the vocal folds pitch - Using a higher or lower pitch than normal will also increase laryngeal stress. voice quality - Using a vocal quality which differs from that habitually used is thought to increase laryngeal stress. In addition, smoking and other types of air pollution might have a negative effect on voice production organs. Symptoms Objective evaluation or measurement of vocal loading is very difficult due to the tight coupling of the experienced psychological and physiological stress. However, there are some typical symptoms that can be objectively measured. Firstly, the pitch range of the voice will decrease. Pitch range indicates the possible pitches that can be spoken. When a voice is loaded, the upper pitch limit will decrease and the lower pitch limit will rise. Similarly, the volume range will decrease. Secondly, an increase in the hoarseness and strain of a voice can often be heard. Unfortunately, both properties are difficult to measure objectively, and only perceptual evaluations can be performed. Voice care Regularly, the question arises of how one should use one's voice to minimize tiring in the vocal organs. This is encompassed in the study of vocology, the science and practice of voice habilitation. Basically, a normal, relaxed way of speech is the optimal method for voice production, in both speech and singing. Any excess force used when speaking will increase tiring. The speaker should drink enough water and the air humidity level should be normal or higher. No background noise should be present or, if not possible, the voice should be amplified. Smoking is discouraged. See also Human voice Vocal rest References Human voice