INTRODUCTION - It is believed that engaging in physical activity leads to better blood circulation in the brain to affect the hypothalamic - apophysis - adrenal axis. When exercising in a person with anxiety disorders, there is a reduction in negative thoughts and worries because cortisol stops being excreted in excessive amounts. According to research, the best results are achieved if aerobic activities are carried out for ten weeks. The effect of physical activity on depression is manifested in increased synthesis and balanced secretion of dopamine, serotonin and endorphins. According to the National Institute of Clinical Origin in the UK, for depression with mild to moderate symptoms, aerobic activities lasting 45 minutes to an hour are recommended, which should be performed at least three times a week for a longer period of time of approximately 10-14 weeks. Quarantine causes negative consequences for mental health. It leads to the development of feelings of boredom, isolation and frustration. Physical activity has been shown to reduce the negative effects of quarantine such as depression, loneliness and boredom. RESPONDENTS AND METHODS - The study involved 53 physiotherapy students at the Faculty of Health Studies in Rijeka who completed a questionnaire on physical activity before and during the COVID-19 pandemic as well as on mental health during the pandemic. RESULTS - Statistical data processing did not find a statistically significant difference in the days and minutes of physical activity of high and moderate intensity before and during the COVID-19 pandemic, but found a statistically significant difference in the number of hours proved by respondents before and during the COVID-19 pandemic. No statistically significant difference was found regarding the fact that those subjects who performed physical activity felt better compared to those who did not perform physical activity. A statistically significant difference was found regarding the negative impact of physical activity on mental health. DISCUSSION - In this study, the first hypothesis was partially confirmed because a statistically significant difference was found only in the number of hours spent sitting before and during the COVID-19 pandemic. The third hypothesis related to the impact of the COVID - 19 pandemic on mental health was confirmed. CONCLUSION - The COVID-19 pandemic affected the occurrence of depression during this period. Physical activity had no effect on mental health, students engaged in both physical activity before and during the pandemic, with no statistically significant difference found between the number of hours spent the next before and during the COVID-19 pandemic.