Left ventricular function and mechanics following prolonged endurance exercise: an update and meta-analysis with insights from novel techniques

Abstract

BackgroundThe cardiac consequences of undertaking endurance exercise are the topic of recent debate. The purpose of this review is to provide an update on a growing body of literature, focusing on left ventricular (LV) function following prolonged endurance exercise over 2 h in duration which have employed novel techniques, including myocardial speckle tracking, to provide a more comprehensive global and regional assessment of LV mechanics.MethodsProspective studies were filtered independently following a pre-set criteria, resulting in the inclusion of 27 studies in the analyses. A random-effects meta-analysis was used to determine the weighted mean difference and 95% confidence intervals (CI) of LV functional and mechanical data from pre-to-post-exercise. Narrative commentary was also provided where volume of available evidence precluded meta-analysis.ResultsA significant overall reduction in LV longitudinal strain (Ɛ) n = 22 (− 18 ± 1 to − 17 ± 1%; effect size (d) − 9: − 1 to − 0.5%), strain rate n = 10 (SR; d − 0.9: − 0.1.3 to − 0.5 l/s) and twist n = 5 (11.9 ± 2.2 to 8.7 ± 2.2°, d − 1: − 1.6 to − 0.3°) was observed following strenuous endurance exercise (range 120–1740 min) (P < 0.01). A smaller number of studies (n = 4) also reported a non-significant reduction in global circumferential and radial Ɛ (P > 0.05).ConclusionThe meta-analysis and narrative commentary demonstrated that a reduction in LV function and mechanics is evident following prolonged endurance exercise. The mechanism(s) responsible for these changes are complex and likely multi-factorial in nature and may be linked to right and left ventricular interaction.

Alterations in Cardiac Function Following Endurance Exercise Are Not Duration Dependent

“…In a meta-analysis by Middleton et al (2006) it was demonstrated that only ultradistance events >10 h elicited reductions in LVEF in trained individuals. In contrast, LV E/A ratio is reduced following endurance exercise as short as 45 min (Donaldson et al, 2019), and E' is reduced after 2 h of exercise (Lord et al, 2018). Left ventricular diastolic function, when assessed via classic measures of E/A ratio and tissue Doppler imaging, was reduced following all exercise durations in the present investigation, as is consistent with previous literature (Middleton et al, 2006;Lord et al, 2018;Donaldson et al, 2019), suggesting that transmitral flow velocities are altered with most forms of aerobic exercise.…”

“…While recreational athletes report participation in events like ultramarathon to improve physical health (Hoffman, 2016), the physiological consequences of participation are incompletely characterized. From a cardiac perspective, there is evidence that prolonged strenuous exercise may transiently alter both left ventricular (LV) (Middleton et al, 2006;Lord et al, 2018) and right ventricular (RV) (Oxborough et al, 2011;Elliott and La Gerche, 2014) function. This alteration is often termed "exercise induced cardiac fatigue, " and event duration and participant cardiorespiratory fitness are thought to play a role in the severity of the associated change (Middleton et al, 2006;La Gerche et al, 2012).…”

“…This alteration is often termed "exercise induced cardiac fatigue, " and event duration and participant cardiorespiratory fitness are thought to play a role in the severity of the associated change (Middleton et al, 2006;La Gerche et al, 2012). Whether or not these functional alterations are a natural and reversable response to prolonged exercise (Scott and Warburton, 2008), are indicative of structural myocardial damage (La Gerche et al, 2012), or are simply a consequence of altered loading conditions post-exercise (Middleton et al, 2006;Lord et al, 2018), is still contested.…”

“…Following prolonged exercise, alterations in post-exercise cardiac loading conditions, including elevated catecholamines and post-exercise hypotension, make it difficult to determine whether cardiac function is truly impaired, or if changes reflect post-exercise alterations to preload, afterload, and heart rate (HR) (Lord et al, 2018). Dehydration during prolonged exercise has been demonstrated to reduce stroke volume (SV) at rest and during exercise, while twist mechanics are maintained or improved (Stöhr et al, 2011b;Watanabe et al, 2020).…”

Factors Related to Cardiac Troponin T Increase after Participation in a 100 Km Ultra-Marathon

“…Bouts of intensive or long-lasting exercise (such as marathons or ultra-marathons) have been shown to increase blood levels of cardiac troponin, a known selective marker for myocardial injury and a major component of a current diagnosis of myocardial infarction [4][5][6][7]. Troponin rise after exercise is 2 of 9 usually discrete with levels returning to reference values within hours [8] and may be accompanied by an increase of natriuretic peptide levels and transient decrease of left or right ventricular systolic function without long-term consequences [9][10][11][12]. In line with that, recent studies with new imaging techniques demonstrated that intensive endurance training does not seem to promote myocardial fibrosis [6,[13][14][15].…”