Why do kidney stones often flare up at night?

Stones flaring up at night may be caused by factors such as changes in body position, vagus nerve excitation, concentrated urine, improper diet, and temperature stimulation. It is recommended to promptly visit a hospital for examination and receive symptomatic treatment under the guidance of a doctor. The detailed analysis is as follows:

1. Change in body position: When the body lies down at night, changes in posture may cause stones to move within the urinary tract or bile ducts, thereby stimulating surrounding tissues and causing pain or discomfort. Patients with kidney stones can try adjusting their sleeping posture, such as lying on their side or back, to reduce irritation to the urinary tract.

2. Vagus nerve excitation: At night, the vagus nerve tends to be more active. Increased vagal tone may lead to contractions of the smooth muscles in the urinary tract, promoting stone movement or irritating the urinary mucosa, resulting in pain. Drinking adequate amounts of water can dilute urine, reduce irritation from stones, and help alleviate discomfort associated with vagus nerve excitation.

3. Concentrated urine: During nighttime, the body's metabolism slows down and fluid intake decreases, which may lead to concentrated urine. Concentrated urine increases the likelihood of minerals and salts crystallizing, thereby promoting stone formation or movement and triggering pain. Reduce consumption of foods high in salt, sugar, and protein that contribute to urine concentration, and increase intake of fresh vegetables and fruits.

4. Improper diet: Consuming excessive amounts of calcium-, oxalate-, or purine-rich foods—such as milk, spinach, and seafood—during dinner or before bedtime may elevate levels of calcium, oxalate, or uric acid in the urine, promoting stone formation or movement. Avoid eating large quantities of high-oxalate or high-calcium foods like spinach, milk, and soy products at night to reduce the risk of stone development.

5. Temperature stimulation: Nighttime temperature changes may stimulate stones to change—for example, increasing in size or shifting position—thereby causing pain. Patients are advised to stay warm and seek medical treatment at a hospital, including surgical options such as extracorporeal shock wave lithotripsy or percutaneous nephrolithotomy.

In daily life, it's important to develop healthy habits, avoid long-term smoking, and engage in moderate physical activities such as jogging or hiking, which benefit overall health.