Download The stress–hypothyroid connection

Could stress be affecting your thyroid?
Key points in this article
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Chronic stress leads to overproduction
of the hormone cortisol.
Cortisol and its precursor (CRH) can
inhibit thyroid-stimulating hormone
(TSH). Cortisol can also inhibit
conversion of the thyroid hormones T4
into T3.
Low T3 can lead to hypothyroid
symptoms.
Simple nutrient and lifestyle
modifications can support thyroid
function and lower the impact of stress
on your overall health and well-being.
Yes, we all know stress isn’t good for our
health, but we don’t always make the
connection between stress and thyroid
problems — nor how to change our lives
in response. Continuous stress leads to
high levels of stress hormones, which can
have a negative impact on thyroid
function, especially if levels stay high over
the long-term.
Adrenal and thyroid function
originates in the brain
Hormones are molecules released by one
area of the body to carry messages to
another area in the body. The thyroid’s
main job is to produce the right amount of
thyroid hormone to “tell” your cells
how fast to burn energy and produce
proteins. The adrenal glands’ primary job is to produce the right amount of stress
respond to stress of a zillion kinds.
hormones that allow you to
The stress–hypothyroid connection
Think of the thyroid and adrenals as guardians, or protective intermediaries of the endocrine (hormone-producing) system. They both
function as complex sensors, continually responding to ever-changing conditions within the body, and relay information back and forth
between the brain and the body.
HPT–HPA interactions & feedback loops
Because both of these endocrine loops trace back to the pituitary and hypothalamus in the brain, and the hormones produced along these
two axes interact, chances of dysregulation are higher along one axis when the other loop is overactive- or underactive.
CRH = corticotrophin-releasing hormone; TRH = thyrotropin-releasing hormone; ACTH = adrenocorticotropic hormone; TSH = thyroidstimulating hormone; T4 = thyroxine; T3 = triiodothyronine.
Yet the signaling for release of both sets of hormones originates in an area of the brain known as the
hypothalamus, which sends hormonal messages to the tiny gland in the brain called the pituitary. From here,
hormonal messages are relayed to both the thyroid and the adrenal glands (along with other destinations beyond the
scope of this article). The adrenals and thyroid, in turn, produce hormones and provide feedback to the brain. We
call this negative-feedback loop the HPTA (hypothalamic–pituitary–thyroid–adrenal) axis.
You need just the right amount of cortisol for your thyroid to function optimally. An imbalance can arise all along
the HPTA axis and result in either an overactive or underactive thyroid or adrenal glands. As you can see from the
diagram, the hormones from each loop interact, and cortisol and thyroid hormone work in concert. So when one of
these loops is overactive or underactive, disruption along the other is more likely. This is one reason symptoms of
thyroid dysfunction can show up even when your thyroid lab tests appear “within normal limits.” Let’s look at how
this happens.
How stress can cause thyroid symptoms
Much of the medical literature has focused on hyperthyroidism and a condition called Graves’ disease as the
main effect of stress on the thyroid. Graves’ is generally caused by an autoimmune response that prompts the thyroid
to make too much thyroid hormone. This has been known to occur after a sudden stressful life change. But too
much stress can also lead to a slowing of the thyroid, hypothyroidism.
Any kind of stress prompts the brain to release CRH (corticotrophin-releasing hormone). This hormone tells
the pituitary to send a message to the adrenal glands: make cortisol! But both cortisol and CRH can inhibit
thyroid-stimulating hormone (TSH) and the conversion of thyroid hormone T4 to T3. Because every cell in
the body uses T3 for healthy function, the decrease in T3 can lead to symptoms like:
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fatigue
cold intolerance
weight gain
memory loss
poor concentration
depression
infertility
hair loss and more
This inhibition of your thyroid and hormone receptors often takes place quietly behind the scenes for years without
causing overt symptoms. And this is why so many women are caught off-guard when they are diagnosed with a
thyroid disorder. They think everything has been going fine and all of the sudden, they feel horrible. The fact is, if
you’ve been experiencing chronic stress, stress hormones may have been inhibiting your thyroid function for years.
Some patients can even remain in what we call subclinical hypothyroidism, where their lab results are still
within the standard normal ranges, but they’re experiencing symptoms.
by Marcelle Pick, OB/GYN NP