The Importance of Kidney Health in Your Senior Years
As we age, our bodies go through numerous changes, and our kidneys are no exception. These vital, bean-shaped organs are responsible for filtering waste from the blood, regulating blood pressure, balancing bodily fluids, and producing hormones. After age 40, kidney function can gradually decline as part of the natural aging process. By age 70, it's common to have a lower kidney function than a younger adult, but this doesn't automatically signify disease. Understanding the metrics, what's considered normal, and how to protect your kidneys is a cornerstone of healthy aging.
How is Kidney Function Measured?
Doctors use several tests to assess how well your kidneys are working. The most common and important ones include:
- Estimated Glomerular Filtration Rate (eGFR): This is the primary test for kidney function. It's a calculation based on your blood creatinine level, age, sex, and body size. The eGFR estimates how many milliliters (mL) of blood your kidneys filter per minute. A higher number is generally better.
- Serum Creatinine: This blood test measures the level of creatinine, a waste product from muscle tissue breakdown. Healthy kidneys filter creatinine out of the blood. A high level of creatinine suggests the kidneys may not be working effectively.
- Urine Albumin-to-Creatinine Ratio (UACR): This urine test checks for albumin, a type of protein. Healthy kidneys keep albumin in the blood, so having it in your urine can be an early sign of kidney damage.
What is a Normal Kidney Function at Age 70?
It's crucial to understand that a single "normal" number doesn't exist for everyone. Kidney function is individual and declines naturally over a lifetime. According to the National Kidney Foundation, the average eGFR for someone aged 70 or older is 75 mL/min/1.73m².
However, healthcare professionals emphasize context. An eGFR between 60-89 is often classified as a mild loss of kidney function, but in an older adult without other signs of kidney damage (like protein in the urine, high blood pressure, or diabetes-related issues), it can be considered a normal part of aging. Some experts argue that for individuals over 65 without other issues, CKD should only be diagnosed if the eGFR drops below 45. The key is to monitor the trend over time with your doctor.
The Stages of Chronic Kidney Disease (CKD)
When kidney function declines to a certain point, it is classified as Chronic Kidney Disease (CKD). Understanding the stages helps doctors determine the best course of action. The stages are based on the eGFR level.
| Stage | eGFR Level (mL/min/1.73m²) | Description |
|---|---|---|
| Stage 1 | 90 or higher | Kidney damage with normal or high GFR. |
| Stage 2 | 60–89 | Mild decrease in GFR. |
| Stage 3a | 45–59 | Mild to moderate decrease in GFR. |
| Stage 3b | 30–44 | Moderate to severe decrease in GFR. |
| Stage 4 | 15–29 | Severe decrease in GFR. |
| Stage 5 | Less than 15 | Kidney failure (End-Stage Renal Disease). |
It's important to note that many older adults live full, healthy lives with Stage 2 or 3a CKD without it ever progressing, as long as it's managed properly.
Proactive Steps to Maintain Kidney Health After 70
While you can't stop the clock on aging, you can take powerful steps to protect your kidneys and slow any functional decline.
1. Manage Blood Pressure and Diabetes
High blood pressure and diabetes are the two leading causes of kidney disease. Keeping these conditions under control is the single most important thing you can do for your kidneys.
- Regularly monitor your blood pressure and blood sugar levels.
- Take all prescribed medications as directed by your doctor.
- A healthy blood pressure reading is typically below 120/80.
2. Stay Hydrated
Water helps your kidneys remove waste from your blood and can help prevent kidney stones. Aim for 1.5 to 2 liters (about 6-8 glasses) of water per day, but consult your doctor, as fluid needs can vary based on your overall health, especially if you have heart or existing kidney issues.
3. Eat a Kidney-Friendly Diet
A balanced diet is crucial. Focus on:
- Reducing sodium: Limit processed foods, canned soups, and fast food. Aim for less than 2,300 mg of sodium per day.
- Heart-healthy foods: Incorporate fresh fruits, vegetables, whole grains, and lean proteins like fish and chicken.
- Moderate protein: Too much protein can strain the kidneys. Your doctor or a dietitian can advise on the right amount for you.
4. Be Cautious with Medications
Long-term, frequent use of over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen can damage the kidneys. For chronic pain, discuss safer alternatives with your healthcare provider. Always ensure your doctor knows all the medications and supplements you take.
5. Exercise Regularly
Physical activity helps control blood pressure, manage weight, and improve overall cardiovascular health, all of which benefit your kidneys. Aim for at least 30 minutes of moderate activity, like brisk walking, most days of the week.
Conclusion: Your Partner in Kidney Health
So, what should your kidney function be at age 70? While an average eGFR is around 75, what's more important is your individual health profile and the trend of your kidney function over time. A lower eGFR is a normal part of aging, but it's also a signal to be proactive. Regular check-ups, managing underlying conditions, and adopting a healthy lifestyle are your best defenses against significant kidney decline. Work closely with your healthcare provider to understand your numbers and create a personalized plan to keep your kidneys working their best for years to come. For more information, you can visit the National Kidney Foundation.
