South Florida heat is not only a summer problem. Warm, humid days can arrive in any month, and many people spend more time outdoors here than they did up north: walking, golfing, gardening, on the water. For most healthy adults, that is a pleasure. For older adults, and for anyone with kidney disease, heart disease or a long medication list, heat deserves a little more planning.

Why heat is harder on older adults

CDC explains that people 65 and older are more prone to heat-related health problems for three main reasons: they do not adjust as well to sudden changes in temperature, they are more likely to have a chronic condition that changes the body’s normal response to heat, and they are more likely to take prescription medicines that affect temperature control or sweating (CDC).

CDC’s advice for older adults is to drink more water than usual in hot weather and not to wait until you are thirsty, unless your doctor has told you otherwise.

What dehydration means for the kidneys

Your kidneys filter the blood and help balance the body’s water and minerals. When you lose fluid through sweat and do not replace it, urine becomes more concentrated. For people who already have reduced kidney function, it is worth asking your doctor whether a hot spell or a change in medicines calls for a lab check.

Concentrated urine also matters for kidney stones. According to the National Institute of Diabetes and Digestive and Kidney Diseases, stones form from minerals in the urine, and you may be able to prevent them by drinking enough water, changing what you eat, or taking medicines. The National Kidney Foundation also lists drinking enough fluid among its most common recommendations for people prone to calcium stones.

Medicines that can raise the risk

Some of the most commonly prescribed medicines for older adults interact with heat. CDC notes that many medicines can make you dehydrated or overheated on hot days, and that some medicines also need to be kept out of hot places (CDC). A CDC report on heat-related deaths named diuretics, beta-blockers and calcium-channel blockers among drugs for chronic conditions that can interfere with the body’s temperature control (CDC MMWR).

Pain relievers deserve a mention too. The National Kidney Foundation points out that some pain medicines, including the NSAID family that contains ibuprofen and naproxen, can harm the kidneys (NKF). We explain more in NSAIDs: risks and side effects.

None of this means you should stop a medicine on your own. CDC is clear on that point: do not stop or change your medicines until you talk to your doctor. Many of these drugs protect the heart and kidneys. CDC’s own guidance for clinicians is to review a patient’s medication list with them ahead of hot weather, especially for older patients who take several medicines (CDC). That conversation belongs with your doctor.

If your doctor limits your fluids

Some people are told to limit fluids, for example because of heart failure or advanced kidney disease. For them, “drink more water” is not simple advice. CDC addresses this directly: if your doctor limits how much you drink or has you on water pills, ask them how much you should drink during hot weather (CDC). It is a good question to raise before summer, not during a heat wave.

Everyday habits for hot days

  • Plan outdoor activity for early morning or evening, and rest in the shade or air conditioning.
  • Keep water within reach and sip through the day rather than all at once.
  • Wear loose, light-colored clothing and a hat.
  • Do not rely on a fan alone when it is very hot; CDC recommends air-conditioned spaces where possible.
  • Store medicines away from hot cars and sunny windowsills.
  • Ask a friend or neighbor to check on you during a heat wave, and do the same for them.

CDC lists muscle cramps, headaches, nausea and vomiting among the symptoms of heat-related illness and advises seeking medical care right away if they appear (CDC). For anything that feels like an emergency, call 911.

Where a nephrologist helps

Dr. Yana Shtern is board certified in both Internal Medicine and Nephrology, so questions about kidney function, blood pressure medicines and fluids sit within one practice. Labs are drawn in our office, which makes it straightforward to check kidney function when the season or a medicine changes. You can read more on our kidney care and hypertension pages.

If you would like to talk through how heat, hydration and your own medicines fit together, a complimentary meet and greet with Dr. Shtern is an easy place to start. Bring your medication list and any recent lab results.

This article is general information, not advice for your situation. Members can call the office with questions about their own care.