For Bijan Shahvali of Brooklyn-based Intramural, “Short-sleeve shirts might be the hardest clothing items to buy, for me at least.” But that’s because he abides by a set of strict guidelines.

NASA’S APOLLO engineers were smart men and that’s why they wore short-sleeved, white dress shirts through sweltering summers in places like Houston. Back in the 1960s, “I don’t think ...