Kidney function naturally declines with age, but the rate of that decline varies enormously and is largely influenced by factors you can control. In healthy adults without high blood pressure, kidney filtration drops by roughly 0.4 to 1.0 mL/min per year. With hypertension, that rate can triple. The good news: a combination of blood pressure management, dietary adjustments, regular movement, and medication awareness can meaningfully slow the process and preserve the kidney function you still have.
What “Normal” Kidney Aging Looks Like
Not every drop in kidney function signals disease. A systematic review published in BMJ Open found that healthy adults lose between 0.37 and 1.07 mL/min/1.73 m² of filtration capacity each year as a normal part of aging. That means someone in their 70s could have a filtration rate 20 to 30 points lower than they did at 40, without any underlying kidney disease.
The concern starts when decline accelerates beyond that baseline. High blood pressure is the single biggest accelerator, pushing annual losses as high as 3.6 mL/min in some studies. Diabetes, repeated use of certain medications, and dehydration compound the problem. The strategies below target those accelerators specifically.
Keep Blood Pressure in a Protective Range
Blood pressure control is the most impactful thing you can do for aging kidneys. The 2021 KDIGO guidelines suggest a systolic target below 120 mm Hg for adults with chronic kidney disease, measured under standardized conditions. For older and frail adults, though, KDIGO acknowledges that hitting 120 may cause problems like dizziness from positional blood pressure drops. In those cases, a less aggressive target is reasonable.
The practical takeaway: work with your doctor to find the lowest blood pressure you can tolerate comfortably. Even modest reductions from uncontrolled levels (say, bringing 150 down to 130) reduce the mechanical stress on the kidneys’ tiny filtering units. Home blood pressure monitoring helps track trends more reliably than occasional office visits.
Adjust Protein Intake by Stage
Protein places a workload on the kidneys. For older adults with mild kidney disease (stages 1 and 2), current guidelines recommend staying below 1.3 grams of protein per kilogram of body weight per day. That’s about 91 grams daily for a 155-pound person, which most Western diets easily exceed.
For more advanced kidney disease (stages 3 through 5, without dialysis), the recommendation drops to 0.6 to 0.8 grams per kilogram per day. At 155 pounds, that means roughly 42 to 56 grams of protein. This lower intake has been shown to slow kidney disease progression and reduce the metabolic burden that damaged kidneys struggle to handle. A chicken breast alone contains about 30 grams, so reaching this limit is easier than you might think.
This creates a tension for older adults, who also need adequate protein to prevent muscle loss. The key is hitting the right amount for your kidney stage rather than defaulting to “more is better.” A renal dietitian can help you balance both priorities.
Move Your Body Regularly
Exercise protects kidneys in older adults, and the evidence is more specific than you might expect. A five-year Norwegian trial of over 1,100 adults with a median age of 72 found that those assigned to high-intensity interval training twice a week had a 25% lower risk of rapid kidney function decline compared to controls. A separate U.S. trial of nearly 1,200 sedentary older adults found that two years of supervised moderate-intensity exercise slowed the rate of kidney decline by about 1 mL/min and reduced the odds of rapid decline by 21%.
Even outside of structured programs, the pattern held. Participants who increased their moderate-to-vigorous activity by more than 20 minutes per week had a 27% lower risk of rapid kidney decline compared to those who kept their activity level the same. You don’t need to train like an athlete. Walking briskly for 30 minutes most days, swimming, or cycling at a comfortable pace all qualify. The consistency matters more than the intensity.
Manage Blood Sugar Carefully
Diabetes is the leading cause of kidney disease, and blood sugar control in older adults directly affects kidney outcomes. A large UK observational study found the lowest risk of kidney complications in people who maintained an HbA1c between 6.5% and 7.5%. Higher levels increased kidney risk, particularly in people over 60 and those already taking blood pressure medication.
