Kidneys filter waste, acid, and excess fluids from the body. Our kidneys filter a cup of blood every two minutes, according to the NIDDK. This process stabilises blood water, salt, and minerals.
Kidney function decreases with age. GFR reduces 6.3 mL each decade, according to Advances in Chronic Kidney Disease. Weakened kidneys can't eliminate as much waste, causing blood toxin accumulation.
Along with a lower GFR, renal tissue decreases. Less renal tissue may reduce function. Nephrons shrink with ageing, which slows the kidneys' waste filtering.