Rumination is both a state and trait tendency to focus on negative events, emotions, and symptoms and their occurrence, causes, and consequences (Nolen-Hoeksema 1991; Rydstedt et al. 2011). Multiple conceptualizations of rumination exist, each having its own measure, and tested in different contexts. The majority of research has tested and shown rumination to play a key role in the onset and maintenance of depression. However, some research also shows that it causes and maintains distress in physically ill patients (see review by Soo et al. 2009). Rumination is a marker of poor adaptation, since it is thought to prolong one’s psychophysiological response to a stressor even long after it has ended. In a review of this domain, Brosschot (2010) views rumination as part of perseverative cognitions, where people have a sustained cognitive representation of past stressors, beyond their mere existence. Brosschot also contends that much of the effects of rumination could also be unconscious, even impacting one’s well-being during sleep. Furthermore, rumination is thought to mediate the association between stress and one’s psychophysiological responses. Rumination, which amplifies one’s failure to achieve goals, can be contrasted with more constructive self-reflection which is more distant and less immersed in one’s experiences. Supporting this, among people moderately high on rumination, promotion failure predicted depressive symptoms. In contrast, among people high on self-reflection, promotion failure was not predictive of severe increases in depressive symptoms (Jones et al. 2009). Looking at physiological indices of stress, Rydstedt et al. (2011) found that rumination interacted synergistically with job ambiguity (a known stressor) in relation to morning cortisol in British workers. As such, rumination amplified the effects of job ambiguity on a physiological marker of stress, namely, morning cortisol. Thus, rumination amplifies and worsens the impact of negative events, both in terms of their “duration” and in terms of their possible psychophysiological consequences. A study conducted by Klein et al. (2012) assessed implicit job-stress associations using the implicit association test. This could reflect to some extent an unconscious measure of rumination about work. Only this implicit measure significantly and positively correlated with waking cortisol, while an explicit measure of job intrusions did not (Klein et al. 2012). This result supports the contention of Brosschot (2010) that even implicit rumination may exert long-term psychophysiological consequences. Some research shows that meditation can reduce levels of rumination. A relevant study by Hanstede et al. (2008) found that meditation led to greater reductions in obsessive-compulsive symptoms, related to rumination, compared to a wait-list control condition. The health consequences, mechanisms, and the ability to reduce rumination with meditation all require further research.