Fatigue is one of the most common—and also one of the most difficult—symptoms to prove in a long term disability (“LTD”) claim. Whether it’s caused by Chronic Fatigue Syndrome, fibromyalgia, Long COVID, autoimmune disease, or another chronic condition, fatigue often lacks clear test results or visible signs. Because of that, insurance companies frequently question its severity or deny these claims altogether.
Below we’ll answer commons questions on building a strong LTD claim when fatigue is your primary disabling symptom.
Yes, you can get long term disability benefits for fatigue alone, but it can be challenging. Fatigue is considered a “subjective” symptom, meaning there’s no single test that can objectively measure how tired you feel. Because of this, insurance companies are often skeptical of disability claims based solely on fatigue.
To be approved, your insurer will require you to show that your fatigue is so severe and persistent that it prevents you from performing the essential duties of your job (or any job, depending on your policy’s definition of disability). This often comes up in cases involving conditions like Chronic Fatigue Syndrome (“CFS”), fibromyalgia, autoimmune disorders, or post-viral fatigue (like Long COVID).
Insurance companies look for strong documentation that supports how fatigue affects your daily function and evidence that your fatigue interferes with work-related tasks like concentration, stamina, or physical endurance. Without strong evidence substantiating your fatigue-related restrictions and limitations, your LTD claim may be at risk of denial or termination.
If you’re filing for long term disability benefits based on fatigue, it’s crucial to prepare a well-documented claim that clearly shows how your fatigue is disabling. An ERISA long term disability attorney can help ensure you present the strongest claim possible.
Proving fatigue in a long term disability (“LTD”) claim can be challenging because fatigue is often a subjective symptom. However, your insurance company will require more than just your word to accept that your fatigue prohibits you from working. However, while objective testing to prove fatigue can be limited, there are options that, in conjunction with regular medical records, your doctor’s support, and other documentation can strongly support your claim.
The most helpful types of medical evidence for proving fatigue include:
To prove to your insurer that fatigue prevents you from working, it’s essential to go beyond just saying you’re tired or providing medical evidence. You need to demonstrate how that fatigue disrupts your ability to perform the essential duties of your job on a consistent and reliable basis.
One way to support your LTD claim for fatigue is providing your insurer a personal affidavit outlining how your fatigue affects your ability to perform occupational duties and other daily activities. Start by describing the real-world impact fatigue has on your workday. If you struggle to focus, maintain stamina, or complete tasks on time, those are key details to include. Your own statements—when clear, specific, and consistent—can be powerful in demonstrating how fatigue interferes with your job performance.
You should also give examples of the specific limitations you experience, such as:
Your personal affidavit can be supported with vocational evidence that explain the full scope of your occupational duties, both physical and cognitive. This can include your official job description, resume, any performance reviews showing a decline in your performance due to your fatigue, and even a vocational assessment that evaluates how your medical condition impacts your ability to work in your occupation.
It’s helpful to highlight how your fatigue affects your ability to work on a full-time, ongoing basis. It’s not enough to show you have bad days—you need to demonstrate that your fatigue prevents you from performing your job reliably, day after day, without frequent interruptions or absences. That kind of evidence can be the deciding factor in whether your long term disability claim is approved or denied.
When you’re filing a fatigue-based long term disability claim, objective evidence can make a major difference. Since fatigue is a subjective symptom—something you feel but others can’t see—insurers often look for any kind of measurable, observable data to support your claim. While there’s no single “fatigue test,” several types of objective evidence can help validate your condition and show how it limits your ability to work.
Here are the most useful forms of objective evidence in a fatigue-based disability claim:
An FCE measures your physical abilities through a series of tests that assess things like lifting, endurance, flexibility, and stamina. It’s especially helpful when fatigue affects your ability to maintain activity over time. The evaluation may reveal reduced tolerance for exertion, need for extended rest, or inability to sustain a typical work schedule—strong support for a fatigue-based claim.
A neuropsychological evaluation, conducted by a neuropsychologist, is used to measure how fatigue affects your cognitive abilities. This objective assessment can show deficits in attention, memory, processing speed, or mental endurance. If your job requires focus or mental stamina, these results can help demonstrate that your fatigue prevents you from meeting those demands consistently.
A CPET can be one of the most powerful tools for proving fatigue. It measures your heart, lung, and muscle function during physical exertion. In conditions like Chronic Fatigue Syndrome or post-viral fatigue, the CPET may show significant reductions in performance on the second day, demonstrating post-exertional malaise and inability to recover from routine exertion.
The tilt table test helps detect autonomic dysfunction, such as orthostatic intolerance or postural orthostatic tachycardia syndrome (“POTS”), which often coexist with chronic fatigue conditions. Abnormal results can objectively explain fatigue triggered or worsened by standing or changes in position.
While these tests may not directly measure fatigue, they can rule out other conditions that cause tiredness and help support your diagnosis. Useful labs might include:
Depending on your condition, MRIs, EEGs, or other scans may show abnormalities related to neurological fatigue. These are more commonly used in cases involving multiple sclerosis, head trauma, or similar diagnoses.
If your doctors consistently document how fatigue impacts your daily function—and if their clinical notes include observations like reduced stamina, poor recovery from activity, or difficulty concentrating—those can be powerful objective-style observations, especially when paired with testing.
While fatigue may not always show up on a scan or lab test, combining multiple sources of objective evidence like these can build a strong case that your fatigue is real, medically supported, and functionally disabling.
Fatigue-based long term disability claims are frequently denied by insurers. This is not because fatigue isn’t real or disabling, but because it can be difficult to prove using the standards insurers rely on. Fatigue is often invisible, subjective, and hard to measure, which puts claimants at a disadvantage from the start.
