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     2355 Canyon Blvd.   |   Suite 102   |   Boulder, CO 80302

Tired of feeling so tired?

Spent. Haggard. Beat. There’s no end to the words we can use to describe being tired, especially in today’s hyperspeed cyber world. My personal favorite? Fried. Many of my patients complain of fatigue. And if they’re not exhausted, they’re wondering what happened to their energy levels—they just can’t seem to do all of the things they used to do.

Did you know that fatigue and low energy are not signs of getting older? There are, in fact, multiple causes for feeling dead on your feet that have nothing to do with your age. I’m diving in deep with fatigue, exploring the many causes and hopefully guiding your journey back to vibrant health and vitality.

When we discuss fatigue, there are many factors that can contribute. It’s quite possible that there’s more than one that’s contributing to your current state of fatigue.

7 possible causes of your fatigue:



  1. Adrenal dysfunction

When you experience stress, your adrenals (your sympathetic nervous system)  kick in to help you cope. The adrenals are one of your compensatory mechanisms that help when you have a lack of natural energy.  . For example, if your cortisol levels are low during the day, this can have you feeling very tired. If your cortisol spikes at night, you may have a very hard time sleeping.  I recommend getting your salivary cortisol levels checked with an adrenal stress index.

  1. Thyroid dysfunction

Symptoms of a low-functioning thyroid include: fatigue, sensitivity to cold, constipation, dry skin, hair loss, headaches, middle of the night wake ups, brain fog and puffiness in the ankles, feet or hands. If these symptoms sound familiar to you, you may have already had your thyroid stimulating hormone (TSH) levels tested and were told they were normaI. I recommend getting a full thyroid panel with a Free T3, Free T4 and Reverse T3 in order to truly see if you are experiencing hypothyroidism.

  1. Poor Sleep

The kind of sleep you’re getting offers clues to what might be causing you to feel tired. Do you fall asleep fast only to lie there wide awake at 3 a.m.? Do you sleep but don’t feel rested when you wake up? Do you dread bedtime because you have such a hard time falling asleep?

There are multiple causes for experiencing poor sleep and I encourage you to find the underlying dysfunction with functional medicine.  May you sleep deeply and see how your energy improves.

In upcoming newsletters I’ll discuss more on adrenal dysfunction, thyroid and insomnia so stay tuned!

  1. Mitochondrial dysfunction

In essence, being deficient in certain nutrients can affect the function of the  mitochondria in your body’s cells. (Remember learning about those in biology class?) Rather than taking 20 supplements and hoping you fill in any gaps, the functional medicine approach is more targeted. I have my patients take a NutrEval test that spells out which vitamins, minerals, omegas, etc. you may not have enough of. There are specific nutrients needed for mitochondrial function and there are certain toxins that can block mitochondrial function. Your mitochondria are the workhorse of the cell, so with mitochondrial dysfunction, you can’t make ATP, and without ATP, you won’t have any energy.

The beauty of this particular test is that it can also test for oxidative stress, heavy metal markers and gut imbalances—all of which can be contributing to your fatigue.

  1. Chronic Infections

There are many different chronic infections that can become active in a weakened system and cause fatigue.  These infections can be bacterial, viral, parasitic or fungal in origin. One example of these is Lyme disease and its co-infections. Not everyone who is exposed to Lyme disease from tick bites develops symptoms but for those that do, it can often be difficult to diagnose because Lyme lives deep inside the body’s cells. People can have had exposure to Lyme many years ago  and not known it.

Today, there are new tests being developed that are designed to get what’s inside cells to come out into the bloodstream for easier detection. Extreme, chronic fatigue can be due to Lyme, along with achiness and joint pain.

  1. Mold toxicity

Even in dry climates like Colorado, mold and other fungi can be another cause of fatigue for many people because it can thrive anywhere from under the living room to the drywall behind your refrigerator. When treating a patient for fatigue, I often look at whether mold could be a contributing factor. (Read more here: What you need to know about mold toxicity.)

  1. Toxic Exposure

Maybe you grew up in a big city in the ‘70s where unleaded fuel permeated the air. Or helped spray pesticides on your family’s farm. Maybe you remodel houses for a living. Or you’ve taken herbs from India or China which can be contaminated with lead. Or there’s lead in your water and soil. Or you’ve traveled abroad and came home with a parasite. All of these activities can expose your body to toxins or biotoxins that inhibit the healthy function of your cells, and you guessed it, make you feel tired all the time.

There are multiple situations that may be contributing to how tired you’re feeling. We can help you discover what’s causing your fatigue so you can get back to optimal vitality and health and feel like yourself again.

To find out if a functional medicine approach can help you get to the root cause of your fatigue, contact us.

If you live outside the Colorado area, look for someone trained by the Institute of Functional Medicine (IFM), who had been Board certified by the Academy of Integrative Health and Medicine (ABIHM), or is a member of the International for Environmentally Acquired Illness.


Dr. Terri Rebibo Fox

Dr. Terri Fox is a holistic, integrative, functional medicine doctor in Boulder, Colorado. She works on your behalf as a medical detective searching for the underlying dysfunction, instead of just treating your symptoms. She has expertise in fatigue, bio-identical hormones, sleep disorders, gastro-intestinal dysfunction, and Chronic Inflammatory Response Syndrome from mold toxicity and Lyme disease.