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What's Causing Your Fatigue? Ten Reasons You're Tired and How to Get Your Energy Back

Fatigue. You know that horrible feeling like you're constantly dragging - almost as if you're fighting to make it through the day, or past your next ___fill in the blank___?

The good news is this: our bodies are not betraying us. Instead, fatigue is a warning sign and a mechanism that keeps us safe. It might be a signal that you're putting your body through more than it can handle (knowingly or unknowingly), and it's slowing you down so you can continue to survive.

Your job? Listen to it.​​

And then, consider what you can do to help your body out! Here are our top 10 reasons why you might be so darn tired and what you can do about it. See what resonates with you, and take baby steps with our suggestions to toward feeling like your awesome, full-of-energy self again.

1. Dehydration

Yes. Sometimes it's that easy. Some estimations have found that up to 75% of us are not drinking enough water. When you're dehydrated, your blood is thicker, making it more difficult to distribute nutrients and oxygen throughout your body. You can do a quick test for dehydration by pinching up the skin on your knuckles or the back of your hand. If it takes longer than a couple of seconds to spring back, you might be dehydrated.


  • Track your water intake for a few days and get a gauge of how well you're hydrating. Shoot for half of your body weight in ounces.

  • Water is preferred, but if you can't stand plain water, try adding a squeeze of lemon or infuse with fruit. Or, try sparkling water.

  • Try to avoid dehydrating/diuretic beverages like coffee or high-sugar fruit juices that can actually contribute to dehydration; these don't count toward your daily hydration goal.

2. Vitamin D Deficiency

Vitamin D is a critical nutrient for generating energy and helping with calcium -- and in fact, it's not a vitamin at all, but a hormone. Your body can make some of its own, but several studies are showing now that sunlight alone, especially when you live in areas that aren't sunny year-round, is not enough. The journal Medicine notes that vitamin D deficiency is commonly found in patients experiencing fatigue; raising vitamin D to sufficient levels significantly reduced symptoms of fatigue. In addition, Vitamin D has shown great results in treating depression.

Don't blindly trust a high/low flag on a lab test to tell you if you're deficient: You could still be deficient, even if your doctor or lab result indicates you're normal. Why? Reference ranges you get from conventional labs indicate illness, like rickets, in the case of Vitamin D. On the flip side, functional ranges tend to be higher because this is the window in which someone feels healthy and well - not just "not-sick." References ranges for Vitamin D are generally around 30 ng/mL, but the Vitamin D council recommends a minimum of 40 ng/mL. Many functional medicine practitioners will aim for a window between 50-80 ng/mL. Over 100 ng/mL starts getting into overdose territory where fatigue and symptoms like stomach cramping and nausea can occur.

Also, you might be burning through vitamin D faster than usual if your immune system is over-activated (like if you're fighting a cold or virus).


  • Ask your doctor to check your Vitamin D levels (specifically the 25(OH)D test, not the 1,25(OH)₂D test) and supplement accordingly to raise up to a maintenance level.

  • Consider working with your doctor to determine why your levels may be low to begin with.

  • And get some sun!

  • Check out our guide on Vitamin D for more info and tips.

3. Nutrient deficiency

There are other nutrients that are important for energy, like B12 and iron/ferritin. Sometimes, all it takes is replenishing your stores and investigating why so you can prevent recurrence.

If you're severely low in either of these nutrients, you may even discover anemia - the condition in which your red blood cell count is too low. When you have too few red blood cells, you'll notice that you get winded much easier, or your endurance is less than it used to be. Anemia can be caused by low B12 or iron. Pernicious anemia is an autoimmune condition in which your immune system is destroying your ability to absorb and use B12. Anemia happens most often in women due to menstruation and loss of additional iron through blood.

Other important nutrients that could be contributing to fatigue include: Vitamin C, magnesium, sodium, L-tryptophan, L-carnitine, coenzyme Q10, and essential fatty acids.


  • Talk to your doctor about testing your nutrient levels, particularly B12 and Iron/Ferritin.

  • Be careful not to blindly supplement, as overdosing on some of these can have disastrous effects!

  • Support digestion with digestive enzymes to break down food & get more nutrients from the food you're eating.

