Previous studies in young adults have shown that physical activity can generate positive emotions and improve attention, among other cognitive functions. This highlights the importance of evaluating how physical activity can affect cognition and affective dimensions. However, to date, the dose of physical activity that could be most effective for these variables has not been established. This project aims to study the impact of acute physical activity on brain health in a university setting. Thus, this study will contribute to expand the current scientific literature on the acute effect of physical activity, a topic of great importance both in the educational field and from a public health point of view.

Students in the university stage face many changes in their lives. These changes, partly derived from academic activity, can cause alterations in their lifestyle and brain health (i.e., cognitive, emotional, and behavioural functioning). Due to the negative association of several indicators of brain health with academic performance during the university stage, it is of interest to promote strategies that can favour it. Among them, previous studies in young adults have shown that physical activity can generate positive emotions and improve attention, among other cognitive functions. However, to date, the dose of physical activity (i.e., type, duration, and intensity) that could be most effective for these variables has not been established. Furthermore, previous studies in the matter have been carried out in laboratories and few investigations have analysed outside them the impact of acute physical activity on brain health in university classrooms. Therefore, expanding the current scientific literature on the acute effect of physical activity is of great importance in the educational field, since it would contribute to the design of active proposals aimed at improving brain health with positive implications for students' academic performance and quality of life.

Accordingly, this project aims to carry out an acute physical activity intervention with different intensities and active breaks with students from the Jaume I University (Castellon de la Plana, Spain). More precisely, a total of 210 students between 18 and 24 years old will participate in the intervention.

To achieve it, a randomized crossover study design will be carried out with the groups of participants compensated in terms of number and sex. Attention will be assessed using the d2-R questionnaire and emotional well-being will be assessed using the Positive and Negative Affect Schedule questionnaire. The tests evaluating attention and emotional well-being will be carried out before and after each condition. The experimental conditions will be: control group (quietly sitting), light intensity (40% VO2max), moderate intensity (63% VO2max), or vigorous intensity (100% VO2max) exercise, all lasting 16 minutes. In addition, an active break will be performed at the intensity of physical activity that proves to have the greatest benefits on cognition and well-being. It will include 12 blocks of 30 seconds of work, performing as many repetitions as possible, followed by 15 seconds of static rest. It will last last 9 minutes and will be conducted after a 2-hour lecture. During the active rest period, heart rate will be monitored using a heart rate monitor to register the intensity.

Taking into account that the lifestyle of students is mainly characterized by the accumulation of prolonged periods of sedentary activity, introducing physical activity in the classroom represents an interesting opportunity for intervention from both an educational and a public health point of view.

Inclusion Criteria:

• Not to be diagnosed with psychological and/or cognitive alterations or pathologies that may limit the understanding and following of the instructions provided by another person.
• Not to suffer physical alterations that may limit the practice of physical activity.
• To be between 18 and 24 years old.

Exclusion Criteria:

• To be diagnosed with psychological and/or cognitive alterations or pathologies that may limit the understanding and following of the instructions provided by another person.
• To suffer physical alterations that may limit the practice of physical activity.
• Not to be between 18 and 24 years old.

The sharing of the data of the participants in the study with third parties is not foreseen or planned.

The assignment to the different conditions will be carried out using a random number generation program stratifying by sex (i.e., the randomizer.org tool).