BACKGROUNDHypertension is a global health crisis that significantly increases the risk of cardiovascular diseases, stroke, and chronic kidney disease. Despite advances in treatment, the prevalence of hypertension continues to rise. It is important to know the association between abdominal obesity, cardiovascular fitness, and hypertension in middle-aged Koreans to develop effective prevention and management strategies for hypertension. This study aims to investigate the association between body composition, physical fitness, and hypertension in middle-aged Korean population. We examined the impact of abdominal obesity and cardiovascular fitness on the risk of hypertension.METHODS and RESULTSA cross-sectional study was conducted among 60 healthy adults (mean aged 54.23±7.34) recruited. Participants underwent assessments of anthropometry, body composition, blood pressure, and physical fitness. The primary outcome was the prevalence of hypertension. Secondary outcomes included body composition measures (body fat mass, body lean mass and waist circumference), and physical fitness assessments (grip strength, sit-ups, sit-and-reach test, and YMCA step test). Participants with hypertension had significantly higher body fat mass and waist circumference compared to those without hypertension. The risk of hypertension was significantly increased by 17.7% with a 1 kg increase in body fat and by 11.9% with a 1 cm increase in waist circumference. The risk of hypertension was significantly increased in the group with hypertension accompanied by abdominal obesity as cardiovascular fitness, measured by the YMCA step test, decreased (Adjusted OR: 0.326, 95% CI: 0.168-0.631).CONCLUSIONThese findings highlight the significant association between abdominal obesity, reduced cardiovascular fitness, and hypertension in middle-aged Korean adults. Abdominal obesity and low cardiovascular fitness were identified as independent risk factors for hypertension in this population. These results suggest that weight management to reduce abdominal obesity and regular physical activity to promote cardiovascular fitness are key to the prevention and management of hypertension.