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Why You’re Always Tired, According To Experts

If you’re always tired, you aren’t alone. In fact, chronic fatigue is a main reason for 10% to 20% of primary care visits, according to a 2021 literature review in the German medical magazine Deutsches Ärzteblatt International. 

Whether you’re having excessive daytime sleepiness or continuing to feel tired even after getting plenty of sleep, it’s important to understand the cause of your fatigue. Here’s what you need to know about common causes of chronic tiredness, from medical conditions to nutritional deficiencies and more.

Potential Reasons Why You’re Always Tired

Life requires energy in order to power your cells and keep your body functioning, says Samuel Werner, D.O., founder of Family Osteopathy in West Hartford, Connecticut. Ideally, your body operates at an energy surplus, but if you have depleted energy stores due to stress, hormonal issues or lack of sleep, you may feel tired, explains Dr. Werner. “Tiredness is a sign that you are operating at an energy deficit,” he adds.

While it’s normal to feel tired occasionally, chronic tiredness can be attributed to a multitude of causes, says Dr. Werner.

Inadequate Sleep

Most adults need seven to nine hours of sleep each night to function optimally, says Brooke Judd, M.D., section chief of Sleep Medicine at Dartmouth Hitchcock Medical Center in Lebanon, New Hampshire. , However, a third of adults routinely get fewer than seven hours of sleep a night, according to the Centers for Disease Control and Prevention (CDC).

Insufficient sleep can cause symptoms like tiredness, excessive daytime sleepiness, irritability and difficulty concentrating, says Dr. Judd. What’s more, chronic sleep deprivation is associated with an increased risk of mental health conditions, heart disease, high blood pressure, obesity, immune system impairment and increased pain sensitivity.

Medical Conditions

Many medical conditions can disrupt sleep and cause fatigue, says Po-Chang Hsu, M.D., a medical content expert at These conditions may include:

Obstructive sleep apnea, a sleep disorder characterized by abrupt pauses in breathing that cause frequent awakenings during the night, says Dr. Hsu. This condition often leads to fragmented, nonrestorative sleep, according to research.


When it comes to sleep apnea, people often do not know where to start. The first step is to get in touch or call 01 213 5644 to discuss your specific concerns and let us help you solve the problem and regain control of your night-time sleep.

Dental Sleep Medicine is an area of clinical expertise that focuses on the management of sleep-related breathing disorders, including snoring, noisy disturbed sleep, sleep apnea, CPAP intolerance a, nd sleep bruxism (teeth grinding), with the design and fitting of customised oral/dentalappliances. Click here to download the Beacon Dental Sleep Patient Brochure


For further information on Sleep Apnoea Treatment, contact us today 


Hypothyroidism, or a decreased production of thyroid hormone, is linked with shorter sleep duration, sleep offset (the time it takes to wake up) and reduced overall sleep quality, says Dr. Hsu. In general, fatigue is a common symptom of hypothyroidism.

Cancer and cancer treatment may cause chronic exhaustion due to surgery, infection, changes in hormone levels, low blood counts or low electrolyte levels. Furthermore, during chemotherapy or radiation, healthy cells are damaged alongside cancerous ones, and because the body uses energy to repair damaged cells, chronic exhaustion may occur, says Dr. Hsu.

Chronic fatigue syndrome is characterized by overwhelming fatigue. While the cause of the condition is unknown, common triggers include severe psychological stress and viral infections, says Dr. Hsu.

Multiple sclerosis (MS) is a disease that can cause extreme fatigue. In fact, fatigue affects 75% of MS patients, according to an article in the journal Sleep. Potential causes of MS-related fatigue include damage to the brain and central nervous system, but this symptom is still poorly understood, according to research.

Chronic Kidney disease causes fatigue in about 70% of patients. This is likely caused by a buildup of toxins in the blood and/or anemia, a condition in which the body doesn’t produce enough red blood cells resulting in a lack of oxygen being delivered to organs, a common complication of kidney disease.

