Finally, as an ex-CFI of a gliding club, let me tell you that the pressure change over the first 1,000 feet in the earth's atmosphere if you have a cold is the worst.
This turns out not to be the case.
I wasn't sure whether I'd fully recovered from a cold, but I thought that if I survived one circuit with an instructor (I was due a club check ride) I'd be OK then going solo, on the "bottom 1,000' is the worst" theory.
This theory turned out to be utter bollocks. I had no trouble at all going up and down 1,000' with the instructor. But coming down from 7,000' on my own later was really not very nice at all.
Ever since then I've given it a full week after the last hint of a departing cold before going flying.