Kidney stones are not only about what you eat or the genes you inherit. They are also about where you live and how hot it gets. Every summer, urologists notice the same pattern: as the temperature climbs, so do the visits for kidney stones. Because heat and humidity do not just make us sweat, they change how our bodies handle water and minerals. Dehydration concentrates the urine, crystals form more easily, and painful stones follow. With global temperatures rising, the connection between climate and kidney stones is becoming more than a seasonal inconvenience; it is a growing public health issue.

The mechanism behind how heat triggers kidney stones

When temperatures climb, your body works harder to keep cool. Sweating is essential for temperature control, but it comes at a cost: You lose fluid before you even realize it. If those losses are not replaced, urine volume drops, and the urine that does remain becomes more concentrated. In this concentrated environment, minerals such as calcium, oxalate, and uric acid are more likely to crystallize and form stones. Humidity adds another layer. On humid days, sweating does not cool the body as effectively. You keep losing water, but because the sweat does not evaporate well, thirst cues are delayed. Many people drink less than they should without noticing.

Heat also subtly alters physiology. Higher sunlight exposure increases vitamin D activation, which can raise urinary calcium levels. Intense physical activity in hot weather may lead to further shifts in electrolytes, compounding the risk. Behavioral choices, like avoiding fluids to cut down bathroom breaks during outdoor work or long drives, make the situation worse. Calcium oxalate stones, the most common, form when concentrated urine provides fertile ground for calcium and oxalate crystals to stick together. Uric acid stones, on the other hand, thrive in hot climates as dehydration and acid-base shifts lower urine pH, creating a setting where uric acid precipitates more easily. Both types become more frequent when the body is persistently underhydrated.

In short, heat and humidity work together to create the perfect storm: less urine, higher concentrations of stone-forming substances, and changes in body chemistry that tilt the balance toward stone formation.

What the studies show: the evidence linking climate and kidney stones

Doctors have long noticed that kidney stones are more common in certain hotspots. In the U.S., for example, people living in the Southeast are more likely to develop stones than those in cooler northern states. Researchers call this the “”stone belt.” With global warming, that belt is expected to creep northward, bringing more cases into areas that historically saw fewer problems. But the risk does not only rise over decades. It can spike within days. A study of over 60,000 patients found that kidney stone visits to emergency departments climbed just one to three days after a heatwave. In other words, a stretch of very hot weather can trigger stones almost immediately.

Certain groups face even higher risks. Outdoor and factory workers who spend hours in hot environments without steady access to fluids have a much greater chance of developing stones. Studies of steelworkers show that constant exposure to high heat, combined with heavy physical labor and limited hydration, places a significant strain on the kidneys. The authors warned that without better cooling systems, welfare facilities, and stronger labor protections, millions of workers could face preventable kidney problems as the climate continues to warm. Finally, climate models warn that if global temperatures continue to rise, we will see tens of thousands of extra kidney stone cases every year, adding hundreds of millions in medical costs. This makes kidney stones not only a painful personal problem but also a growing public health challenge.

Real-world costs and consequences

Each summer surge of kidney stones has consequences that reach well beyond the clinic. Emergency visits increase, operating rooms see more urgent procedures, and patients lose days of work or travel. In the United States, the overall price tag for kidney stone care already runs into the billions every year, and climate projections suggest those costs will only rise. In one study from South Carolina, warmer summers alone were expected to add tens of millions in extra charges over the next few decades. For patients, though, the cost is more than financial. Stones strike suddenly and can be so painful that people describe them as “worse than childbirth.” Even when treated successfully, the episode can leave someone anxious about when the next attack will come. For those who repeatedly form stones, the condition can become a chronic source of disruption. Not everyone shares the burden equally. Outdoor workers and communities without reliable cooling are on the front line, often with fewer resources to prevent or manage stones. These differences highlight how climate and social factors combine to make an already painful problem even harder to face.

