How Adrenal Function Influences the Thyroid in Times of Stress

Most of us are exposed to a variety of stressors every day. We lead very busy lives. We are overscheduled, overworked, and juggling many different responsibilities at once. This can take a toll on our health and wellbeing, and for some, it can lead to health issues involving our adrenals and thyroid function. Let's explore how our bodies handle stress and what can go wrong when it's just too much.

The HPA Axis

The Hypothalamic Pituitary Adrenal Axis (HPA Axis) is a term used for the working relationship between the hypothalamus, pituitary gland, and adrenals. This axis is responsible for the body's hormonal response to stress. When a stressful stimulus presents itself to us, it signals the hypothalamus to release corticotropin-releasing hormone (CRH). CRH then triggers the anterior pituitary gland to release adrenocorticotropic hormone (ACTH), which stimulates the adrenals to release cortisol.

Cortisol is commonly known as the stress hormone. You may have heard the term 'fight or flight' alongside stories of running from tigers or bears. These stories illustrate that our stress response was once triggered more often by immediate short-lived threats to our safety instead of the stress we experience now. In these modern times, we experience more frequent and sustained stress.

The experience of stress is very individual. What may be stressful to one person may not be for another. This is why learning to tune into your body and emotions is so vital to health. Still, there are some common stressors for most of us:

• Taking care of someone with a long-term illness

• Divorce

• Marriage

• Moving

• Death of a loved one

• Losing a job

• Starting a new job

• Being chronically ill

• Unresolved emotional trauma

• Financial hardship

• Birth of a child

• Difficult relationships

• Environmental toxins

Why is the difference between short-lived and sustained stressors important?

When the body releases cortisol, its purpose is to slow down processes of the body that are not needed to overcome the current stressor and to divert energy and resources to those functions that are needed (like liberating glucose to fuel muscles for running away).

Some examples of physiological functions that are put on hold or slowed down include: digestion, metabolism, reproduction, immune response, and thyroid hormone production and distribution.

In the case of a short-lived threat to safety (a bear chasing you), the stress response is triggered and then subsides shortly thereafter once the body has achieved its goal of thwarting the stressor and finding safe ground. This allows the body to recover and resume the important physiological processes that were placed on hold.

In today's very hectic world, this stress response lasts much longer because our bodies perceive things like a difficult work environment, challenging relationships, financial hardship, or chronic illness as threats to safety. As such, the body either does not recover as it needs to from the stress response or the stressors come one after another, and the crucial functions that were slowed are now impaired long-term.

There is debate about whether the adrenals become fatigued when subjected to chronic stress and therefore produce less cortisol or if a constant release of cortisol ultimately makes cells less sensitive to cortisol signaling. Either way, the effect is a diminished cortisol response.

Click below for an in-depth video on the physiology of stress.

What is the thyroid’s role?

The thyroid is responsible for regulating many functions in the body, the main being metabolism. Metabolism, put simply, is the breakdown of food and the synthesis of compounds which are then used to supply energy to the body. The products of metabolism provide needed fuel for reproductive function, body temperature regulation, digestive function, cholesterol management, and more.

The thyroid does its job using the hormones T3 and T4. T4 converts to the active form T3, and it is in this form that it can act on cells. Every cell in our body has a receptor for thyroid hormone. When the body is under significant stress, this conversion process is disrupted, and T3 is stored in its inactive form, reverse T3, rendering the hormone unusable until the stress has subsided.  

Stress can also cause inflammation which can make our cells less receptive to thyroid hormone.

How do the adrenals affect thyroid function?

We discussed that the stress-induced release of cortisol slows down functions like metabolism to conserve energy for the mechanisms necessary for fight or flight. To slow down metabolism, thyroid function must be slowed. With thyroid function reduced, all the related activities we've discussed are disrupted.

When stress is chronic and recovery from the stress response is hampered, our bodies stay in this state of impaired function for longer periods of time. This can suppress the functioning of the thyroid long-term resulting in hypothyroidism. Symptoms of hypothyroidism include cold extremities, difficulty losing weight, increased cholesterol, mood imbalances, hormone imbalances and fatigue.

Because of the significant impact that stress has on the body, it is crucial to manage our exposure. Removing stressors can be immensely helpful, but if that is not possible, using various coping strategies to stabilize our stress response is also effective. Activities like yoga, meditation, exercise, breathing exercises are all great choices. Making a list of things you find relaxing and prioritizing these activities in your schedule can help improve stress management as well.

Think you might be dealing with over-stressed adrenals or disrupted thyroid health? Schedule a Discovery Call with Jade to discuss how you might best go about finding balance in your body.

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