In college, your classes will be time consuming. However, if you work efficiently, you will certainly have time to stay in shape and partake in the hobbies you enjoy, including exercise. You will likely be more productive if you are happy, so it is important to keep doing activities you like.
To ensure you have time, try to maintain a calendar to keep track of all of your deadlines, including exams. If you do your work in advance, you will have lots of free time. Try not to procrastinate!