The most relatable statement of all time: “I’m exhausted.” Life is stressful, busy, and often feels like an impossible balancing act. Besides the demands of endless work tasks and social obligations, there are legit health reasons that could explain why you have lingering fatigue. If you're chugging coffee on the regular and still wondering, Why am I so tired? it's worth considering whether something that's happening in your body is the cause of your low energy level.
Obviously, if you stay up binging a new series or push yourself harder than usual while training for an upcoming race, you’re gonna feel sluggish the next day. But there’s a difference between feeling tapped out from time to time and long bouts of fatigue that just won't go away.
"Fatigue is chronic extreme tiredness," says Antoinette Price, MD, MPH, the senior chief resident of family medicine at the University of Illinois Hospital. From headaches, dizziness, achy and sore muscles to irritability, brain fog, and moodiness, fatigue manifests differently in each person.
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If you always feel drained, it may be time for you to see your doctor and talk these things through with them. If you feel like something is off, don’t ignore it―there are many health issues, both mental and physical, that can make it difficult for you to last through the entire day without wanting to collapse in bed. Here are all the possible causes for why you may be dealing with this issue, according to doctors.
1. Your allergies are acting up.
There are classic symptoms of seasonal allergies, like sneezing and having watery eyes. Then there are lesser-known symptoms, like low energy and fatigue. “If left untreated, seasonal allergies can cause fatigue,” says Purvi Parikh, MD, an allergist and immunologist with Allergy & Asthma Network. Why? Your body is working hard to fend off the allergen, and that requires extra energy. That’s true whether you have allergies to stuff outside, like ragweed or pollen, or issues with indoor allergens like dust mites, says Dr. Parikh.
It’s not just the allergens that can trigger fatigue issues—allergy medications can too. “Some of the over-the-counter allergy pills like antihistamine unfortunately cause fatigue as well,” says Dr. Parikh.
How to fix it: Struggling with feeling completely spent due to allergies is a sign that your current treatment plan isn’t working. So, check in with your doctor about your options. They’ll likely recommend medication (or a different one) to help get things under control. Running a HEPA air purifier in your home can also help clear up the air at your place, notes Dr. Parikh.
2. You’ve been more sedentary than usual.
While going hard during your at-home workouts can wear you out, the opposite can do the same. “The human body gets more tired with progressive sedentary habits due to generalized deconditioning of the body and, ultimately, muscle loss,” explains Sobia Khan, MD, an assistant professor of general internal medicine and the director of Women's Center for Comprehensive Care at Baylor College of Medicine.
Basically, your body takes a “use it or lose it” approach to fitness. And, if you don’t exercise regularly, you’re going to feel more tired when you actually start moving, and during the time when you're at rest.
How to fix it: This solution is pretty simple—get moving more. Just a reminder, the general physical activity recommendation is that you get 150 minutes of moderate-intensity exercise each week, along with two or more days a week of muscle-strengthening activity. Once you start moving again, it’ll be easier to get through your day-to-day stuff without being a zombie.
3. You’re overdoing it on sugar and refined carbs.
When you eat things that are sugary or high in refined carbs (think: white bread, pasta, pastries), it causes your blood sugar to spike, explains Jessica Cording, RD, the author of The Little Book of Game-Changers. In the moment, that can make you feel kinda hyper. But, unfortunately, you're also in for an inevitable crash, which can leave you feeling totally wiped.
If you continue overloading on a ton of sugar and refined carbs, you may also develop something known as insulin resistance in your body, adds Dr. Khan. That is when your body can’t use glucose (a.k.a. sugar) as well as it should for energy. The result: You just can't even.
How to fix it: Cut back on how much sugar and refined carbs you’re having on a regular basis, Cording says. FWIW, the CDC recommends limiting your intake of added sugars to less than 10 percent of your total daily calories. (So, if you eat a 2,000-calorie diet, no more than 200 of those calories should come from added sugars.)
When you’re going to have sugary or carb-filled foods, balance out the meal with some protein and fat, like adding nut butter atop your crackers. This can help lower the odds that you’ll crash afterward, Cording notes.
4. You’re stressed out big time.
Stress isn’t just a mental thing—it can affect you physically as well. “Your mind and body are closely linked and are in constant communication with one another,” says Monifa Seawell, MD, a board-certified psychiatrist in Atlanta, Georgia. “When there is a shift in your emotional state, be it positive or negative, it is not at all uncommon for that change to also show up in some physical way in your body.”
You can start getting headaches, an upset stomach, and, yep, fatigue, says Dr. Seawell.
How to fix it: Addressing the root of your stress is the best way to go. While some stressors are unavoidable, doing your utmost to limit stress that you can do something about can be helpful.
Dr. Seawell also recommends packing 20 to 30 minutes of exercise into your daily schedule. That can often help boost your energy levels when you can’t completely obliterate your stress, she says. If you’re still struggling, try talking to a licensed mental health professional. They “can help you process your emotions and learn healthy coping skills,” says Dr. Seawell.
