Homeostasis: How your body keeps in balance--or not

Our bodies continually seek to keep everything in balance—a condition called homeostasis. For example, we maintain an internal temperature of around 98.6 degrees no matter the outside temperature. Our bodies can also maintain an acid/alkali balance as well as levels of fluid, glucose, and calcium. In general, these balancing activities are the result of hormonal triggers.

All very nice. But stress can throw a monkey wrench into our nicely balanced systems. When stressed, our bodies release hormones such as cortisol and adrenalin to facilitate our “fight or flight” responses. While these reactions might come in handy for fighting off a predator, they result in wear and tear on our bodies. Specifically, high blood pressure (hypertension) is a normal response to chronic stress. Over time, adrenaline and cortisol tighten blood vessels and cause salt retention, conditions that can lead to long-term changes such as arterial wall thickening. Thickened arterial walls increase the blood pressure set point. Our bodies adapt to the higher set point and work to maintain it.

 Populations dealing with racism, poverty, fractured families, and joblessness are extremely stress-prone. In fact, high blood pressure disproportionately affects blacks, especially in poor communities. (American blacks have hypertension at a much higher rates than West Africans). Anyone with an increased and continuous need for vigilance—ready to flee or fight—is especially vulnerable to hypertension. But other stressors can have the same effect. In the U.K. studies of postal workers showed that people at the lowest level of the Civil Service occupational hierarchy—people with little job control and more financial instability—had nearly twice the death rate than that of administrators.

A new term, allostasis, has been coined as an alternative to the word homeostasis. While homeostasis is about preserving constancy, allostasis is about adapting to external circumstances, allowing for fluctuations in response to changing demands, including social circumstances. In the words of cardiologist Sandeep Jauhar, my source for this information, “Allostasis is a politically sophisticated theory of human physiology.” It also explains many modern chronic diseases.

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