Written by Lucy Peters
Every summer breaks new temperature records. The periods of extreme heat that used to occur only rarely have become normal and are increasingly long and frequent. For the healthcare system, the unusual environmental phenomenon has long since become a serious clinical issue in dealing with older people. Heat-related illness is becoming a common clinical issue as the climate continues to heat up. However, heat does not just cause dehydration. In fact, it can worsen existing disease, interact with medicines and even cause transient cognitive impairment or alter mental status in otherwise stable patients.
Why Heat Has Become a Growing Healthcare Concern
Global average temperature is still rising and abnormal weather such as longer lasting and stronger heat waves keeps occurring all over the world. In addition, the temperature in cities is getting higher. This is because city surfaces, roads and buildings made of concrete and asphalt retain heat throughout the day, and create what researchers describe as the urban heat island effect.
Extremes of heat are becoming a predictable seasonal challenge for health care systems. Besides placing increased pressures on hospital and emergency department services and other health care services and programs in the community, a very large proportion of younger and middle aged people are admitted due to the effects of heat. However, older adults account for a disproportionate number of heat-related admissions, and the reasons extend far beyond spending too much time outdoors. The reality is that aging changes how the body responds to heat in ways that many people never consider.
Ageing Changes the Body’s Response to Heat
Keeping your internal temperature at a constant level is very important. Your body has a natural defense in the form of the cardiovascular system, kidneys, nervous system and your skin. As we age, the protective functions are weakened. Less sweat is produced by your sweat glands, which means that evaporation cannot take place to cool down your body. Blood vessels respond more slowly, which limits the body’s ability to move heat from its core to the skin where it can dissipate. Cardiac reserve also declines with age, reducing how effectively the heart can increase circulation during periods of thermal stress.
A reduced sense of thirst can also affect older people. Consequently, they can become seriously dehydrated before feeling thirsty and experiencing its effects. These natural changes of aging and the uncomfortable conditions of extreme weather can quickly create problems for older people such as dehydration, and imbalanced supply of electrolytes. So what causes mild discomfort for a fit, young person could cause a problem like heat exhaustion for someone over 75 years of age.
Chronic Illnesses Multiply the Risks
Most older adults are managing at least one long-term health condition, while many live with several. During periods of extreme heat, these conditions can become considerably harder to control. Heart failure provides a clear example. As temperature rises, blood vessels dilate to release excess heat. This normal cooling response causes blood pressure to drop. The heart of failing patients therefore, tries to compensate for decreased blood pressure by increasing work to attempt to maintain circulation. Since the failing heart is already working suboptimally, an increase in its work can lead to a decline in clinical status and even to hospitalization.
People with kidney disease also need consideration. Their kidneys rely on a constant supply of blood to be able to clear waste products from the body. In the dehydrated patient with kidney disease, the blood supply to the kidneys can rapidly drop, which can lead to a sudden decline in kidney function and may result in a patient developing acute kidney injury even after relatively modest fluid loss.
People with diabetes have additional issues to contend with in heatwaves. The higher temperature can cause the insulin in a diabetic patient to be absorbed more quickly into the body, leading to a risk of a hypoglycemic attack. In addition, they are at risk of fluctuations in blood glucose levels due to dehydration. Therefore, diabetes management becomes far more complex during a prolonged heatwave.
The problems of respiratory disease can also increase in extreme heat. The hot stagnant air can be very loaded with pollutants and with ozone which can irritate the inflamed airways of people suffering from respiratory disease such as asthma or chronic obstructive pulmonary disease. Combined, they explain why extreme heat can destabilize patients whose health had previously been well managed.
Medications Can Increase Heat Vulnerability
As we’ve discussed, the conditions themselves are causing enough issues, but many of the typical medications for older adults also affect the body’s ability to regulate in the heat. Diuretics for example cause increased fluid loss thus increasing the chance of dehydration in hot, long periods of time. Other blood pressure medications (e.g. ACE and angiotensin receptor blockers) may contribute to declining kidney function when dehydration develops. Beta blockers reduce the heart’s ability to increase its rate in response to heat stress, limiting one of the body’s natural cooling mechanisms.
Certain types of antidepressants and antipsychotics have anticholinergic effects, and can cause people to stop sweating with severe consequences in hot weather. Because older people are often on medications for long-term health conditions, the risk of severe heat-related illness becomes even higher. But the good news here is that medication reviews help patients before the warm months and also during the warm months. These reviews become even more valuable when the weather gets hotter, and this is especially true for patients who manage several chronic illnesses.
Practical Steps Healthcare Professionals Can Take
Prevention of heat related illness starts well before temperatures reach dangerous levels. Use of routine medical appointments to discuss patients’ hydration and to review their medications for potential effects of heat is important. By asking questions such as whether the patient lives alone, whether they have air conditioning and can easily leave their home during a heatwave may reveal risks that would otherwise remain hidden.
Strategies to cool down the body are important to reduce the body load. Air conditioning is especially effective, as it not only cools down but also reduces the humidity. This way the body can lose heat by evaporation, which is the most beneficial and effective for people of any age. It’s also important to mention that even spending a few hours each day in a cool environment can significantly reduce the risk of heat-related illness for vulnerable older adults.
In addition to early warning signs of severe heat illness, such as dizziness, unusual fatigue, muscle cramps, confusion, headaches and reduced urine output, patients should be encouraged to monitor for these early signs of heat illness. Patients during periods of extreme heat can also benefit from cooling centers, from welfare checks and home support services during prolonged periods of extreme heat. Home safety should also be part of these conversations. Portable air conditioners, ceiling fans and other cooling devices can only be effective if the home’s electrical system can safely support them. This means a property could have old wiring or too many appliances on for too long a time, potentially resulting in an electrical fault. Where upgrades or repairs are needed, families can use local trusted directories to search for qualified electricians to complete the work. Also, family caregivers need education as well. Many people think that offering a drink now and then is enough, but older adults often need frequent reminders to drink water before they feel thirsty.
Heat Will Continue to Shape Future Patient Care
Heat is becoming a regular feature of clinical practice, affecting people with cardiovascular disease, kidney disease, diabetes, respiratory illness and cognitive decline. To address heat, healthcare needs to think differently about it, because dehydration is no longer considered a seasonal health problem but a clinical risk factor that affects health in every dimension for older people. Early education, proactive medication reviews, environmental assessments and coordinated community support can all prevent serious illness and its consequences before they occur.
Author bio
Lucy is a freelance writer who enjoys contributing to a range of publications, both in print and online. She spent almost a decade working in the care sector with vulnerable people before taking a step back to start a family and now focuses on her first love of writing.
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