Cognitive PerformanceIt is now generally accepted that the afferent neurological signals the heart sends to the brainhave a regulatory influence on many of the ANS signals that flow from the brain to the heart, tothe blood vessels, and to other glands and organs. However, it is less commonly appreciated thatthese same cardiovascular afferent signals involved in physiological regulation also cascade upinto the higher centers of the brain and influence their activity and function. Of particularsignificance is the influence of the hearts input on the activity of the cortexthat part of thebrain that governs thinking and reasoning capacities. As we will see, depending on the nature ofthe hearts input, it can either inhibit or facilitate working memory and attention, corticalINTEGRAL REVIEWDecember 2009Vol. 5, No. 2processes, cognitive functions, and performance (Hansen, Johnsen, & Thayer, 2003; Lacey &Lacey, 1974; Rau, Pauli, Brody, Elbert, & Birbaumer, 1993; Sandman, Walker, & Berka, 1982;van der Molen, Somsen, & Orlebeke, 1985).Our research on psychophysiological coherence has provided new insight into the relationshipbetween heart activity and cognitive performance. The context for this is described in detail inAppendix B. It describes how psychophysiologists John and Beatrice Laceys baroreceptorhypothesis identified a relationship between the hearts activity and cognitive performance. Thiswork was furthered by Christoph Wolk and Manfred Velden in Germany, who identified theimportance of heart rates pattern and stability in influencing neurological functioning. Althoughwe agree with Wolk and Veldens conclusions, the primary focus of previous work in this areahas been on micro-scale temporal patterns of cardiac activity, occurring within a single cardiaccycle, or, at most, across 34 heartbeats. However, the interactions between the heart and brainare much more complex and also occur over longer time periods (sequences of heartbeatsoccurring over seconds to minutes). Based on the evidence we report below, we believe thatpatterns of the hearts rhythmic activity over a longer time scale are also involved in influencingcognitive performance. Moreover, it appears that these macro-scale temporal patterns ofcardiovascular afferent activity can have a much greater effect on performance than micro-scalepatterns. Therefore, a broader hypothesis is called for.The Heart Rhythm Coherence Hypothesis: A Macro-Scale PerspectiveIn the course of conducting our studies, we had received numerous reports from individualsable to maintain the psychophysiological coherence mode that their performance in variousactivities had noticeably improved. These involved faculties and abilities requiring theprocessing of external sensory information (e.g., speed and accuracy, coordination, andsynchronization, such as in sports and the performing arts) as well as processes requiringprimarily internal focus (e.g., problem solving, decision making, creativity, and intuition, such asin business and intellectual activities). This led us to postulate that psychophysiologicalcoherence and the associated macro-scale patterns of the temporal organization of the heartsrhythmic activityheart rhythm patterns occurring over seconds to minutesalso have animportant effect on cognitive processes and intentional behavior. Focusing on the nature of theorganization of the hearts rhythmic activity, which reflects emotional state, we hypothesize thatemotion-driven changes in global psychophysiological function, and the resulting change in thepattern of heart rhythm activity, are also directly related to the facilitation or inhibition of thebrain processes involved in cognitive function. In specific terms, sustained positive emotionsinduce psychophysiological coherence, which, in