Patients with Diabetes mellitus type 1 or 2 commonly experience fatigue due to a lack of insulin in the body. As a result, cells don’t get the glucose, or energy, they need to function normally, which can lead to exhaustion, explains Dr. Hsu.

Fibromyalgia is characterized by severe and widespread bodily pain that can negatively impact a person’s quality of life and sleep, leading to low energy levels and fatigue, says Dr. Hsu. Additional fibromyalgia side effects like unrefreshing sleep, anxiety, depression and cognitive difficulties may worsen fatigue.

Infection (bacterial, viral or parasitic) can cause fatigue as the body’s immune system attempts to recover, says Erica Steele, a naturopathic doctor at Holistic Family Practice in Virginia Beach, Virginia.

Menopause often causes sleep disturbances due to changes in hormone levels, hot flashes, night sweats and other factors.

Lack of Physical Activity

Physical activity levels can impact fatigue, says Maddie Pasquariello, a registered dietician at Nutrition with Maddie in Brooklyn, New York. “While a strenuous bout of physical activity can make us feel more tired (as we use up energy and need to replenish it), regular physical activity a few times each week can actually boost overall energy levels,” she says.

Frequent exercise leads our bodies to produce more mitochondria,the part of the cell responsible for energy production, which increases the amount of energy our body can produce, Pasquariello says. A sedentary lifestyle, however, leads to diminished mitochondrial function, lower energy levels and fatigue.

Nutrient Deficiencies

Certain nutrient deficiencies, primarily deficiencies in vitamin D, vitamin B12 and vitamin C as well as sodium, zinc, magnesium, iron and fatty acids, can lead to fatigue, says Pasquariello. Vitamin D, which is made in our bodies following exposure to sunlight, is one of the more common vitamin deficiencies, she says. Overindulgence in unhealthy snacks and processed foods throughout the day, such as sugary drinks and baked goods can also be problematic, says Dr. Hsu. These foods cause a sudden spike in blood sugar and can cause feelings of a quick burst of energy followed by a sudden drop in energy levels, resulting in daytime tiredness, he explains.


Daily and chronic stress are among the top reasons for poor sleep and insomnia, says Dr. Hsu. Internalized stress can originate from holding onto difficult emotions, a lack of emotional coping mechanisms or an inability to communicate feelings or thoughts, adds Dr. Steele.

What’s more, individuals who have experienced unresolved trauma have a tendency to be hypervigilant, meaning their brains remain in an increased state of alertness, making it harder to sleep, says Dr. Steele.

Depression and Anxiety

Many mental health and behavioral conditions can contribute to chronic fatigue and/or sleep issues, says Aaron Sternlicht, an addiction specialist and co-founder of Family Addiction Specialist based in New York City. For example, depression, or low mood, can cause fatigue and insomnia, he adds.

“Anxiety is another common mental health issue whose symptoms include fatigue and sleep disturbance,” says Sternlicht. If continuous exhaustion or sleep issues are not related to a physical health issue, Sternlicht recommends seeking out a mental health professional for an evaluation.


Caffeine intake impacts the quality and quantity of our sleep, says Pasquariello, and drinking too much caffeine can cause insomnia. Caffeine has a half-life of about five to six hours, so if you have a cup of coffee at 9 a.m., only half of it remains in your system by 3 p.m. (which is when many people start to feel drowsy or sluggish), explains Pasquariello.

“The more caffeine we drink over the course of the day, the more it [may start] to eat away at the quality and quantity of sleep we get,” she says.


Water plays vital roles in our bodies: It’s responsible for distributing nutrients around our cells, removing waste, regulating temperature and more, says Pasquariello. “When we’re dehydrated, these core functions can’t happen, and our bodies react to preserve energy, making us feel sleepy,” she says.

Dehydration can also make the blood thicker, making it harder for the heart to pump blood throughout the body, which can contribute to fatigue, adds Dr. Hsu.


Individuals with obesity can be at higher risk for fatigue and daytime sleepiness, regardless of whether they also experience sleep apnea and general loss of sleep, says Pasquariello. This may be due to co-occuring conditions, such as diabetes, depression and metabolic disease, she says. These conditions are not exclusive to individuals with obesity, but obesity increases the risk of each.



