Consistency of hand use and sleep problems.

In this study, we measured the relationship between the consistency of hand use and three symptoms of insomnia, i.e., delayed sleep onset, frequent awakenings during sleep, and trouble returning to sleep after an awakening. For each of these insomnia-related symptoms, university students who were classified as inconsistent in the use of their hands (n = 30) were significantly more likely to report problems than their consistent hand-use peers (n = 30). These data were discussed both in relation to the literature on handedness classification and sleep problems and the emerging literature on consistency of hand use and health-related problems.