The present study was devised to clarify the characteristics in blood pressure and cerebral blood flow volume during chewing at different intensities in middle-aged and elderly persons. Measurements were taken of blood pressure (SBP, DBP), heart rate (HR), wave height of plethysmography (WHPTG), blood flow volume of the common carotid artery (BFVCC) and blood flow velocity (Vel.BF) by ultrasound doppler using the A- mode method, and tympanum temperature (Tty) during chewing at three kinds of intensities while in a upright sitting position. Chewing consisted of one bite per second for 6 minutes and was conducted at each of the relative intensities of 25%, 50% and 75% of the maximal occlusal force (OFmax). In addition, some physiological responses were reviewed in terms of cardiovascular and cerebral blood flow controls in middle-aged and elderly persons. Fourteen male volunteers (7 persons in the 38~75-yr group as the ME group, 7 persons in the 19~26-yr group as the Y group) cooperated as the subjects of this study. In the Me group, ΔBFVCC (Δindicates the difference from the resting value), ΔVel.BF, Tty increased significantly at 50% and 75% chewing. SBP, DBP and HR also were enhanced from the resting values significantly at 25%~75% chewing, and the elevation of SBP and the depression of WHPTG were typically greater in comparison with changes in the Y group. Based on these physiological changes, it was predicted that the sympathetic nervous system was activated in the process of chewing. Furthermore, significant positive correlations were recognized between ΔHR and Vel.BF (r=0.701), ΔHR and BFVCC (r=0.616), and DBP and Vel.BF (r=0.670) at chewing. Based on these results, we estimated that vessel contraction and pressure response with chewing in the ME group were obviously greater than in the Y group. In conclusion, it was indicated that blood pressure increased more typically than cerebral blood flow volume during chewing in middle-aged and elderly persons. Therefore, it was suggested that chewing exercise might activate a brain function and keep flexibility of brain vessels by increasing cerebral blood flow during chewing. However, further increase of blood pressure would be expected by the strong chewing in the patients with hypertension. Finally, frequent chewing in a weak or moderate intensity might be recommended in daily life.

DESCENTE SPORTS SCIENCE Vol.24/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE