Each person has the capacity to find their niche. We do it by interacting in different modes/intensities in order to form a more complete understanding of the world around us. The primary purpose of training is to develop capacity in each of these modes.
Imagine a person being inserted into a different country and having to find his way around. At first he would not know what to look out for, so he would have to look our for anything. This mode is called excitability. Without enough excitability, for example, it would be impossible to form new memories, fight infection, or make it up a steep hill. We normally use weight training to build up people excitability.
After a few minutes of scanning, certain things will stand out and become the subject of focus, which is the second type of physiology that can be trained. Maybe it will be the cars or a specific restaurant or peoples behavior. Understanding any subject requires alternating between excitablility and focus like a camera zooming in and out.
While the first two gears have to do with mapping the environment, the second two have to do with mapping memories. Doing a more intense repetitive task like running puts a person on autopilot in which the environment blurs and memories are now the subject of the zooming in and out. This is called endurance.
The fourth mode is by far the least intense. We just call it posture, but it would be best exemplified by a monk who is wide awake with no stimulation. This is the physiology most closely resembling sleep, and good sleep would be impossible without a degree of strength in the posture mode.
As mentioned above, each gear has a specific intensity range just like there is a range of how far the pedal is pushed in a gas car. When you are excited or focusing, you are actively shoving fuel into the engine in order to perform. At some point the engine or cells will become congested. If you are in the endurance or posture zone, the working of the engine draws the fuel in and allows for the congestion to be cleared out. If you were to go on a relaxing walk, the heart rate will go up not because you are that excited, but because your muscles are actually using extra fuel, and after some lag, the fuel will be drawn in.
A garbage disposal in the kitchen sink analogy could be used interchangeably with a car engine or cell. During excitability and focus food is shoved into the garbage disposal and eventually will become backed up. That is why after a period of excitabily, you have to spend some time not shoving more food in order to let the garbage disposal catch up or process all the food/information that had become backlogged.
The art of training is the same as using a garbage disposer. If you have periods of leaning new things followed by time to digest and apply them, you will have the best life and be healthy and fit and perform the best. Some people are overwhelmed because the are very capable of absorbing new things but aren’t good at processing. Others are bored because they are not capable of absorbing new things. You can learn in a short period of time to understand where you are being bottlenecked and correct it with your training schedule.
Most people incorrectly believe that disease development is a radom process with no purpose. In reality when a person is overwhelmed, their cells are overwhelmed which is the same thing as it being chemically impossible for their cells to process all the fuel. At that point, the body either rejects the sugar (diabetes), diverts it to fat cells, reduces the capacity of the fuel line (arteriosclerosis), decreases the capacity of the lungs (misnamed COPD), doesn’t let the food in in the first place (indigestion), skips a beat of the heart, stops breathing (apnea), etc. The end result of all of these necessary processes, which are features and not flaws in our genetic code, is a diminished capacity which we call deconditioning.