Thanks, I hadn't heard of countercurrent heat exchange! I do find it remarkable, though, that the nasal turbinates don't seem to thermalize with the rest of th

Thanks, I hadn't heard of countercurrent heat exchange! I do find it remarkable, though, that the nasal turbinates don't seem to thermalize with the rest of the body in the time between inhale and exhale (which is of the order of several seconds). Or maybe it does thermalize quite a bit (even though not fully): A quick search for "nasal turbinates countercurrent heat exchange" reveals that human nasal turbinates are not particularly great heat exchangers, with air exiting at temperatures of up to 33°C during exhales.