5. You’re skimping on sleep.
Adults should be getting seven hours or more a night, according to the CDC. Definitely getting less? Enter: Fatigue.
“Minimum seven hours of sleep is required for effective rejuvenation of the body and restfulness of the brain,” says Dr. Khan. Here’s the thing: Even one night of bad sleep can mess with your circadian rhythm (your sleep-wake cycle) and throw you off for a few days, she says.
How to fix it: At baseline, the solution is simply to get more sleep. But, of course, sometimes that’s easier said than done. You need to first figure out what’s the culprit—stress? Netflix? Crappy sleep hygiene?—and then address it. If that still doesn't do the trick, talk to your doctor about your options. You may need an intervention such as cognitive behavioral therapy to treat insomnia, for example.
6. You’re dealing with depression.
Depression can cause a range of symptoms, and decreased energy or fatigue is definitely one of them, according to the National Institute of Mental Health (NIMH). “Whenever I am screening a patient for depression, feelings of fatigue and loss of energy is one of the symptoms I always inquire about,” says Dr. Seawell.
These are the symptoms of depression to be familiar with, according to the NIMH.
- Persistently feeling sad, anxious, or "empty"
- Feelings of hopelessness, or pessimism
- Irritability
- Feelings of guilt, worthlessness, or helplessness
- No longer feeling pleasure in your hobbies and activities
- Low energy or fatigue
- Moving or talking more slowly
- Feeling restless or having trouble sitting still
- Difficulty concentrating, remembering, or making decisions
- Difficulty sleeping or oversleeping
- Appetite and/or weight changes
- Ideation about death or suicide
- Pain, aches, headaches, cramps, or digestive problems that don't have a clear cause or get better with treatment
Worth noting: Not everyone with depression experiences every symptom, per the NIMH. So, it’s entirely possible for you to feel tired on the regular and not even realize that it’s due to depression.
How to fix it: This is another issue where you have to fix the problem that’s causing your fatigue before you’ll feel better. Depression can be treated with psychotherapy, medication, or a combination of the two. If you suspect that your fatigue is linked to depression, though, it’s best to talk to your doctor about getting evaluated.
7. You have a thyroid issue.
Your thyroid is a small butterfly-shaped gland in the front of your throat that produces hormones regulating the way your body uses energy. When it doesn't produce enough thyroid hormone, it causes a condition known as hypothyroidism, which can mess with or slow down many of your body's functions, according to Medline Plus.
“Thyroid hormones have receptors on essentially every organ of the human body and their deficiency can cause fatigue by excessively slowing the metabolic pathways,” explains Dr. Khan.
How to fix it: The treatment for hypothyroidism is taking medication to replace the hormone that your own thyroid can no longer make or create a sufficient amount of to keep your body functioning normally. Just know this: It could take a little while for you to feel better. Your doctor may need to adjust your medication until you reach the optimal level.
8. You’re getting over an infection.
Just because you’re on the mend from, say, a virus doesn’t mean you should expect to automatically bounce back energy-wise. Recovery can take time. "A viral or bacterial infection can cause dehydration, generalized inflammation, and immense fatigue," says Dr. Khan.
How to fix it: Give yourself time to recoup, first and foremost. Drink plenty of water and just take it easy, and you should feel less tired and more like yourself in a week or two.
9. You have anemia.
Anemia is a condition where your blood has a lower-than-normal amount of red blood cells or hemoglobin, according to the National Heart, Lung, and Blood Institute (NHLBI). Hemoglobin is an iron-rich protein that helps red blood cells carry oxygen from the lungs to the rest of the body. If you have anemia, your body does not get enough oxygen-rich blood, per the NHLBI. So, if you have the condition, you can struggle with “fatigue and excessive tiredness,” says Dr. Khan.
How to fix it: It depends on the type of anemia you have. For some types of mild to moderate anemia, you may just need to add OTC or prescription iron supplements to your regimen. But your doctor may also suggest certain vitamins, IV therapy, or medicines that make your body produce more red blood cells, according to the NHLBI. You may also need to incorporate more iron-rich foods into your diet. Basically, you really need to see your doc for this one.
10. You have an issue with gluten.
In case you’re not familiar with it, gluten is a protein found in wheat, barley, and rye. In some people, gluten damages the small intestine and causes symptoms like bloating, diarrhea, constipation, gas, nausea, stomach pain, vomiting, and yep, fatigue, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). That happens to people with celiac disease.
This condition can also cause long-term digestive issues and keep you from getting the nutrients you need, and in turn, cause ongoing fatigue.
How to fix it: Celiac disease can be a tricky one to diagnose, but after doing a physical exam, your doctor may recommend that you take a blood test and undergo an intestinal biopsy to look for inflammation in your small intestine. If you are confirmed to have celiac disease, you’ll need to avoid foods containing gluten in the future.
