How does heat affect the kidneys?


The tristate has been under heat advisory warnings for much of the summer. These warnings are issued when temperatures and humidity levels are dangerously high. When it’s hotter and harder to breathe outside, your body is at risk for heat illness. Here are a few things you should know about heat illness and how to stay safe this summer.

What is heat illness? 

Heat illness happens when your body can’t cool itself down effectively. In normal conditions, your body releases heat in the form of sweat to help lower your temperature.

But when humidity levels are high (typically above 70%), sweating becomes much less efficient.

Because the atmosphere is already saturated with moisture, your sweat takes longer to evaporate. If sweat can’t leave your skin, your body temperature can rise to dangerous levels.

Who’s at risk?

Heat illness can affect anyone, but certain populations are more susceptible. Children, older adults, individuals with cardiovascular conditions, and those who work long hours outdoors are particularly at risk.

What happens to the kidneys during heat illness?

A body temperature of 104 degrees or more can cause significant damage to the kidneys and other organs.

Dehydration can occur if your body is sweating out lots of fluids faster than you’re replacing them. When your body is dehydrated, your blood pressure begins to drop due to a decrease in blood volume. Maintaining a normal blood volume is essential for your organs to receive the oxygen and nutrients they need to function.

Watch out for these symptoms of dehydration:

  • Fatigue
  • Thirst
  • Dry mouth
  • Dark colored urine (and/or) urinating less frequently
  • Dizziness
  • Confusion
  • Slurred speech

When the organs aren’t getting enough blood, metabolic systems can begin to shut down. This includes the kidneys. The body begins to break down muscle tissue and divert blood flow to the kidneys during heat illness, which can result in renal failure.

How to keep safe during a heat wave

There are several important steps you can take during a heat wave to keep yourself and others safe from heat illness.

  • Stay in air conditioned spaces.
  • If you’re spending time outdoors, do so early in the morning or in the evening when conditions are less intense. Bring water with you.
  • Replenish your body with hydrating fluids and foods.
  • Wear loose-fitting clothing in lightweight fabrics.
  • Protect your skin by applying sunscreen and wearing a hat and sunglasses if you go outside.
  • Never leave humans or pets in a closed car in a hot environment.
  • Use external cooling techniques like a mist fan or wet towel around your neck.
  • Keep blinds and curtains closed to reduce indoor heat.
  • Avoid alcoholic beverages, as these can speed up dehydration.
  • Avoid spicy foods.
  • Check in regularly with those at risk of developing heat illness.

If you suspect that someone has heat illness, get them to a cool location immediately and call 911. Heat illness can be a life threatening emergency, so it’s important to act quickly.

Stay cool out there!



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Nephrology Associates of Greater Cincinnati
4750 E Galbraith Road, Suite#103
Cincinnati, OH 45236

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