What is a good activity to do between studying each subject?

One good activity to do between studying each subject is to take a short break and engage in physical activity. This could include a quick workout, a walk outside, or some stretching exercises. Physical activity can help improve concentration, and give you a mental refresh before diving into the next subject. Other activities to consider include listening to music, doing some deep breathing exercises, or practicing mindfulness and meditation. Ultimately, it's important to find an activity that helps you relax and recharge, so you can come back to your studies feeling refreshed and focused.