Fever: It’ll Help You Fight off Infection

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One of the key naturopathic and Darwinian medicine concepts[i],[ii] is that suppression of a normal response by the body to a pathogen may reduce the effectiveness of outcome.

Naturopathic Medicine is a form of alternative medicine based on a belief in vitalism, which posits that a special energy called vital energy or vital force guides bodily processes such as metabolism, reproduction, growth, and adaptation. Naturopathic philosophy favours a holistic approach, and, like conventional medicine seeks to find the least invasive measures necessary for symptom improvement or resolution, thus encouraging minimal use of surgery and unnecessary drugs.[iii]

Evolutionary medicine or Darwinian medicine is the application of modern evolutionary theory to understanding health and disease. It provides a complementary scientific approach to the present mechanistic explanations that dominate medical science, and particularly modern medical education.[iv]

Fever provides a helping hand

With cold and flu season almost here, the next time you’re sick, think twice before taking something for your fever. That’s because scientists have found more evidence that elevated body temperature helps certain types of immune cells to work better.[v] Fever has been conserved during evolution through millennia, obviously because of its advantage for host defence. Despite of these arguments most doctors, nurses and patients treat fever with antipyretics.[vi]

Fever (also known as pyrexia) is a common medical sign characterised by an elevation of temperature above the normal range of 36.5–37.5 °C (98–100 °F) due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.

Increased body temperature has been described and recognised since ancient times to be associated with infection and inflammation, since a febrile response is highly conserved in nature (even so-called cold blooded animals move to warmer places when they become ill) it would seem important that immunologists devote more attention to this interesting response.

What did the scientists discover?

Scientists found that the generation and differentiation of a particular kind of lymphocyte (white blood cell), known as a “CD8+ cytotoxic T-cell” (capable of destroying virus-infected cells and tumour cells) is enhanced by mild fever-range hyperthermia. Specifically, their research suggests that elevated body temperature changes the T-cells’ membranes which may help mediate the effects of micro-environmental temperature on cell function.

90 million is the number of children who contract seasonal influenza annually around the world, according to a study published online 10 November in the The Lancet.

To test this, researchers injected two groups of mice with an antigen, and examined the activation of T-cells following the interaction with antigen presenting cells. Body temperature in half of the mice was raised by 2 degrees centigrade, while the other half maintained a normal core body temperature. In the warmed mice, results showed a greater number of the type of CD8 T-cells capable of destroying infected cells.

Having a fever might be uncomfortable,” said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology, “but this research report and several others are showing that having a fever is part of an effective immune response.


Previously researchers had suggested that fever prevented replication and slowed growth of pathogens, but this paper in JLB also suggests that the immune system might be temporarily enhanced functionally when our temperatures rise with fever. Although very high body temperatures are dangerous and should be controlled, this study shows that we may need to reconsider how and when we treat most mild fevers.


[i] Román-Franco AA. Medicine in the 21st century: towards a Darwinian medical epistemology. P R Health Sci J. 2009 Dec;28(4):345-51. Review. View Abstract

[ii] Mertens G. Evolution, health and disease–Darwinian approaches to medicine. Acta Clin Belg. 2009 Jan-Feb;64(1):2-6. View Abstract

[iii] Sarris, J., and Wardle, J. 2010. Clinical naturopathy: an evidence-based guide to practice. Elsevier Australia. Chatswood, NSW.

[iv] Nesse RM, Bergstrom CT, Ellison PT, Flier JS, Gluckman P, Govindaraju DR, Niethammer D, Omenn GS, Perlman RL, Schwartz MD, Thomas MG, Stearns SC, Valle D. Evolution in health and medicine Sackler colloquium: Making evolutionary biology a basic science for medicine. Proc Natl Acad Sci U S A. 2010 Jan 26;107 Suppl 1:1800-7. Epub 2009 Nov 16. View Abstract

[v] : Thomas A. Mace, Lingwen Zhong, Casey Kilpatrick, Evan Zynda, Chen-Ting Lee, Maegan Capitano, Hans Minderman, and Elizabeth A. Repasky. Differentiation of CD8+ T cells into effector cells is enhanced by physiological range hyperthermia. J. Leukoc Biol November 2011 90:951-962. View Abstract

[vi] Schaffner A. [Fever–useful or noxious symptom that should be treated?]. Ther Umsch. 2006 Mar;63(3):185-8. German. View Abstract

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