Background: Chronic glomerulonephritis (GN) is a kidney disorder characterized by glomerular inflammation and damage, often triggered by immune-mediated mechanisms and infections. The relationship between proteinuria, physical activity, and left ventricular hypertrophy (LVH) remains unclear. This study aimed to investigate the association between proteinuria and LVH in non-diabetic patients with chronic GN and to assess the impact of physical activity on cardiovascular health. Methods: A total of 165 male chronic GN patients (mean age: 55.65 ± 15.81 years) were compared with 90 age-matched healthy males. Proteinuria was measured using 24-hour quantification (24 h QP). Echocardiographic parameters, including left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), and LVH, were assessed. Physical activity levels were evaluated using a validated self-reported questionnaire. Results: Proteinuria ≥3.5 g/day (nephrotic range) was observed in 54 (32.7%) patients. Chronic GN patients had significantly higher creatinine, LVMI, and LVH compared to controls. Patients with nephrotic proteinuria exhibited greater LVMI and LVH than those with non-nephrotic proteinuria. A significant association was observed between LVMI and LVH in patients with nephrotic syndrome. Univariate regression analysis showed that increased LVMI and LVH were associated with higher nephrotic proteinuria. Notably, higher physical activity was associated with reduced nephrotic proteinuria and lower for cardiovascular health. Conclusions: LVH was more prevalent among patients with chronic GN, particularly those with nephrotic proteinuria. The findings underscore the importance of physical activity in reducing cardiovascular risks in this population. These results support the integration of tailored exercise programs into the clinical management of chronic kidney disease (CKD) patients.