The fight-or-flight response and exercise are characterized by the increased sympathetic tone and decreased parasympathetic tone.The diving response is associated with increased parasympathetic and sympathetic tone.The cold pressor response is characterized by increased sympathetic activity to the hea and blood vessels.Emotional Fainting--Vasovagal Syncope: An interesting vasodilatory reaction occurs in people who experience intense emotional disturbances that cause fainting. In this case, the muscle vasodilator system becomes activated and, at the same time, the vagal cardioinhibitory center transmits strong signals to the hea to slow the hea rate markedly. The aerial pressure falls rapidly, which reduces blood flow to the brain and causes the person to lose consciousness. This overall effect is called vasovagal syncope. Emotional fainting begins with disturbing thoughts in the cerebral coex.Ref: Guyton; 13th edition; Chapter 18 Nervous Regulation of the Circulation and Rapid Control of Aerial Pressure