4. Adrenal Dysfunction or Stressed Adrenals

Between the thyroid and adrenals, these two glands control virtually every aspect of our metabolism, including energy production and storage. The adrenals pump out cortisol to help keep us alive, and it's cortisol's job to regulate our circadian rhythm, fat storage, and also prioritize other body functions. When your body is under stress, cortisol is dispatched to come to your rescue. Over time, if you're constantly stressed & sending out massive amounts of inflammatory cortisol to boot, your brain (the hypothalamus) will turn down the volume on cortisol to protect your body from further damage. That's when the tiredness sets in because you simply can't any longer.

Stressors aren't just emotional. They can include: blood sugar dysregulation, over-exercise, high toxic burden, and perceived mental stress (like that presentation you had to give for a group of 50 people at work).

Do you have adrenal dysfunction? Symptoms vary, but at the point of fatigue, you'll notice a drop in endurance and maybe experience being tired-but-wired. You might also notice elevated (LDL) cholesterol and hold most of your weight around your mid-section.


  • You can test for adrenal dysfunction with a saliva collection test.

  • Support the adrenals with herbal supplements called adaptogens, and feed them plenty of vitamin C.

  • Check out our blog post for more strategies to heal the adrenals & reverse your fatigue.

  • Also, get at least 8 hours of sleep per day -- in experiments, scientists generally use sleep deprivation as the fastest way to induce adrenal dysfunction in lab rats.

5. Low Thyroid Function

The thyroid is the other thermometer for the body and it has the power to turn down all of our metabolic processes, including energy production, when our bodies are in survival mode. There are several root causes for low thyroid function, including: toxicity, food intolerances, nutrient depletions, stress (physical or mental), and more. When we're under stress, our bodies can also produce a hormone called Reverse T3, which is a look-alike for active thyroid hormone, but it's like a key that fits in the door but doesn't turn the deadbolt lock. We feel tired as a result because RT3 is blocking usable thyroid hormones.

If you've been diagnosed with hypothyroidism, you might be within the 90-95% of the hypothyroid patient population with autoimmune thyroiditis (Hashimoto's). It might be hypothyroidism if you notice whole-body weight gain (vs. around the mid-section), dry skin, or are simply missing the outer third of your eyebrows. It's a strange indicator, but it's true! People with hypothyroidism tend not to sweat very heavily either.


  • If you suspect hypothyroidism, get your thyroid checked: TSH, Free T4, Free T3, Tg and TPO Antibodies, and Reverse T3. Also note functional versus reference ranges, looking first for a TSH between 1.0 - 2.0.

  • There is much you can do to reverse hypothyroidism, starting with quick hits like specific nutrition for your thyroid, and eliminating iodine from food or salt.

  • Consider working with a coach to address the many root causes & heal your thyroid.

6. Viral or Bacterial Infection and Parasites

We have lots of critters living inside us, some friendly and some not-so-friendly.

Here are a few types, all which can can become active (reactivated) in times of stress:

  • Epstein-Barr/mono virus - as much as 90% of the population carries this virus

  • Borrelia Burgdorferi - associated with Lyme disease

  • Human Herpes Virus - HHV-6

  • Cytomegalovirus - CMV

  • Parasites

These viruses can infect the DNA of our cells and insert themselves into body tissues. They can cause inflammation that affects our mitochondria (the energy factories within our cells), or even immune system confusion. For example, the Epstein-Barr virus has been studied & found to live inside thyroid cells. When the immune system attacks the virus, it also attacks the thyroid gland in the process (which would then be autoimmune).

You might suspect a virus if you've experienced sudden and debilitating fatigue after a stressful event or few weeks. Parasite symptoms are more interesting - grinding your teeth in your sleep, bloating, gas, achy-ness, and nutrient deficiencies. Parasites & bacterial infections can often set in after food poisoning, or international travel after you've been exposed to environments and pathogens that are out of the ordinary for you.


  • It's worth getting tested, because taking action without a diagnosis/confirmation can be pretty harmful. Parasites involve a stool test.

  • Vitamin C tends to be helpful for fighting viruses, as well as getting enough sleep and all of the actions you would take to support your adrenals - this gets your body in an ideal state to repair & recover.

  • There are herbal ways to treat these organisms without destroying your gut with antibiotics, and an integrative or functional medicine doctor is a great place to start.

7. Toxicity

A heavy toxic load can cause strain on your liver. The liver also plays a big role in energy storage and production, as well as converting and creating active thyroid hormone. When the liver gets backed up, you'll notice elevated liver enzymes on your labs, as well as symptoms like brain fog/difficulty concentrating, constipation, muscle aches, digestive issues, difficulty sleeping, headaches, hormone imbalance, mood disorders, and skin issues.

