I think it's important to differentiate between the zombies that threaten the future of this world. There is the classic zombie, a la George Romero, which shumbles along at a slow pace; and then there is what I like to call the SWAT Team Zombie, a la 28 Days Later, which runs along side your car as you attempt to zoom away. With any luck, the upcoming zombie infestation will be composed of the classic zombies, which are much easier to deal with. While they will undoubtedly grow to hundreds of thousands, if not millions (billions?), their lack of agility lends itself to common sense defense/attack strategy. This is not the case with the SWAT Team Zombie. These creatures jump into your home through skylights, where they will gouge out your eyes before feasting upon your flesh. It will take more than a brisk pace to outstrip these.
It is time to step up your cardio routine.