BACKGROUND: Obesity is a chronic disease characterized by the excessive accumulation of body fat that is harmful to the individuals that can cause respiratory disorders. In obese individuals, structural changes of the thoracic–abdominal region lead to limited diaphragm mobility and rib movement, both essential for appropriate ventilatory mechanics. Athletes have higher lung volumes than sedentary controls, mostly caused by respiratory adaptations to training. The concept of “lung age” to express pulmonary function by age so that participants could understand their pulmonary function easily and clearly. The aging of lung is associated with increased closing volumes. This concept is easy to understand by the general population. AIM: To find out the correlation of lung age in healthy, obese and athletic individuals. MATERIALS AND METHODOLOGY: 60 subjects, age ranging between 18 to 25 years of both the genders were taken, and equally divided according to BMI into normal, obese and athletic group where the individuals were playing sports regularly were taken. Any structural deformity, history of hospital visits in past 6 month and smokers were excluded. PFT spirometry – lung age was taken as an outcome measure. RESULT: The primary object of the study was to find out the correlation of the lung age of normal healthy, obese and athletes individuals. When all the lung age was corelated with each other, the group with the obese individuals showed the older lung age compared to normal healthy and athlete group. While the group with the athletic individuals showed decreased lung age in compare to normal healthy and obese group. And the normal group didn’t show any significant decrease and increase in the lung age. CONCLUSION: The current study showed that the higher BMI are associated with the older young age, where regular physical activity can improve cardiovascular fitness therefore it shows decrease in the lung aging.