Given the increasing health risks associated with climate change, particular attention is focused on the elderly as a vulnerable group. This study aimed to analyze how these climate extremes impact the health and hospitalization rates of these patients. In this ecological time series study, daily Meteorological and environmental pollutants data for Dezful and hospitalization records for cardiovascular diseases based on International Classification of Diseases, 10th codes were collected from 2013 to 2019. Definitions for heat waves and cold waves were established Based on previous studies in this field. The study utilized a combination of Distributed Lag Nonlinear Models and Quasi Poisson analysis to investigate the association between each definition of cold and heat waves and hospitalization. The results indicate that heat waves are associated with an increased risk of hospital admissions due to cardiovascular disease in individuals over 75 years of age. Additionally, cold waves significantly increase the risk of hospitalization due to cardiovascular disease in individuals aged 65 to 74 years. Specifically, in the section on added effects, the results show that Cold Wave impacts the risk of hospitalization in patients aged 56 to 74 years (added effects: lags of 0, 0–2, 0–6, and 0–13). This study highlights the significant impact of heat and cold waves on the risk of hospitalization for cardiovascular diseases in Dezful. Older adults, especially those over 65, are particularly vulnerable to these climate-related health risks. As climate change progresses, it is essential to implement public health strategies that protect at-risk populations during extreme weather events.