Kill Your Pathogens
Cross an ecological border, and make life tougher on them than it is on you
Everything has a niche. The human niche is particularly broad, but even we have our limits. Some places and conditions push us beyond what we can endure—extreme hot or cold, insufficient water or food, lack of particular nutrients even when other nutrients are in abundance. But we are remarkably resilient.
Those things that would make us sick almost always have narrower tolerances than we do ourselves. Those “things that would make us sick” are parasites and pathogens—two terms that have some overlap. They’re all freeloaders. Parasites are organisms that take resources from the host, but don’t necessarily directly cause disease. Parasites come in two broad forms: ectoparasites, which remain on the outside of the body, such as ticks, fleas and mosquitos; and endoparasites, which set up shop inside the body of their hosts. At the point that a parasite causes disease in its host, it may also be referred to as being pathogenic. Pathogens are often organisms (e.g. bacteria, protozoans, or fungi), but can also be other kinds of entities, such as viruses or prions. Pathogens inherently cause disease in their host.
The endoparasites and pathogens that can withstand the ecological conditions inside of a human body are but a subset of all the parasites and pathogens in the world—a subset that can live under our conditions.
As humans we are capable of inhabiting a huge range of environmental conditions, but our internal condition remains remarkably stable. Consider temperature. Most animals generate their heat from the environment, and as such, their body temperatures fluctuate throughout the day. When a lizard is sunning himself on a rock, his body temperature is elevated, and his physiological processes run both hotter and faster than at night, when he has little source of heat.
In comparison, mammals, like birds, are both endotherms and homeotherms: rather than seeking heat from the external environment, we generate it internally (endo thermy), and we maintain a constant body temperature (homeo thermy). As such, species tend to thrive in fairly narrow internal temperature ranges. Downstream of that: the same is true of our freeloaders. Whatever environment the host provides is the environment in which the parasite lives and is adapted to. Whereas the internal parasite of a lizard may need to endure a large temperature range on any given day (depending on where the lizard lives), the internal parasite of a mammal, such as yourself, has it pretty easy.
All mammal species have somewhat different optimal temperature ranges from one another, which has at least two repercussions for health. First, our endoparasites and pathogens will be fairly tightly adapted to individual species. Second, it should therefore be fairly easy to get rid of them by elevating (or reducing) the temperature in which they are living.
Part of our human ability to reside in a wide range of niches is due to our physical resiliency. We are capable of enduring extreme conditions for brief periods of time. Therefore, if a person is willing and able to tolerate conditions that aren’t wholly normal for them, they can often take out the pathogens that are making them sick.
What kinds of things should a human consider tolerating in order to get rid of their freeloaders?
Maintain a fever. This is the classic example, and also follows naturally from the endothermy and homeothermy discussed above.
Often, but not always, fever is an adaptive response rather than an error. When adaptive, fever involves the body changing its environment sufficiently that on-board pathogens cannot survive.
“Fever as adaptive” was first intuited in the West by Julius Wagner-Jauregg, early in the 20th century1. He found that when people with syphilis were infected with malaria—which famously causes high, cyclic fevers—those patients’ chances of recovery substantively improved. He attributed this to the high fever brought on by malaria.
In their 1996, landmark book Why We Get Sick: The New Science of Darwinian Medicine, evolutionary biologists George Williams and Randy Nesse discussed the evidence for the adaptiveness of fever. When their book came out nearly 40 years ago, they observed that Western doctors were more likely to prescribe pills than let the body do what it wanted to do. It’s only gotten worse since then. Regarding Wagner-Jauregg’s receipt of the 1927 Nobel Prize in Physiology or Medicine, Williams and Nesse wrote, “At that time, the value of fever was much more widely recognized than it is now.”
Next time you find yourself locking horns with a pathogen, consider giving a pass on the fever reducing medications and instead allowing, or even facilitating, fever. Endure a not-too-high fever for a few days, and see if you don’t come out the other side feeling wrung out but free of whatever was ailing you. If your body has not provided you with a fever, you can induce short-term fever with sauna, intense exercise, lying out in the sun, or hiking in a hot place. Always, you should be in a position to lower your temperature if need be. Our tolerances are not that wide with regard to body temperature. Heat stroke is real, and dangerous. But short bursts of high heat are more likely to damage your parasites than you.
Reduction of core body temperature is a far less common physiological response in combatting parasites. This is likely, in part, because the rate of chemical reactions, and thus, the rate at which physiological processes operate, are highly temperature dependent. Cool things down and they slow down as well; you may indeed make things more difficult for your parasites, but everything in your body becomes sluggish and less agile, and when things amp up again, heat wise, both your body and your parasites may effectively wake up from their cool, slow sleep. Add heat to speed things up, however, and while your body can’t take it for all that long, the parasites can (hopefully) withstand it for even less, as they are already operating with lower tolerances due to their smaller size and shorter life spans, and their own reactions and processes are now being sped up2.
Dry Fast.
Remove food and water from your pathogens, and they won’t last long. Once again: Cross an ecological border, and make it harder to be a pathogen than it is to be you.
Fasting—abstaining from eating or drinking anything but water—is good, but dry fasting is better. A dry fast is just what it sounds like: you take in nothing. No food, no water, nothing.
Every day you already dry fast for some time, while you are sleeping. Make the dry fast last longer, and your body will begin to source its food and water from within—engaging in autophagy of old, diseased, and damaged cells; breaking down fat to release the water and energy stored there. The water and nutrients released by the body during a dry fast are, we think, conserved for use within the body’s systems. They are not available to your freeloaders. And so the freeloaders starve, and desiccate.
I will write a separate piece on dry fasting, but if you are interested in more information now, watch Think Fast, an Evolutionary Lens episode of DarkHorse that aired in November 2024, which Bret and I did after conducting a seven day dry fast (yes: seven days without ingestion of any food or drink at all. Yes, we survived. Yes, it was difficult. And also exhilarating. You should not consider such a thing for yourself without considerable thought and preparation). Also consider reading The Phoenix Protocol: Dry Fasting for Rapid Healing and Radical Life Extension, by August Dunning, a former NASA scientist; online, the Dry Fasting Club is an excellent source of information.
Get salty.
Take a swim in the ocean, and find that wounds and infections often heal faster than you were expecting. To kill off fungal or bacterial infections on your skin’s surface, immersing yourself in salt water is a better first approach than smearing yourself with topical antibiotics (e.g. Neosporin) or antifungals. Wounds heal and fungus flails in the sea. An Epsom salt bath might do the trick as well. The ocean, however, probably has additional benefits, many of which we do not yet know. One of the likely benefits is that it grounds you—puts you in electrical connection with the Earth—which itself is health-giving.
Stick a steak on a botfly. (Or use ivermectin.)