The concept of decreasing human life spans after the Flood is considered by analogy to a quality factor that one observes in physical systems. It is found that the concept is not inconsistent with what we observe from the decreasing life spans of the Patriarchs listed in Genesis. (This article is a bit mathematically technical. It is really just speculation but I found very interesting. Edited from an article first published online here.)
In physics we define the quality factor (or Q-factor) of a system using the time it takes for it to dissipate 1/e of its energy. If we then look at human life spans in terms of a quality factor we would all have to agree that length of life or age at death defines a sort of a quality factor.
One researcher examined entropy of living systems and concluded that essentially we die because we come into thermal equilibrium with our environment at senile old age.1 This is where we can no longer generate enough heat to sustain life in the body and we die. So to live a long time means we have some sort of higher quality factor and it takes longer for the state to arrive where the cells in the body can no longer generate enough heat. This is of course what entropy is all about. Living things are complex systems and while functioning properly are highly complex low entropy systems.