I just started to use my bike for all my work commuting but I have a question thats bugging me.

Is it ok to bike 7 days/wk for commuting? I go to work 5 days per week, and on my off days I usually visit friends or go to the library. On the day I go to the library I will try to keep that day light for a total of 8 miles that day while I normally bike around 16-20 miles most other days.

Physiologically will I be ok? Are there any studies on this? Anecdotal stories perhaps? Will my muscles get used to it?

~Brandon