| The conventional wisdom in medicine holds that disease and aging arise
from stress on an otherwise orderly and machinelike system
— that the stress decreases order by provoking erratic responses or by
upsetting the body's normal periodic rhythms.
In the past five years or so we and our colleagues have discovered that
the heart and other physiological systems may behave most erratically when
they are young and healthy. Counterintuitively, increasingly regular behavior
sometimes accompanies aging and disease. |
Irregularity and unpredictability, then, are important features of
health. On the other hand, decreased variability and accentuated periodicities
are associated with disease. Motivated by these ideas, we and other physiologists
have looked for periodic behavior that might indicate developing sickness
(especially diseases of the heart). In addition, we have begun to analyze
the flexibility and strength of irregular fractal structures and the adaptability
and robustness of systems that exhibit apparently chaotic
behavior. |