The things that can add to your toxic load include:

  • Heavy metals - copper, lead, mercury, aluminum, nickel

  • Radiation - gadolinium from MRI imaging, EMF from air travel or use of electronics

  • Chemicals - plastics/BPA; hormone disruptors from cosmetics, perfume, hand soap, laundry detergent; fire retardants from furniture and mattresses; pesticides; exhaust

  • Mold - mold and worse, their by-product, mycotoxins can poison your household, causing inflammation and immune reactivity.

If you've been busting your butt eating perfectly and working out enough, but you still can't seem to lose that stubborn weight, consider toxicity -- toxins get stored in fat cells, and detoxing can release them.


  • We're fans of gentle, food-based detoxes because detoxing too fast can cause worse symptoms & health issues if they get mobilized and lodged in other places (like your brain!).

  • Incorporate more greens & colorful veggies into your diet.

  • Reduce your toxic load by healthying-up your personal care & cleaning products at home.

  • Check out for a toxicity score for virtually every product you use.

  • Try sauna, exercise/sweating, and dry brushing to move toxins out of your system.

8. Poor Sleep Quality

Poor sleep can lead to the other challenges described above, like compromised liver function and stressed adrenals. A few consistent nights of restorative sleep could turn around your fatigue in a matter of a few days.

Check first if you have any sleep issues - take this quick quiz to determine if you could be within the 20% of the population that has sleep apnea, a condition in which you stop breathing multiple times while you sleep.


Hack your sleep.

  • Try liposomal melatonin or magnesium citrate before bed (bonus: Mg citrate keeps your bowels regular, to help with detox)

  • Dim the lights everywhere 15-30 minutes before you go to sleep.

  • Try meditating before bed

  • Use the blue-light blocker apps on your phone or computer to avoid triggering the wake-up hormones that could keep you awake.

  • Try blackout curtains or a sleep mask.

  • Unplug and move electronics at least 8 feet away from your head or bed to avoid disruptive radiation from EMFs.

  • As tough as this may be, kick your fur babies out of bed - this could make a big difference!

9. Food Intolerance/Sensitivity

Eating foods you can't tolerate or are sensitive to can cause inflammation and strain on your body/immune system. Fatigue is a common symptom of a food intolerance, and it's a sneaky one because food intolerances/sensitivities can display delayed symptoms as late as 48 hours after you eat a particular food. This is why personalizing diet & nutrition plans is so important -- as an example, carrots can be generally considered healthy for all people, but if you have an intolerance to carrots, eating them may cause more harm than benefit.

If you've got a food sensitivity, intolerance, or even an allergy on your hands, you might notice symptoms like bloating/gas, diarrhea or constipation, undigested food in your stool, skin issues (like acne), overall lethargy, or anxiety.


  • Keep a written food journal and track any and all symptoms, including gut/digestive issues, tiredness, skin condition, etc.

  • See if you notice any patterns, and do a trial of eliminating the offending food.

  • Common offenders include: gluten, dairy, soy, sugar, alcohol, nuts, eggs, nightshades (ex: tomatoes, peppers)

10. Low Blood Oxygenation - Poor Circulation

What do humans need in order to live and thrive? Oxygen. Our cells need two key ingredients, glucose and oxygen, in order to create ATP - energy. Without it, we feel exhausted because we can't generate energy at the cellular level. Later on down the process, poor circulation can prevent oxygenated blood from reaching all parts of your body, commonly the head/brain feet, and hands. A great way to check is by looking at your nail beds - are they white or pink? (Pink means sufficient circulation.) How cold is the tip of your nose?


  • Exercise is one of the best ways to improve circulation, particularly high-intensity interval training (HIIT)

  • Belly-breathe. Can you recall the last time you breathed all the way down to your diaphragm? Close your eyes, and take a long, deep breath through your nose. Exhale through your mouth or nose. Repeat 3-5 more times.

  • Restrict coffee consumption. Research shows that caffeine restricts the blood vessels in the brain.

  • Do yoga. Exercise, particularly yoga, focuses on enhancing circulation, and even simple forward folds are inversions that can get blood flowing to all extremities.


What Else Can You Do?

We've only just scratched the surface with our Top Ten list. In addition, you may have some unique causes for your fatigue, and a functional medicine doctor or health coach could help you identify and address them.

For additional guidance and support on your particular case, get in touch with a coach and decide if hiring one is the right choice for you to tackle your fatigue.

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