The kidneys are among the most quietly essential organs in the body. They filter roughly 200 liters of blood every day, regulate fluid balance, control blood pressure, manage electrolytes, activate vitamin D, and produce hormones that stimulate red blood cell production. Most people give them almost no thought until something goes wrong — which is precisely when they become difficult to ignore.
What makes kidney health particularly relevant for older adults is that kidney function declines with age as a normal biological process — and that decline interacts with medications, chronic conditions, and lifestyle factors in ways that can accelerate significantly if not recognized and managed. Chronic kidney disease affects an estimated 38% of adults over 65 in the United States, and the majority of those affected don't know it because the condition produces no symptoms until it is significantly advanced.
Understanding what happens to the kidneys with age, what accelerates that decline, and what older adults can do to protect kidney function is genuinely useful knowledge — not because kidney disease is inevitable, but because much of what damages kidneys is preventable or modifiable.
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What Happens to the Kidneys With Age
Several changes in kidney structure and function occur with normal aging, independent of disease.
Kidney mass declines. The kidneys lose approximately 25 to 30 percent of their mass between the ages of 30 and 80, primarily through loss of nephrons — the functional filtering units. A young adult has roughly one million nephrons per kidney. By age 70, a meaningful proportion of those have been lost through the normal cellular aging process.
Glomerular filtration rate — the primary measure of kidney function, reflecting how much blood the kidneys filter per minute — declines at roughly 1% per year after age 40 in most people. By the time a person reaches their 70s, GFR may be 30 to 40 percent lower than it was at peak function. This decline is so consistent that age-adjusted GFR reference ranges exist — what would be considered mildly abnormal in a 30-year-old may be within the expected range for a 75-year-old.
The kidneys become less able to concentrate urine with age, which means they are less efficient at conserving water when fluid intake is low. This contributes to the increased dehydration risk in older adults. The renal tubules — responsible for reabsorbing useful substances from the filtrate and excreting waste — become less efficient, affecting the handling of electrolytes, drugs, and other substances.
Blood flow to the kidneys decreases with age, partly through cardiovascular changes and partly through structural changes in the renal vasculature. Reduced blood flow means reduced filtration capacity and reduced ability to respond to acute stressors like dehydration, blood pressure drops, or infection.
These changes are normal — they don't constitute kidney disease, and they don't necessarily progress to kidney failure. But they do reduce the kidneys' reserve capacity, meaning they have less ability to compensate when additional stressors are imposed.
Chronic Kidney Disease — What It Is and Why It's So Often Undetected
Chronic kidney disease is defined as kidney damage or reduced kidney function persisting for more than three months. It is staged from 1 to 5 based on GFR, with stage 5 representing kidney failure requiring dialysis or transplantation.
The reason CKD is so often undetected is that the kidneys have substantial reserve capacity — they can lose a significant proportion of function before any symptoms appear. By the time someone feels unwell from kidney disease, function has typically declined to a small fraction of normal. Symptoms — fatigue, swelling, reduced urine output, confusion — appear late and are nonspecific.
The only reliable way to detect CKD early is through blood and urine tests. A serum creatinine measurement allows calculation of estimated GFR. A urine albumin-to-creatinine ratio detects the protein leakage that is an early sign of kidney damage. These simple tests, done as part of routine blood work, provide the information needed to identify CKD at a stage when intervention can slow or stop its progression.
The American Diabetes Association recommends annual kidney function testing for all people with diabetes. Guidelines from kidney disease organizations recommend testing for all adults over 60, particularly those with hypertension or diabetes — the two most common causes of CKD. In practice, these recommendations are inconsistently followed, and many older adults with early CKD are never told they have it.
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The Main Drivers of Kidney Decline in Older Adults
While some kidney function loss with age is inevitable, the rate of that decline varies enormously between individuals. The factors that accelerate kidney decline are largely modifiable.
