eGFR
| Clinical | Optimal | |
|---|---|---|
| Male | Above 60 ml/min/1.73m2 | Above 90 ml/min/1.73m2 |
| Female | Above 60 ml/min/1.73m2 | Above 90 ml/min/1.73m2 |
What is eGFR?
Estimated glomerular filtration rate (eGFR) is a calculated value that estimates how effectively your kidneys are filtering waste products from your blood. It is derived from your blood creatinine level, adjusted for your age, sex, and ethnicity using a standardised formula (CKD-EPI equation).
The glomerular filtration rate represents the volume of blood that passes through the tiny filtering units of your kidneys (glomeruli) each minute. Healthy kidneys filter approximately 90-120 ml of blood per minute. As kidney function declines, the filtration rate drops and waste products begin to accumulate in the blood.
eGFR is the standard measure used by the NHS and healthcare providers across the UK to assess and stage kidney function. It provides a more clinically meaningful measure than creatinine alone because it accounts for individual variation in creatinine production. eGFR is the cornerstone of chronic kidney disease diagnosis and monitoring.
Why eGFR Matters for Your Health
Chronic kidney disease (CKD) is a silent epidemic, affecting approximately 1 in 10 adults in the UK, with the vast majority unaware of their condition. Early-stage CKD produces no symptoms, yet it significantly increases cardiovascular risk and can progress to kidney failure if left undetected.
For longevity, kidney function is one of the most critical parameters to monitor. The kidneys are not merely filters; they regulate blood pressure, produce erythropoietin (which stimulates red blood cell production), activate vitamin D, and maintain electrolyte and acid-base balance. Declining kidney function has systemic consequences that accelerate ageing.
eGFR naturally declines with age at approximately 1 ml/min per year after the age of 40. However, accelerated decline can be driven by diabetes, hypertension, obesity, and certain medications. Tracking your eGFR over time allows you to distinguish normal age-related decline from pathological kidney damage and intervene early if needed.
eGFR& Your Wearable Data
Estimated glomerular filtration rate (eGFR) is calculated from your creatinine level and provides the best overall estimate of kidney function. Because it is derived from creatinine, the same wearable-related factors apply: muscle mass from strength training, recent intense exercise, and hydration status all influence your eGFR result. A muscular individual with high creatinine may have a falsely low eGFR despite normal kidneys.
Regular physical activity tracked by your wearable is protective for kidney health. Studies show that moderate exercise (150+ minutes per week of moderate activity) is associated with better preserved eGFR over time and reduced risk of chronic kidney disease. Your wearable's weekly activity summaries help ensure you are meeting these protective thresholds.
Blood pressure, which some wearables now estimate, is the most important modifiable factor for kidney function. Sustained hypertension is the leading cause of declining eGFR. If your wearable provides blood pressure or pulse wave data, tracking trends alongside eGFR results helps identify early cardiovascular-renal risk that can be addressed through lifestyle modification.
What High eGFR May Suggest
An eGFR above 90 ml/min generally indicates normal kidney function. Very high eGFR values (above 120-130 ml/min) can sometimes be seen in early diabetes or pregnancy, where the kidneys are hyperfiltrating, working harder than normal. This hyperfiltration can be a very early sign of kidney stress.
In the context of diabetes, hyperfiltration may precede a later decline in kidney function and is considered an early warning sign. If your eGFR appears elevated and you have diabetes or pre-diabetes, this is worth discussing with your healthcare provider.
For most people without diabetes, a high eGFR is simply a reflection of healthy kidney function and is not a cause for concern.
What Low eGFR May Suggest
Reduced eGFR indicates that your kidneys are not filtering blood as efficiently as they should. The UK uses eGFR to stage chronic kidney disease: Stage 1 (eGFR above 90 with evidence of kidney damage), Stage 2 (60-89), Stage 3a (45-59), Stage 3b (30-44), Stage 4 (15-29), and Stage 5 (below 15, indicating kidney failure).
Common causes of reduced eGFR include diabetes, hypertension, glomerulonephritis, polycystic kidney disease, chronic urinary tract obstruction, and prolonged use of nephrotoxic medications. Acute causes include dehydration, severe infection, and urinary obstruction.
It is important to note that eGFR can fluctuate temporarily due to dehydration, illness, or medication effects. A sustained decline across multiple measurements is more significant than a single low reading. If your results suggest reduced eGFR, your GP will typically repeat the test and may arrange further investigations.
How to Optimise Your eGFR
Food
Reduce sodium intake to less than 6g of salt per day, as excess sodium drives high blood pressure, which is a leading cause of kidney damage, Stay well hydrated with adequate water intake throughout the day to support healthy kidney filtration, Follow a balanced diet moderate in protein, as very high protein intake may place additional burden on compromised kidneys, Increase intake of anti-inflammatory foods including berries, leafy greens, fatty fish, and turmeric to reduce kidney inflammation
Lifestyle
Control blood pressure rigorously, as hypertension is one of the two most common causes of progressive kidney damage, Manage blood sugar effectively if diabetic, as poor glycaemic control directly damages the kidney's filtering units, Avoid regular use of NSAIDs (ibuprofen, naproxen) and other nephrotoxic substances, discussing alternatives with your GP, Stop smoking, as smoking accelerates kidney function decline and compounds cardiovascular risk, Maintain a healthy body weight, as obesity is an independent risk factor for kidney disease
Supplements
Omega-3 fatty acids (1-2g daily) may provide anti-inflammatory kidney protection, Vitamin D (1000-2000 IU daily if deficient) supports kidney health, as the kidneys are responsible for activating vitamin D, Coenzyme Q10 (100-200mg daily) may support mitochondrial function in kidney cells and reduce oxidative damage
When to Speak to Your GP
See your GP if your eGFR results suggest levels below 60 ml/min on two occasions at least three months apart, as this meets the criteria for chronic kidney disease stage 3. Seek prompt medical advice if eGFR is below 30 ml/min, as this indicates significant kidney impairment requiring specialist input. Urgent assessment is needed if there is a sudden drop in eGFR or if reduced eGFR is accompanied by blood or protein in the urine, swelling, or difficulty controlling blood pressure.
References
- NHS. Chronic kidney disease — Diagnosis. Updated 2024. nhs.uk
- NICE. Chronic kidney disease: assessment and management. NG203. nice.org.uk
- KDIGO. KDIGO 2024 Clinical Practice Guideline for the evaluation and management of CKD. Kidney Int. 2024;105(4S). pubmed.ncbi.nlm.nih.gov
- BMJ. Levey AS, et al. A new equation to estimate glomerular filtration rate. Ann Intern Med. 2009;150(9):604-612. pubmed.ncbi.nlm.nih.gov
- Lancet. Matsushita K, et al. Association of estimated glomerular filtration rate and albuminuria with all-cause and cardiovascular mortality. Lancet. 2010;375(9731):2073-2081. pubmed.ncbi.nlm.nih.gov
Medical Disclaimer— This content is for general educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Omniwo Ltd is a wellness information service and is not a medical device, clinical laboratory, or regulated healthcare provider under MHRA guidelines. The “optimal ranges” presented on this page are based on published clinical guidelines (WHO, NICE, NHS) and peer-reviewed research; they represent functional wellness targets and may differ from standard laboratory reference ranges. Individual results should always be interpreted by a qualified healthcare professional (such as your GP) who understands your full medical history. Do not start, stop, or change any medication or supplement based solely on this information. If you are experiencing symptoms, seek medical attention promptly.