fromseconds to hours (Schofl, Prank, & Brabant, 1995). As most heart hormones are released insynchronicity with the contractions of the heart, there is a rhythmic pattern of hormonal releasethat tracks the heart rhythm.This is particularly relevant to our discussion of coherence, as it suggests that changes in heartrhythm patternssuch as those generated during psychophysiological coherenceimpact thebrain and body in yet another way: that is, they change the pattern of hormonal pulses releasedby the heart. Although the influence of these changes in hormonal pulse patterns on biological,emotional, and behavioral processes is still unknown, it is likely that the transmission of suchhormonal information constitutes another pathway by which the effects of psychophysiologicalcoherence on health, well-being, and performance are mediated.INTEGRAL REVIEWDecember 2009Vol. 5, No. 2With every beat, the heart generates a powerful pressure wave that travels rapidly throughoutthe arteries, much faster than the actual flow of blood. These waves of pressure create what wefeel as our pulse. The heart sounds, generated by the closing of the heart valves and cardiacmurmurs, can be heard all over the chest and can extend as far as the groin. Similarly, thepressure waves traveling through the arteries and tissues can affect every organ in the body,especially when the mechanisms that control blood pressure are compromised. In fact, thephysical shock wave generated by the heartbeat expands the chest wall to such an extent that theheartbeat can be detected by measuring the chest expansion (this is called theballistocardiogram).Important rhythms also exist in the oscillations of blood pressure waves. In healthyindividuals, a complex resonance occurs between blood pressure waves, respiration, and rhythmsin the ANS. Because pressure wave patterns vary with the rhythmic activity of the heart, theyrepresent yet another language through which the heart can communicate with the rest of thebody. In essence, all of our cells sense the pressure waves generated by the heart and aredependent upon them in more than one way. At the most basic level, pressure waves force theblood cells through the capillaries to provide oxygen and nutrients to the cells. In addition, thesewaves expand the arteries, causing them to generate a relatively large electrical voltage. Thewaves also apply pressure to the cells in a rhythmic fashion, causing some of the proteinscontained therein to generate an electrical current in response to the squeeze.Experiments conducted in our laboratory have shown that a change in the brains electricalactivity can be seen when the blood pressure wave reaches the brain, around 240 millisecondsafter the contraction of the heart. An example is shown in Figure 7.Figure 7. Evoked potentials in the EEG due to effects of the blood pressure wave. The toptrace is the EEG recorded at the Cz location, and the middle trace is the blood pressure wave,INTEGRAL REVIEWDecember 2009Vol. 5, No. 2detected at the earlobe. Note that the blood pressure wave arrives at the brain around 240milliseconds after the heartbeat, and a positive shift in the evoked potential in the EEG can beclearly seen upon its arrival.We hypothesize that, in a similar manner to the encoding of information in the space betweennerve impulses and in the intervals between bursts of hormonal