Will 3 summer classes (8 credits) be too much in 1 semester?

<p>First Summer semester I took stats which was really easy. Right now I'm signed up for 2 classes for second semester but a third one is open that I need. The classes are- Principles of Fitness and Health, College Writing I, and Business Computer Applications. Are any of these classes challenging? Is this too much for one summer semester?</p>