Physiological Cardiac Hypertrophy

Physiological cardiac hypertrophy is an adaptive increase in heart muscle mass that occurs in response to increased physiological demand rather than disease-related stress. It is seen most clearly with sustained exercise training and during pregnancy. In the adult heart, this growth occurs mainly through enlargement of existing cardiomyocytes rather than production of large numbers of new heart muscle cells .¹

During physiological hypertrophy, increased cardiac size is generally accompanied by preserved or enhanced heart function. Exercise training, for example, can increase ventricular mass and chamber dimensions in a coordinated remodeling process often called the athlete's heart. The precise pattern depends on factors including the type and amount of exercise, and the traditional division into purely eccentric changes with endurance exercise and concentric changes with resistance exercise is an oversimplification .^1,2

At the cellular level, physiological hypertrophy involves signaling pathways that support cardiomyocyte growth while maintaining energy production and contractile function. Signaling through insulin-like growth factor 1, phosphoinositide 3-kinase, and AKT is particularly associated with physiological cardiac growth. This remodeling can also regress when the stimulus is reduced or removed, as may occur after prolonged reduction in athletic training .^1,2

Physiological cardiac hypertrophy is distinct from pathological cardiac hypertrophy and hypertrophic cardiomyopathy. Pathological hypertrophy develops in response to disease-related stresses and can involve fibrosis, cellular dysfunction, and progression toward heart failure. Physiological hypertrophy, by contrast, is generally an adaptive remodeling response with preserved cardiac function, although distinguishing physiological from pathological hypertrophy can sometimes require detailed clinical assessment .^1,2