Theoretical Molecular Models of Frailty

Given the evidence for multisystem decline, and the high likelihood that the development of frailty is a nonlinear process, some authors have used nonlinear dynamics and chaos theory in order to provide new insights into how investigators might detect and quantify changes at the physiological and molecular level. Lipsitz et al. (1992) have hypothesized that the decline in complexity of response to stimuli observed in aging and perhaps in frailty in part may be due to loss of complexity in fractal patterns. Fractals are geometric subunits that resemble larger scale units. Many anatomical structures and physiologic processes such as alveoli, neural networks, and bony trabeculae have such repeating subunits and therefore fractal properties. These investigators have theorized that aging and frailty can both, in part, be characterized by a progressive loss of complexity in the fractal architecture of anatomic structures and dynamics of physiologic processes. This loss of structural and functional complexity may impair an organism's ability to communicate within and between systems and to adapt to stress. In addition, most physiologic systems have an ability to undergo reactive tuning, which enables normalization after periods of physiologic stress. It was hypothesized that this retuning may not be possible with loss of complexity, and this may result in the vulnerability to further decline and poor outcomes seen in frailty. In this hypothesized model, frailty is a continuous, nonlinear process, characterized by a progressive loss of physiologic reserve where those individuals who reach a threshold in the continuum can no longer compensate for a given stress, and enter into a spiral of clinical and functional decline.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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