Soaring summer heat across parts of the US can make certain existing health problems harder to manage, and experts say people with chronic conditions should take extra precautions during extreme temperatures.
Southern California is under a heat advisory on Tuesday, June 23, with the National Weather Service warning that temperatures are expected to climb well above seasonal norms through Thursday evening.
The alert from the National Weather Service is scheduled to remain active until 9pm on Thursday, June 25.
Forecasts suggest inland and valley communities could see some of the hottest conditions, with temperatures climbing into the upper 90s and even topping 100°F in some areas. Parts of the region are also being urged to prepare for warm overnight lows, which can make it harder for the body to recover from daytime heat.
At the time of writing, heat advisories are also in effect in parts of New Mexico, Texas, Oregon, Washington, and Florida.
Residents in affected areas are being advised to stay hydrated, spend time in air-conditioned spaces, avoid direct sun exposure, wear light clothing, limit strenuous outdoor activity, and check in on neighbors and family members.
The NWS has also stressed that children and pets must never be left alone in a vehicle.
‘under any circumstances’.
Health specialists say prolonged high temperatures can aggravate some medical conditions. That’s partly because heat makes the heart work harder, increases fluid loss, and can worsen dehydration, electrolyte imbalance, and air-quality-related breathing problems. Four issues in particular may become more problematic during extreme heat.
People with heart-related conditions may feel the effects of heat more intensely, according to exercise physiologist Michael Crawford, ACSM-CEP, who explained how the body responds when temperatures rise.
“Your cardiovascular system really ramps up efforts to radiate heat and cool you down.
“This makes your heart rate go up and your sweat increase — and that can potentially lead to your blood pressure going down. The longer you’re in the heat, the greater the toll on your heart.”
Health officials also warn that hot weather can aggravate heart failure, high blood pressure, arrhythmias, and other cardiovascular problems because the body redirects blood to the skin to cool down. For some people, that added strain can be especially risky if they are older, take certain medications, or already have trouble regulating body temperature.
High temperatures can also push a person’s heart rate above its usual level, which in some cases may result in tachycardia. That condition can sometimes become dangerous, especially if it comes with dizziness, chest pain, shortness of breath, or fainting.
Hot weather can also increase the likelihood of kidney stones, said Cedars-Sinai urologist Arash Akhavein, MD, largely because dehydration becomes more common.
“Dehydration when you’re in drier, hotter climates is a big risk for the formation of stones,” said Alhavein. “The more you sweat or lose fluids, the more concentrated your urine becomes.”
“When urine is too concentrated, it won’t dilute minerals effectively, and those are the conditions under which stones may form.”
Doctors say the risk may be even higher for people who already have a history of kidney stones or chronic kidney disease. Heat can also make it harder for the body to flush out waste products efficiently if a person is not drinking enough fluids, which is why steady hydration matters throughout the day rather than only after thirst sets in.
Gout, a form of arthritis, may also flare more easily in summer conditions. Gout attacks happen when uric acid builds up and forms sharp crystals in a joint, often causing sudden pain, redness, and swelling.
Some research and expert guidance suggest hot and humid weather can contribute to more gout attacks, especially when sweating and dehydration are involved.
“Higher temperatures cause increased sweating, which can lead to dehydration,” explains the Gout Education Society. “Dehydration causes uric acid levels to increase, leading to a gout flare.”
People who take diuretics, drink alcohol heavily, or already have poor kidney function may be at greater risk of flare-ups. Staying hydrated and avoiding excessive alcohol can help lower the odds of a painful attack during extreme heat.
Headaches and migraines may become more common in warm weather too, as shifts in pressure and temperature can contribute to head pain.
The American Migraine Foundation also says that one in three migraine sufferers identify dehydration as a trigger.
Strong sunlight may play a role as well, particularly for people whose migraines are linked to light sensitivity.
“The stress of dealing with uncomfortable temperatures also elevates cortisol levels, another known trigger,” adds WMC Health.
Experts say the best ways to reduce heat-related problems are straightforward but important: drink water regularly, avoid alcohol and excess caffeine, seek shade or air conditioning, take frequent breaks if you must be outdoors, and watch closely for warning signs such as confusion, rapid heartbeat, vomiting, severe weakness, or a body temperature that keeps rising.
If someone shows signs of heat stroke, emergency care is needed right away.