What they reveal about your health
Kidney function is a key element of every blood test, and for good reason. The kidneys are high-performance filters: they clean around 1,500 liters of blood daily, regulate fluid and electrolyte balance, produce hormones (e.g., erythropoietin for blood cell production), and control the acid-base balance.
What many men don't know: The kidneys are sensitive to hidden risk factors , such as high blood pressure or certain medications (e.g., painkillers, supplements).
Which laboratory values provide information about kidney health?
Kidney function cannot be determined by a single value. Instead, a combination of different parameters is used:
- Creatinine: a metabolic waste product from muscles; levels rise with impaired kidney function.
- Cystatin C: Sensitive marker for glomerular filtration rate (GFR); less dependent on muscle mass
- eGFR (estimated glomerular filtration rate): Estimated value of the kidney's filtration capacity, calculated from creatinine or cystatin C.
- Urea (BUN): Produced during protein breakdown; elevated in cases of protein excess or poor kidney function.
- Electrolytes: Especially potassium, sodium, phosphate – often become imbalanced in chronic kidney problems.
- Albumin/creatinine ratio in urine: Important early marker for "silent" kidney damage
Tip: In physically active men with a lot of muscle mass, creatinine levels are often slightly elevated, which does not necessarily mean impaired kidney function. Cystatin C can provide more precise information in these cases.
Why should men know their kidney function?
Many early forms of kidney failure are asymptomatic. The diagnosis is often only made when 50–70% of kidney function has already been lost. Men with the following risk factors, in particular, should have their kidney function checked regularly:
- High blood pressure or diabetes
- regular use of painkillers (e.g. ibuprofen, diclofenac)
- Severe dehydration due to exercise, heat, or fasting
- Family history of kidney disease
- Proteinuria (protein in urine)
What are the early signs of impaired kidney function?
The symptoms are often nonspecific, which is why an emerging kidney problem often goes unnoticed for a long time. Early warning signs can include:
- Fatigue, decline in performance
- Unexplained high blood pressure
- Muscle cramps
- Fluid retention (especially in the ankles or eyelids)
- Nighttime urinary frequency
- Itching or dry skin
- Nausea, loss of appetite (in more advanced stages)
How can kidneys be protected and stabilized?
The kidneys are resilient, but sensitive to prolonged overexertion . Supporting them early on can help maintain their function well into old age.
- Drink enough fluids daily (2-32 liters depending on activity)
- Regular blood and urine tests are recommended for those at risk.
- Avoid long-term use of painkillers
- Optimize blood pressure (< 130/80 mmHg)
- Maintain moderate salt consumption
Micronutrients such as magnesium, vitamin D and omega-3 can also have a positive effect on inflammatory processes in the kidneys.
Conclusion
The kidneys perform precise work every day, often behind the scenes, but with an enormous impact on metabolism, blood pressure, hormones, and performance. Men, especially those focused on physical activity or hormones, should have their kidney function checked regularly, ideally including cystatin C levels , to avoid muscle-related imbalances.
Good kidney function means you can exert yourself, regenerate and build up strength - without a quiet brake in the background.
