compared to pool-based training.

Purpose of the Study:

• To investigate the acute effects of a 25-km open-sea swim on left ventricular (LV) function and morphology.
• To assess cardiac sympathetic outflow and key hematological markers post-exhaustive swimming.

Main Methods:

• Echocardiography and cardiovascular tracings were used to evaluate LV function and morphology pre- and post-swim.
• Blood samples were analyzed for hematocrit and plasma concentrations of various biomarkers (e.g., a-ANP, renin, lactate).
• Twenty elite male swimmers participated in this exhaustive 25-km open-sea swimming study.

Main Results:

• Significant reductions in LV fractional shortening (-13%), ejection fraction (-11%), and stroke volume (-25%) were observed.
• Increased cardiac index (+31%) and significantly elevated LV wall stress (+101-102%) indicated higher afterload.
• Post-exercise blood analysis revealed elevated hematocrit, a-ANP, renin, lactate, myoglobin, and CPK-MB.

Conclusions:

• Prolonged exhaustive swimming leads to depressed LV function in elite athletes.
• Reduced stroke volume and ejection fraction are key indicators of this functional impairment.
• Increased afterload is identified as the primary factor contributing to the observed cardiac alterations.