Abstract We investigated the influence of swearing on physiological systems in high school students by measuring heart rate variability (HRV) and electroencephalography (EEG). In total, 15 male students of the first grade in high school were divided into two groups based on their frequency of swearing: highly frequent swearing (HFS, n = 8) and low frequency swearing (LFS, n = 7). They were listened to under three conditions of conversation: every-day conversation without swearing (EC), a conversation consisting of light swearing (LS), and conversation consisting of severe swearing (SS). The results of the HRV analysis were as follows: the HRV of the two groups showed a significant difference in SS conditions in both LF and HF. The LF norm was higher in LFS (HFS: 47.6, LFS: 63.3) and the HF norm was higher in HFS (HFS: 52.4, LFS: 36.7). The LF/HF ratio in the SS condition was significantly different between the groups. (HFS: 1.0, LFS:1.9). The results of the spectrum analysis of the EEG were significantly different in the alpha wave of Fp2 in the EC condition between HFS and LFS, although no significant difference was found in other brain waves under LS and SS conditions. In the severe swearing condition, the LFS group showed higher activity of the sympathetic system and the HFS group showed a higher parasympathetic response. This indicates that students using highly frequent swearing become physiologically desensitized to the severe swearing condition. Also, on the basis of the neuroanatomical structures associated with cortico-subcortical inhibition, this desensitization may suggest a negative influence on cognition, emotion regulation, or even psychological health.