It’s normal to feel tired once in a while, especially as we get older.
But when that tired feeling doesn’t go away and starts affecting daily life, it’s important to look deeper for the cause.
Most people think of things like poor sleep, stress, or anemia when they feel run-down. While these are common reasons, there are also some lesser-known causes of fatigue that can be overlooked—especially in older adults.
One of these hidden causes is an underactive thyroid, also known as hypothyroidism. The thyroid controls metabolism, and if it doesn’t make enough hormones, everything in the body can slow down. This can lead to extreme tiredness, weakness, and even feeling depressed.
While this condition is more common in women, it can affect men too. A 2019 study showed that fatigue is often the first and main symptom in older adults with mild thyroid problems.
Another cause is adrenal insufficiency. The adrenal glands, which sit on top of the kidneys, make hormones like cortisol that help us deal with stress and stay energized. If these glands don’t work properly, cortisol levels drop.
This can lead to serious fatigue, dizziness, and muscle weakness. It’s often mistaken for other conditions like depression, which means it can go undiagnosed in older people.
Fatigue can also be an early warning sign of heart problems. While most people expect chest pain or shortness of breath, tiredness can actually be one of the first symptoms of heart disease. A 2021 study found that older adults who felt unusually tired—without any other clear cause—were more likely to have early signs of heart trouble.
Another issue that drains energy is chronic inflammation caused by autoimmune diseases like lupus or rheumatoid arthritis. These conditions make the immune system attack healthy parts of the body, which leads to inflammation and uses up a lot of energy.
A 2018 study showed that many older people with autoimmune problems feel exhausted, even if they don’t have a lot of pain.
Vitamin deficiencies can also lead to fatigue. While many people know that low iron or vitamin B12 can cause tiredness, fewer realize that not getting enough vitamin D can do the same.
A 2020 study found that older adults with low vitamin D often felt weak and tired. This vitamin helps with energy and immune function, so a lack of it can really affect how you feel.
Finally, sleep disorders like sleep apnea can be a hidden reason for tiredness. Sleep apnea causes short stops in breathing while you sleep, which interrupts rest without you even knowing it.
Surprisingly, many older people with sleep apnea don’t snore loudly or gasp for air, so the condition can go unnoticed. A 2021 review showed that untreated sleep apnea makes daytime fatigue worse and lowers quality of life.
In short, if you’re feeling tired all the time and it’s not going away with rest or healthy habits, it might be due to one of these hidden issues. Getting checked by a doctor can help uncover the real reason. With the right treatment, many of these conditions can be managed—and your energy and quality of life can improve.
If you care about brain health, please read studies about inflammation that may actually slow down cognitive decline in older people, and low vitamin D may speed up cognitive decline.
For more health information, please see recent studies about common exercises that could protect against cognitive decline, and results showing this MIND diet may protect your cognitive function, prevent dementia.
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