Prevention and coping

The good news is that heat-related kidney stones are not inevitable. Small, steady habits can make a real difference, especially during the hottest months. Hydration is the cornerstone: aiming for pale-yellow urine throughout the day is a far better guide than counting glasses of water. For those working outdoors, drinking at regular intervals before thirst sets in is crucial because by the time you feel thirsty, dehydration is already underway. Dietary choices matter too. High salt intake increases calcium in the urine, while excessive animal protein can push up uric acid levels. Adjusting meals to include more fruits, vegetables, and adequate but not excessive calcium helps balance the chemistry of the urine and lowers stone risk. For people who already know they are prone to stones, keeping up with follow-up visits and prescribed preventive medications is especially important in the summer.

Beyond individual habits, prevention often depends on the environment and policy. Access to cool rest areas, reliable drinking water, and fair work schedules can protect outdoor workers who otherwise face the greatest risks. On a community level, this means investing not only in health care but also in infrastructure that allows people to stay hydrated and avoid prolonged heat stress. Ultimately, the same strategies that protect against heat exhaustion (hydration, shade, and cooling) also guard against kidney stones. The difference is that while heat exhaustion shows up quickly, kidney stones may not declare themselves until days or weeks later. Taking preventive steps now helps avoid both.

Looking forward

Despite decades of research, there is still much we do not fully understand about how heat interacts with kidney stone disease. Most large studies have been done in North America and parts of Asia, but we lack comparable data from other hot regions, including southern Europe, the Middle East, and Africa, places where climate change is expected to intensify the most. There are also unanswered questions about stone types. Calcium oxalate stones are the most common worldwide, but evidence suggests that hot climates may especially favor uric acid stones because of persistently low urine pH. Understanding those differences could help tailor prevention strategies more precisely.

Another gap is adaptation. Humans are remarkably resourceful at adjusting to climate through air conditioning, hydration campaigns, and occupational protections, but we do not yet know how much these measures can offset rising baseline temperatures. Projections suggest that without such interventions, kidney stones will become steadily more common, but effective public health strategies could change that trajectory. What is clear is that kidney stones should be part of the broader conversation on climate and health. Just as we discuss the risks of heat stroke or cardiovascular strain during heat waves, we should recognize stone disease as another consequence of a warming world.

Conclusion

Kidney stones are painful, and anyone who has passed one knows it is an experience you do not forget. What is less obvious is how much the weather around us shapes the odds of going through it. Hot days do not just make us sweat; they quietly change the chemistry of our urine in ways that set the stage for stones. That connection matters because it gives us a chance to act. Drinking more water on a summer afternoon may feel like a small choice, but for your kidneys it can mean the difference between balance and a stone attack. For outdoor workers or communities living without reliable cooling, the challenge is bigger, and that is where health systems and policies need to step up. As a urologist, I see how climate shows up in the clinic every summer. The lesson is simple but powerful: when the heat rises, your kidneys notice. Protecting yourself does not require anything dramatic, just paying attention to hydration, diet, and recovery from the heat. As we face a warming world, these small, steady habits may prove to be some of the best protection we have.

Martina Ambardjieva is a dedicated urologist and medical educator with extensive experience in both clinical practice and academic instruction. She earned her MD from the University “Sv. Kiril i Metódij” in Skopje and is a PhD candidate in urological oncology, with a focus on bladder carcinoma. Her scholarly work includes numerous publications in oncologic urology, urinary calculosis, and men’s health.

Dr. Ambardjieva currently serves as a urologist at the PHI University Surgical Clinic “Naum Ohridski” and completed her residency training at the University Urology Clinic in Skopje. Earlier in her career, she practiced as a general medical doctor at Sante Plus General Hospital and completed a medical internship at the University of Ljubljana.

In addition to her clinical responsibilities, Dr. Ambardjieva is a teaching assistant at the Medical Faculty in Skopje. She works additionally as a collaborator for Dr. Telx. She has held leadership positions in the European Medical Students’ Association and actively participates in international medical education and policy. She has attended numerous congresses and workshops in France, Italy, Canada, and Turkey, and serves as a delegate for the European Association of Urology (EAU), contributing to cross-border initiatives in urology. Certified in laparoscopic surgery, she continues to integrate patient care, research, and education in her professional work.