June 19, 2023
Summer brings cookouts, pool days and beach vacations. But though it's a fun time to relax under the sun, health experts warn that the excess heat can lead to the development of kidney stones if people don't drink enough water.
Kidney stones are solid, hard deposits made from salts and minerals inside the kidneys. Urine is typically made up of fluid with waste dissolved in it, but a lack of fluids can lead to an excess amount of concentrated urine, which then begins to crystallize and form kidney stones. As kidney stones grow, the crystals move through the urinary tract.
The crystals, typically made of calcium and oxalate, can become stuck and block the flow of urine, causing intense, stabbing pains in the lower back and groin. This pain often is accompanied by nausea or vomiting. When the stone gets caught in the ureter, which is about two or three millimeters wide, the ureter contracts and attempts to push the stone through the bladder.
About 500,000 people seek emergency treatment for kidney stones in the United States each year, with some needing surgery or prescription medications to pass their stones and reduce pain. The percentage of Americans who experience kidney stones has been on the rise since the 1970s, with about 1 in 10 people now expected to develop a kidney stone in their lives.
"What we know is that this excess calcium in your urine can eventually develop into kidney stones," Dr. Sri Sivalingam, a urologist at Cleveland Clinic, said in 2020. "Being physically active can protect you from stone development. So, if like many of us, you're less active in the winter, that also adds to your risk for kidney stones. Then, when warm weather hits, increased temperatures and dehydration lead to further growth of the stones that formed over the winter months and can suddenly move."
Dehydration leads the body to look for ways to conserve water and may lead to dizziness, headaches and stomach pain. During the summer, when people are physically active outside, they may lose a lot of the fluids through sweat. If that fluid is not replaced with water consumption, they may experience lower urine volume, which can lead to the concentration of urine and, eventually, kidney stone formation.
"In the summer, people lose a lot of fluid through sweat and get dehydrated, because of the hot weather," Dr. Kunal Malhotra, a kidney specialist at MU Health Care, said in 2018. "If this fluid loss is not replaced by drinking extra water, the kidneys will make concentrated urine to conserve body water and this concentrated urine is a perfect condition for the formation of kidney stones."
In addition to low urine volume and dehydration, obesity and certain diet choices also increase the likelihood of kidney stones. Being overweight can alter the acid level in urine and increase the risk of developing stones, while consuming a lot of animal protein can increase acid levels in urine, which can put people at a higher risk.
There are plenty of preventative measures that people can take to prevent kidney stones from developing.
One of the best ways to prevent kidney stones is to drink plenty of water, particularly when spending time out in the heat, according to the National Kidney Foundation. Staying hydrated and urinating a lot flushes the kidneys and ensures that urine doesn't concentrate in the kidneys and form painful crystals. Dr. Marcos Del Rosario-Santiago, a urologist in the Mexican navy, recommends people who are prone to kidney stones drink about six pints of water per day.
Some research suggests that eating less foods that are rich in oxalate can be beneficial for people who are prone to kidney stones. These foods include peanuts, rhubarb, spinach, beets, chocolate and sweet potatoes.
The National Kidney Foundation notes that it's important to eat and drink foods that are rich in calcium and oxalate together to ensure that the compounds bind to one another and reduce the likelihood that stones will develop.