One of the main reasons insurers deny these claims is the lack of objective evidence. Unlike a broken bone or a visible injury, fatigue doesn’t show up on an X-ray or lab test. Even when it’s caused by a well-documented condition like Chronic Fatigue Syndrome (“CFS”), fibromyalgia, long COVID, or autoimmune disease, insurers may still argue that there’s not enough measurable proof of impairment.
Here are some of the most common reasons fatigue-based claims get denied:
Another hurdle is how disability is defined in your policy. Many long term disability plans, especially under ERISA, require you to prove not just that you have fatigue, but that it prevents you from performing the essential duties of your job—or any job, depending on the stage of your claim. If you can’t clearly demonstrate how fatigue interferes with those duties on a full-time, ongoing basis, your claim is more likely to be denied.
To avoid these pitfalls, it’s essential to submit thorough medical records, obtain strong physician support, and include objective evidence whenever possible. A long term disability attorney can be essential in the process. An experienced attorney can help you identify any missing information from your claim, red flags in your documentation that can be preemptively addressed with your insurer, and build a more persuasive case.
Your treating doctors play a critical role in proving fatigue for a long term disability (“LTD”) claim. They are often the most trusted source of evidence because they have firsthand knowledge of your condition, your treatment history, and how fatigue affects your daily life. Their support can make or break your claim—especially when fatigue is one of your primary disabling symptoms.
One of the most important things your doctor can do is document your symptoms consistently. Insurance companies look closely at medical records to see whether your reports of fatigue are mentioned at every visit, how long they’ve been ongoing, and whether they’re affecting your ability to function. If your doctor doesn’t make note of your fatigue (or only mentions it in passing), your insurer may argue it’s not serious or disabling.
Treating physicians can also provide valuable documentation, including:
In addition, your physician’s opinion carries even more weight if they’re a specialist (such as a rheumatologist, neurologist, or infectious disease doctor) who regularly treats patients with fatigue-related conditions. These specialists can tie your symptoms to a specific diagnosis and explain why your fatigue is consistent with the condition.
It’s also crucial that your doctor understands the importance of clarity and detail. Vague statements like “patient feels tired” aren’t enough. Insurers want to see how that tiredness prevents you from performing your job reliably. A well-supported medical opinion should explain why your fatigue keeps you from sustaining a normal work schedule and why those limitations are expected to last.
Finally, your treating doctor’s credibility can help counter the insurer’s use of peer reviewers—doctors who never examine you in person but still claim you can work. A clear, thorough, and supportive opinion from your physician is often one of the strongest tools you have in proving your disability.
Tracking your daily symptoms of fatigue is one of the most effective ways to support your long term disability (“LTD”) claim. Since fatigue is subjective and hard to measure, keeping a consistent, detailed record can help you provide your insurer with a clearer picture of how your condition impacts your daily life and ability to work.
One of the best ways to track your fatigue is by keeping a symptom diary. Below are tips for recording your fatigue effectively.
Use a notebook, spreadsheet, or fatigue-tracking app to record key details about each day. Focus on:
Be specific about how your symptoms interfere with things you would normally do on the job, such as concentrating, sitting through meetings, or maintaining physical endurance. If you’re unable to follow a consistent schedule, include that too. It helps show that you can’t sustain full-time work.
Insurers often look for consistency. Your log can highlight recurring symptoms, flare-ups, and how long it takes to recover after minor activity. If your fatigue is unpredictable or worsens after exertion, make sure that’s reflected. This is especially important if you experience post-exertional malaise, where you feel worse after even modest activity.
If your treating physician reviews or references your symptom log in their records, it adds more credibility. The more your personal tracking aligns with your doctor’s notes, the stronger your claim becomes.
Don’t exaggerate your fatigue, but don’t minimize it either. If you have a slightly better day, note it. If your symptoms fluctuate, record that too. Insurance companies may use surveillance or social media to challenge your claim, so consistency across all sources is key.
A detailed symptom journal won’t win your LTD claim on its own, but when paired with strong medical evidence and physician support, it helps build a fuller, more convincing case. It also shows that you’re being proactive in documenting your condition.
If you have fatigue along with other symptoms like pain, brain fog, or cognitive difficulties, your long term disability (“LTD”) claim may actually be stronger—if the additional symptoms are well-documented and consistently tied to a diagnosed condition. These overlapping symptoms often come with chronic illnesses such as fibromyalgia, Chronic Fatigue Syndrome (“CFS”), lupus, multiple sclerosis, long COVID, or autoimmune disorders, and they can compound each other to make full-time work impossible.
When multiple symptoms interact, it’s important to show how they affect your overall functioning. Insurance companies may try to pick apart each symptom and argue that none are severe enough on their own to be disabling. Your goal is to demonstrate how the combined impact of fatigue, pain, and cognitive or physical issues prevents you from performing your job reliably.
Here’s how you can strengthen your claim when dealing with multiple symptoms:
Having fatigue along with other symptoms can strengthen your claim if the full picture is clearly documented and presented. Make sure your medical team is aware of all your symptoms and that your records reflect the complexity of your condition. The more complete and cohesive your documentation, the better your chances of claim approval.
An ERISA long term disability attorney can play a vital role in helping you prove your long term disability claim for fatigue, especially when you’re up against skeptical insurance companies. Fatigue-based claims are often denied because insurers view fatigue as a “subjective” symptom—something that can’t be easily measured or seen on a test.
A knowledgeable long term disability attorney understands how to overcome that bias by building a strong, well-documented case that clearly shows how your fatigue prevents you from working.
Here’s how an attorney can help:
Fatigue-based claims are often denied not because you’re not truly disabled, but because the claim wasn’t presented in the way insurers expect. An experienced attorney helps close that gap by gathering the right evidence, ensuring it’s properly documented, and protecting your rights every step of the way.