Exercise-Induced Cardiac Fatigue in Soldiers Assessed by Echocardiography.

Marion Charton,Frédéric Schnell,François Carré,Erwan Donal,Solène Le Douairon Lahaye,Gäelle Kervio,David Matelot,Elena Galli,Thibault Lachard

doi:10.3389/fcvm.2021.785869

Abstract

Background: Echocardiographic signs of exercise-induced cardiac fatigue (EICF) have been described after strenuous endurance exercise. Nevertheless, few data are available on the effects of repeated strenuous exercise, especially when associated with other constraints as sleep deprivation or mental stress which occur during military selection boot camps. Furthermore, we aimed to study the influence of experience and training level on potential EICF signs.Methods: Two groups of trained soldiers were included, elite soldiers from the French Navy Special Forces (elite; n = 20) and non-elite officer cadets from a French military academy (non-elite; n = 38). All underwent echocardiography before and immediately after exposure to several days of uninterrupted intense exercise during their selection boot camps. Changes in myocardial morphology and function of the 4 cardiac chambers were assessed.Results: Exercise-induced decrease in right and left atrial and ventricular functions were demonstrated with 2D-strain parameters in both groups. Indeed, both atrial reservoir strain, RV and LV longitudinal strain and LV global constructive work were altered. Increase in LV mechanical dispersion assessed by 2D-strain and alteration of conventional parameters of diastolic function (increase in E/e' and decrease in e') were solely observed in the non-elite group. Conventional parameters of LV and RV systolic function (LVEF, RVFAC, TAPSE, s mitral, and tricuspid waves) were not modified.Conclusions: Alterations of myocardial functions are observed in soldiers after uninterrupted prolonged intense exercise performed during selection boot camps. These alterations occur both in elite and non-elite soldiers. 2D-strain is more sensitive to detect EICF than conventional echocardiographic parameters.

Highlights

Despite the evident cardio-protective effect of moderate regular aerobic exercise, several studies have questioned the possible deleterious cardiac consequences induced by strenuous longduration exercise [1,2,3]
Data on this topic are scarce in athletes, and to our knowledge no specific study has addressed the evaluation of Left ventricular myocardial work (LV MW) by pressure-strain loops analysis among this population after a prolonged endurance exercise
Exercise-induced decrease of SBP was only observed in the non-elite group (121.2 ± 10.2 vs. 113.5 ± 10.6 mmHg; p = 0.001, respectively, before and after exercise) (p = 0.032 for interaction), without any change in DBP

Summary

Introduction

Despite the evident cardio-protective effect of moderate regular aerobic exercise, several studies have questioned the possible deleterious cardiac consequences induced by strenuous longduration exercise [1,2,3]. A transient alteration of ventricular systolic or diastolic function following such exercise has frequently been reported, which is often called exerciseinduced cardiac fatigue (EICF) [4,5,6]. Previous publications demonstrate a relationship between LV MW and LV contractility [10,11,12] and remodeling [13]. Data on this topic are scarce in athletes, and to our knowledge no specific study has addressed the evaluation of LV MW by pressure-strain loops analysis among this population after a prolonged endurance exercise. Echocardiographic signs of exercise-induced cardiac fatigue (EICF) have been described after strenuous endurance exercise. We aimed to study the influence of experience and training level on potential EICF signs

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