It was a joke. She said the temperature going from 101F one day to 85 another day would be stressful on my body, making it difficult and exhausting for me to bike; and also that walking out of 70F buildings into 85F-95F weather would put major stress on my body, which would then be compounded when I hopped on a bicycle...

Before the industrial revolution and the invention of electricity, that whole north africa/south europe desert region was inhabited by either nomatic desert folks in tents or settled desert folk in stone huts, neither of which had AC and thus had to rely on turbans to keep their heads cool.

The natural synthesis of these two bits of information is, of course, that the desert folk struggling to find water and salt (oh, yes, by the way, salt is more valuable than gold in the desert) are better off than lazy Americans lounging around in their air conditioned apartment units and office complex. As the Russians may say, you are all soft, and would not last a day in Siberia!