Being a strong subscriber to the single breath concept....it took some getting used to to fly 4-5000 feet offshore like we do here...but in time I got used to it....not all that uncommon a sensation. In Alaska years ago....got involved in doing some sling work from sealevel to the top of Eagle Glacier...8,500-10,000 feet MSL.....and straight down to the beach....had to do ITO's until clear of the cliff edge and headed downhill. I find my last company's maintenance standards was what scared me from flying very high.....never knew when you would be wishing you were down there instead of up here!