Bruxism occasional tooth grinding. It has been shown that the majority (86%) of sleep bruxism episodes occur during periods of sleep arousal. One study reported that sleep arousals which were experimentally induced with sensory stimulation in sleeping bruxists triggered episodes of sleep bruxism. Sleep arousals are a sudden change in the depth of the sleep stage, and may also be accompanied by increased heart rate, respiratory changes and muscular activity, such as leg movements. Initial reports have suggested that episodes of sleep bruxism may be accompanied by gastroesophageal reflux, decreased esophageal pH (acidity), swallowing, and decreased salivary flow. Another report suggested
Grinding (gaming) have the potential to be rewarded in the future, and will have no reason to quit. Though grinding is used to provide a "level playing field", this effect could be achieved with any time-consuming behavior that is accessible to all and provides game advancement; The behavior need not be tedious or repetitive, as the term "grinding" generally implies. For example, in a game where advancement is gained by killing monsters, the game could provide such a huge variety of monsters and environments that no two kills are ever the same. As long as all players remained equally capable of killing