Is the normal heartbeat chaotic or homeostatic? Author: A L Goldberger1 Affiliation: <sup>1</sup> Harvard Medical School, Boston, MA 02215. <sup>2</sup> Harvard Med Sch, Boston, Cardiovascular Div Conference/Journal: News Physiol Sci Date published: 1991 Apr 1 Other: Volume ID: 6 , Pages: 87-91 , Special Notes: doi: 10.1152/physiologyonline.1991.6.2.87. , Word Count: 54 Limits to the usefulness of homeostasis as a guiding physiological principle are revealed by new mechanisms derived from study of nonlinear systems that generate a type of variability called chaos. Loss of complex physiological variability may occur in certain pathological conditions including heart rate dynamics before sudden death and with aging. PMID: 11537649 DOI: 10.1152/physiologyonline.1991.6.2.87