Aerobic training protects cardiac function during advancing age: a meta-analysis of four decades of controlled studies

Background
In contrast to younger athletes, there is comparatively less literature examining cardiac structure and function in older athletes. However, a progressive accumulation of studies during the past four decades offers a body of literature worthy of systematic scrutiny.

Objectives
We conducted a systematic review, meta-analysis and meta-regression of controlled echocardiography studies comparing left ventricular (LV) structure and function in aerobically trained older athletes (> 45 years) with age-matched untrained controls, in addition to investigating the influence of chronological age.

Methods
Electronic databases were searched from inception to January 2018 before conducting a random-effects meta-analysis to calculate pooled differences in means, effect size and 95% confidence intervals (CIs). Study heterogeneity was reported using Cochran’s Q and I2 statistic.

Results
Overall, 32 studies (644 athletes; 582 controls) were included. Athletes had greater LV end-diastolic diameter (3.65 mm, 95% CI 2.66–4.64), interventricular septal thickness (1.23 mm, 95% CI 0.85–1.60), posterior wall thickness (1.20 mm, 95% CI 0.83–1.56), LV mass (72 g, 95% CI 46–98), LV mass index (28.17 g·m², 95% CI 19.84–36.49) and stroke volume (13.59 mL, 95% CI 7.20–19.98) (all p < 0.01). Athletes had superior global diastolic function [ratio of early (E) to late (A) mitral inflow velocity (E/A) 0.18, 95% CI 0.13–0.24, p < 0.01; ratio of early (e′) to late (a′) diastolic annular tissue velocity (e′/a′) 0.23, 95% CI 0.06–0.40, p = 0.01], lower A (−8.20 cm·s⁻¹, 95% CI −11.90 to −4.51, p < 0.01) and a′ (−0.72 cm·s⁻¹, 95% CI −1.31 to −0.12, p = 0.02), and more rapid e′ (0.96 cm·s⁻¹, 95% CI 0.05–1.86, p = 0.04). Meta-regression for chronological age identified that athlete–control differences, in the main, are maintained during advancing age.

Conclusions
Athletic older men have larger cardiac dimensions and enjoy more favourable cardiac function than healthy, non-athletic counterparts. Notably, the athlete groups maintain these effects during chronological ageing.