Hypertension is the second leading cause of kidney failure after diabetes. High blood pressure damages the small blood vessels within the kidneys — the glomeruli — reducing their filtering capacity. The damage is cumulative and largely silent until significant function has been lost. Blood pressure control is one of the most effective interventions for slowing CKD progression in people with hypertension — and for preventing kidney damage in people whose kidneys are still healthy. The target blood pressure for people with CKD is typically lower than for the general population, often below 130/80.
Diabetes is the leading cause of kidney failure in the developed world. Chronically elevated blood sugar damages the kidneys through multiple mechanisms — glycation of proteins in the glomerular basement membrane, inflammatory signaling, and oxidative stress. Tight blood sugar control significantly reduces the risk of diabetic kidney disease and slows its progression in people who already have it.
NSAIDs — nonsteroidal anti-inflammatory drugs including ibuprofen, naproxen, and similar medications — are among the most common causes of acute kidney injury in older adults and contribute to chronic kidney damage with regular long-term use. NSAIDs reduce blood flow to the kidneys by blocking prostaglandins that dilate renal blood vessels. In a young person with normal kidney reserve, occasional NSAID use rarely causes lasting harm. In an older adult with already reduced renal reserve — particularly one who is dehydrated, taking diuretics, or has heart failure — NSAIDs can precipitate acute kidney injury. These medications appear on the Beers Criteria for older adults for this reason, and their use warrants discussion with a physician.
Dehydration is a significant and underappreciated contributor to both acute kidney injury and long-term kidney decline in older adults. The age-related reduction in thirst sensation, combined with reduced urine concentrating ability, makes older adults more vulnerable to dehydration — and the kidneys are among the first organs to suffer when blood volume drops. Adequate hydration is one of the simplest and most accessible kidney protection strategies available.
Contrast dye used in CT scans and certain cardiac procedures can cause contrast-induced nephropathy — acute kidney injury triggered by the contrast agent. In people with normal kidney function, this risk is low. In people with reduced GFR, the risk is meaningfully higher, and pre-procedure hydration and dose minimization are important precautions. Anyone with known kidney disease or reduced GFR should make sure their physician is aware before any imaging procedure involving contrast.
Recurrent urinary tract infections and untreated urinary obstruction can cause kidney damage over time. Older adults — particularly women — have higher rates of UTIs, and symptomatic infections should be treated promptly. Incomplete bladder emptying from an enlarged prostate or other causes increases infection risk and warrants medical evaluation.
Medications and the Aging Kidney — A Critical Interaction
The kidneys are responsible for excreting most medications from the body. As kidney function declines, drugs that are renally cleared accumulate to higher levels than intended — increasing both therapeutic effects and side effects at doses that would be appropriate for people with normal kidney function.
This interaction affects an enormous range of commonly used medications. Metformin — widely used for type 2 diabetes — is contraindicated at low GFR levels because it can accumulate and cause lactic acidosis. Many antibiotics require dose adjustment in kidney disease. Direct oral anticoagulants — apixaban, rivaroxaban, dabigatran — used for atrial fibrillation and DVT prevention require dose adjustment based on kidney function, and dabigatran is contraindicated in severe CKD. Gabapentin and pregabalin, used for nerve pain and other conditions, accumulate significantly in kidney disease and can cause sedation and confusion at doses appropriate for normal kidney function.
The practical implication for older adults is that kidney function should be known — through regular testing — and that any prescribing physician should be made aware of kidney disease or reduced GFR. Medication lists should be reviewed periodically with a pharmacist or physician with kidney function in mind. This is an area where errors are common and consequences can be serious.
What Protects Kidney Health After 60
The same lifestyle factors that protect cardiovascular health largely protect kidney health — which makes sense given how intimately the two systems are connected.
Blood pressure control is the single most important modifiable factor for most older adults. Keeping blood pressure consistently below 130/80 — or lower in people with existing kidney disease — reduces the mechanical and inflammatory damage that hypertension causes in the renal microvasculature. This requires knowing your blood pressure, taking it seriously, and working with a physician if medication is needed.
