Fatigue in people over 70 is rarely caused by a single problem. In most cases, it results from a combination of physiological aging, chronic illness, medication side effects, nutritional deficiencies, and psychological factors working together. A 74-year-old woman who feels exhausted by midmorning might be dealing with mild anemia, disrupted sleep from arthritis pain, and a blood pressure medication that causes drowsiness — each individually manageable, but together producing profound tiredness that her doctor might dismiss as simply “getting older.” This article covers the most common physical, medical, and lifestyle-related causes of fatigue in older adults, along with what distinguishes normal aging tiredness from fatigue that signals something more serious.
Understanding this distinction matters enormously for older adults and their caregivers. Fatigue is the most commonly reported symptom in people over 70, yet it remains chronically underreported and undertreated. Many older adults assume persistent tiredness is inevitable, when in fact identifiable and treatable causes are present in the majority of cases. The sections below break down the primary drivers of fatigue in this age group — from cardiovascular and thyroid conditions to polypharmacy, poor nutrition, depression, and disrupted sleep architecture.
Table of Contents
- Why Do So Many People Over 70 Experience Chronic Fatigue?
- What Medical Conditions Cause Fatigue in Older Adults?
- How Do Medications Contribute to Fatigue in People Over 70?
- What Role Do Nutritional Deficiencies Play in Fatigue After 70?
- How Does Sleep Disruption Drive Fatigue in Older Adults?
- Can Depression and Anxiety Cause Physical Fatigue in People Over 70?
- What Does Emerging Research Suggest About Fatigue and Brain Health in Older Adults?
- Conclusion
- Frequently Asked Questions
Why Do So Many People Over 70 Experience Chronic Fatigue?
Aging itself changes the body’s energy systems in ways that make fatigue more likely even in otherwise healthy individuals. Muscle mass declines steadily after age 50 in a process called sarcopenia, and by the mid-seventies, most people have lost 15 to 20 percent of the lean muscle they had at 40. Less muscle means more effort is required for any physical task — climbing stairs, carrying groceries, even standing from a chair. The cardiovascular system also becomes less efficient with age, as the heart pumps less blood per beat and blood vessels lose elasticity, reducing oxygen delivery to tissues during activity. At the cellular level, mitochondrial function declines with age, meaning the body’s ability to generate ATP — the molecule that powers virtually every biological process — becomes less efficient. This is not a disease; it is a normal feature of aging.
But it creates a baseline reduction in energy reserves that leaves older adults with less capacity to absorb additional stressors. Add a poor night’s sleep, a skipped meal, or a mild respiratory infection, and someone in their seventies may find themselves genuinely incapacitated for days. A 72-year-old man in good health might feel energetic on most days but find that a minor cold leaves him bedridden for two weeks rather than two days — not because something is wrong, but because his physiological reserve is thinner. The key comparison to make here is between primary aging fatigue and secondary fatigue from a specific underlying cause. Primary aging-related tiredness tends to arrive gradually, correlates with activity level, and improves with rest. Secondary fatigue — from illness, medication, or deficiency — often appears suddenly, persists despite adequate rest, and may be accompanied by other symptoms. That distinction is the first thing a clinician should evaluate.
What Medical Conditions Cause Fatigue in Older Adults?
Chronic medical conditions account for a large share of fatigue in people over 70, and the list is long. Heart failure is one of the most common culprits — reduced cardiac output means the body’s organs and muscles receive less oxygen, producing profound tiredness even with minimal exertion. Chronic obstructive pulmonary disease (COPD) similarly limits oxygen uptake, and fatigue is often the symptom that worsens first before breathing difficulty becomes obvious. Kidney disease, which becomes substantially more prevalent after age 65, causes fatigue through a combination of anemia, fluid imbalance, and the buildup of metabolic waste products that the kidneys can no longer filter efficiently. Thyroid dysfunction deserves particular attention in older adults because its symptoms are frequently attributed to normal aging or depression. Hypothyroidism — an underactive thyroid — slows metabolism throughout the body, causing fatigue, cold intolerance, constipation, and cognitive slowing.
It affects approximately 10 to 15 percent of women over 65, and many cases go undiagnosed for years. Diabetes is another major contributor; chronic high blood sugar damages blood vessels and nerves, disrupts sleep, and — particularly when poorly controlled — causes fatigue directly through glucose metabolism dysfunction. However, it is important to note that treating the underlying condition does not always resolve fatigue entirely. A person with well-controlled heart failure may still experience significant tiredness because the structural changes to the heart persist even when symptoms are managed. Similarly, someone whose hypothyroidism has been corrected with medication may find that full energy recovery takes months, and some individuals never return fully to their pre-illness baseline. Caregivers should set realistic expectations rather than assuming fatigue will disappear once a diagnosis is treated.
How Do Medications Contribute to Fatigue in People Over 70?
