Unpleasant Sensation

Pain is an unpleasant sensation. People generally associate pain with physical injuries or illnesses. But feelings and emotions can also produce pain. For example, an noyance can produce painful tension in the neck muscles. Pain is highly personal sensation. An injury that causes severe pain is one person might produce only moderate pain in another. Physicians find it difficult to measure pain and must rely largely on the patient's description of the sensation. Headache pain, for instance, provides little measurable evidence, yet headache sufferers often report extremely severe pain.

Nerves carry pain signal to the brain in the form of electric impulses. The brain responds to these signals in different ways, depending on the situation. In some cases, the brain does not react immediately to the signals. For example, an athlete injured during a game may not notice any pain until the contest is over. In such cases, the brain ignores the pain signals because it is concentrating on other tasks.

Severe pain can serve as a useful warning that something is physically wrong with the body. In most such cases, the pain disappears after the fault is corrected. Physicians refer to such short-lived, severe pain as a acute pain. It differs from chronic pain, which last a longtime. Some chronic pain results from disorders that cannot be completely cured, such as certain types of cancer and arthitis. But in other cases, pain persists even though its physical cause has been corrected. This type of chronic pain resists treatment and can lead to mental breakdowns and drug abuse. Some persons undergo many unsuccessful surgical operations in effort to control such incurable pain.

People instinctively recoil from pain and often react to it with fear and tension, which in themselves may increase the discomfort. Yet the mind and body have an innate capacity for mastering the perception of pain to some degree. Soldiers at the battle front with terrible wounds have often reported far lesser degrees of pain and required fewer analgesics than civilians with comparable injuries.

It is also possible to summon up the body's pain-regulating mechanism through training and effort. Religious ascetics purposely inflict injury on themselves to pursue a spiritual goal, yet they experience no pain when they practice such extreme forms of self-mortification as walking through fire. Women trained in psychoprophylaxis, a relaxation technique for natural childbirth, can endure labor pains with little or no medication.

In such instances, the brain has probably mobilized the body's endorphins-morphine-like substances in the nervous system and gut that suppress pain. One experiment showed that when people believe pain will be lessened, it is. A group of patients who were told they had received a painkiller but were in fact given a placebo- a pill without analgesic effect- actually increased the levels of endorphins in their systems and experienced a decline in discomfort.