Pushing HbA1c too low carries its own risks in older adults, including dangerous drops in blood sugar. The 6.5% to 7.5% window represents a sweet spot: tight enough to protect the kidneys, loose enough to avoid hypoglycemia. For older adults with diabetes, a newer class of blood sugar medications (SGLT2 inhibitors) has shown particular promise, reducing the risk of progressive kidney disease and heart failure hospitalization in patients 65 and older, and even in those 75 and above.
Avoid Medications That Damage Kidneys
Some of the most common over-the-counter medications are harmful to compromised kidneys, and older adults are especially vulnerable. The biggest offenders:
- Pain relievers (NSAIDs): Ibuprofen (Advil, Motrin), naproxen (Aleve), and aspirin used for pain relief all reduce blood flow to the kidneys. Prescription versions like diclofenac (Voltaren) and celecoxib (Celebrex) carry the same risk. Acetaminophen (Tylenol) is generally the safer alternative for pain.
- Decongestants: Pseudoephedrine (Sudafed), phenylephrine (Sudafed PE), and nasal sprays like oxymetazoline (Afrin) raise blood pressure and stress the kidneys.
- Antacids: Magnesium-based antacids (Rolaids, Mylanta) and calcium-based ones (Tums, Maalox) can cause dangerous mineral buildup when kidneys can’t filter efficiently.
- Bismuth subsalicylate: Pepto-Bismol and Kaopectate contain a compound related to aspirin and are not safe with kidney disease.
- Appetite suppressants and supplements containing ephedrine or black licorice also pose risks.
Before taking any new medication, including herbal supplements, check whether it’s cleared by the kidneys. Many drugs that are perfectly safe for younger adults with normal kidney function become problematic when filtration is reduced.
Stay Hydrated Without Overdoing It
Dehydration forces the kidneys to concentrate urine, which stresses already compromised tissue. Older adults are particularly prone to dehydration because the thirst sensation weakens with age. A general target of 6 to 8 cups (1,500 to 2,000 mL) of fluid per day works for most older adults, but the right amount depends on your kidney stage, heart health, and whether you’re retaining fluid.
In advanced kidney disease or heart failure, too much fluid can be just as harmful as too little, leading to swelling and shortness of breath. Plain water is the best choice. Sugary drinks and excessive caffeine can work against you. If you notice swollen ankles, sudden weight gain, or reduced urine output, those are signs your fluid balance needs medical attention.
Reduce Sodium and Watch Mineral Intake
Sodium drives up blood pressure and forces the kidneys to work harder. Most adults eat well over 3,000 mg of sodium daily; reducing to under 2,000 mg can lower blood pressure significantly and ease the kidney workload. The biggest sources are restaurant meals, processed foods, canned soups, and deli meats, not the salt shaker at the table.
As kidney function drops, the body also has trouble balancing potassium and phosphorus. There are no universal milligram limits for these minerals because the right amount depends on your lab results and kidney stage. This is one area where individualized guidance from a dietitian makes a real difference. Foods high in potassium (bananas, potatoes, tomatoes) and phosphorus (dairy, processed meats, dark colas) may need to be moderated, but not everyone with kidney disease needs to restrict them.
Get Regular Monitoring
Kidney disease is silent for years. By the time you feel symptoms, significant function has already been lost. Two simple blood and urine tests track kidney health: one measures filtration rate (eGFR) and the other checks for protein leaking into urine (albumin-to-creatinine ratio). How often you need these tests depends on your risk level. Someone with diabetes, high blood pressure, or a family history of kidney disease needs more frequent checks than someone without those risks. Current guidelines recommend individualizing the testing schedule based on your baseline results and what treatments you’re on, so ask your doctor what interval makes sense for you.
Tracking your numbers over time is more useful than any single result. A filtration rate that drops 3 or 4 points over a year is more concerning than a low but stable number. Keeping a personal record of your results helps you and your doctor spot trends early, when intervention is most effective.