Impact of Isometric Exercise on Left Ventricular Mechanics Assessed by Global Longitudinal Strain and Myocardial Work in Healthy Adults

Background: Traditional volumetric parameters have limitations in detecting subtle left ventricular (LV) systolic dysfunction.Global longitudinal strain (GLS) and myocardial work (MW) allow a more sensitive assessment of ventricular mechanics.Objectives: To evaluate changes in GLS and MW indices during isometric handgrip exercise compared with resting conditions.Methods: A total of 30 healthy individuals (29.3 ± 6.1 years; 50% male) were included in the sample.Echocardiography was performed at rest and during handgrip exercise (30%-40% of maximal strength).GLS, LV ejection fraction (LVEF), and MW indices were assessed: i) global work index (GWI), ii) global constructive work (GCW), iii) global wasted work (GWW), and iv) global work efficiency (GWE).Comparisons were performed using paired tests.Statistical significance was set at p < 0.05.Results: Handgrip exercise increased both systolic blood pressure (115 ± 16 vs 133 ± 18 mmHg; p < 0.0001) and diastolic blood pressure (69 ± 9 vs 79 ± 13 mmHg; p = 0.0002), without significant changes in LVEF (64.8% vs 64.4%; p = 0.62).A decrease in GLS was observed (20.38% ± 2.57% vs 19.60% ± 2.52%; p = 0.028), along with increases in GWI (+244 mmHg%; p = 0.0002), GCW (+313 mmHg%; p < 0.0001), and GWW (+52 mmHg%; p = 0.0008) as well as a decrease in GWE (94.8% ± 1.8% vs 93.6% ± 2.5%; p = 0.022).Conclusions: Handgrip exercise induces measurable ventricular mechanical changes in healthy individuals, reflecting a physiological response to acute pressure overload.