When fatigue leaves you drained, depleted, and dumbfounded

photo of a tired woman sitting at a desk with a laptop, rubbing her face with her hands

If you feel as though you're dragging through your days feeling weary, weak, and listless, fatigue has arrived at your doorstep.

But what's the line between feeling fatigued and merely tired? Fatigue means no amount of sleep helps you feel refreshed. Forget about mustering joie de vivre — you can barely get through the day without becoming exhausted.

"Being tired or sleepy is different from fatigue," says Dr. Daniel Sands, a primary care doctor at Harvard-affiliated Beth Israel Deaconess Medical Center. "It's true they can overlap, because if you're not getting enough sleep, you'll feel fatigued. But fatigue is different — everyday things like walking to the bathroom or doing the dishes wear you out."

You might chalk it up to getting older, since fatigue is commonly viewed as a normal part of aging instead of a symptom of an underlying ailment. But often, something is indeed amiss. Between 40% and 74% of older adults with a chronic condition deal with fatigue, according to a 2021 research review in Rehabilitation Nursing.

When it lingers for weeks or months, fatigue is a problem that needs to be solved. A long list of both obvious and more opaque conditions can lead to it, some of them serious.

"I get worried when people have stopped doing the things they love — like going for walks, babysitting their grandchildren, or cooking," says Dr. Soheyla Gharib, an internist at the Phyllis Jen Center for Primary Care at Harvard-affiliated Brigham and Women's Hospital. "If they say they're not doing those things, that's a huge red flag and we definitely want to find out why."

Gamut of causes

Some contributors to fatigue are abundantly clear: if you're not sleeping well, for instance, or have allergies, a cold, the flu, or COVID, you're likely to feel drained. Chronic illnesses such as heart disease, cancer, diabetes, kidney disease, multiple sclerosis, or rheumatoid arthritis are also widely known to sap energy.

But the list of less-recognized causes is just as long. You might not suspect

sleep disorders
depression or anxiety
thyroid problems
infections
iron-deficiency anemia
poor diet
medication use.

Chronic fatigue syndrome — characterized by prolonged tiredness, fever, and aches — might be on your radar if you have unshakable fatigue, but it's rarely the case, Dr. Sands says, and only considered after other reasons are ruled out.

Pathway to answers

How do you know it's time to see a doctor about your fatigue? Not only when it's unexplained, prolonged, and debilitating, but also if it's joined by other symptoms such as

weight loss or gain
frequent headaches
chronic pain
muscle weakness
thinking or memory problems
mood changes
sleep problems such as insomnia, severe daytime sleepiness, or restless sleep.

"If you have actual weakness, like you can't climb stairs; shortness of breath; or trouble getting dressed or making meals — or if you're nodding off in the middle of the day when you never used to — those are all big warning signs," Dr. Gharib says.

In addition to performing a thorough physical exam, your doctor will likely ask about your sleep habits and use of alcohol and other substances as she carefully reviews your medical history. Additionally, comprehensive blood testing can unearth a variety of fatigue culprits, including anemia, thyroid issues, certain infections, and liver or kidney problems, as well as guide further testing.

Typically, doctors follow a well-worn credo when investigating fatigue and other such nebulous symptoms: "When you hear hoofbeats, think horses, not zebras." That means they first consider the obvious causes before looking to less likely possibilities.

"If someone gets almost no physical activity and tells me she's worn out all the time now, most likely she is deconditioned. I get more concerned when I see a patient who runs a 5K three times a week and suddenly can't run a mile," Dr. Sands says. "What goes along with fatigue often tells us whether something is serious or not. But in someone with no obvious clues, it's rare there's something serious going on," he adds.

To combat fatigue, rise up and exercise

When you're tired, the last thing you may feel like doing is exercising. Yet that's exactly what can help break the cycle of persistent fatigue and reboot your energy levels, a recent study suggests.

The analysis, published June 3, 2022, in Frontiers in Psychology, reviewed 81 earlier studies that involved a total of more than 7,000 adults. Researchers found that regular exercise leads to small-to-moderate improvements in fatigue as well as feelings of energy and vitality. Regular exercise was defined as exercising at least once a week and included resistance training (such as weight lifting) and aerobic exercise (such as brisk walking, cycling, or swimming).

How can exercise beat back fatigue and boost energy levels? By increasing blood flow to muscles and organs, releasing feel-good chemicals called endorphins, and improving sleep quality, says Dr. Daniel Sands, a primary care doctor at Beth Israel Deaconess Medical Center.

"It increases your cardiovascular reserve — the ability of your heart and lungs to pump blood and extract oxygen from it," Dr. Sands says. "You're toning up your system."

If you feel you can't begin exercising on your own, ask your doctor for help devising a plan to incorporate more physical activity into your days, Dr. Sands says. And start small by taking the stairs instead of an elevator, parking farther from the front door of a store, or getting off a train a stop earlier than planned and walking the rest of the way.

Vitality-enhancing tactics

If your check-up didn't unearth anything worrisome — or you're now being treated after a new diagnosis — the next step is to proactively boost your oomph. Try these strategies:

Move more. Staying active helps maintain muscle mass and strength, which helps stave off fatigue. (See "To combat fatigue, rise up and exercise.") "It's paradoxical — you can't get good sleep if you're not exercising," Dr. Gharib says. "You'll feel even more tired, ironically. If you're starting from zero, even 15 minutes a day of exercise will get you going, with the goal of getting to 30 minutes of physical activity a day, five days a week."

Optimize your diet. You can't drink from an empty cup, as the adage goes. Fuel your body appropriately by filling your plate with high-protein options such as lean meat or fish, along with complex carbohydrates such as whole grains, fruits, and vegetables. These choices will help you avoid the plummeting energy levels common after eating processed, high-sugar foods. "Healthy eating and good hydration will do wonders for making you feel better," Dr. Gharib says.

Use caffeine strategically. There's no question it can help you feel powered up, but caffeine can also disrupt sleep patterns, especially when consumed in midafternoon or later.

Limit alcohol use. Alcohol has a sedative effect, ultimately causing an energy slump. Additionally, while it may help you doze off, the effect often wears off in the wee hours, leaving you awake when you should be sound asleep.