well?
what would you define as the minimum level of aerobic and anaerobic fitness people should ascribe to?
a couple of things i didn't initally mention are and individual physical limitations. to be clear, physical limitations are things, genetic/accident/injury/disease related, that would prevent people from being able to participate in physical activities.
age is something that may include physical limitations, but those limitations may have been caused by inactivity over a lifetime. from a purely observational standpoint, i have seen many older adults who are capable of achieving the minimum standards i suggested. one of the reasons i see for this is their consistent particitipation in physical activity over the course of their lifetime. i think it's fair to say though that expectations may decrease as age increases.
We don't know what our limits are, so to start something with the idea of being limited actually ends up limiting us.
Ellen Langer