You should feel lucky you can get out that much and stay in top shape but not everyone can.
a lot of people will find this harsh, but the time excuse is the one i hear the most - there really is no excuse for not being reasonably fit. of couse i'm not going to include people who are ill with cancer or some other disease/affliction, but the whole 'i don't have enough time thing' is just a bs excuse to keep one's ass parked. sure i may get labeled a fitness nazi because of it, so be it.
the funny thing is that i am not super fit, i don't go out and run a marathon each week, and i don't have sub 10% bodyfat, but i do perscibe to maintaining what i believe to be a minimum standard or decent level of fitness. and that standard is not extremely high, it is something that is achievable by nearly everyone. i train a woman who has cerebral palsy and is in a wheelchair, but she comes in to exercise on a regular basis and does what she can to maintain and improve her health.
nobody is so busy that on 4 out of 7 days per week they couldn't find 10-15 minutes two times over the course of the day to do some exercise. if you can't you're just lying to yourself.
with my rant over, i would say that walking your bike up fromme is getting some exercise.
Luck is what happens when preparation meets opportunity ~ Seneca