Definition of Pain

Pain is more than a sensory experience

Pain is a sensation familiar to all of us, but what lies really behind this alarmed feeling? Pain is defined, as “an unpleasant sensory and emotional experience associated with acute or potential tissue damage or described in terms of such damage”.1

Pain is not only a purely sensory experience, it also impacts emotionally. Inadequately treated pain can have severe consequences on the mental and physical health of the persons concerned as well as their families.

Origin of Pain:

Any mechanical, thermal, chemical or electrical stimulus can induce pain if it exceeds a certain level or if there is cellular or tissue damage. Pain stimulates the sympathetic nervous system2.

The consequences are:

  • Increased blood pressure caused by constriction of the vessels
  • Increased heart rate caused by increased stimulation of the sympathetic nervous system (next to the parasympathetic nervous system part of the autonomic nervous system that regulates the cardiac activity, the bloodstream and the inhibition of digestive processes)
  •  Nutritional disorders caused by inhibition of the digestive processes
  • Hyperventilation with increasing blood pH-value and resulting muscular spasms and/or unconsciousness
  • Immune system is also affected and the defense mechanism is weakened if pain last over a longer period.

The intensity of pain is considerably determined by environmental, cultural and social influences. Depending on mood, experience and expectation the pain threshold may also vary considerably in individual cases.

1 IASP. International Association for the Study of Pain | IASP Taxonomy, 2011. (Accessed May 2, 2011, at…isplay.cfm&ContentID=1728).

2 Schlereth T, Birklein F. The Sympathetic Nervous System and Pain. Neuromol Med 2008;10:141–7.