Excessive alcohol use leads to poor sleep quality, says Sternlicht. “Although alcohol can help individuals fall asleep, it disrupts rapid eye movement (REM) sleep,” he says. REM sleep begins about 90 minutes after falling asleep and is the period of sleep in which the majority of dreaming occurs. Your eyes move rapidly from side to side, and your limbs become temporarily paralyzed during this stage of sleep. Alcohol’s sedating effect wears off after a few hours, leading to fragmented sleep the rest of the night, and chronic alcoholism is related to major sleep disruptions, according to a 2018 study in the Handbook of Clinical Neurology.


Certain medications may impact sleep quality or cause sedation (tiredness) during the day, says Dr. Judd. Medications that may make it more difficult to sleep include stimulant medications, antidepressants (bupropion, or Wellbutrin, in particular), inhaled corticosteroids, oral corticosteroids (like prednisone), decongestants containing pseudoephedrine or phenylephrine and beta-blockers. If you have difficulty sleeping or feel tired during the day, ask your health care provider whether any of your medications may be contributing to your fatigue.


Seasonal and year-round allergies commonly cause fatigue due to symptoms, such as congestion, sneezing and generally not feeling well, can make getting high-quality sleep difficult. The release of histamines caused by allergic triggers also causes fatigue.


How to Improve Energy Levels

If you’re feeling tired all of the time, there are many measures you can take to improve your symptoms.

  • Practice good sleep hygiene: The CDC recommends sticking to a consistent sleep schedule, which means going to bed and waking up at the same time each day, even on weekends. Make sure that your bedroom is dark, comfortable and free from electronics, and avoid eating large quantities of food or drinking alcohol or caffeine close to bedtime.
  • Get moving: Even a light walk or a simple cardio exercise for 20 minutes is beneficial, says Dr. Hsu. The key is consistency, especially if you’re sedentary during the day due to work or school.
  • Eat a healthy diet: Nourishing, balanced meals with plenty of protein, complex carbohydrates and a source of healthy fat can help stabilize your energy throughout the day, says Pasquariello.
  • Consider taking supplements: If you know that you’re lacking certain vitamins, minerals and/or electrolytes, supplements can help optimize your energy levels, says Dr. Steele.
  • Spend time outdoors: Going outside shortly after waking in the morning can help increase your Vitamin D intake and reset your circadian rhythm, which relies on light input, says Dr. Werner. About 10 to 15 minutes of sunlight each day is enough to enhance vitamin D production, according to research.
  • Practice stress reduction techniques: Engaging in activities like meditation, yoga and journaling may help reduce anxiety, says Sternlicht. Writing down all of your lingering thoughts and worries at the end of the day, called a “brain dump,” can be helpful in reducing stress, he adds.
  • Limit caffeine: Caffeine generally stays in your system for at least six hours after consumption, meaning caffeine intake later in the day can negatively impact your sleep, says Sternlicht.
  • Stay hydrated: Water is essential, but it’s easy to forget to drink enough, says Pasquareiello. Keeping a pitcher of water at your desk or even setting a reminder on your phone to drink a glass every few hours can help maintain your water intake throughout the day, she says.
  • Avoid alcohol: Sternlicht advises abstaining from alcohol to support sleep. If you do imbibe, try to stop drinking at least two to three hours before going to bed to avoid sleep disruption.

When To See A Doctor

If lifestyle changes don’t improve your sleep or energy levels, there may be an underlying physical or mental health issue that’s contributing to your fatigue, says Sternlicht. Additionally, if your fatigue or sleep disturbance consistently impacts your life in a negative way, contact your health care provider, he says. “Chronic fatigue or insomnia tend to exacerbate over time and can lead to other mental or physical health issues if not addressed,” says Sternlicht.


Beacon Dental Sleep Medicine Clinic is based in the Beacon Dental Clinic, Beacon Consultants Clinic, Dublin, D18 E7P4, Ireland

Tel: +353 01 5310088| Fax: +353 1 213 5645 | Email:


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