Pain can be described using a variety of terms and concepts. Pain is a noxious stimulus resulting from an actual or potential tissue damaging event that stimulates nociceptors. Nociceptors are receptors sensitive to a noxious stimulus or to a stimulus which would become noxious if prolonged (Seaman 1997). The experience of pain begins with the pain threshold, which is the smallest pain producing stimulus a person can perceive as painful, and pain tolerance, which is the maximum intensity of a stimulus that evokes pain and that a subject is willing to tolerate. An individual can modify pain tolerance and to a lesser extent pain threshold based on their perception of the pain sensation. There are also physiological mechanisms that can occur that modify pain threshold and pain tolerance. The pain experience can be altered by using changes in perception and activating physiological pain control mechanisms. These methods will be described in future chapters.

Some individuals experience pain due to hyperalgesia and/or sensitization. Hyperalgesia is an increased response to a stimulus which is normally painful. In other words the body overreacts to a pain producing stimulus. Hyperalgesia may include a decrease in both pain threshold and pain tolerance. Sensitization, a neurophysiological process resulting, is an increased responsiveness of neurons to their normal input or recruitment of a response to normally subthreshold inputs. In other words the body is interpreting nonpainful stimuli as pain. Like hyperalgesia, sensitization includes a drop in pain threshold and an increased sensitivity of neuroresponse. The nervous system may generate pain signals without any stimulus and increase the receptive field size. Pain tolerance is usually affected as well. Peripheral sensitization is an increased responsiveness and reduced threshold of nociceptors to stimulation of their receptive fields. Central sensitization is an increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input, which may be due to dysfunction of the endogenous pain control system.

Figure 3.1 Biochemical, biomechanical, and psychosocial influences on health.

(Adapted from Chaitow & DeLany 2000.)

In simple terms hyperalgesia is like the saying making mountains out of mole hills, and sensitization is making something out of nothing. Knowing this terminology is all well and good in our task of understanding pain and being able to communicate with multidisciplinary heath care professions. However, these terms and descriptions do not describe what it is like to be in pain and to live the pain experience. Massage therapists must appreciate the mechanisms causing, enhancing, and creating the pain experience to competently use massage to help those experiencing pain. It hurts to be in pain whether that pain is acute or chronic, physical, emotional or spiritual, helpful or harmful. There are differences between harm and hurt. Pain hurts whether there is harm or not. Hurting is disempowering, fatiguing, miserable, and the foundation of suffering (Box 3.1).

Box 3.1 A pain experience

Even though every individual’s experience of pain is unique to them there is a level of shared understanding. Following is author Sandy Fritz’s pain experience story.

I have had babies and experienced the productive process of labor except with my third child. He was stuck full-face presentation. The labor pain was not productive, I could not push him out, and I was afraid. It was the only time I recall begging for help. I finally did push him out resulting in structural damage to my pelvis that continues to produce a level of chronic pain over 20 years later but my youngest son is a constant reminder to me that in the whole scheme of life, an aching and stiff sacral iliac joint is not horrible even if it is aggravating.

At age 54 I had open heart surgery (coronary artery triple bypass) – a big surprise, sort of. The post surgery experience was very painful. I am forever grateful for morphine and Demerol. Recovery was acutely painful. When the chest cavity and ribs have been injured everything is painful but currently there is not another way to correct the blockage I had. I could be dead instead. If pain exists you are alive and I feel blessed to have been sawed open, replumbed, and sewn and wired closed. Currently my chest and mid back will ache and I get stiff. There are a couple of spots that remain painful but every time I stretch to relieve the sensations I am thankful I am alive.

When I was 55 my eldest child was tragically killed when hit by a car. I cannot imagine an experience more horrible than the gut wrenching experience of pain. I felt as if I stood by his side as he died. Not only do I continue to experience physical, emotional, and spiritual pain but I also suffer. His first and only child was born four months later. I was the labor coach for my daughter-in-law and she commented that the real honest productive pain of giving birth actually felt right and good in contrast to her pain and suffering of a broken heart. My granddaughter heals us all and yes, when I carry her around it makes my back and chest stiff and painful, but she alleviates my suffering and supports my hope and joy. I am a massage therapist and have been for many, many years. I know that when I massage someone in pain that hurts I help them for a while. I am much more tolerant, understanding, and compassionate of others because of my own pain experiences.

