Abstract
(1) Background: The present study was designed to analyze the relationship between masticatory muscle activity, oxygen body saturation, and heart rate in patients with temporomandibular disorders (TMDs). (2) Methods: A total of 104 individuals with a painful form of TMDs were included in the study, consisting of 72 women and 32 men, with an average age of 24 ± 3 years. The control group included 77 individuals, comprising 44 women and 33 men, with an average age of 24 ± 3 years. An electromyographic study was conducted at rest, focusing on the temporalis (TA) and masseter muscles, alongside an oxygen saturation and heart rate analysis using a pulse oximeter. (3) Results: Analysis of the correlations between oxygen saturation and the studied muscles revealed a positive correlation between the resting activity of the TA and oxygen saturation, with a small effect size in the TMDs group. This positive correlation suggests increased muscle oxygenation is associated with higher resting activity in TMDs patients. (4) Conclusions: This study indicates that oxygen body saturation is associated with increased resting activity in the temporalis muscles of individuals with TMDs. Increased muscle tension in TMDs patients may impact the metabolism of the temporalis muscle, leading to higher energy and oxygen demands. This could be linked to hypermetabolism and an increased energy burden in these muscles at rest.