Polypharmacy — the use of five or more medications simultaneously — affects more than 40 percent of adults over 65 in the United States, and fatigue is one of its most consistent side effects. Many drug classes commonly prescribed to older adults carry sedation or fatigue as direct side effects. These include beta-blockers (used for heart disease and high blood pressure), antihistamines, benzodiazepines, many antidepressants, muscle relaxants, opioid pain medications, and certain antiepileptic drugs. Even medications not typically associated with sedation can cause fatigue indirectly by disrupting sleep, lowering blood pressure, or affecting nutrient absorption. A concrete example: a 78-year-old man with hypertension, chronic back pain, and anxiety might be prescribed a beta-blocker, a low-dose opioid, and a benzodiazepine.
Each drug has individually modest fatigue-inducing properties, but their combined effect on alertness and energy can be substantial — and because each was prescribed by a different specialist, no single physician may recognize the cumulative burden. This is sometimes called “prescribing cascade,” where side effects of one drug are treated by adding another, compounding fatigue further. Medication review should be a routine part of fatigue evaluation in older adults. A pharmacist or geriatrician conducting a comprehensive medication review can often identify drugs that are no longer necessary, alternatives with fewer sedating properties, or dosing adjustments that reduce side effects. In one well-documented pattern, switching from a first-generation antihistamine (like diphenhydramine, found in many over-the-counter sleep aids) to a non-sedating second-generation alternative can produce a noticeable improvement in daytime alertness within days.
What Role Do Nutritional Deficiencies Play in Fatigue After 70?
Several nutritional deficiencies that become increasingly common after age 70 directly cause fatigue, and many are easily correctable once identified. Iron deficiency anemia is among the most significant — low iron reduces the blood’s oxygen-carrying capacity, producing tiredness, weakness, and often shortness of breath. In older adults, iron deficiency is frequently a sign of chronic slow bleeding (from gastrointestinal sources like ulcers or colon polyps) rather than inadequate dietary intake, which makes it important to investigate rather than simply supplement without evaluation. Vitamin B12 deficiency is particularly prevalent in older adults because the absorption of B12 from food depends on a protein called intrinsic factor, production of which declines with age and is further impaired by common medications including metformin and proton pump inhibitors. B12 deficiency causes fatigue, but also neurological symptoms including tingling in the hands and feet, balance problems, and cognitive changes — which is especially relevant for dementia care contexts, since B12 deficiency can mimic or worsen dementia symptoms.
Vitamin D deficiency, affecting an estimated 50 to 70 percent of adults over 70, contributes to muscle weakness, fatigue, and low mood, and is particularly common in individuals with limited sun exposure. The tradeoff in nutritional supplementation is worth noting: high-dose supplementation without confirmed deficiency is not universally beneficial. High-dose iron supplementation in someone without iron deficiency can cause gastrointestinal distress and constipation. Excess vitamin A can be toxic in older adults, whose kidneys clear it more slowly. The appropriate approach is to test before supplementing, rather than assuming deficiency and treating empirically for every fatigued older adult.
How Does Sleep Disruption Drive Fatigue in Older Adults?
Sleep architecture changes profoundly with age. People over 70 spend less time in deep slow-wave sleep and REM sleep, wake more frequently during the night, and often experience phase advancement — a shift in the internal clock that causes them to feel sleepy earlier in the evening and wake earlier in the morning. Total sleep time typically decreases by 30 to 60 minutes compared to middle age. These are normal changes, but they reduce sleep’s restorative quality and create a foundation for daytime fatigue even when the total number of hours spent in bed appears adequate. Sleep disorders become substantially more common with age. Obstructive sleep apnea — in which breathing repeatedly stops and restarts during sleep — affects an estimated 30 to 60 percent of adults over 65, far higher than in younger populations.
Because apnea often causes fragmented sleep without the person being aware of waking, many older adults attribute their exhaustion to unrelated causes, or simply accept it as aging. Restless legs syndrome and periodic limb movement disorder similarly disrupt sleep without always causing conscious waking, contributing to fatigue that seems inexplicable during the day. Nocturia — waking to urinate, which affects the majority of men over 70 with prostate issues and many older women — can fragment sleep three to five times per night, severely impairing its restorative function. A critical warning: treating sleep disorders in older adults requires careful medication selection. Benzodiazepines and the related “Z-drug” hypnotics (zolpidem, eszopiclone) are widely prescribed for insomnia in older adults but are listed on the Beers Criteria as potentially inappropriate for this age group. They suppress slow-wave and REM sleep, worsen cognitive function, increase fall risk, and can produce physical dependence. Cognitive behavioral therapy for insomnia (CBT-I) has stronger evidence for long-term benefit in older adults and carries none of these risks, but it remains underused due to limited access and physician awareness.
Can Depression and Anxiety Cause Physical Fatigue in People Over 70?
Depression is both underdiagnosed and underappreciated as a cause of physical fatigue in older adults. Unlike younger adults who typically report sadness as their primary symptom, older adults with depression more often present with somatic complaints — fatigue, pain, sleep problems, and loss of appetite — without prominent mood complaints. This “masked depression” is frequently attributed to physical illness alone, and the psychological component goes untreated.
