Vocal loading is the stress inflicted on the speech organs when speaking for long periods.
[1] That includes professions such as teachers, sales personnel, actors and singers, and TV and radio reporters.
In a larger scope, this involves millions of sick-leave days every year, for example, both in the US and the European Union.
Voiced speech is produced by air streaming from the lungs through the vocal cords, setting them into an oscillating movement.
It is intuitively clear that the vocal fold tissue will experience some tiring due to this large number of hits.
However, researchers' largest interest lies in stress exerted on the vocal folds.
Objective evaluation or measurement of vocal loading is very difficult due to the tight coupling of the experienced psychological and physiological stress.