Why Hot Weather Raises Your Risk of Kidney Stones

Kidney stones are often associated with middle-aged men, but doctors are seeing them more frequently in young people and even teenagers. According to Loren Jones, M.D., a urologist at Urology Austin, heat is a major factor. Sweating causes the body to lose more water than urine, which concentrates the urine and creates conditions where mineral particles are more likely to crystallize into stones.

That is why people who live in hot climates face higher risk. Jones points to what doctors call the Stone Belt, a band of warmer regions stretching from Southern California through the Southeast, where kidney stones are more common than in cooler parts of the country. People who spend a lot of time outdoors, including outdoor workers and endurance athletes training in the heat, also face elevated risk.

Family history remains the single biggest risk factor, Jones said. Genetics, combined with environmental conditions, play a larger role than age alone.

Kidney stones often develop without clear warning signs. Some patients notice subtle changes, such as cloudy urine or slight discoloration, before pain sets in. For most people, however, the first sign is severe pain that requires emergency care.

Prevention centers on hydration. Jones recommends drinking about 3 liters of fluid a day, roughly 100 ounces, with a goal of producing about 2.5 liters of urine daily. He suggests mixing a quarter cup of lemon juice into a liter of water and drinking it throughout the day, since the citrate in lemons binds with calcium in urine and helps prevent it from combining with oxalate to form stones.

Diet also plays a role. Foods high in oxalate, including spinach, kale, nuts, beets, rhubarb, coffee, dark chocolate and tea, can raise stone risk, though Jones does not recommend avoiding them entirely unless someone forms stones frequently. High-salt diets are another concern, since sodium prompts the body to release more calcium into the urine.

Jones also encourages anyone who has passed a stone to follow up with a urologist, since about half of patients form another stone within five years without targeted prevention.