Health management system
The health management system (HMS) is an evolutionary medicine regulative process proposed by Nicholas Humphrey in which actuarial assessment of fitness and economic-type cost-benefit analysis determines the body’s regulation of its physiology and health. This incorporation of cost-benefit calculations into body regulation provides a science grounded approach to mind-body phenomena such as placebos that are otherwise not explainable by low level, noneconomic, and purely feedback based homeostatic or allostatic theories.
- Many medical symptoms such as inflammation, fever, pain, sickness behavior, or morning sickness have an evolutionary medicine function of enabling the body to protect, heal or restore itself from injury, infection or other physiological disruption.
- The deployment of self-treatments have costs as well as benefits with the result that evolution has selected management processes in the brain such that self-treatments are used only when they provide an overall cost benefit advantage. The brain controls such physiological process through top down regulation.
- External treatment and the availability of support is factored into the health management system’s cost benefit assessment as to whether to deploy or not an evolved self-treatment.
Placebos are explained as the result of false information about the availability of external treatment and support that mislead the health management system into not deploying evolved self-treatments. This results in the placebo suppression of medical symptoms.
Since Hippocrates, it has been recognized that the body has self-healing powers (vis medicatrix naturae). Modern evolutionary medicine identifies them with physiologically based self-treatments that provide the body with prophylactic, healing, or restorative capabilities against injuries, infections and physiological disruption. Examples include:
- Immune responses
- Sickness behavior
- Morning sickness
These evolved self-treatments deployed by the body are experienced by humans as unpleasant and unwanted illness symptoms.
Such self-treatments according to evolutionary medicine are deployed to increase an individual’s biological fitness.
Two factors affect their deployment.
First, it is usually advantageous to deploy them on a precautionary basis. As a result, it will often turn out that they have been deployed apparently unnecessarily, though this has in fact been advantageous since in probabilistic terms they have provided an insurance against a potentially costly outcome. As Nesse notes: "Vomiting, for example, may cost only a few hundred calories and a few minutes, whereas not vomiting may result in a 5% chance of death" page 77.
Second, self-treatments are costly both in using energy, and also in their risk of damaging the body.
- Immunity – energy for activating lymphocyte and antibody production, and in the risk of an immune response resulting in an immune related disorder.
- Fever – energy (each 1 °C raise in blood temperature increases energy expenditure by 10–15%. 90% of the total cost of fighting pneumonia goes on increased body temperature. There is also the risk of hyperpyrexia.
- Sickness behavior – restricted ability by an animal to forage and defend itself
- Nausea – loss of food nutrients, and potential risk of aspiration
- Morning sickness – loss of food nutrients when a mother needs additional, not less, nourishment
- Hypoferremia – impairment in biological processes needing iron resulting in iron deficiency anemia
- Depression – impaired activity and problem solving.
- Pain – restricted movement and the inability to concentrate
Another is higher level control in which the brain takes into account what it learns about circumstances and how that makes it well and ill. Conditioning shows the existence of such learnt control: give saccharin paired in a drink with a drug that creates immunosuppression, and later on, giving saccharin alone will produce immunosuppression. Such conditioning happens both in experimental rodents and humans.
Cost benefit analysis
Economic resource management
Evolution, according to Nicholas Humphrey, has selected an internal health management system that uses cost benefit analysis upon whether the deployment of a self-treatment aids biological fitness, and so should be activated.
a specially designed procedure for “economic resource management” that is, I believe, one of the key features of the “natural health-care service” which has evolved in ourselves and other animals to help us deal throughout our lives with repeated bouts of sickness, injury, and other threats to our well-being.
An analogy is explicitly made with the health economics consideration used in management decisions involving external medical treatment.
Now, if you wonder about this choice of managerial terminology for talking about biological healing systems, I should say that it is quite deliberate (and so is the pun on NHS.) With the phrase “natural health-care service” I do intend to evoke, at a biological level, all the economic connotations that are so much a part of modern health-care in society.
External medications will affect the cost benefits advantages of deploying an evolved self-treatment. Some animals use external ones. Wild animals, including apes, do so in the form of ingested detoxifying clays, rough leaves that clear gut parasites, and pharmacologically active plants Complimentary to this, research finds that animals have the ability to select and prefer substances that aid their recuperation from illness.
The welfare of social animals (including humans) depends upon other individuals (social buffering). The actuarial assessments of the costs and benefits of deploying a self-treatment therefore will depend upon the presence, or not, of other individuals. The presence of helpful others will affect, for example, the risk of predators when incapacitated, and—in those case in which animals do this (such as humans)—the provision of food, and care during sickness.
The health management system factors in the presence of such external treatment and social support as one aspect of the circumstances needed to determine whether it is advantageous to deploy or not an evolved self-treatment.
All humans societies use external medications, and some individuals exist that are considered to have special healing knowledge about illnesses and their treatments. Humans are also usually supportive to those in their group. The availability of these things will affect the cost benefits of the body deploying its own biological ones. This could, in turn, lead to the health management system (given its beliefs (information) about treatments and support) to deploy or not, or doing so differently, the body’s own treatments.
