After lecturing for 3-4 hours my throat is often quite sore. Some days, I must lecturer for 6 hours (in past semesters, I've had some days which require lecturing for 8 hours). The problem is that for my later classes I have difficulty speaking comfortably.
I drink a lot of water, don't smoke, and use lozenges from time to time (when I'm in pain).
Are there any other known (scientific or folklore) solutions to this problem of getting a sore throat after lecturing for 3-4 hours?