Introverts have higher levels of activity in the cortico-reticular loop of the brain, so are chronically more critically aroused than are extroverts. If so, crowds and noise would very quickly create a sensory overload for such an individual.

Book: LIVE RIGHT 4 YOUR TYPE - Dr. Peter J.D'Adamo

Sympathetic Nervous System: Responsible for our Fight or Flight Response.

Parasympathetic: Responsible for relaxing the nervous system after whatever set off the alarms indicating danger has passed.

The proper functioning of both is a critical component to our health. (Luckily, we all have them)

Together, the two branches of the nervous system communicate with your endocrine system and internal organs to help you maintain proper function and respond to a wide range of potential challenges.

They are antagonists. They tend to work best in balanced opposition to one another.

Sympathetic: Causes your heart to beat faster and more forcefully.

Parasympathetic: Slows down your heart rate and unclenches the arterial muscle walls, allowing free blood flow and oxygenation of the heart muscle.

Problems occur when one of the two parts of this system has a continued dominance over the other for prolonged periods of time.

Remember to take breaks when you're involved in work that takes a lot of focus and concentration. You can be more productive if you don't work to the point of exhaustion - rather "bracket" your mental activities with other activities.

Switch between mental and physical projects every day. The effect is rehabilitating. It allows me to distance myself from each activity, affording greater objectivity and creativity. This strategy also reduces my tendency to neurose over details to the point where a project is ruined.

Winston Churchill can rest parts of his mind by simply using other parts of his mind. In the midst of World War II, he always had time for his watercolours.