Cardiovascular responses in humans to experimental chewing of gums of different consistencies

paid to such responses to jaw muscle activity. The aim here was tn investig ate the general cardiovascular effects uf chewing activity in a single-blin d, cross-over design. Ten healthy individuals performed one of the followin g chewing tasks in four separate sessions: chewing a very hard gum, chewing a moderately hard gum, chewing a soft gum, and "empty chewing" without a b olus. Unilateral chewing of gum or empty chewing was performed for 20 min o n the participant's most convenient chewing side at a constant rate of 80 c ycles/min. In each session, heart rate and arterial blood pressure were rec orded together with electromyographic activity in the masseter and anteriol temporalis muscles on the chewing side. Ratings of perceived masticatory fa tigue were recorded with visual analogue scales. The heart rate and blood p ressure were significantly increased (ANOVA; p less than or equal to 0.01) during the chewing tasks and the increases were, in parallel with the muscl e activity, more pronounced the harder the gum. With the very hard gum, hea rt rate increased by up to 11 beats/min, the systolic blood pressure was 14 mmHg (1.9kPa) higher, and the diastolic blood pressure was ii mmHg (1.5kPa ) higher. The perceived fatigue was proportional to the level of muscle act ivity. After 10 min of recovery from exercise, heart rate and arterial bloo d pressures were slightly but still significantly elevated. The results dem onstrate that chewing is associated with general circulatory effects propor tional to the bolus resistance. (C) 1999 Elsevier Science Ltd. All rights r eserved.