Your activity level should be based on the details provided on the drop down menu for activity factor. (http://www.zoneliving.com/ZoneTools...ult.aspx).
If you’re doing only the 20-minute intense training consider “light” if you’re doing more during the week try increasing the level. If you experience loss of strength or longer recovery between workouts consider adding in a little more P/C/F per day. Reaching complete muscular failure will increase inflammation. Following the Zone and supplementing with EicoRx will help reduce inflammation and recovery times. You may find Chapter 18 (How to Build a Better Athlete) in “The OmegaRx Zone” to be of interest.