Transmission of pain impulses depends on the intensity of the stimulus causing the pain. The greater the intensity of the stimulus, the more pain is tranimitted. However, some chemicals produced by the body inhibit transmission of painful impulses.
- Endorphins and Enkephalins. The term "endorphin" is a combination of two words: endogenous and morphine. It means "morphine within." Endorphins and as related enkephalins are peptides found in heavy concentrations in the central nervous system. They relieve pain by the same mechanisms as morphine and other narcotics. They are thought to inhibit pain by blocking pain impulse transmission within the brain and spinal cord. These substances explain why different people feel different amounts of pain from the same stimuli. Individual differences in endorphin levels, as well as situational factors, such as anxiety, influence pain transmission. People with more endorphins feel less pain, and vice versa. Certain techniques, such as mental imagery, may relieve pain by increasing endorphin and enkephalin levels.
- Reactions to Pain. A kick to the groin is painful to practically every male but individual responses to the pain may vary considerably. Reaction to pain has physiological manifestations that are fairly constant in people, such as high blood pressure, muscle tension, loss of appetite, vomiting, nausea, irritability, and restlessness. However, behavioral responses may vary widely between individuals. A person's physical condition, emotional state, diet and sleep patterns, and, most importantly, the way a person has been conditioned to respond to pain, will influence reactions.
- Pain Threshold. Pain threshold the point at which a noxious stimulus is perceived as pain. It is influenced by psychological and sociocultural factors, but primarily by physiological factors. It depends on the duration and intensity of pain that a person will accept before making an overt response. Pain thresholds may be high or low. People with neurotic disorders or a lack of interest in conditioning themselves to pain have a low pain threshold and will give in to the pain sooner. People who subject themselves to increasing amounts of pain stimulus are able to condition themselves to resist pain. They are able to withstand pain and push themselves to continue during painful experiences. Other factors affect pain thresholds, such as age, male or female, physical conditioning, emotional state, and attitude. Factors that may increase pain threshold include anxiety, fear, anger, depression, introversion, sympathy, and analgesics.
Pain may be divided into two types: acute and chronic. Acute pain is relatively short-lived. It normally follows trauma and is experienced by everyone at some stage of their Taekwondo training. Chronic pain is persistent pain, and may be disabling. It may hinder or even prevent further training.