Nicholas Humphrey describes how the health management system explains placebos – an external treatment without direct physiological effects – as follows:
Suppose, for example, a doctor gives someone who is suffering an infection a pill that she rightly believes to contain an antibiotic: because her hopes will be raised she will no doubt make appropriate adjustments to her health-management strategy – lowering her precautionary defences in anticipation of the sickness not lasting long.
The health management system, in other words, when faced with an infection is tricked into making a mistaken cost benefit analysis using false information. The effect of that false information is that the benefits of the self-treatment cease to outweigh its costs. As a result, it is not deployed, and an individual does not experience unwanted medical symptoms.
Lack of harm
Failure to deploy an evolved self-treatment need not put an individual at risk since evolution has advantaged their deployment on a precautionary basis. As Nicholas Humphrey notes:
many of the health-care measures we’ve been discussing are precautionary measures designed to protect from dangers that lie ahead in an uncertain future. Pain is a way of making sure you give your body rest just in case you need it. Rationing the use of the immune system is a way of making sure you have the resources to cope with renewed attacks just in case they happen. Your healing systems are basically tending to be cautious, and sometimes over-cautious, as if working on the principle of better safe than sorry.
Therefore, not deploying an evolved self-treatment, and so not having a medical symptom due to placebo false information might be without consequence.
The health management system’s idea of a top down neural control of the body is also found in the idea that a central governor regulates muscle fatigue to protect the body from the harmful effects (such as anoxia and hyperglycemia) of over prolonged exercise.
Like with the health management system, the central governor shares the idea that much of what is attributed to low level feedback homeostatic regulation is, in fact, due to top down control by the brain. The advantage of this top down management is that the brain can enhance such regulation by allowing it to be modified by information. For example in endurance running, a cost benefit trade exists off between the advantages of continuing to run, and the risk if this is too prolonged that it might harm the body. Being able to regulate fatigue in terms of information about the benefits and costs of continued exercise would enhance biological fitness.
Low level theories exist that suggest that fatigue is due mechanical failure of the exercising muscles ("peripheral fatigue"). However, such low level theories do not explain why running muscle fatigue is affected by information relevant to cost benefit trade offs. For example, marathon runners can carry on running longer if told they are near the finishing line, than far away. The existence of a central governor can explain this effect.
- Central governor
- Deployment cost-benefit selection in physiology
- Evolutionary medicine
- Health science
- Management control system
- Neural top down control of physiology
- Placebo Effect
- Psychogenic disease
- Psychosomatic medicine
- Humphrey, Nicholas (2002). "19. Great Expectations: The Evolutionary Psychology of Faith-Healing and the Placebo Effect" (PDF). The Mind Made Flesh: Essays from the Frontiers of Psychology and Evolution. Oxford [Oxfordshire]: Oxford University Press. pp. 255–85. ISBN 0-19-280227-5. reprinted from Hofsten, Claes von (2002). Psychology at the Turn of the Millennium: Social, Developmental and Clinical Perspectives 2. East Sussex: Psychology Press. pp. 225–46. ISBN 1-84169-199-2.
- Humphrey, Nicholas (2004). "The Placebo Effect". In Gregory, Richard Langton. The Oxford companion to the mind (2nd ed.). Oxford [Oxfordshire]: Oxford University Press. ISBN 0-19-866224-6.
- Nesse RM (May 2001). "The smoke detector principle. Natural selection and the regulation of defensive responses". Ann. N. Y. Acad. Sci. 935: 75–85. doi:10.1111/j.1749-6632.2001.tb03472.x. PMID 11411177.
- Lochmiller R, Deerenberg C (2000). "Trade-offs in evolutionary immunology: just what is the cost of immunity?". Oikos 88: 87–98. doi:10.1034/j.1600-0706.2000.880110.x.
- Romanyukha AA, Rudnev SG, Sidorov IA (July 2006). "Energy cost of infection burden: an approach to understanding the dynamics of host-pathogen interactions". J. Theor. Biol. 241 (1): 1–13. doi:10.1016/j.jtbi.2005.11.004. PMID 16378624.
- Rodriguez DJ, Sandoval W, Clevenger FW (October 1995). "Is measured energy expenditure correlated to injury severity score in major trauma patients?". J. Surg. Res. 59 (4): 455–9. doi:10.1006/jsre.1995.1191. PMID 7564317.
- Roe CF, Kinney JM (January 1965). "The Caloric Equivalent of Fever II. Influence of Major Trauma". Ann. Surg. 161 (1): 140–7. doi:10.1097/00000658-196501000-00022. PMC 1408758. PMID 14252624.
- Ader R, Cohen N (1975). "Behaviorally conditioned immunosuppression". Psychosom Med 37 (4): 333–40. doi:10.1097/00006842-197507000-00007. PMID 1162023.
