Keeping your kidneys healthy comes down to a handful of consistent habits: staying hydrated, eating less sodium, managing blood pressure and blood sugar, staying active, and being cautious with certain medications. Most of these are the same things that protect your heart and brain, which makes sense since your kidneys filter about 50 gallons of blood every day and are deeply connected to your cardiovascular system.
Stay Hydrated, Especially if You’ve Had Kidney Stones
Water helps your kidneys flush waste products and excess minerals out through urine. When you’re consistently underhydrated, those waste products can concentrate and, over time, form kidney stones or put extra strain on your filtering system. For most people, drinking when you’re thirsty and aiming for pale yellow urine is a reasonable guide.
If you’ve already had a kidney stone, the bar is higher. UT Southwestern Medical Center recommends at least 2 liters (8 cups) and ideally 3 liters (12 cups) of water per day for people with a history of stones. Hot weather, strenuous work, and heavy sweating all increase the target because sweat reduces your urine output, giving minerals more opportunity to crystallize.
Keep Sodium Under 2,300 mg Per Day
Sodium pulls water into your bloodstream. When you eat a lot of it, blood volume increases, blood pressure rises, and your kidneys have to work harder to filter that extra fluid. Over time, the elevated pressure damages the small blood vessels inside the kidneys. The Dietary Guidelines for Americans sets the daily limit at less than 2,300 mg, roughly one teaspoon of table salt, though most Americans eat well above that.
The biggest sources aren’t the salt shaker on your table. Bread, deli meats, canned soups, frozen meals, pizza, and restaurant food account for the majority of sodium intake. Reading labels and cooking more at home are the two most effective ways to bring your numbers down.
Watch for Hidden Phosphorus in Processed Foods
Phosphorus is a mineral your body needs in small amounts, but excess phosphorus can stress the kidneys, especially if function is already declining. The tricky part: phosphorus that occurs naturally in foods like beans, nuts, and dairy is absorbed at a rate of 40% to 70%. Phosphate additives used in processed foods, however, are absorbed at rates greater than 90%, meaning your body takes in almost all of it.
These additives show up in fast food, processed meats, bottled beverages, and packaged baked goods. On ingredient labels, look for terms like disodium phosphate, phosphoric acid (common in colas), sodium hexameta-phosphate, and trisodium phosphate. You don’t need to memorize the full list. A good rule of thumb: if the ingredient list includes a word containing “phosph,” the product has added phosphorus.
Manage Blood Pressure
High blood pressure is both a cause and a consequence of kidney damage. The force of elevated blood flow wears down the delicate filtering units inside each kidney, and as those units fail, blood pressure climbs further. The CDC recommends keeping blood pressure below 140/90 mm Hg to protect kidney function. Your doctor may set a tighter target depending on your other risk factors.
For many people, blood pressure responds to the same lifestyle changes that protect the kidneys directly: less sodium, regular exercise, maintaining a healthy weight, and limiting alcohol. When those aren’t enough, medication can close the gap. The important thing is that blood pressure stays controlled consistently, not just on the day you visit a clinic.
Control Blood Sugar if You Have Diabetes
Diabetes is the leading cause of kidney failure in the United States. Chronically high blood sugar damages the tiny blood vessels in the kidneys over years, gradually reducing their ability to filter waste. The key metric is your A1c, a blood test that reflects average blood sugar over the previous two to three months.
Current guidelines recommend an A1c target of approximately 7% for people with diabetes, and research published in the American Diabetes Association’s journal found that an A1c range of 6.7% to 7.1% was the most favorable for reducing long-term complications in people who already have significant kidney disease. Getting below 7% and staying there meaningfully reduces the risk of diabetic kidney damage. This typically involves a combination of dietary changes, physical activity, and medication.
Move Your Body Most Days
Regular physical activity lowers blood pressure, improves blood sugar control, and helps maintain a healthy weight, all of which reduce strain on the kidneys. The National Kidney Foundation recommends planning some type of exercise on most, if not all, days of the week. That doesn’t require a gym. Walking, gardening, cycling, swimming, and other activities that use large muscle groups all count.
If you’re starting from a sedentary baseline, even short daily walks make a difference. The benefits accumulate over weeks and months through steadier blood pressure and better metabolic health, not through any single workout.
Be Careful With Over-the-Counter Pain Relievers
Nonsteroidal anti-inflammatory drugs, the category that includes ibuprofen and naproxen, reduce blood flow to the kidneys. Occasional use for a headache is generally fine for people with healthy kidneys, but regular or high-dose use can cause acute kidney injury or accelerate existing damage. This risk increases if you’re dehydrated, older, or already have reduced kidney function.
Acetaminophen (Tylenol) is typically easier on the kidneys, though it carries its own risks for the liver at high doses. If you rely on pain relievers frequently, it’s worth discussing the safest option for your situation with a healthcare provider.
Know Your Kidney Function Numbers
Kidney disease is often called a “silent” condition because it causes no symptoms until function has dropped significantly. The main screening tool is a blood test that estimates your glomerular filtration rate, or eGFR, which measures how efficiently your kidneys filter blood. In adults, a normal eGFR is above 90, but it naturally declines with age:
- Ages 20 to 29: average eGFR of 116
- Ages 30 to 39: average eGFR of 107
- Ages 40 to 49: average eGFR of 99
- Ages 50 to 59: average eGFR of 93
- Ages 60 to 69: average eGFR of 85
- Ages 70 and older: average eGFR of 75
An eGFR between 60 and 89 indicates mild loss of function. Between 30 and 59 is moderate. Below 15 is kidney failure. A simple urine test can also reveal protein in the urine, one of the earliest signs of kidney damage, sometimes present even when eGFR is still normal. If you have diabetes, high blood pressure, or a family history of kidney disease, routine screening gives you the chance to catch problems early, when lifestyle changes and treatment are most effective.