Why Are You Always Tired? 16 Reasons for Excessive Fatigue Beyond the Afternoon Slump

Picture this: It’s 2PM, and you’re itching to reach for a pick-me-up coffee. Sound familiar? Experiencing low energy in the middle of the afternoon, or an “afternoon slump,” is fairly common. But maybe you’re feeling tired all the time, no matter how much sleep you get, and you’re wondering why. 

While there are normal variations in energy levels, other factors might contribute to frequent tiredness. Sometimes, minor lifestyle changes can help boost your daytime energy. But in some cases, an underlying medical condition could be the reason you feel tired all the time. 

Let’s take a closer look at reasons you may be feeling tired and when it might be time to schedule a visit with a healthcare professional. 

Why do you always feel exhausted?

It turns out there are many possible reasons for low energy and excessive fatigue. Many people feel tired in the afternoon — this is common. But sometimes, that feeling of sleepiness isn’t limited to an afternoon slump. While it’s normal to feel burned out from time to time, being tired all the time is not.

If nothing in your life has changed and you still don’t have enough energy to get through the day, it may be worth talking to a healthcare professional to see if there’s an underlying reason for your fatigue. 

Lifestyle reasons for feeling tired all the time

When it comes to feeling tired, a hectic lifestyle can play a big role. Some lifestyle habits are easy to change and can have a big impact on daytime fatigue. 

Here are five common reasons your lifestyle might make you feel tired all the time.

1. Not getting enough sleep

Not surprisingly, if you don’t sleep enough at night, you’re going to feel more tired during the day. But many of us don’t realize when we’re not getting enough sleep. The recommended amount of sleep for most adults is around 7 to 9 hours each night. Research shows that 1 in 3 adults in the U.S. aren’t getting enough sleep on a regular basis. 

2. Not getting quality sleep

Maybe you’re technically getting enough sleep, but the quality of your sleep is poor. If you wake up frequently at night, you may feel tired throughout the day. Conditions that interfere with quality sleep include: 

• Obstructive sleep apnea 

• Gastroesophageal reflux

• Restless legs syndrome

• Sleep disorders 

EXPERT PICKS: WHAT TO READ NEXT

• Is your medication making you sleepy? These prescription medications commonly cause fatigue.

• Dietary choices and fatigue: The foods you eat can affect how tired you feel.

• Chronic fatigue syndrome: Learn more about the causes, symptoms, and treatment of this condition.

3. Excessive stress

Chronic stress can sometimes lead to chronic fatigue. While researchers aren’t certain exactly how the two are connected, there’s some evidence that persistent stress can lead to chronic inflammation, making you feel more tired. Adding to the cycle, not getting enough sleep makes you more prone to stress.

4. Exercise

Exercising too soon before your bedtime might actually boost your energy levels and make it harder to fall asleep. Experts generally recommend avoiding exercise in the evening for this reason. But a meta-analysis published in Sports Medicine found that exercise only interfered with sleep if it was vigorous and done within an hour of going to sleep. So, you don’t need to worry about going for an evening jog as long as it’s not immediately before bedtime.

5. Too much caffeine

Consuming caffeine can make it harder to fall asleep, decrease the amount of time spent sleeping, and worsen the quality of the sleep you do get. This effect is more pronounced in some people than others. As you get older, you tend to become more sensitive to caffeine. So, if you’ve “always” had an afternoon latte without any trouble but have lately found it harder to fall asleep, consider that you may have become more sensitive to caffeine’s influence. 

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Medical conditions that may cause fatigue

Medical conditions are common causes of being chronically tired. Medications and illness can take a toll on you mentally and physically which can negatively affect your energy and sleep. 

Here are 11 of the common medical conditions that can cause fatigue.

6. Depression

When a person has depression, they often have low energy or feel fatigued. In fact, fatigue is one of the core criteria used to diagnose depression. 

To make matters worse, experiencing depression often makes it difficult to fall asleep, which can make the fatigue even worse. 

7. Menopause

Menopause refers to the stage in which you haven’t had a period for a full year. The average age at which menopause occurs is 52, but shifts in hormones usually start in your mid-40s. 

Perimenopause refers to the stage of life when hormones begin to decline, leading to more irregular periods. Both perimenopause and menopause are associated with fatigue.

