Tired All the Time? Here’s What Could Be Behind Your Fatigue

Laine Bergeson Becco
Medically Reviewed
April 17, 2020

Feeling tired all the time is a symptom many doctors brush off—and, of course, sometimes the equation is simple: if you’re a new parent getting up multiple times a night with your baby, it makes sense that you’re tired. Or if you’re working on a big (but temporary) project at work, you might feel more run down than usual.

But sometimes feeling fatigued all the time is an indicator that something else is going on.

“When someone is tired all the time, the key question is: Is it just sleepiness or is it an internal experience of exhaustion,” says Parsley Health San Francisco physician Dawn Jacobson, MD . If the source of the problem turns out to be something beyond not enough sleep , it warrants further investigation to identify the root cause. Feeling tired all the time can signal a variety of different imbalances in the body, from hormone disruption to thyroid issues to a nutrient deficiency. Even if lack of sleep or poor quality sleep turns out to be the root cause, it deserves attention. Disruptions in the sleep-wake cycle are associated with a variety of chronic conditions and erode quality of life.

Here are some of the top causes of day-in and day-out exhaustion, how and why they crop up, and what to do if you suspect one of them is happening to you.

1. Regular circadian disruption

Short-term disruptions in the circadian cycle are part of life from time-to-time—you have a new baby or a new puppy, are up late one night finishing a big project, or you’re honeymooning in Thailand and the jet lag hits you like a truck. Those are part of life.

But regular disturbances in the sleep-wake cycle can contribute to feelings of fatigue, and it’s not uncommon for people to experience ongoing interference in their sleep-wake cycle. “Circadian rhythm disruption is very common in my practice,” says Jacobson.

Because the downstream effects of chronic circadian rhythm disruptions can be significant, it is important to identify and address them. What are some of the top causes of irregular, insufficient, or poor quality sleep? Shift work is a common cause, or jobs with long, taxing shifts like truck driving. People who travel to different time zones for work each month. “People travel to Asia or the East Coast regularly from San Francisco, where I’m based,” says Jacobson.

Other factors play a role, too. “I like to tell people that circadian disruption isn’t just about sleep anymore,” says Jacobson. “It’s also about when you eat.” Eating a big meal late at night can disrupt the body clock, throw a wrench in the sleep-wake cycle, and leave you feeling tired all the time. “We know from various research that it is not healthy to eat a large meal at midnight,” continues Jacobson. She adds that she expects more research to come out in this area and shed light on how and why food timing plays such a big role.

The advice she gives patients now is: “Eat during daylight hours. Just eat when the sun is out and don’t eat when it isn’t.” If you do shift work or travel frequently for work or pleasure, talk with a trusted healthcare professional about ways to minimize the circadian impact.

2. Sleep apnea

Sleep apnea is a disorder in which breathing stops and starts during sleep and it affects up to 22 million Americans . One of the top signs of sleep apnea is feeling exhausted after a full night’s sleep. The causes of sleep apnea vary. Sometimes the brain doesn’t send the right ‘stay open’ signals to the muscles that control your airways, and some people are born with narrow airways that predispose them to sleep apnea.

Carrying excess body weight is also a risk factor for sleep apnea—it can put extra weight on your throat when lying horizontal, causing the airway to temporarily collapse—but it is a myth that the condition only affects those who are overweight or have obesity, says Jacobson. She’s encountered sleep apnea in many different groups of people, including those at a healthy weight and younger folks. Other risk factors include age, smoking, chronic congestion, diabetes, high blood pressure, and asthma.

If you find yourself dragging, day after day, but you appear to get a good night’s sleep, ask your doctor about being checked for sleep apnea. It’s important to catch the condition as early as possible because, left untreated, the condition has been associated with a variety of serious conditions , including cardiovascular disease, diabetes, depression, high blood pressure, headaches, and stroke.

3. HPA axis dysregulation

The hypothalamic-pituitary-adrenal axis, or HPA axis, is a triad of glands that’s part of the biological system that controls the body’s stress response. When the signaling between these glands is off, or dysregulated, symptoms include persistent fatigue, brain fog , and trouble falling asleep and/or staying asleep.

Chronic stress is a risk factor for HPA dysregulation. “When the adrenal glands secrete stress hormones all the time, eventually that revved-up response doesn’t ever fully resolve. “It just continues on a regular basis,” says Jacobson. “The ‘turn off’ mechanism of the stress response stops turning off.” Lack of sleep and/or overdoing caffeine can make HPA dysregulation worse.

One of the telltale signs of HPA axis dysfunction is feeling tired but wired, or being exhausted but not being able to fall asleep. If you suspect HPA dysregulation is the cause of your fatigue, check with a functional medicine practitioner. “This is where functional medicine really shines,” says Jacobson. “We really want to understand the stress response in the body.”

4. Nutrient deficiencies

When a patient presents with chronic fatigue, says Jacobson, it’s important to rule out nutrient deficiencies like low iron or low B vitamin levels. “You want to make sure those numbers are solid,” says Jacobson. “Those are easily treated with food and temporary supplements .” It’s also important to check iodine, which plays an important role in hormone production. At Parsley Health, your practitioner may run a 24-hour urine iodine test and a complete blood panel to check for micronutrient deficiencies.

5. Thyroid disease

Thyroid disease, like Hashimoto’s thyroiditis, is common, notes Jacobson. So is having a sluggish or underperforming thyroid gland, even if it doesn’t meet the parameters for an official diagnosis. One risk factor is the simple, unavoidable act of aging, which is correlated with decreased production of thyroid hormone. Chronic fatigue is a common symptom of thyroid trouble, along with other problems like thinning hair , weight loss resistance, and difficulty with body temperature (always feeling cold).

If you suspect a thyroid issue , ask your doctor for a full thyroid test panel, like we do at Parsley Health. “We don’t just do a TSH,” says Jacobson. (TSH stands for thyroid stimulating hormone.) It’s important to test the levels of all the different thyroid hormones that might be at play. “We want to figure out the different levels of T3 and T4, and I like to measure the ‘free’ versions of those because they are the most active in the body.” Jacobson is also interested in a patient’s level of reverse T3, which is what puts the brakes on the thyroid hormones.

6. Mitochondrial dysfunction

More and more, researchers are looking at problems with the mitochondria—which are the engines of our cells—as a cause of chronic fatigue and other health problems. Mitochondrial dysfunction is linked to oxidative stress and inflammation , which are known enemies of good health.

“A lot of this is still being studied,” says Jacobson. But it is a hot area of research that has scientists intrigued, and that is already starting to produce helpful interventions for sluggish or inefficient mitochondria. Supplements such as NAD and NAC may help with mitochondrial dysfunction. A physician familiar with mitochondrial dysfunction, like those at Parsley Health, can run tests to assess the health of your mitochondria and suggest supplements and other supportive strategies.

Ultimately, by finding the underlying reason for why you’re so tired all the time, you’ll be able to begin a path to healing and find your energy again.

Laine Bergeson Becco

Laine Bergeson Becco is a freelance journalist, ghostwriter, and functional-medicine certified health coach. She recently won a Folio award for Best Range of Work by Single Author for her writing in Experience Life magazine. In her spare time, she is an avid jigsaw puzzler and a mediocre piano student.

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