Why should caregivers worry about extreme heat? 

Older people are among those most vulnerable to falling ill and dying when the mercury rises.  

This is according to an article published in Harvard Medicine, the magazine of Harvard Medical School. More than 80 percent of the estimated 12,000 people in the United States who die of heat-related causes annually are over age 60.   As Earth gets hotter and human populations skew older, heat-related fatalities among older adults are expected to grow.

Climate is driving more frequent, intense, and longer heat waves. It raises nighttime lows, preventing body temperatures from resetting when the sun sinks. The volatility that climate change provokes in day-to-day highs can truncate the lives of older people with certain health conditions,

Medical professionals are rethinking what heat stress is and the damage that it can do.  

Studies  show it is hard for  healthy older adults to tell when it’s too hot or if they’re dehydrated. Cognitive decline worsens these problems. Older bodies also hold more heat than younger ones when the temperature climbs. Glands don’t release as much sweat. The heart doesn’t circulate blood as well, so less heat is released from vessels in the skin.  Systems from the cardiovascular to the immune struggle to compensate.

Doctors are broadening their understanding of the effects of heat on aging and chronically ill populations. 

A new study (June 2025)  from the University of California, Irvine’s Joe C. Wen School of Population & Public Health adds to that list.  Researchers discovered how frequent and intense heat waves and  aging, work together to weaken the immune system, damage the gut, and elevate risk of severe infection. The results of tests with probiotics suggest that supporting gut health may be key to boosting immune resilience during heat exposure.  This is just new and research continues, but it shows how our understanding of the effect of heat on human bodies is growing and changing.  It is a serious issue. 

 Problems also occur at temperatures lower than earlier thought.   

There are problems with hydration, sleep, and cognitive decline at 85 degrees and lower.    One conclusion researchers have agreed upon is that temperatures don’t have to hit 90 or 100 degrees to be dangerous; they only have to rise beyond a region’s normal range. If someone  used to living in 75 degree temperatures, suddenly experiences a rise of just a few degrees, their body will react strongly to the extra heat.  Which puzzles the person who lives with 85 degree summer temperature.  Doctors realize that it is not the numbers on the thermometer so much as a difference in the norm.  In short, don’t think heat is not an issue to your loved one because of the reading on the thermometer.

Caregivers on the front line need to know WHY heat is an important issue.

Many seniors have chronic health conditions such as heart disease, diabetes, or respiratory issues, which can be exacerbated by extreme heat on their own.  Other conditions  such as an anxiety disorder, a woman in menopause, or hyperthyroidism can cause heat intolerance in someone of any age. 

Medications, including diuretics, blood pressure drugs, and antidepressants, can further impair the body’s response to heat, increasing the risk of dehydration and overheating.  A diseased heart isn’t able to pump as much blood, further reducing blood flow to the skin. And if the nerves become affected in people with diabetes, the body might not receive the message that it needs to start sweating. 

Certain medications many seniors take,  like diuretics and  high blood pressure drugs can affect people’s hydration, blood flow, and even the sweat response. 

As people age, they don’t feel thirsty so they tend to drink less. In hot conditions, they become dehydrated faster.   Some older adults, particularly if they have some form of dementia or cognitive decline, may not be aware of temperature changes. They won’t respond by moving to someplace cool or taking other preventive measures.

Ask your doctor if any medications on your loved one’s list will affect the ability to stay healthy and hydrated in hot weather.  If so, find out if there is an alternative.

If you do not live with your loved one, make arrangement for family, neighbors, or caregivers to check on elderly individuals regularly, especially during prolonged heat waves. Simple actions like ensuring they have access to cool water, helping them adjust their home environment, or providing transportation to a cooler location can be lifesaving.

Plan Ahead is the topic for next article in this series. 

Sources: 1)Magazine,hms.harvard.edu   (2)Senior Resource.com (3) Public Health.uci.edu/2025/6/24

Other posts in this series include:

What to Do in a Heat Wave and No Air Conditioning

Vulnerable Populations