The present investigation was carried out to address the relationship that exists between physical activity, mood and psychological well-being, both on a theoretical level and in the daily life of people. The main objective was to establish the changes in psychological well-being and mood in people who did physical activity for a month, through two measuring instruments: The Psychological Well-Being Scale and the Profile of the Mood States (POMS) . The results of the study show that a single session of physical activity could significantly reduce the levels of tension and depressed mood in students. On the other hand, he also showed that in this case, physical activity was not enough to generate changes in the psychological well-being of the students.