My Commute is 11-12 miles RT depending on the route I take. I commute year round. I also use my bike for groceries,library, and joy rides so my weekly mileage is much higher. My commute goes from sparse traffic, to a semi truck gauntlet, to city traffic. You could always try your commute on a non-working day and see how you do. As for being exhausted,tired, or sore if you don't bike much it is bound to happen, but I love it!