Aim: To compare mental health indicators in security sector employees who complied (Group A) and did not comply (Group B) with the motor activity regimen during their training and combat activities. Materials and Methods: The research, which was conducted in 2024-2025, involved 450 security sector employees – cadets (n = 276), officer trainees (n = 71) and commissioned officers (n = 103) of the National Academy of Internal Affairs (Kyiv, Ukraine) who complied (Group A, n = 115) and did not comply (Group B, n = 335) with the motor activity regimen during their training and combat activities. Research methods: analysis and generalization of literature sources, methods of psychodiagnostic, biostatistical methods. Results: It was found that in the course of training and combat activities, mental health indicators (stress level, propensity to develop stress, stress resilience, nervous and emotional tension, stress resistance, reactive anxiety, emotional state) of security sector employees of both groups deteriorated. Still, in Group A, the changes are unreliable (p > 0.05), and in Group B, reliable (p . 0.01-0.001). It was found that at the end of the research, cadets, officer trainees, and commissioned officers of Group A had all the studied indicators significantly (p . 0.01-0.001) better than those of Group B. Conclusions: The effectiveness of motor activity (physical exercises) in overcoming stress and strengthening mental health in security sector employees during their training and combat activities under martial law has been proven.