8. Iron deficiency (with or without anemia)

Iron is an important building block of red blood cells, which carry oxygen throughout your body. When your iron levels are low, the number of red blood cells can decrease, leading to iron-deficiency anemia. This condition is especially common in people who menstruate, follow a vegetarian diet, or have reduced iron absorption. 

In recent years, more attention has been given to the diagnosis of iron deficiency without anemia. This happens when your iron stores are low, but this hasn’t yet caused a drop in the number of red blood cells. Even if you don’t develop anemia, an iron deficiency can lead to many of the same symptoms. Apart from making you feel tired all the time, an iron deficiency can cause symptoms like:

• Dizziness

• Leg cramping

• Shortness of breath

If you’re concerned that you may have low iron or iron deficiency anemia, talk with a healthcare professional about which tests are right for you. 

9. Thyroid disorders

Thyroid hormones are essential for regulating metabolism and the growth and development of organs throughout your body. If your thyroid hormones are out of balance, it can lead to a variety of symptoms, including fatigue. Feeling tired all the time can be one of the main presenting features of hypothyroidism, a condition in which your body doesn’t make enough thyroid hormone. 

In addition to fatigue, a person with hypothyroidism might also experience:

• Weight gain

• Hair loss

• Depression

• Constipation

• Dry skin 

10. Medications

Certain medications are known to cause sleepiness. If you feel tired throughout the day, check to see if fatigue is a known side effect of any medications you take. Some of types of medications that commonly lead to sleepiness include:

• Antidepressants, including serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs)

• Antihistamines like diphenhydramine (Benadryl) or hydroxyzine (Unisom)

• Beta blockers like propranolol (Inderal) or metoprolol (Toprol)

• Benzodiazepines like lorazepam (Ativan) or alprazolam (Xanax)

• Muscle relaxants like cyclobenzaprine (Flexeril) or tizanidine (Zanaflex) 

• Topiramate, a medication used for seizures, migraines, and weight loss

• Opioids like oxycodone (Roxycodone) or tramadol 

11. Illness

Anyone who has ever spent a few days in bed fighting off the flu knows that sleepiness is a natural result of your body’s immune system fighting off an infection. Fatigue is a common symptom of many different types of infection. 

But sometimes the sleepiness doesn’t resolve when the infection goes away. This is especially true in viral infections like COVID-19. Post-viral fatigue refers to the exhaustion that lingers even after the other symptoms of a viral infection have resolved.

Experts don’t know why post-viral fatigue happens. But one theory is that the inflammation involved in fighting off the virus might lead to inflammation in the brain, causing persistent fatigue.

12. Pregnancy

Fatigue is very common during pregnancy. Some people feel exhausted throughout their entire pregnancy, while others may not feel nearly as tired. The first trimester is when fatigue is most common. It tends to get better during the second trimester but often returns in the third. 

There are many reasons for this, ranging from hormonal changes to anxieties around parenthood. As the pregnancy progresses, it’s often harder to get good sleep at night due to factors like reflux, changes in body position, and the frequent need to urinate. 

13. Diabetes

Feeling exhausted when you have diabetes is so common that some have proposed labeling it as “diabetes fatigue syndrome.” The fatigue caused by diabetes might be related to a combination of nutritional and lifestyle factors, psychological factors, and hormonal or medical factors. 

In some cases, feeling tired all the time can be the first sign that you’re developing diabetes. Besides sleepiness, diabetes can bring about symptoms like:

• Frequent thirst and urination

• Dry mouth

• Headaches

14. Narcolepsy

Narcolepsy is a rare sleep disorder that causes extreme sleepiness throughout the day and occasional sleep attacks, in which you’re overcome with the need to sleep. It usually starts between late childhood and early adulthood, and some people don’t receive a diagnosis for years. 

Apart from feeling tired all the time, no matter how much you sleep (a symptom known as excessive daytime sleepiness), other symptoms of narcolepsy include:

• Cataplexy: The sudden loss of muscle tone and strength, often triggered by laughing. 

• Sleep paralysis: The inability to move or speak for a few seconds as you’re falling asleep.

• Hallucinations: Seeing or hearing things that aren’t actually there.

