Feeling tired from time to time is a normal part of life.
A busy schedule, poor sleep, stress, or recovering from an illness can all leave people feeling low on energy.
However, when tiredness continues for weeks or months and starts affecting daily activities, it may be a sign of an underlying health problem that needs medical attention.
Many people think of anaemia or lack of sleep when they feel exhausted. While these are common causes, doctors say there are several less obvious conditions that can also lead to ongoing fatigue, especially in older adults.
Recognising these hidden causes early may help people receive treatment before the problem becomes more serious.
One possible cause is an underactive thyroid, also called hypothyroidism. The thyroid gland produces hormones that control how fast the body uses energy. When the gland does not make enough hormones, many body functions slow down, leading to tiredness, weakness, weight gain, feeling cold, dry skin, and sometimes low mood.
Research published in 2019 found that fatigue is often one of the earliest and most noticeable symptoms in older adults with mild thyroid disease.
Another condition is adrenal insufficiency. The adrenal glands sit above the kidneys and produce hormones, including cortisol, which helps the body respond to stress and maintain normal energy levels. When cortisol levels become too low, people may experience severe fatigue, dizziness, muscle weakness, weight loss, and low blood pressure. Because these symptoms can resemble depression or other illnesses, the condition is sometimes missed.
Persistent tiredness can also be an early warning sign of heart disease. Many people expect heart problems to cause chest pain or shortness of breath, but unusual fatigue may appear first, particularly in older adults. A 2021 study reported that unexplained tiredness was linked to early signs of heart disease in some older people, highlighting the importance of medical assessment.
Autoimmune diseases such as rheumatoid arthritis and lupus may also drain the body’s energy. In these conditions, the immune system mistakenly attacks healthy tissues, causing long-term inflammation. This ongoing inflammation requires extra energy from the body, leaving many people feeling exhausted even when they have little pain. A 2018 study found that fatigue is one of the most common and disabling symptoms experienced by people with autoimmune diseases.
Vitamin deficiencies are another often-overlooked cause of low energy. While iron and vitamin B12 deficiencies are well known, low vitamin D can also contribute to tiredness, muscle weakness, and reduced physical function. A 2020 study found that many older adults with low vitamin D levels reported feeling more fatigued than those with healthy levels.
Sleep disorders can also prevent the body from getting proper rest. One of the most common is obstructive sleep apnoea, in which breathing repeatedly stops for short periods during sleep.
Some older adults do not snore loudly or notice these breathing pauses, making the condition difficult to recognise. A 2021 review found that untreated sleep apnoea significantly increased daytime tiredness and reduced quality of life.
If tiredness continues despite getting enough sleep and following healthy habits, it is important to speak with a doctor rather than assuming it is simply part of getting older. Blood tests, heart checks, or sleep studies may help identify the real cause.
Many of these conditions can be treated successfully, allowing people to regain their energy and improve their overall health and quality of life.
If you care about wellness, please read studies about how ultra-processed foods and red meat influence your longevity, and why seafood may boost healthy aging.
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