11. You have multiple sclerosis (MS).
This is a less likely diagnosis, but it’s still worth mentioning. MS is an autoimmune disease where the immune system attacks the brain and spinal cord, damaging the covering of nerve fibers called myelin, according to the National Multiple Sclerosis Society (NMSS).
Fatigue is a very common symptom in people with MS—about 80 percent of patients struggle with it, according to the NMSS. The fatigue can significantly interfere with a person’s ability to function, even if they feel good otherwise. It can be caused by treatable medical side effects of medication, or other causes.
How to fix it: There are specific treatments to help people with MS manage fatigue, including occupational therapy to simplify tasks at home, physical therapy to learn energy-saving ways of walking and performing other day-to-day tasks, a regular exercise program, sleep regulation, and psychological interventions, per the NMSS.
12. Cancer can also be a cause of tiredness and low energy.
This is another one to add to the category of “unlikely but worth knowing.” Cancer-related fatigue is incredibly common: At least 80 percent of people diagnosed with the condition experience it, according to the American Cancer Society (ACS). While cancer treatments could be to blame, people with cancer can also feel wiped out just from the disease itself. It can overtake almost all the metabolic pathways and sabotage the mitochondrial energy of the body, explains Dr. Khan.
How to fix it: First, don't freak out that you have a serious health issue. But know that getting a proper diagnosis is important and, from there, proper treatment is needed, which usually involves chemotherapy, radiation therapy, surgery, or immunotherapy. The exact course depends on what type of cancer you have and how advanced it is. That's why seeing your doctor to rule it out is key if you haven't been able to shake your tiredness for a long time.
13. You're not getting enough nutrients.
Here's the thing: Our body needs a number of nutrients and a certain amount of calories per day in order to run at its normal capacity. Those numbers vary for everyone. "You need to not only make sure that you're providing yourself with sufficient amount of calories per day to function, but also you need to be providing yourself with the appropriate nutrients," says Dr. Price.
If you're not eating enough nutrient-rich foods, your energy levels drop, so doing even the smallest task feels monumental. You can also become constipated, adds Dr. Price, which can add to the fatigue.
How to fix it: Eating a well-balanced diet and making sure that you're eating enough fruits, vegetables, and proteins, is essential to combatting fatigue, says Dr. Price. With the proper amount of nutrients, your body is able to create the energy you need to go about your day.
14. You're consuming too much caffeine.
You've heard it before, but it's true: Caffeine is a drug. Once your body gets accustomed to it, especially if you have coffee or soda every day, you become dependent on it. While it gives you a boost, caffeine also comes with highs and lows, and that in itself can cause you to feel extremely tired, says Dr. Price. "Because you're burning calories when you have caffeine, you're moving at a faster pace and you get to your peak of exhaustion much quicker," she explains.
If you absolutely need to have coffee in order to get through your day, that should be a warning sign. "You should not have to have coffee in order to function, and something else is going on in your life that is causing you to be extremely fatigued," notes Dr. Price.
How to fix it: Switch up how you get your caffeine and start weaning yourself off of it. It'll take some adjustment and you might get headaches at first, but once your body no longer depends on coffee, you'll feel a lot better.
15. You have long COVID.
While the medical world is still trying to figure out the long-term effects of COVID-19, we do know the toll the disease has on your body is that it makes you extremely exhausted, says Dr. Price. Your body tries to recuperate when you're infected—you don't have an appetite, your muscles are extremely fatigued, and your body is working in overdrive.
“Your body is doing the most to get you back to your normal self and to fight off COVID, so once you're done with it, you're not just going to bounce right back to yourself," says Dr. Price. “It's also been shown that the peak symptoms of COVID can sometimes be 14 days later. People must keep in mind that this is not a short illness. There are different and great severities of it."
Long COVID usually occurs two months after a person had COVID, says Dr. Price. If after two months of contracting the novel coronavirus you’re still feeling worn out, then it could be long COVID, she says.
How to fix it: The best way to protect yourself against COVID and the long-term complications is to get vaccinated and boosted and keep practicing precautionary measures like masking up when in public and social distance. While research into a cure is ongoing, your doctor may prescribe supplements and medications to manage symptoms of long COVID, according to CDC guidance. If you suspect that you have long COVID, visit your primary care provider and discuss your symptoms with them, advises Dr. Price. They can help you figure out the next steps to take.
Here’s when low energy and tiredness warrants a visit to your doctor.
Feeling tired once in a while is pretty normal—but experiencing constant fatigue isn’t. If you’re struggling, Dr. Khan recommends seeing your doctor. They’ll likely want to do a bunch of tests, including a physical exam and blood work, to try to figure out what, if anything, is happening.
"It's never too soon to go and talk to your doctor," says Dr. Price. What you thought might be something minor, the doctor might look more into. "Or maybe you started googling things and, of course, Google will tell you you're dying, so talking to your doctor can give you relief and reassurance," Dr. Price adds.
The upside: the sooner you seek help, the sooner you can get answers—and get back to your rejuvenated and energetic self.
