Learn to listen to your body, and lighten up on your personal goals. Cycling is way less stressful on the old bod than running so you can cycle with less chance of injury. Ride everyday if you have time, but LISTEN TO YOUR BODY! If you feel a muscle twinge in the back or calf or anywhere on your body, stop immediately and call a friend or someone to sag you in. Don't try to "play hurt" as if you were a twenty year old again. At this point a few days of rest would be warranted. At our age we have to respect our bodies more than we did when we were younger.

That being said... It would be better to implement regular rest days into your schedule. Your muscles need time to rest. Stretching exercises would be good to work in on rest days.