Hormones and Immunity, Part 1: Stress, Adrenals, and Letting the Lion Sleep
This is the first of a three-part post on hormones and immunity, and is part of our Superpower Series on defending ourselves in the COVID-19 era.
Summary
Lots of information here, so allow me sum-up first and provide details afterward.
There’s a tug-of-war going on inside us. On one side of the rope is our psychological response to daily stressors, and on the other side is our biologic response. Why are they at odds? Because our biologic responses were born and nurtured in a world far different than our world today.
For the sake of ease (not specificity), let's label them the Modern World — that's where we live and worry about the battery life of our phones and whether or not we should answer the 10pm text from our boss — and the Ancestral World — where we largely worried about what we were going to eat and what was trying to eat us. Psychologically we're focused on the Modern World, but our biologic responses are still rooted in the Ancestral World. There's the mismatch, and here's what it looks like:
The boss's text comes in at 10pm. Something is due, and we “stress” out about it. Psychologically, Modern World Us knows that no one is going to get eaten if we don't answer the text, but biologically, Ancestral World Us has no adaptation protocol for the nuances of "text from boss". Biologically, our Ancestral adaptations look at the stress and think, "Text? Hmm, that's close enough to being eaten by a lion, so… RUN!" We begin to sweat and our heart races. Our bodies start shutting down kidney and gut functions, raising our blood sugar, shifting our immune system response, interrupting our circadian rhythm, predisposing us to depression, and more. All of which are normal, helpful responses to running from a lion.
But what does a "run" response have to do with getting a text? How is that going to help us respond (or not)? It isn't. And this is where Modern Us can really yank on that tug-of-war rope.
Biologically, it costs us a lot to run from a life threatening stress, and that's okay… as long as we're running from a life threatening stress. But for most of us, late night texts — or dare I say Personal Protective Equipment? — rarely have anything to do with someone starving or freezing to death or being gored by a wooly mammoth. So when our Ancestral adaptations overreact to a Modern World stress perhaps a better way to manage it is to:
Differentiate between the Modern World stressor (non-life threatening text) and Ancestral World perception (“lion!”)
Recognize how ancestral adaptations work …and their related consequences
Use our “Inner Shrink” to self-talk us off of the Ancestral ledge, eg, "nobody's gonna die, this is not life threatening, at the end of today everybody's probably going to be okay.” (Bob Newhart’s “Stop It’ is a cheeky yet potentially helpful model for an Inner Shrink — sometimes I use it with myself but obviously never with my patients!)
Experience the health benefits of a properly calibrated stress-response system: ie, flexible and appropriately adaptive nervous and immune systems.
In the mighty jungle of daily life, Modern Us has to teach Ancestral Us what is a lion and what it isn’t, and when to just let the darn thing sleep.
Now for the details:
Modern Stresses and Ancestral Perceptions
Most organisms on our planet have two primary goals: to survive and to reproduce. As humans in a socially and technologically complex global community, however, very few of us really grapple with these issues on a daily basis. At least not consciously. So it can be easy to forget how dramatically our Ancestral physiology is designed to react to pressures which affect these objectives. In fact, our bodies’ reactions can often feel like a nuisance and counterproductive — like getting a blemish on your wedding day or sweating during a presentation. However, a blemish can reflect a change in sex hormones in preparation for pregnancy, and sweat keeps our adrenaline-pumped brain and muscles from overheating and dying. From the body’s “point of view” it makes perfect sense and serves the ultimate survival/reproduction goals.
We humans have the unique ability to dramatically change our environments, but we seldom take into account the effects of that change on our subconscious physiology which has been carefully adapted over hundreds of generations to a completely different physical, social, and psychological environment. Think of all the changes in just the past century, roughly three generations. One hundred years ago in the United States, electricity, automobiles, and public education were all relatively new inventions. And only one generation ago in India, my father lived in a thatched-roof ox-dung hut without water or indoor plumbing.
Yesterday’s needs for food, shelter, and community have become today’s “needs” for credit cards, internet access, and cell phones. Although our physiology was carefully molded and refined to a world more like my father’s, our modern environment is a bewildering and inscrutable confusion of unfamiliar and utterly novel forces to our Ancestral selves. This means we can’t afford to simply rely on our instincts but will have to be more conscious of ways that our previously adaptive responses have been suddenly rendered maladaptive.
Biologically speaking, the issue isn’t stress vs. health. Optimal health is actually a balance between stress and adaptation. In other words: stress + appropriate adaptation = health and happiness.
How Adaptation Works and What Controls It
Physiologically, we control, execute, and regulate adaptations to the environment using the NEI (NeuroEndoImmune) Super System (mentioned in an earlier post). It’s easier to understand if we liken it to the three branches of our government: Executive, Legislative, and Judicial. Today we will focus mostly on the Legislative and Judicial branches.
Endocrine System / Legislative Branch
The endocrine system, composed of our body’s hormone-secreting glands, is a huge part of the NeuroEndoimmune system — in fact, it’s its middle name. If the NEI system were a government, the endocrine system would be the legislative branch, writing the basic rules that the other branches execute (Nervous System) and enforce (Immune System). Some laws, such as amendments to the Constitution, are long-term and rarely change, while others, like the budget, expire and are frequently rewritten to meet the needs of the current situation. Some laws are enacted nearly overnight to deal with emergencies, while others may remain endlessly debated in committee for revision after revision.
Rather than writing a law for every situation in life, a more efficient approach is to adopt a flexible system of guidelines that can be modified on-the-fly to suit all the unexpected variables. Overall, when the fundamental laws (ie, hormone levels) are moderate, the other two branches (Nervous and Immune Systems) have latitude to adapt to a wider array of contexts. When the laws are rigid and extreme, however, the actions of the other two systems are constrained and unable to accommodate differing circumstances. Flexibility in the system is especially critical in our Modern World with its novel stressors, which we are often biologically unprepared to face.
Adrenal Glands / Committees and Subcommittees
Enter the adrenal glands: two small pyramidal shaped glands resting just atop the kidneys. These small but powerful organs are prime determinants of how the body allocates energy and resources, similar to the Ways and Means Committee which controls the budget. Some sample functions under adrenal control include blood sugar levels, mental energy level throughout the day, cardiovascular capacity, mood, electrolyte and fluid balance, constructive and break down processes, emergencies, and, of course, regulating the immune system.
Because they manage emergency situations, many of us (including doctors) think of the adrenals as the “stress glands” and think of cortisol, one of its main hormones, as “stress hormone.” While this is technically true, it is a vast understatement and oversimplification of the amazing adrenals (and of cortisol!).
(For a short and entertaining book on the subject, I highly recommend Why Zebras Don’t Get Ulcers: A Guide to Stress, Stress-Related Diseases, and Coping, by Stanford professor Robert Sapolsky, PhD, or download his related pdf Stress and Your Body.)
One reason that we all oversimplify adrenal function to emergency management is that the usual functions of the adrenal glands are often secondary to the nearly constant “crises” our Ancestral bodies perceive. Our adrenals are nearly always managing emergencies — that is, our Ancestral adaptations falsely represent our Modern stresses as life-or-death emergencies, even though they rarely are. …
In Part 2 we’ll go further and talk about the Health Consequences of Stress Management.
