Differences in Left Ventricular Function at Rest and during Isometric Handgrip Exercise in Elite Aquatic Sport Athletes

PURPOSE: Elite swimmers (Sw) have lower diastolic function compared with elite runners, possibly as an adaptation to the aquatic training environment. Water polo players (WP) and artistic swimmers (AS) are exposed to the same hydrostatic pressures as Sw, but they are subject to different training intensities, postures, and hemodynamic stressors. Our purpose was to compare resting and exercising cardiac function in elite Sw, WP, and AS, to characterize the influence of training for aquatic sport on left ventricular (LV) adaptation. METHODS: Ninety athletes (Sw, 20M/17F; WP, 21M/9F; AS, 23F) at the 2019 Fédération Internationale de Natation World Championships volunteered for resting and stress (3 min 30% maximal isometric handgrip) echocardiographic assessment of LV global function and mechanics. RESULTS: Male Sw displayed greater resting systolic and diastolic function compared with WP; however, both groups maintained stroke volume under high-pressure handgrip stress (Sw, ∆-4% ± 12%; WP, ∆-1% ± 13%, P = 0.11). There were no differences between female Sw and WP resting LV function, but Sw demonstrated greater function over AS. During isometric handgrip, all female sport athletes maintained stroke volume (Sw, ∆3% ± 16%; WP, ∆-10% ± 11%; AS, ∆-2% ± 14%, P = 0.46), but WP had improved apical rotation (∆1.7° ± 4.5°), which was reduced in AS (∆-3.1° ± 4.5°) and maintained in Sw (∆-0.5° ± 3.8°, P = 0.04). Unlike Sw and WP, AS displayed a unique maintenance of early filling velocity during handgrip exercise (Sw, ∆-3.5 ± 14.7 cm·s-1; WP, ∆-15.1 ± 10.8 cm·s-1; AS, ∆1.5 ± 15.3 cm·s-1, P = 0.02). CONCLUSIONS: Among male athletes, Sw display primarily volume-based functional adaptations distinct from the mixed volume-pressure adaptations of WP; however, both groups can maintain stroke volume with increased afterload. Female Sw and WP do not demonstrate sport-specific differences like males, perhaps owing to sex differences in adaptation, but have greater volume-based adaptations than AS. Lastly, AS display unique functional adaptations that may be driven by elevated pressures under low-volume conditions.