Great question — answering as the UphillTech team:
It would depend on the shoe. A full leather shoe would "Breathe" less because the air has more difficulty circulating all the way down to the toe and back. However, on a good "breathable" shoe, it wouldn't matter so much. My fast drying breathable shoes are all mesh with the vast majority of airflow coming straight through the shoe. For those, low versus high does not matter at all. If you're going for breathable shoes, the focus should be primarily on the material. The height of the shoe won't be a significant factor.
Full answer by Russell Steen: https://outdoors.stackexchange.com/a/4946 (CC BY-SA 3.0).
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