As an individual, What parts of our body do we depend on for performance?
There are certain lifestyle choices that affect our physical performance. These can include:
These can also affect our mental performance. Why?
The brain is dependent on healthy, well oxygenated blood. Anything that affects the quality of your blood will affect your brain.
As far as Pilot Performance is concerned, all Skills are affected when mental performance is reduced. However, Situational Awareness and Decision Making are cognitive skills and are very dependent on physiological and psychological conditions.