Arousal

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The act of arousing, or the state of being aroused.

Whatever has associated itself with the arousal and activity of our better nature.

The state of being prepared for action. The intensity of arousal ranges from deep sleep to extreme excitement. Heightening of arousal is brought about by stimulation of the sympathetic nervous system and an increase in secretion of the hormones adrenaline and noradrenaline. As the body becomes prepared for action, the electrical activity of the brain changes; sweating becomes more profuse; muscle tension, heart rate, and metabolic rate all increase; and some blood is diverted from the gut to the skeletal muscle. Exercise psychologists have established that there is an optimal state of arousal above and below which a person underperforms (see catastrophe theory). Excessive levels of arousal can be very uncomfortable and are better referred to as anxiety.

The state of general preparedness of the body for action. It varies along a continuum ranging from deep sleep to extreme excitement. The term arousal is sometimes used synonymously with alertness and interchangeably with anxiety, although the latter is more correctly confined to situations of high arousal accompanied by unpleasant sensations. Arousal involves the activation of various organs under the control of the autonomic nervous system, especially the reticular activating system. The degree of arousal is reflected by a number of physiological indicators including blood pressure, electroencephalograph brain wave patterns, galvanic skin reaction, heart rate, muscle tension, and respiration rate. Biochemical indicators include concentrations of adrenaline and noradrenaline in the blood. There is not a perfect correlation between these indicators. Different sports have different optimal arousal levels. The relationship between arousal and performance is often described by the inverted U-hypothesis. This hypothesis is based on the assumption that arousal is unidimensional, but there is evidence that there are two or more arousal systems in the brain. Some workers distinguish between psychological arousal (the readiness of an individual to respond to stimuli) and physiological arousal (as indicated by heart rate, sweating, etc.). See also catastrophe theory.

The noun has 4 meanings:

Meaning #1: the act of arousing
  Synonym: rousing

Meaning #2: a state of heightened physiological activity

Meaning #3: awakening from sleep

Meaning #4: mutual sexual stimulation prior to sexual intercourse
  Synonyms: foreplay, stimulation

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