Despite the burgeoning of mindfulness research, it remains unclear which components of mindfulness are directly related to symptom reduction. Furthermore, little is known about the experience of daily life mindfulness or the relationship between stress regulation and mindfulness in insomnia patients. Using a neurovisceral integration model of self-regulation, the proposed study seeks to examine the association between individual differences in mindfulness, executive abilities, and psychophysiologic arousal in response to daily life and laboratory stressors. Because mindfulness is associated with enhanced prefrontal cortex (PFC) functioning, and PFC activation is associated with parasympathetic activation and self-regulation, it is predicted that mindfulness may improve stress regulation and/or sleep quality via PFC-associated parasympathetic activation. To investigate these issues in normal adults and insomnia patients, the current study will obtain and link real-time subjective (i.e., self-report via PDA) and objective (i.e., psychophysiology via ambulatory Holter monitor) data from individuals exposed to stressors in daily life.