Blood sugar management matters for everyone with diabetes or prediabetes. The renal consequences of chronically elevated blood sugar are serious and largely preventable with adequate glucose control. Newer diabetes medications — particularly SGLT2 inhibitors like empagliflozin and dapagliflozin — have demonstrated direct kidney-protective effects independent of their glucose-lowering action and are now recommended as first-line therapy for people with diabetes and CKD.
Adequate hydration is simple and important. For most older adults, six to eight glasses of water per day provides adequate hydration — more in hot weather or during illness. The goal is pale yellow urine throughout the day. Dark urine is a reliable indicator of inadequate hydration.
Limiting NSAID use — particularly long-term, regular use — reduces one of the most avoidable causes of kidney damage in older adults. Acetaminophen is a safer alternative for many pain management needs, though it too has limits at high doses and in people with liver disease.
A diet lower in sodium and processed meat supports kidney health. High sodium intake raises blood pressure and directly stresses the kidneys. High intake of processed and red meat increases the acid load on the kidneys and may accelerate GFR decline. A dietary pattern resembling the DASH or Mediterranean diet — abundant vegetables and fruits, whole grains, lean protein, limited sodium — supports both cardiovascular and kidney health.
Avoiding smoking is relevant for kidney health specifically — smoking reduces renal blood flow and accelerates GFR decline in people with existing kidney disease.
When to Talk to a Doctor
Several situations warrant a specific conversation about kidney health with a physician.
Anyone with diabetes or hypertension should be having kidney function checked annually — serum creatinine with eGFR calculation and urine albumin-to-creatinine ratio. If this isn't happening, it's worth asking for it.
Anyone over 70 should know their approximate kidney function level — not because something is necessarily wrong, but because it affects medication dosing and risk assessment for procedures.
Swelling in the legs or ankles that is new or worsening, persistent fatigue without clear explanation, changes in urine output or color, or foamy urine — which can indicate protein in the urine — are symptoms that warrant evaluation.
Before any CT scan or procedure involving contrast dye, kidney function should be checked if it hasn't been recently. This is standard practice in careful clinical settings but doesn't always happen automatically.
A Practical Summary
| Action | Why It Matters |
|---|
| Know your kidney function (eGFR) | Most CKD has no symptoms until advanced |
| Control blood pressure below 130/80 | Hypertension is the second leading cause of kidney failure |
| Manage blood sugar if diabetic | Diabetes is the leading cause of kidney failure |
| Stay adequately hydrated | Dehydration causes acute and chronic kidney damage |
| Limit NSAID use | NSAIDs reduce renal blood flow and cause kidney damage |
| Review medications with kidney function in mind | Many drugs accumulate with reduced kidney function |
| Annual kidney function testing if over 65 | Early detection allows intervention before significant damage |
Closing Thoughts
Kidney health is one of the most consequential and least discussed aspects of health in older adulthood. The combination of age-related function decline, high prevalence of the conditions that damage kidneys, and the wide range of medications whose safety depends on kidney function makes it an area that deserves more attention than it typically receives.
The encouraging reality is that much of what damages kidneys is preventable or treatable — blood pressure control, blood sugar management, adequate hydration, and judicious use of nephrotoxic medications address the main modifiable drivers of kidney decline. And early detection through simple blood and urine tests allows intervention at a stage when it can meaningfully change the trajectory.
Knowing your kidney function is a reasonable thing for any adult over 60 to prioritize — not as a cause for alarm, but as useful information that supports better decisions about medications, procedures, and the lifestyle factors that protect one of the body's most essential and quietly hardworking organs.
This article provides general educational information about kidney health for adults over 60, based on current nephrology and geriatric medicine guidelines. Individual kidney health concerns should be discussed with a qualified healthcare provider.
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