Swimming is an internationally recognized and popular sport, swimming has evolved over the years with the inclusion of real-time analytics, body analysis, and a lot of cell- and body-level research around the world, but particularly in India, the amount of research on it is very minimal and with the popularity for the sport raising, it was apt for me to start research on it. To evaluate and compare physiological and body composition parameters among different ages and genders during one mesocycle in swimmers. The study involved a sample collection from 60 (n = 60) active national swimmers in the under 16 age categories of which 33 were male and 27 were female. Anthropometric measurements, body composition, and VO2 max parameters were analyzed by using universally accepted and used equipment for the purpose of tests such as anthropometry, body composition, lung capacity, etc., on athletes. Anthropometrical measurements are the basic measurements such as height, weight, BP, SPO2, etc. Body composition tests are conducted using the InBody 770. Spirometry test is used to conduct forced vital capacity. Post spirometry test a breath-by-breath analysis test (CPET) is conducted for VO2 max. The sample was further classified on the basis of their age and gender and a t-test was used for two independent samples in order to compare the classified groups. The statistical analysis was done with the help of software named IBM SPSS Statistics 20. From the study, we were able to conclude that parameters such as anthropometry, body composition, and lung functions play a vital role in the performance of an athlete depending on their age, gender, and training protocol, also working on these parameters would surely help them improve their performance.