In the last post we began the discussion of fatigue and lack of energy discussing adrenal gland imbalance. As a review, the three common causes of these symptoms are:
The second is thyroid gland imbalance. As we will see, it relates to adrenal gland imbalance. Both glands produce hormones that regulate energy levels. In a simplified sense, the thyroid gland sets our “idle” level or our baseline energy level, and the adrenal gland acts as the accelerator for our energy level when demand is higher.
Many people with “normal” thyroid blood tests have functional hypothyroidism. They have many or all of the symptoms of low thyroid function, yet the standard blood tests are consistently normal. Functional hypothyroidism is the result of an imbalance in active thyroid hormone or T3 and the levels of an inactive thyroid hormone called reverse T3 or rT3.
The thyroid makes the initial hormone T4 called so because it has 4 iodine molecules on it. T4 is primarily a transportation form of hormone used to transport hormone from the thyroid to the cells in the body which must use it. T4 has low cell stimulating effect and a cell enzyme called a “deiodinase” must remove on iodine creating the more active T3 (3 iodine’s).
Sometimes different circumstances cause cells to make a different enzyme that remove the wrong iodine making a backwards T3 molecule called “reverse T3”. Reverse T3 looks enough like regular T3 to fit into the cell receptors for T3, but because it is configured differently, it does not cause “activation” of the receptor and thus the lack of thyroid signaling effect.
The standard blood tests used to look at thyroid function include TSH and T4. TSH, or thyroid stimulating hormone, is a hormone made by the pituitary gland to stimulate the thyroid to produce more hormone. The levels of these blood factors may be normal yet the cells which must produce the energy do not do so simply because the message never gets to them due to high reverse T3 levels.
For persons with the typical symptoms of low thyroid function yet normal standard blood tests, high levels of reverse T3 is a likely cause. These symptoms may include:
Reverse T3 syndrome as it is called is best evaluated by measuring free blood T3 and rT3 to allow the determination of the T3 to rT3 ratio. T3/rT3 should normally be between 1.06 and 2.2 but preferably more than 1.5. Elevated rT3 will lower the ratio.
Why would the body make reverse T3 in the first place? If the body needs to conserve energy or simply thinks that it needs to, it will do so by producing reverse T3. By blocking cell energy production, energy is maintained by reduced usage. An example may be during a period of hypoglycemia, or low blood sugar. As we produce cortisol during this time to maintain blood sugar, it would seem as if cortisol would be a good stimulus to rT3 production. In fact, it is one of the strongest. This is why weight loss simply by chronic caloric restriction does not work. It causes more periods of low blood sugar, more periods of high cortisol output which results in more rT3 production which simply slows our energy use down.
Anything that causes chronic adrenal stimulation and cortisol production increases rT3 production. Common factors that chronically raise cortisol production include:
Ironically, chronic adrenal stimulation will eventually cause adrenal fatigue which we discussed in the preceding blog. Some patients with chronic fatigue/low energy start out having it result from high cortisol causing reverse T3 syndrome. They gradually fatigue their adrenal glands transitioning from reverse T3 syndrome to adrenal fatigue or both. As you would guess, sorting out fatigue and lack of energy requires a methodical evaluation of each of these problems.
In next week’s blog, we will talk about the 3rd cause of excessive fatigue and lack of energy, cell energy processing deficits.