15. Fibromyalgia

Fibromyalgia is a condition that can lead to a variety of symptoms like:

• Exhaustion

• Generalized pain

• Brain fog

• Depression

• Anxiety

Scientists don’t fully understand what causes fibromyalgia, but a central component seems to be an increased sensitivity to pain. There’s no blood test for fibromyalgia, but the American College of Rheumatology has developed criteria to help make a clinical diagnosis based on symptoms. Although it can affect anyone, it occurs more often in women than in men. 

16. Anxiety

Anxiety is another underlying condition that can leave you feeling exhausted. If you’ve ever lain in bed at night with a racing mind, you know that anxiety can make it hard to fall into a peaceful slumber. 

This seems to be one of the main reasons that anxiety leads to fatigue — people with anxiety are more prone to repetitive thinking, which can lead to trouble sleeping. 

Symptoms of an afternoon slump vs. chronic fatigue

Keeping track of the timing of your symptoms can help you get a better handle on what’s causing them. If you experience sudden tiredness during the day, and the sleepiness is mostly limited to the afternoon, then it’s likely an afternoon slump. If you feel like you’re tired all the time, you may be developing fatigue that’s more chronic.

Signs of excessive, chronic fatigue can include: 

• Mood swings: Feeling tired all the time can dampen anyone’s mood. There’s a connection between sleep deprivation and mood changes. When you don’t get enough rest, it can make your afternoon slump worse by increasing anger and aggression. 

• Cravings: Studies have shown that sleep deprivation causes people to crave saltier, sweeter, and more calorie-dense foods. It might be tempting to grab an energy drink for a quick boost, but energy drinks can lead to dehydration, anxiety, and even worse sleep later on. Look for healthier alternatives when you have those cravings instead.

• Stress: Being stressed can affect your body’s ability to stay alert and refreshed. This can also negatively impact how much you sleep at night.

• Headaches: Fatigue can trigger headaches and migraines in some people. In a large study of migraine sufferers, half said that sleep disturbances contributed to their migraines. 

• Trouble focusing: Poor sleep can lead to problems with memory, attention, and cognitive performance. 

• Stomach aches and digestive problems: Inadequate sleep can cause disturbances in your gut health, leading to abdominal pain, constipation, and diarrhea. 

• Frequent yawning: You might find yourself yawning quite often when you’re very fatigued. 

• Difficulty with vision: When you feel tired, your eyes may twitch or spasm. Not getting enough sleep can also lead to light sensitivity and blurry vision, which can cause sight problems. 

How can I stop feeling tired all the time?

Thankfully there are proven techniques to help decrease fatigue. In addition to reaching out to a healthcare professional if you’re always tired, you can try many of these methods to get more energy during the day:

• Get more sleep: Choose your favorites from these 25 tips for better sleep. Even if you just start out with one small shift in your habits, every small change helps.

• Go outside more often: Exposure to the sun for at least 10 minutes per day boosts vitamin D production. Low energy or fatigue is a common symptom of vitamin D deficiency. Plus, exposure to sunlight or other bright light can increase wakefulness. 

• Eat balanced meals: A carb-heavy meal might be responsible for your sleepiness. Opt for a balanced lunch with fruits and vegetables, whole grains, and high-fiber foods for more energy.

• Take a quick nap: A short nap (15 to 30 minutes) can reduce sleepiness, increase memory retention, and make you more alert and responsive. A longer nap will probably make you more tired.

• Exercise: One of the quickest ways to increase your energy is to work out. Getting your blood and oxygen pumping can give you the boost you need to continue with your day. If you don’t have time to complete a full workout, take a walk or try stretching to get your blood circulating. 

• Reduce your stress levels: Decreasing your stress levels will help you get quality sleep. Data shows that adults with lower stress levels report sleeping more hours at night than adults with higher stress levels.

• Chew gum: It might surprise you to learn that the small act of chewing gum may increase alertness.

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Written by:

Karen Hovav, MD, FAAP

Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician in a variety of clinical settings. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

Edited by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

Reviewed by:

Frank Schwalbe, MD

Frank Schwalbe, MD, is an assistant professor of anesthesiology at the Yale School of Medicine. He has practiced anesthesiology for 30 years.

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