2018 Volume 47 Issue 2 Pages 69-76
The ratio of the low frequency (LF) and high frequency (HF) bands of heart rate variability (LF/HF) was used to evaluate the balance between sympathetic and parasympathetic nervous activities, and HF was used for evaluating the parasympathetic nervous activities. In the present study, we set two conditions using two types of gummy candy (hard: gelatin 11%, soft: gelatin 6%). In the hard condition, the LF/HF was significantly higher during the chewing period (gummy) than the period before the chewing (pre-gummy) (p<0.0001). Furthermore, the LF/HF was significantly lower during the period from just after chewing to 5 minutes after chewing (post-gummy 1) than in the pre-gummy period (p<0.05). In addition, the LF/HF ratio was significantly lower during the period from 5 minutes to 10 minutes after chewing (post-gummy 2) than in the pre-gummy period (p<0.05) in the hard-gummy condition. In the soft condition as the control, the LF/HF ratio was also significantly higher during the gummy chewing than in the pre-gummy (p<0.0001). However, during the post-gummy 1 and post-gummy 2, the LF/HF was not significantly different from that observed in the pre-gummy (p>0.05, respectively). On the other hand, there was no significant changes in HF and heart rate throughout the testing. The results demonstrate that the hardness of food during chewing exercise has an influence on autonomic nervous activity after chewing.
