Sound health is considered a basic need of every individual. It allows a person to enjoy routine activities. Objective: To examine the impact of moderate intensity exercise on aerobic fitness. Methods: Participants of the study were voluntarily selected from the department of sports science and Physical Education, Gomal University, Dera Ismail Khan, KPK, Pakistan. In addition, the participants of the study were categorized as; control group (CG =20) and experimental groups (EG-20). A self-made exercise protocol of twelve weeks was applied on the selected subjects and thus for the assessment of aerobic fitness, Harvard Step Test, developed by Brouha et al., (1943) was used. The collected data were tabulated and were analyzed by using appropriate statistical tools i.e. Percentage, Means, Standard Deviation, Paired Sample t-Test and ANOVA. Results: The study found significant difference were found between pre & post cardiovascular fitness of male subject i.e. t (9) = -21.433, sig. = .000 < a= .05. Similarly, significant difference was found between pre & post cardiovascular fitness of female subject i.e. t (9) = -25.249, sig = .000 < a= .05. According to the results of this research study, it may be recommended that the Physical education and exercise must be a necessary subject for all college, school and university level students or the student is necessary to take the subject of physical education and exercise for each year so that their cardiovascular fitness is maintained. Conclusions: The study concluded that moderate intensity exercise has significant impact on aerobic fitness of respondents.