The link is bidirectional: fatigue from chronic illness contributes to depression, and depression amplifies the experience of fatigue, creating a reinforcing cycle. Anxiety disorders, though less often discussed in the context of fatigue, produce exhaustion through chronic physiological arousal — elevated cortisol, muscle tension, and hypervigilance that consumes enormous energy over time. An 80-year-old woman who lies awake worrying about her health, her finances, or her family may be genuinely exhausted by the end of each day from the metabolic cost of sustained anxiety alone, even if she has no diagnosable physical illness. Grief, social isolation, and the loss of purpose that can accompany retirement or bereavement are similarly exhausting psychological states that deserve direct attention rather than medical workup alone.
What Does Emerging Research Suggest About Fatigue and Brain Health in Older Adults?
Recent research has begun to examine fatigue not just as a symptom of other conditions, but as a marker of brain health in its own right. Studies have found that chronic fatigue in older adults correlates with increased risk of cognitive decline, independent of known risk factors like cardiovascular disease. One hypothesis is that neuroinflammation — low-grade inflammation in brain tissue, which increases with age and is associated with Alzheimer’s pathology — produces fatigue as a direct byproduct, similar to the profound tiredness that accompanies acute infection.
This would explain why many people in the early stages of dementia report significant fatigue before memory symptoms become prominent. This emerging picture suggests that persistent, unexplained fatigue in a person over 70 should not be dismissed or simply attributed to aging. It may warrant neurological evaluation alongside the standard medical workup. Conversely, interventions that reduce systemic inflammation — regular moderate exercise, adequate sleep, social engagement, and anti-inflammatory diets — may address both fatigue and cognitive risk simultaneously, making them particularly high-value targets for older adults concerned about brain health.
Conclusion
Fatigue in people over 70 is almost always multifactorial and almost always amenable to some degree of improvement with proper evaluation. The most common contributors — chronic illness, polypharmacy, nutritional deficiencies, sleep disorders, and depression — are all identifiable and at least partially treatable. The key step is resisting the assumption that tiredness is simply the price of aging. A systematic evaluation that addresses each potential cause in turn, rather than attributing fatigue to age alone, frequently reveals one or more correctable problems.
For caregivers and family members supporting an older adult with significant fatigue, the most practical action is to request a comprehensive review — medical history, full medication list including over-the-counter drugs and supplements, blood work covering thyroid function, complete blood count, B12, vitamin D, and kidney function, and a sleep history. Bringing this to a geriatrician or primary care physician with a bias toward active investigation rather than watchful waiting can make a genuine difference in quality of life. Fatigue is not a diagnosis. It is a signal that something underlying deserves attention.
Frequently Asked Questions
Is it normal for people over 70 to feel tired every day?
Some increase in tiredness with age is expected due to changes in muscle mass, cardiovascular efficiency, and sleep architecture. However, feeling exhausted daily — especially if it limits normal activities or does not improve with rest — is not simply a normal part of aging and warrants medical evaluation.
What blood tests should be done for fatigue in an older adult?
A standard fatigue workup typically includes a complete blood count (to check for anemia), thyroid-stimulating hormone (TSH), vitamin B12, vitamin D, fasting glucose or HbA1c, kidney function tests (creatinine, BMP), and sometimes ferritin (iron stores). Additional tests may be ordered depending on other symptoms.
Can dehydration cause fatigue in people over 70?
Yes. Older adults have a diminished sense of thirst and are at higher risk of chronic mild dehydration, which reduces blood volume and can cause fatigue, confusion, and dizziness. Many older adults do not drink enough fluid during the day, particularly in warm weather or when taking diuretic medications.
How is fatigue related to dementia or cognitive decline?
Fatigue frequently precedes and accompanies cognitive decline. It may result from neuroinflammation, disrupted sleep from early Alzheimer’s changes, depression associated with early cognitive symptoms, or the metabolic burden of the brain working harder to compensate for declining function. Persistent unexplained fatigue in an older adult should prompt cognitive screening.
Should an older adult take supplements for fatigue without a doctor’s recommendation?
Generally no, and particularly not iron. Supplementing without confirmed deficiency can cause harm — excess iron causes gastrointestinal side effects and, in rare cases, organ damage. Testing first and supplementing based on confirmed deficiency is the appropriate approach. Vitamin D supplementation at moderate doses is widely considered low-risk and is often appropriate given the high prevalence of deficiency in older adults.
Does exercise help or worsen fatigue in people over 70?
Regular moderate exercise consistently improves fatigue in older adults, even in those with chronic illness. It improves cardiovascular efficiency, preserves muscle mass, reduces depression, and enhances sleep quality. The key is starting gradually and building slowly — overexertion worsens fatigue in the short term, but sustained gentle activity (walking, swimming, chair exercises) reduces it over weeks to months.
