Sleep Bruxism is Associated with a Rise in Blood Pressure

Objectives: Sleep Bruxism (SB) is a movement disorder identified by tooth grinding and rhythmic masticatory muscle activity (RMMA). It is often associated with body movements and sleep arousals. Increases in autonomic sympathetic activities that characterize sleep arousal precede SB. These events include an augmentation of the following variables: sympathetic cardiac activity (-4 minutes), electroencephalography frequencies (-4 seconds), heart rate and respiratory amplitude (-1 seconds), and suprahyoid muscle activity (-0.8 seconds). This study examined whether these sympathetic activities are associated with significant changes in arterial blood pressure (BP). Methods: Ten subjects with SB (5 male; 5 female; mean age ± standard error = 26 ± 1.8) underwent 3 nights of full polysomnography that included non-invasive beat to beat BP recording. The first night served as a screening and habituation night. Analysis was performed on second and third night recordings. Overall analysis was based on single SB episodes occurring in stage 2 sleep only, for a total of 65 episodes. Systolic and diastolic BP measurements were taken from a window of 20 beats before and 23 beats after onset of each SB episode. SB episodes were categorized as: 1) SB + cortical arousal; 2) SB + body movement (BM); 3) SB + cortical arousal + BM. A fourth category, SB alone, was also analysed but used as preliminary data since the category consisted of only 4 episodes. Results: Both systolic and diastolic BP increased with SB episodes. This increase was significant for both systolic and diastolic BP for SB events with cortical arousal and/or BM (p≤0.05). The average BP surges (systolic/diastolic ± SE) were: 28.4 ± 2.4/13.2 ± 1.5mm Hg for SB + cortical arousal; 30.7 ± 1.6/19.4 ± 2.3mm Hg for SB + BM; 26.5 ± 2.8/14.6 ± 2.0mm Hg for SB + cortical arousal + BM; 22.9 ± 5.2/12.4 ± 3.3mm Hg for SB episodes occurring alone. Conclusion: Sleep bruxism is associated with blood pressure fluctuations during sleep. This BP surge is greater in SB episodes associated with cortical arousal and/or BM, which often co-occur with SB events. These results are congruent with our previous observations, where SB is preceded by a rise in sympathetic activity and sinus tachycardia.