Why do both kidneys hurt after intense exercise?

After intense exercise, pain in both kidneys may be related to extrarenal factors, or could result from intrarenal causes such as nephroptosis (kidney ptosis), kidney stones, or pyelonephritis. Specific details are as follows:

I. Extrarenal Factors

In individuals who rarely exercise, intense physical activity can easily lead to local muscle spasms or improper movements causing muscle strain, resulting in localized pain—usually in the lower back. This pain is often mistaken for kidney pain, thus giving the impression of kidney pain after strenuous exercise.

II. Intrarenal Factors

1. Nephroptosis (Kidney Ptosis)

The kidneys are located bilaterally in the renal fossae between the thoracic and lumbar vertebrae. They are normally stabilized by the longitudinal back muscles and abdominal organs, preventing excessive displacement. However, because there is a potential loose space beneath the perirenal fat capsule, when intra-abdominal pressure decreases, the kidney may shift downward, leading to nephroptosis. This condition can cause kidney pain following intense physical activity.

2. Kidney Stones

Once formed, kidney stones can move within the local area. During exercise, if the stone shifts significantly, it may irritate the ureter or renal pelvis, causing post-exercise kidney pain. Diagnosis can be confirmed via renal ultrasound.

3. Pyelonephritis

In patients with pyelonephritis, inflammatory mediators associated with the disease repeatedly stimulate local tissues, causing kidney pain. Physical activity may intensify this stimulation, worsening the pain.

Besides the above-mentioned causes, other conditions such as ruptured renal cysts or kidney cancer may also be responsible. It is important to seek timely medical evaluation so that a physician can determine the underlying cause through appropriate examinations and initiate targeted treatment.