Brief thoughts on exercise, adaptation and entropy.

According to the 2^nd law of thermodynamics, the entropy (or disorder) in a closed system continually increases. Even if you work hard to maintain order within a system, the total disorder within the universe itself is increased. In his book ‘a brief history of time’ Stephen Hawking explains that although the storing of information on a computer hard drive appears to be creating order, the heat released by the computers cooling fan still results in an increase in total entropy in the environment. A more practical example concerns my kid’s bedrooms which rapidly descend into the state of disorder. In my futile attempts to reverse this process I generate heat via use of the Hoover and washing machine, as well as contribute to disorder in my own ‘system ‘through the process of the physical work involved.

Entropy increases in living organisms (biological systems) as they progress through the lifespan. To function properly, organisms require a high degree of organisation, or low levels of entropy (death is therefore the default condition). To allow relatively brief periods of life to occur, organisms must therefore ‘fight’ entropy. It does this by extracting energy from foodstuffs and using this to build order within itself, whilst at the same time increasing entropy in the nutrients ingested and releasing heat energy into the environment. This can only happen for a while though – the process becomes less efficient over time, eventually order cannot be maintained, and death becomes inevitable.

Relating this to exercise training is interesting. Whenever we attempt to increase performance, we need to build protein structures within the muscle cells. The exact structures will depend on the type of training performed, but include contractile elements, mitochondria, enzyme structures and so on. Part of me wonders if this is one of the reasons why exercise appears able to delay the ageing process to some extent -does it simply maintain biological order (or delay entropy) for longer? In terms of practical applications though, little comes to mind apart from the obvious, and already well known, need to maintain a net positive energy balance if biological adaptation is the goal. Presumably, detraining represents an increase in entropy due to neglecting the work required to maintain a high degree of biological order?