concluding that "adding reflexology to standard analgesic care is effective in reducing postoperative pain at rest and in motion, especially for patients experiencing moderate to severe pain".
Analgesic Effects of Refleoxlogy in Patients Undergoing Surgical Procedures: A Randomized Controlled Trial
J Altern Complement Med. 2018 Aug;24(8):809-815. doi: 10.1089/acm.2017.0167. Epub 2018 Jun 8.
"Pain, which is caused by an unpleasant (noxious) stimulus, is a stressor that can threaten homoeostasis. The body’s adaptive response to pain involves physiological changes, which are useful and potentially life-saving in the initial stages. If the adaptive response persists, harmful and life-threatening effects may ensue. Pain is noxious, which makes it a powerful protective force: indeed the inability to feel pain is associated with a shortened life expectancy (Shin et al, 2016). After injury, pain encourages us to adopt behaviours that help the healing process; for example, resting the painful part of the body...
..Pain inhibition can be stimulated or enhanced by endogenous or synthetic opioids. Endogenous opiods can be stimulated by acupuncture, exercise and transcutaneous electrical nerve stimulation (TENS) (Claydon et al, 2011), and by touch therapies such as Reflexology through which sensory input competes with pain signals, which reduces the onward signalling of pain by the brain
Pain inhibition can also be stimulated by hypnosis (deep relaxation), which has been used with good effect in acute and long-term pain... (Brugnoli, 2016, Uman et al, 2013)..."
Understanding the effect of pain and how the human body responds
Evaluation of the Effect of Reflexology on Pain Controñ and Analgesic Consumption after Appendoctomy
.J Altern Complement Med. 2015 Dec;21(12):774-80. doi: 10.1089/acm.2014.0270. Epub 2015 Sep 24