Why It Matters
eGFR, or estimated glomerular filtration rate, provides insight into kidney function. It quantifies how efficiently the kidneys filter waste from the blood, serving as the primary clinical measure of renal health. (source, source)
eGFR is calculated from serum creatinine using the CKD-EPI equation, which accounts for age, sex, and race. For athletes and high-performers, eGFR carries particular significance; the kidneys must sustain filtration rates sufficient to clear the elevated metabolic waste produced by intense training, high protein diets, and the muscle turnover inherent to adaptation. A declining eGFR signals reduced renal reserve that can compromise recovery, electrolyte regulation, and long-term health. (source, source)
Low eGFR: Reduced Kidney Filtration
Low eGFR can be influenced by physiological factors affecting kidney function, as the kidneys play a crucial role in filtering waste products from the blood. From a nutritional standpoint, factors such as excessive intake of sodium along with inadequate hydration can contribute to decreased kidney function and lower eGFR. (source, source, source)
Potential Performance Impact
- Impaired clearance of metabolic waste products reducing recovery capacity
- Compromised electrolyte and fluid regulation during training stress
- Accumulation of uremic toxins impairing cardiovascular and neuromuscular function
- Reduced capacity to handle high-protein dietary loads necessary for muscle adaptation
Optimization
Select Mediterranean-style meals. The Mediterranean diet is rich in fruits and vegetables and has been shown to be beneficial when correcting eGFR (source).
Protocol: Consume a Mediterranean-style diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats. One serving examples: Chicken Breast (3.5 oz), Brown Rice (cooked) (1 cup), Salmon (3 oz), Lentils (1 cup)
Exercise at a high intensity. Regular exercise also supports kidney health by improving renal blood flow and cardiovascular function. (source, source)
Protocol: Complete at least two sessions of high-intensity exercise, like HIIT or Tabata training, weekly.
High eGFR: Favorable Kidney Function
Elevated eGFR can be influenced by physiological factors related to kidney function, as the kidneys play a vital role in filtering waste and excess fluids from the blood. Nutritionally, factors such as adequate hydration and a balanced diet low in sodium can support kidney health and potentially contribute to higher eGFR levels. (source, source)
Generally, high eGFR readings are considered to be a sign of good health.
Optimization
High eGFR readings usually do not require any specific treatment unless it is associated with a specific illness. There is no suggested nutritional, lifestyle, or supplement-based intervention.
