Response from: Monica

I think one important issue is that people who move out, still work in the city, and need quite some time for transportation, that has to be in car or public transportation. Probably it's not possible to walk or go by bike, and as newer suburbs tend to be further and further away, it can take a while to get back after work in the evening. So - maybe the time just isn't there to do excercise...

Response from: Mayogi

Another thing that might influence as well is that often the best gyms are in the city and in many places there isn´t even a gym in the suburb. So if you work in the city you would have to stay in the city to go to the gym and then travel home. That is asking too much for a lot of people.