Thanks, everyone - this is a quiet but friendly corner of FT and I really appreciate the encouragement! Yes, the endless corridors and the memory of waiting 45 minutes at DEN baggage claim were exactly the sort of thing I was worried about.
The irony is that my whole life has been based on avoiding wear-and-tear: look up "sedentary" in the dictionary and you'll see my picture.
My doctor warned about not getting enough exercise, and now looks at the x-ray shaking her head and saying, "did you do a lot of jogging when you were younger???" Ummm, no.
Travel has been the only time I got any real exercise - I can't be bothered walking around the block at home but I love walking for hours in a strange city. Fortunately (?) this trip is for business and I won't have much time for sightseeing. And I've joined the swimming club at home to get regular (boring) exercise.
Thanks again - I feel better about this and will report back how it all goes.