Most of China is boiling hot, too, from what I understand. (Especially Guangzhou City). A couple of my friends went there with their sister to pick up their niece, and said it was absolutely brutal in terms of heat/humidity/smog. So being in shape helps you not only deal with the heat and humidity, but makes your body more efficient when delivering oxygen to your body. Not to mention it helps you handle the stresses of sleep deprivation and jet-lag coupled with all the walking; you end up doing a bit better than if you're huffing and puffing and exhausted all the time. Not to mention having your sense of humor probably helps with the whole transition process...
And, if you end up going to Beijing, would you REALLY want to give up an opportunity like climbing up the Great Wall? I understand it's like 18" steps... and lots of them.
I had a tubal ligation 2 years ago, because I don't want biological kids. I dunno... I've always figured if I was going to have kids, I'd adopt them from China or Korea. My boyfriend seems to think that's a fine idea too... but right now, I'm just hanging out worrying about grad school, my weight, etc. And, if the time never comes for kids, that's ok too. Motherhood isn't really something I've felt compelled towards, but I've got a plan if it ever starts bugging me.