Preserving the health of student youth is one of the state's priority tasks. The relevance of the issue results from the students’ health deterioration. The study was aimed to assess physical development in students of the medical higher educational instutution considering their lifestyle. We performed comparative assessment of physical development in 940 first-year students of the Pacific State Medical University. The source of information was primary medical documentation (form No. 025-CZ/u). Polling was used to assess the students’ lifestyle. The CHAID algorithm for decision trees was used in 2021 to estimate the effects of lifestyle on the indicators of physical development in students. It was found that the students’ body length decreased over 20 years. The chest circumference of students increased (p = 0.001). The right and left hand grip strength decreased (p < 0.001). A significant increase in the vital capacity was reported in males only (p = 0.007). We revealed the increase in the number of students with disharmonious physical development (by 9.4% in males and 15.3% in females) due to overweight, along with reduction of body weight by 12.5% in males. The risk factors of disharmonious physical development with the highest impact factor in males were as follows: the lack of vegetables in the diet and the use of social media and computer games during free time. In females, the risk factors were as follows: daily consumption of cereals, pasta, and bread and living apart from parents. The findings make it possible to estimate the risk factors of disharmonious physical development and determine the priority directions for the development of preventive measures for preservation of students’ health.