What is Thyroid-Related Fatigue?

Energy is the backbone of life. All systems in your body need energy to function properly. How you produce and distribute energy is complex; thyroid hormone function has a major impact on all of your energy systems. However, not all fatigue or tiredness is due to thyroid malfunction. 


How do you tell the difference?

Thyroid hormone governs the basal metabolic rate, which is like the idling speed of a car engine. Even when you are sitting in a chair or sleeping your 100 trillion cells keep making energy. This type of energy production is the foundation for all other energy and hormonal systems. If it is not up to par, no other system in your body works as well as it should.

When you step on the gas pedal during the day, this is not thyroid hormone that goes into action. Increased activity of any kind is controlled by adrenaline, muscle activity, increased calorie burning, and an increased speed at which your cells make energy. If you have a sluggish thyroid you may still be able to make yourself have the energy to do things based on adrenaline-driven necessity. You may also notice that you have too much reliance on stimulants such as caffeine, sugar, or cigarettes.

A demanding day may deplete muscles of fuel and induce enough wear and tear so that natural tiredness follows. Such fatigue is normal and why we need to sleep. Even pushing it day after day and cutting sleep short may not be a thyroid problem. However, such a poor lifestyle is pushing your system and you may eventually develop a thyroid problem as a result. Getting less than seven hours of sleep per night is asking for trouble.

Thyroid-related fatigue starts to show up when you cannot sustain energy long enough, especially when compared to a past level of fitness or ability. If the thyroid foundation is weak, sustaining energy output is difficult. You will notice you just don’t seem to have the energy to do the things you used to be able to do.

The menstrual cycle, pregnancy, exercise, stress, and physical demands are all examples of increased energy demands requiring increased energy output. Thus, PMS is almost always a thyroid problem to a degree. The increased energy demands of the menstrual cycle are simply too much, partly due to an underlying thyroid weakness. Pregnancy is always a major test of the thyroid, as one’s thyroid is called upon to do metabolic work for two bodies. This is why thyroid issues often flare up during or following pregnancy.

Thyroid hormone is synergistic with growth hormone in muscles, and when these two are working properly together then muscles feel fit. Exercise conditions thyroid hormone to work properly to assist general energy production and a lack of exercise contributes to poor thyroid function. The more fit your muscles feel, the less likely thyroid-related fatigue will be an issue for you. If you have poor thyroid function you frequently feel like you don’t have the energy to exercise and usually don’t on a consistent basis. Muscle weakness is a classic hypothyroid symptom.

One of the key symptoms of thyroid fatigue is a heavy or tired head, especially in the afternoon. Thyroid hormone activity is regulated differently in the brain than anywhere else in the body, as brain cells themselves convert T4 to T3 (active thyroid hormone). Your head is a very sensitive indicator of thyroid hormone status. This is different than low blood sugar symptoms from not having eaten for a while. The head just feels sluggish or tired, lacking clarity or sharpness. When this head tiredness occurs too many hours in the day then you will feel like you want to sleep all the time and you will feel depressed, signs of more advanced thyroid-related fatigue.

Another key sign of thyroid fatigue is conking out as soon as you sit down and don’t actually have to do something (there is no necessity making you have to do something). In this case it feels like your body is a car idling too slowly at a stop sign and it just stalls and goes to sleep. This is a clear sign of thyroid fatigue.

You either do or don’t have the symptoms of thyroid-related fatigue. If you wake up energized, maintain decent energy throughout the day, are able to maintain mental alertness/sharpness, have energy as needed to meet demands, and your muscles feel fit, you do not have thyroid-related fatigue. The more you don’t feel this way, the greater the problem. No lab test is needed. In many cases thyroid lab tests may still be normal, even though you clearly are not. The symptoms tell the story and they never lie.