When you play some kind of Role Playing Game (RPG) you always try to avoid all depletion your character's Hit Point (HP). Full depletion of HP means game over or die (in some RPG titles). There so many things that alter your character's current HP such as being hit by some kind of monster, step into some kind of trap, drinking some kind of potion, eating some kind of in-game food, etc.
All of those things actually not so far different with real life, including very concept about HP. In real life however, the term that actually have similarity (very likely) with HP is free energy that is utilized in the body.
Let we look into this term
with F is free energy, E is total energy, and S is entropy.
In our everyday life, our body had some mechanism that ruled by hypothalamus (the thermostat) to maintain our body temperature constant at 37 centigrade. By using that such fact and extra assumption that the total energy is kept constant, free energy could be expressed as just function of entropy (to make it simple).
Based on our RPG HP analogy the free energy term could be written as
To maximize current HP, what can we do is minimize depleted HP. Not so far different with HP what can we do to maximize free energy is to minimize the entropy.
The second law of thermodynamics states that the total entropy can never decrease over time for an isolated system.
Do you realize that our body did not form a good relationship with your surrounding because attempting to keep away from equilibrium? The equilibrium condition of our body with the surrounding is disintegrating (dead; vanish). Based on that fact, our RPG HP analogy become more relevant with real life free energy.
To maintain "life" we must maintain low entropy. Low entropy means highly ordered, high entropy means high disorder. The second law of thermodynamics may raise a question about how life maintain such low entropy (to keep alive). Basically, our body is not categorized as an isolated system even closed system, because there were mass and energy exchange with our surrounding. So it's even possible the reduce the "disorder" and maintain it at low level. What actually happened is there was exchange of entropy by our body with the surrounding, so actually the total entropy of the universe (total system) is increased (which is still obeying second law of thermodynamics). The sun is supplying energy to the earth and all of the living creatures. At the same time, the sun acting as entropy machine, raising the global entropy. Our body do that too, did act as entropy generator, consuming order to generate much disorder.
The RPG HP analogy must be revised as such when we doing something, the HP will decrease (it is uncommon to RPG having this mechanism) even at rest (basal metabolism; it is more uncommon to RPG having this). We need to maintain enough level of HP (free energy) to keep our body ordered (alive; by eating for example). Although when we consume some food there is a chance to get poisoned or whatsoever (which bad for our body), that of course will lower our HP. Our body order is increased by the conversion of what we eat to energy that can be used by our body.
EOF.
Stay alive, don't let our HP fully depleted.
Yep another bad conclusion. No problem. This is not even a conclusion.
Sauce: