Evaluation of the Heart Function of Swimmers Subjected to Exhaustive Repetitive Endurance Efforts During a 500-km Relay.

Robert Gajda,Sławomir Rybka,Witold Śmigielski,Ewa Rębowska,Michał Nowak,Wojciech Drygas,Ewa Kowalik,Magdalena Kwaśniewska,Piotr Hoffman

doi:10.3389/fphys.2019.00296

Abstract

Aim: Knowledge of the human body’s ability to adapt to repeated endurance efforts during swimming is limited. We echocardiographically assessed the impact of an exhausting and repetitive swimming effort on cardiac activity.Materials: Fourteen well-trained amateur swimmers (8 female swimmers aged 16–43 years and 6 male swimmers aged 13–67 years old) participated in an ultramarathon relay. Over 5 days, swimmers swam 500 km in the Warta River (in 5-km intervals). Each swimmer swam seven intervals, each within 44:46 to 60:02 min. Objective difficulties included low water temperatures, strong winds, rain, and night conditions.Methods: Transthoracic echocardiography (TTE) was performed three times: at baseline (the day before exertion), at peak effort, and during recovery (48 h after the event). The heart rate (HR) of each swimmer was monitored.Results: Swimmers completed the ultramarathon relay within approximately 91 h. The average HR value at the end of each interval was 91% HRmax. TTE test results showed no significant changes indicative of deterioration of myocardial function at peak effort or after 48 h. Significant increases in left ventricular (LV) ejection fraction, LV fractional shortening (LVFS), LV myocardial systolic velocity, and right ventricular (RV) fractional area changes observed on day 2 after swimming were compared to baseline values and peak effort values. No significant changes in diastolic heart function were observed.Conclusion: Echocardiography assessment indicated that prolonged intense swimming does not affect LV or RV function. Supercompensation of the post-event RV function and increased global LV systolic function demonstrated ventricular interaction after prolonged intense swimming.

Highlights

Knowledge regarding the adaptations of the human body following long hours of exhaustive swimming is limited (Alexiou et al, 2005; Drygas et al, 2014; Stepien et al, 2017)
Open-water swimming in seas, lakes, and rivers is associated with distinct threats to health (Nelemans et al, 1994; Castro et al, 2009; Tipton and Bradford, 2014)
According to information provided by the media, some swimmers who undertake extremely long, uninterrupted efforts must stop due to extreme fatigue, hypothermia, hyperthermia, or injuries caused by dangerous sea creatures (Keith, 2014; Halliday, 2018; Amazon Swim, 2019; Caldas, 2019)

Summary

Introduction

Knowledge regarding the adaptations of the human body following long hours of exhaustive swimming is limited (Alexiou et al, 2005; Drygas et al, 2014; Stepien et al, 2017). Many swimmers undertake extremely difficult challenges such as attempting to cross extremely long distances in seas, lakes, and rivers (Khodaee et al, 2016; Valenzano et al, 2016). Long-distance swimming is associated with high risks to the health of the swimmer. Open-water swimming in seas, lakes, and rivers is associated with distinct threats to health (Nelemans et al, 1994; Castro et al, 2009; Tipton and Bradford, 2014). Deaths among high-level competitors during swimming marathons have been reported (Harris et al, 2017; Smith et al, 2017). In our recently published studies, we presented detailed changes in biochemical and hematological indicators and clotting and fibrinolysis parameters experienced by a 61-yearold swimmer who swam solo for a distance of 120 km over the course of 27 h without leaving the river (Drygas et al, 2014; Stepien et al, 2017)

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