Pain is an unpleasant part of life, and we try to avoid it as much as possible. It takes many forms, both physical and emotional, and is usually caused by trauma. As Remedial Massage Therapists, we focus on understanding the causes of pain so we can help the body heal itself by restoring balance and function. Pain is a very complex process. If you are experiencing pain (either from an injury or on a regular basis) and would like to understand it better, here is an overview of the different types of pain and how it is perceived in the body.
Nociceptive pain – when we injure ourselves
This is the most straightforward type of pain – the pain caused by physical damage (e.g. if you sprain your ankle) or potential damage to the body (when your toe hits the corner of the shower). It is felt when a stimulus (i.e. a trigger) is detected by pain receptors called “nociceptors” (“noci” means pain, “-ception” means perception of). These pain receptors are located almost everywhere in the body, from our muscles to our organs (but not in the brain!).
This type of pain is usually acute: it is often sudden, sharp and specific. It is perceived by the brain within 0.1 seconds and we expect it to resolve itself within a reasonable amount of time. Unpleasant as it may be, this type of pain is actually useful – our body is letting us know that it has sustained damage (or potential damage at least). As a result, acute pain protects us from further injury – we remove ourselves from a dangerous situation, and we instinctively protect the injured/painful area and give it a chance to heal.
Nociceptive pain includes:
Somatic pain: when the pain receptors in our muscles, bones or skin are triggered – this is the type of pain we think of by default. It is often stimulated or aggravated by movement, and it is usually localised and specific.
Radicular pain: a rather fancy term to describe a reasonably common occurrence when nerve roots are pinched as they exit the spine and become irritated as a result. This type of pain can radiate down your arm or your leg, and may cause numbness, weakness, tingling or pins and needles. If you have been diagnosed with bulging discs causing nerve root compression, this is your pain.
Visceral pain occurs when internal organs are injured or inflamed. This type of pain is usually described as an ache and can be difficult to pinpoint (think of kidney pain, which can feel like back pain).
Chronic pain – when pain doesn’t equal tissue damage
Strictly speaking, chronic pain is pain that continues beyond the expected healing time (usually beyond 3 months depending on the nature of the injury). It is often dull and diffuse, but can be quite severe. It is considered a health condition in itself and affects an estimated 1 in 5 Australians.
Chronic pain occurs when nerves or certain regions of the brain become over-sensitive because they have been over-stimulated for too long – they keep firing and signalling pain, even when the source of pain is no longer present. This type of pain progressively becomes less specific, but can still be quite severe and debilitating. (Note that this is different from having recurring episodes of lower back or shoulder pain for example, where there is every time a mechanical cause or trigger.) In the case of chronic lower back pain for example, nerves continue to send pain signals to the brain even after compression of nerve roots has been resolved. This “pain memory” leads to a pain sensitisation, where nerves send the wrong signals to the brain.
Chronic pain is often challenging to treat. It can create limitations in our daily activities, our ability to work and can cause changes in our brain chemistry, which can have a significant impact on mood and mental health. The common approach to addressing chronic pain includes exercise, education and manual therapy.
Neuropathic pain
Neuropathic, or nerve pain, is caused by injury or dysfunction of the nerves themselves. This type of pain is chronic and can be caused by trauma, surgery or disease. It is often experienced as burning, sudden pain and can be associated with tingling, numbness and pins & needles. It can cause something as minor as a gentle breeze to be experienced as painful. Phantom pain resulting from the amputation of a limb is another form of neuropathic pain. Difficult to diagnosed and to treat, it is usually managed through a combination of medication and non-medical strategies (stretching, exercise, meditation, manual therapy, etc.).
“All pain is in the brain”: the pain pathway
You may have heard the phrase “All pain is in the brain”. From a physiology point of view, this is absolutely correct, because pain is always felt in the brain, no matter where the cause of pain is located. It doesn’t mean however that your pain is not real!
Let’s look at how pain signals are transmitted in the body. We have already mentioned that pain signals are transmitted by pain receptors called nociceptors. These specialised nerve endings are present everywhere in the body, except in the brain itself. First of all, in response to tissue damage, the body releases chemicals (prostaglandins, kinins, histamine, serotonin and potassium ions) which activate local nociceptors – these are basically “letterboxes” waiting for pain messages to come in. Because these chemicals linger until they are eliminated from the system, pain can persist some time after the cause of pain is gone.
Nociceptors are not easily desensitised to pain, probably because our ability to feel pain is so important for survival. Once activated, nociceptors relay pain signals in the form of electrical impulses along peripheral nerves all the way to the spinal cord, where they are filtered and prioritised: severe pain messages are sent to the brain at high speed and strength, whereas less severe pain signals travel slower. Signals travel to the brain stem and the cerebrum, where the brain makes sense of them and responds accordingly by sending more blood to the injured area to promote healing, or by releasing pain-suppressing chemicals.
When pain messages travel through the brain, they pass through emotional and thinking regions. As a result, the way we experience pain is also significantly influenced by factors such as mood, fatigue, general health, genetics, gender, but also whether the pain was sudden or expected, as well as our past experience of pain. As a result, we are more likely to feel intense pain when we don’t understand its nature or cause. For this reason, education on the nature of the injury or condition and having a treatment plan in place are essential to treat pain effectively.
How can remedial massage help in the treatment of pain?
Massage releases tight, achy muscles that cause pain and discomfort (think of those tight neck and shoulder muscles that hold so much tension). Muscles that are elastic and loose are able to function better and create more power when needed (e.g. sprinting, jumping). Short and tight muscles are not able to function correctly, making movement less safe, and are more likely to develop trigger points, which in turn can cause pain to radiate down a leg, an arm or into the neck.
Massage can help correct posture and faulty body mechanics causing inflammation, a major factor in pain (e.g. arthritic pain).
Massage promotes blood and lymph flow, and hence tissue healing.
Massage releases chemicals such as serotonin, a natural analgesic produced by the body to suppress pain signals, helping the brain “rewire” itself.
By reducing stress (cortisol production) and improving deep sleep in particular, regular massage can decrease pain sensitivity and improve healing.
Where pain is caused by over-sensitive nerves in a specific area of the body, massage can help desensitise nerves and decrease pain.
In the case of radicular pain caused by nerve root compression (usually in the neck or lower back), the brain’s response to protect the affected area is to tighten the surrounding muscles, which can in turn increase pressure on a pinched nerve and cause more pain. Massage decreases muscle tension, letting the brain know it is safe to move again and decreasing inflammation in the affected area.