The aim of this study is to investigate the relationship between venous calf muscle pump (CMP) hemodynamic, physical activity levels, and cardiorespiratory endurance in individuals diagnosed with Chronic Venous Disease (CVD). An exploratory cross-sectional study was conducted, involving 21 adult participants with CVD (17 females, 4 males), aged 42–85 years. Data collection included completion of a characterization form, assessment of venous CMP hemodynamic using photoplethysmography (BITalino), and calculation of various parameters such as volume, refilling time, ejection fraction after 1 heel raise, residual volume, residual volume fraction, and Venous Filling Index after 10 heel raises. Physical activity levels were assessed using the International Physical Activity Questionnaire, while cardiorespiratory endurance was measured using the 6 Minute Walk Test (6MWT). Additionally, CVD severity was evaluated using the Venous Clinical Severity Score. Subsequently, the relationship between CMP hemodynamic, physical activity levels, and cardiorespiratory endurance was analyzed. Furthermore, the association between CVD severity, certain risk factors (age, body mass index, sedentary lifestyle), and physical activity levels was assessed. Results revealed a lower level of physical activity in adults with CVD, which was associated with a higher venous filling index (r = − 0.54; p = 0.04). Moreover, greater final fatigue (6MWT) and increased sedentary behaviour were linked to higher CVD severity (p < 0.05). No other significant correlations were observed. In conclusion, adults with CVD who engage in low physical activity appear to exhibit poorer venous CMP hemodynamic functions. Additionally, individuals with higher levels of sedentary behaviour and poorer cardiorespiratory endurance tend to present with higher severity of CVD.