Abstarct: Introduction: Obesity and overweight are considered one of the problems of human societies that depend on several factors. However, to prevent or solve this problem, the benefits of physical activity can be used. Swimming is one of the sports that, in addition to being fun, can help increase calorie consumption and maintain a desirable weight. Since limited studies have compared the two types of high-intensity and low-intensity swimming, the aim of the present study is to compare the effects of the two types of high-intensity and low-intensity swimming on the appetite response and the levels of some related hormones in overweight female swimmers. Materials and Methods: The statistical population of this study was overweight female lifeguards in Neyshabur city. The eligible subjects met the inclusion criteria for this study, which included a body mass index between 25 and 30, age between 30 and 45 years, healthy and without any specific disease. A total of 15 subjects were selected, of which one withdrew and the study was conducted with 14 subjects. The subjects were divided into two random crossover groups and engaged in swimming in the follicular phase of the menstrual cycle (between 5-11 days after menstruation) in two separate sessions with a minimum interval of 72 hours between the two exercises. The subjects arrived at the test site at 7:30 am and in a fasting state (9 hours). After having a standard breakfast (20% of daily requirement) at 8 am, they rested for 60 minutes and then performed their high-intensity or low-intensity exercise according to the initial division. High-intensity training consisted of 6 times of 50-meter swimming at maximum speed, swimming and resting for 5 minutes, for a total of about 30 minutes, and low-intensity training consisted of continuous swimming of 1000 meters for about 30 minutes. After that, they rested for 60 minutes and were then allowed to request lunch. The subjects were also required to be present at the test site until 2:00 and were not allowed to leave the site. The appetite questionnaire [(subjects' appetite (hunger, fullness, satiety and food craving) with visual analog scale of appetite (VAS)] was completed by the subjects before breakfast, before training, after training, one hour after training and at the time of requesting lunch. Chemical factors included: hormones ghrelin and lactate, which were performed before training, after training and at the time of requesting lunch, and finally the data obtained were analyzed using statistical tests. Results: The level of ghrelin in low-intensity swimming decreased significantly at the second time of blood collection (p <0.05), but it was not significant in high-intensity swimming. Feeling Hunger and fullness were significant during low-intensity activity (p <0.05), but not for feelings of satiety and desire to eat on any of the activity days. Lactate levels were also not significant on any of the two training days, and the comparison of calorie intake at lunch between the high-intensity and low-intensity days was also not significant. Conclusion: It seems that low-intensity swimming has an effect on ghrelin levels and appetite reduction compared to high-intensity swimming, and at the same time, considering the lack of desire to consume more food at lunch, it can be a good option that can be used as a method for weight loss.