Seneca, Letters to Lucilius 55.1
a gestatione cum maxime venio, non minus fatigatus quam si tantum ambulassem quantum sedi; labor est enim et diu ferri, ac nescio an eo maior quia contra naturam est, quae pedes dedit ut per nos ambularemus, oculos ut per nos videremus. debilitatem nobis indixere deliciae, et quod diu noluimus posse desimus.
When I get home from being carried in my sedan chair, I am no less tired than if I had walked the same distance that I had sat down for; it’s hard work to be carried for a long time, perhaps all the more so in that it is contrary to nature, which gave us feet so that we could walk for ourselves, just as it gave us eyes so that we could see for ourselves. Our luxuriousness has inflicted this infirmity upon us, and we have become unable to do what we have long been unwilling to do.
These philosophical considerations don’t seem to have encouraged Seneca to actually do some walking of his own though…