How stress can wreak havoc on your thyroid

Before we start damming stress, I want you to know that stress is NOT a bad thing. Stress is incredibly important for the body, providing episodes are short and sweet (acute). Your body is hardwired to run from a sabre tooth tiger or deal with short periods of famine. In fact, short episodes of stress can help to reduce inflammation. Hence the reason why cold-water exposure and fasting has been shown to be incredibly beneficial for your health via a process known as hormesis.

Before you rush off to jump in an ice tub, just bear with me!

Whilst short episodes of stress can be helpful, chronic, or ongoing stress, can be incredibly damaging to the body and especially the THYROID.

The Impact of Stress on your Thyroid


Stress is your body’s natural response to dealing with danger or dealing with survival.  When your body faces a life-threatening situation, the adrenal glands (located just above each kidney) will produce cortisol.

During periods of stress your body will ensure that the organs and bodily systems that most need the support gets it. This therefore means that your heart rate will increase, blood pressure and blood sugar will increase to the muscles and the brain to help you respond to the ‘life-threatening’ situation. At the same time thyroid hormone production will take a back seat, as will digestion, sex hormones and sleep!

Cortisol has an important relationship with the thyroid and the rest of the body for that matter. Sufficient cortisol levels are vital for your quality of life and ability to function under stress. If you don’t have optimal levels of cortisol, you may experience fatigue, brain fog, pain, anxiety, low mood/depression, autoimmune disease, cognitive decline and more. Cortisol enhances the biological effects of T3 in the cell (your active thyroid hormone) and both cortisol and T3 need to be at good levels for you to be healthy.

The problem is that chronic stress/high cortisol levels can also be incredibly damaging to the body. In fact, chronic stress can lead to high blood pressure, changes in the brain, anxiety, depression, weight gain, IBS or gut problems, hypothyroidism, and Hashimoto’s (to name a few).

When the body is constantly dealing with ‘life-threatening’ situations, the sequence of hormonal changes and physiological responses can overtime significantly impact overall health.

Now, I know you are most probably thinking, ‘but I am not dealing with life threatening events, and yet I generally feel like I can’t handle stress in my life?!’

The Impact of Stress on your Thyroid

Are you able to handle stress in your life?

The truth of the matter is that what was once a sabre tooth tiger has become daily life for many. High pressured jobs, long hours working whilst juggling home life and family. Years of malnourishment through eating a diet high in refined/processed foods. Less sleep and an increase in blue-light exposure with enhancements in technology. Higher intake of alcohol (one of your thyroid’s biggest poisons). The pressures of social media and generally being left feeling not good enough/lack. Dealing with isolation, social anxiety, fear, loss of income, loss of a loved one all connected to the pandemic. Limiting self-beliefs and habitual thought patterns to keep you locked in fight-or-flight.

The list can go on, but I am sure you get my point.

The biggest problem is that most of us are dealing with this daily!

This brings me to the key points of how stress causes havoc on your thyroid.

If you think of your thyroid gland as a furnace and the pituitary gland as the thermostat. Thyroid hormones are like heat and when the heat gets back to the thermostat it turns the thermostat off. As soon as the room cools, the thyroid levels drop and then the thermostat turns back on again and TSH increases, and the furnace (thyroid) produces more heat (T4 and T3).

The impact of too much stress on thyroid Hormone Production

The thyroid produces thyroid hormone on instruction of the pituitary gland. It relies on iodine and various other factors which I discuss here. The important part for today’s post is to understand the role of T4, T3 and reverse T3 (rT3) and how stress impacts these hormones. When thyroid hormone levels are low, the hypothalamus will instruct the pituitary to release TSH, which will prompt the thyroid to make thyroid hormone, or release it for that matter. This all operates via a negative feedback loop.

When cortisol is released, T3 will become more biological active as this is to support the energy getting to the mitochondria within the cell, so the body can respond to danger. At the same time the body will also produce less enzymes to convert T4 to T3 and increase the rate at which any excess T4 is cleared out of the system via reverse T3 (rT3).

The role of rT3 is to lower the body’s metabolic rate, which is important when you are running away from a tiger.

The body’s key focus is to always keep you safe; this means that during periods of starvation, high stress, illness, surgery the body will want to slow metabolism down (as not a priority – think sabre tooth tiger) and it will therefore decrease T4 to T3 conversion and increase rT3. This helps to slow the metabolism and get rid of any excess T4 and T3. The biggest driver for this is cortisol!

This can result in optimal T4 levels, but low T3 because it’s being overly converted to rT3. And guess what? You’re symptoms are still there:

🙅‍♀️ Fatigue

🙅‍♀️ Muscle pain

🙅‍♀️ Brain fog

🙅‍♀️ And the list goes on!

In these circumstances, it’s critical to evaluate both rT3 and T3 itself, which to be fair very few people actually do! This is why getting the right testing done is so incredibly important. You can’t guess the picture in all situations. This is also why so many women just don’t feel better when they take Levothyroxine. The bottom line – in many cases it is just NOT addressing the problem!

If you are dealing with chronic stress, your body will continue to take that levothyroxine and dump it out via rT3.

The next steps

Looking at ways in which you can mitigate stress is key. I will be discussing this with you in the next post.

If you fed up with feeling below optimal despite everything you are doing to support your health, then book in for a free breakthrough session with me.

Nutritional Therapist Cheshire, Health, Nutritionist Cheshire, Functional Medicine Cheshire, Rootcause Solution