Oral digestion of a complex-carbohydrate cereal: effects of stress and relaxation on physiological and salivary measures.

A comprehensive study was undertaken with 12 dental hygiene students to ascertain whether the time of chewing or the degree of relaxation is more important in the oral digestion of complex carbohydrates. In addition, we studied whether the effects of stress and relaxation on salivary alpha-amylase activity was corroborated by physiologic measures. The dental hygiene students chewed an oat cereal for either 20 or 60 s while under two different orders of stress and relaxation conditions: 1) stress/20 s, stress/60 s, relax/20 s, relax/60 s; and 2) relax/20 s, relax/60 s, stress/20 s, stress/60 s. Galvanic skin resistance, pulse rate, and blood pressure (systolic and diastolic) were used to physiologically verify the effects of stress and relaxation on amylase activity. Amylase activity was judged by spectrophotometric analysis of maltose produced from a specific dilution of expectorated saliva. Results showed that the physiological measures significantly corroborated the salivary determinations of stress and relaxation and that deep relaxation was significantly more important than thorough chewing in the oral digestion of complex carbohydrates.