- Alvarez-Borda B, Ramírez-Amaya V, Pérez-Montfort R, Bermúdez-Rattoni F (September 1995). "Enhancement of antibody production by a learning paradigm". Neurobiol Learn Mem 64 (2): 103–5. doi:10.1006/nlme.1995.1048. PMID 7582817.
- Oberbeck R, Kromm A, Exton MS, Schade U, Schedlowski M (February 2003). "Pavlovian conditioning of endotoxin-tolerance in rats". Brain Behav. Immun. 17 (1): 20–7. doi:10.1016/S0889-1591(02)00031-4. PMID 12615046.
- Pacheco-López G, Niemi MB, Kou W et al. (2004). "Behavioural endocrine immune-conditioned response is induced by taste and superantigen pairing". Neuroscience 129 (3): 555–62. doi:10.1016/j.neuroscience.2004.08.033. PMID 15541877.
- von Hörsten S, Exton MS, Schult M et al. (May 1998). "Behaviorally conditioned effects of Cyclosporine A on the immune system of rats: specific alterations of blood leukocyte numbers and decrease of granulocyte function". J. Neuroimmunol. 85 (2): 193–201. doi:10.1016/S0165-5728(98)00011-3. PMID 9630168.
- Goebel MU, Trebst AE, Steiner J et al. (December 2002). "Behavioral conditioning of immunosuppression is possible in humans". FASEB J. 16 (14): 1869–73. doi:10.1096/fj.02-0389com. PMID 12468450.
- Engel, Cindy (2003). Wild Health : Lessons in Natural Wellness from the Animal Kingdom. Boston: Houghton Mifflin. ISBN 0-618-34068-8.
- Klein N, Fröhlich F, Krief S (April 2008). "Geophagy: soil consumption enhances the bioactivities of plants eaten by chimpanzees". Naturwissenschaften 95 (4): 325–31. doi:10.1007/s00114-007-0333-0. PMID 18188538.
- Fowler A, Koutsioni Y, Sommer V (January 2007). "Leaf-swallowing in Nigerian chimpanzees: evidence for assumed self-medication". Primates 48 (1): 73–6. doi:10.1007/s10329-006-0001-6. PMID 16897194.
- Huffman MA (May 2003). "Animal self-medication and ethno-medicine: exploration and exploitation of the medicinal properties of plants". Proc Nutr Soc 62 (2): 371–81. doi:10.1079/PNS2003257. PMID 14506884.
- Koshimizu K, Ohigashi H, Huffman MA (December 1994). "Use of Vernonia amygdalina by wild chimpanzee: possible roles of its bitter and related constituents". Physiol. Behav. 56 (6): 1209–16. doi:10.1016/0031-9384(94)90368-9. PMID 7878093.
- Green KF, Garcia J (August 1971). "Recuperation from illness: flavor enhancement for rats". Science 173 (3998): 749–51. doi:10.1126/science.173.3998.749. PMID 5568508.
- Kikusui T, Winslow JT, Mori Y (December 2006). "Social buffering: relief from stress and anxiety". Philos. Trans. R. Soc. Lond., B, Biol. Sci. 361 (1476): 2215–28. doi:10.1098/rstb.2006.1941. PMC 1764848. PMID 17118934.
- Hill AV, Long CNH, Lupton H (1924). "Muscular exercise, lactic acid and the supply and utilisation of oxygen. Parts I–III" (PDF). Proc. R. Soc. Lond. 97: 438–75.
- St Clair Gibson A, Baden DA, Lambert MI et al. (2003). "The conscious perception of the sensation of fatigue". Sports Med 33 (3): 167–76. doi:10.2165/00007256-200333030-00001. PMID 12656638.
- Noakes TD, St Clair Gibson A, Lambert EV (February 2005). "From catastrophe to complexity: a novel model of integrative central neural regulation of effort and fatigue during exercise in humans: summary and conclusions". Br J Sports Med 39 (2): 120–4. doi:10.1136/bjsm.2003.010330. PMC 1725112. PMID 15665213.
- Noakes TD, Peltonen JE, Rusko HK (September 2001). "Evidence that a central governor regulates exercise performance during acute hypoxia and hyperoxia". J. Exp. Biol. 204 (Pt 18): 3225–34. PMID 11581338.
- Noakes TD (June 2000). "Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance". Scand J Med Sci Sports 10 (3): 123–45. doi:10.1034/j.1600-0838.2000.010003123.x. PMID 10843507.
- St Clair Gibson A, Lambert ML, Noakes TD (2001). "Neural control of force output during maximal and submaximal exercise". Sports Med 31 (9): 637–50. doi:10.2165/00007256-200131090-00001. PMID 11508520.
- Edwards RHT (1983). "Biochemical bases for fatigue in exercise performance: catastrophe theory in muscular fatigue". In Knuttgen HG, Vogel JA, Poortmans J. Biochemistry of exercise. Champaign, IL: Human Kinetics. pp. 1–28. ISBN 978-0-608-07112-1.