The purpose of this study was to investigate the health effects of an adapted tennis-based exercise program, in middle-aged men with moderate risk of cardiovascular diseases (CVD). Fifteen men (44.9 ± 4.9 years) with two or more CVD risk factors, completed an eight-week health program that included a continuous tennisbased exercise protocol with constant and controlled intensity between 70%-85% of maximum heart rate and a standard nutritional orientation. Participants were assessed at the beginning and end of the exercise program for standard parameters related to CVD and the Framingham risk score, motor skills and cardiopulmonary fitness, peripheral inflammation (neopterin levels), oxidative stress (nitric oxide and carbonylated protein content), and mitochondrial function (lymphocyte complex I activity). Exercise improved muscle strength and power, speed, agility and flexibility, V O 2 max and metabolic equivalents. The participants experienced decreases in body mass index, waist circumference, total and LDL-cholesterol, and reduction in the Framingham Risk Score. Exercise also decreased peripheral oxidative stress and production of nitric oxide. In addition, the increased V O 2 at ventilatory threshold 1 correlated with enhanced mitochondrial activity in blood lymphocytes. The tennis-based exercise program adapted to sustaining moderate and constant intensity represents a valuable non-pharmacological intervention to prevent CVD.speed, muscle power and endurance, among others. Outdoor sports are motivating and enjoyable with high adherence levels [6].