Is London a healthy city?

Following my previous questions on positive effects and benefits of exercise - or even just physical activity of some kind- I came to wonder whether London was actually a fairly healthy city. In comparison with other British cities it may seem congested, dense, polluted and constantly busy, but London organises an array of sporting events - not to mention the upcoming Olympic Games. The city is host to hundreds of charity runs, sports groups, clubs, and probably the widest choice of activities from rock climbing to taichi and yoga. London also seems to have picked up the cycling bug, with a 400% increase in cyclist in the past 4 years. I see joggers out at any time of day or night, all over town - from early risers on a chilly Saturday morning to night runners in Hyde park- and I believe London may just have the highest concentration of fit, healthy people in the country. Is this a fact? What about other cities? I hear that in Birmingham health levels are deteriorating, with obesity being a serious issue. So serious in fact that stairs in one of the inner city shopping malls are branded with signs stating how many calories can be burned by using them instead of lifts! They've reached the point where any form of activity -even walking up a few stairs- is crucially needed. In this case, London rates much higher. I see escalators often being ignored in favour of old fashioned stairs, which many magazines advocate as an excellent 'mini step' class - no better way to tone and lift those buttocks. Hmm, not quite I had in mind, but the thought is there. I can just picture those lovely ladies, determinedly going for stairs in hope of a better bottom. No matter what, the activity bug is there, firmly rooted in our psyches - and today this can only be a good thing. When one lives in a built up, busy city, what better way to move your limbs, clear your head and relieve stress, than a daily dose of exercise. And I believe London isn't too bad at encouraging this.