Sci. Aging Knowl. Environ., 21 April 2004
Vol. 2004, Issue 16, p. pe16
[DOI: 10.1126/sageke.2004.16.pe16]


Physiological Complexity, Aging, and the Path to Frailty

Lewis A. Lipsitz

Lewis A. Lipsitz is at the Hebrew Rehabilitation Center for Aged, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA 12131, USA. E-mail: Lipsitz{at}

Key Words: complexity • variability • fractal • power law • heart rate • frailty

Abstract: Healthy physiological processes require the complex interaction of multiple control systems operating over multiple time scales. The output of these processes (for example, heart rate, blood pressure, hormonal rhythms, or postural sway) demonstrates complex variability that can be quantified using the concept of fractals, derived from the field of nonlinear dynamics. Complex physiological dynamics enable an organism to rapidly respond to the internal and external perturbations of everyday life. Aging and disease are associated with a loss of complexity in the dynamics of many physiological systems. This loss of complexity may reduce the ability to adapt to stress and lead to the syndrome of frailty.

Citation: L. A. Lipsitz, Physiological Complexity, Aging, and the Path to Frailty. Sci. Aging Knowl. Environ. 2004 (16), pe16 (2004).

Read the Full Text

Dynamical Indicators of Resilience from Physiological Time Series in Geriatric Inpatients: Lessons Learned.
J. L. Rector, S. M. W. Gijzel, I. A. van de Leemput, F. B. van Meulen, M. G. M. Olde Rikkert, and R. J. F. Melis (2020)
   Abstract »    Full Text »    PDF »
Age-dependent changes in GI physiology and microbiota: time to reconsider?.
R. An, E. Wilms, A. A. M. Masclee, H. Smidt, E. G. Zoetendal, and D. Jonkers (2018)
Gut 67, 2213-2222
   Abstract »    Full Text »    PDF »
Brain Dynamics of Aging: Multiscale Variability of EEG Signals at Rest and during an Auditory Oddball Task.
R. Sleimen-Malkoun, D. Perdikis, V. Müller, J.-L. Blanc, R. Huys, J.-J. Temprado, and V. K. Jirsa (2015)
eNeuro 2, ENEURO.0067-14.2015
   Abstract »    Full Text »    PDF »
Challenging Gait Conditions Predict 1-Year Decline in Gait Speed in Older Adults With Apparently Normal Gait.
J. S. Brach, S. Perera, J. M. VanSwearingen, E. S. Hile, D. M. Wert, and S. A. Studenski (2011)
Physical Therapy 91, 1857-1864
   Abstract »    Full Text »    PDF »

Science of Aging Knowledge Environment. ISSN 1539-6150