Figure 3.2 Massage for medical purposes.

(Photograph courtesy Laura Cochran.)

Massage can help reduce pain and suffering for a short period but the complex process of suffering requires multilevel intervention. The connection between physical and mental pain has been studied extensively by Matthew Lieberman, Naomi Eisenberger, and associates at the Social, Cognitive Neuroscience Lab at UCLA, Department of Psychology. Their research has shown that the pain and suffering that occurs when social relationships are damaged or lost and the pain experienced from physical injury share parts of the same underlying physiological processing system (Eisenberger & Lieberman 2004). Since physical and social pain rely on similar neural systems, factors that increase tolerance of the experience of social pain, such as social support, should also increase the tolerance to physical pain.

Grieving over the death of a loved one and being treated unfairly also activate these regions. Grief is one of life’s most painful experiences (Eisenberger & Lieberman 2005). In 1998, researchers suggested that the social attachment system uses opiate substrates of the physical pain system. This overlap in function results in pleasure when with those we care about and elicits distress when we are separated from the social attachment system. This pleasure/pain experience of connectiveness and separation piggyback onto the pre-existing pain system, borrowing the pain signal to signify and prevent the danger of social separation (Nelson & Panksepp 1998, Panksepp 1998). Ongoing studies by Lieberman and Eisenberger (Eisenberger, Lieberman & Williams 2003, Eisenberger et al 2004, 2006, 2007, Eisenberger & Lieberman 2005, Lieberman & Eisenberger 2005) continue to support that pain distress and social distress share neurocognitive function and increased social distress will increase sensitivity to physical pain and vice versa. Understanding this overlap in the neural systems underlying pain distress and social distress supports alternative ways to treat and manage chronic pain conditions. For example, rather than treating pain symptoms directly, it may be possible to reduce physical pain symptoms by addressing the social stressors that may go along with them.

Massage therapists need to realize the importance of multidisciplinary care in the treatment of pain and appreciate the importance of nurturance and compassion as aspects of the massage application.

This relationship may also help to explain why massage and the therapeutic relationship are effective in pain management systems.

Pain is the individual or subjective experience to a stimulus, not only the perception of the noxious stimulus but also the interpretation of that sensation as an unpleasant one. Without this psychological component, the noxious stimulus would not constitute a painful stimulus, and the individual could not be said to be in pain (Seaman 1997).

To appreciate how the experiences of pain occurs it is necessary to understand the neuroanatomy.

The pain network consists of the dorsal anterior cingulate cortex, insula, somatosensory cortex, thalamus, and periaqueductal gray area. The somatosensory cortex is associated with sensory aspects of cutaneous physical pain (e.g. its location on the body); the dorsal anterior cingulate cortex is associated with the distressing aspect of pain (suffering).

The reward or pleasure network consists of the ventral tegmental, ventral striatum, ventromedial prefrontal cortex, and the amygdala. The brain’s reward circuitry consists of neural structures receiving the neurotransmitter dopamine. Major dopaminergic targets in the brain have been implicated in reward/pleasure processes (Lieberman & Eisenberger 2009).

According to pain experts Melzack and Wall (McMahon & Koltzenburg 2010), pain has three dimensions:

In other words, the pain experience results in the perception of tissue damage and the interpretation of the unpleasantness, and the aversive nature of the experience motivates responses to avoid further injury or promote healing (voluntarily or involuntarily). All pain experiences are a normal response to what your brain perceives as a threat. And the amount of pain you experience does not necessarily relate to the amount of damage to tissue.

If massage therapy is going to be beneficial in pain management it must interact with the pain/pleasure anatomy and physiology. One of the greatest benefits of massage is that it feels good. Massage is pleasurable. The pain/pleasure system is like so many processes in the body. One dominates the other and then vice versa. When the agonist muscle is activated the antagonist muscle is inhibited. When the pain network dominates it is difficult to feel pleasure and also if the pleasure network is activated it is hard to experience pain (Fig. 3.3).

Figure 3.3 Gate-control theory of pain (based on Melzack and Wall’s gate-control theory of pain).

(From Fritz 2004.)