Source: National Climate Assessment, Figure 14.2
Extreme temperatures associated with heat waves can make everyone uncomfortable. When combined with conditions such as high humidity, sun exposure, stagnant air, and poor air quality, high temperatures can also become a health concern. Some groups face a greater risk of heat-related illness than others. For instance, outdoor workers and athletes are at greater risk than office workers because they have increased exposure to heat. Other groups may be disproportionately affected by the effects of high heat as a result of age or poor health, or the lack of resources that enable them to adapt or recover. Identifying specific factors that increase risk for some populations gives us a way to reduce exposure and vulnerability through adaptive actions. In some cases, simply increasing awareness of the risks that extreme heat poses to health can encourage people to take adaptive actions, such as going indoors or getting to a cooling center.
Groups most at risk to heat include, but are not limited to: children, older adults, people experiencing homelessness, people with pre-existing conditions, people with disabilities, indoor and outdoor workers, emergency responders, incarcerated people, low income communities, pregnant people, athletes, and more.
This page will be continually updated to correspond with the NIHHIS “Overlooked and Overburdened’ webinar series.
Children
As dependents, children rely on others to keep them safe, and some may not have the resources or knowledge to protect themselves from extreme heat. Children spend a good portion of their time in schools or day care settings, some of which may lack air conditioning.
Children are less efficient thermoregulators than adults; they have a smaller cardiovascular output and a higher metabolic rate than adults, which can increase vulnerability. Additionally, children often play outside in structured and unstructured activities. This exposes them to some of the same risks as outdoor workers and athletes experience (see below).
Prevention is the best defense in addressing extreme heat.
- As much as you can, keep children out of direct sun.
- Move outdoor activities to the morning and evening rather than middle of the day.
- Stay hydrated, wear loose and light clothing, and practice sun safety (including wearing sunscreen).
Additionally, never leave children alone in a parked car – temperatures inside a car can rise 20 degrees in just 10 minutes, even with an open window.
Learn About Children and Their Risk to Extreme Heat
Athletes
Athletes are at risk of heat illness due to the combination of exposure, exertion, and, in some cases, wearing protective gear that traps heat. Outdoor activity exposes athletes to high temperatures, and conditions can be exacerbated by direct sunlight and/or poor air quality. Decision makers can use common tools to check current and future forecast air temperatures (NWS Graphical Forecasts), solar exposure (the opposite of cloud cover), and air quality (AirNow Air Quality Forecast), and factor those conditions into decisions about where and when to conduct practices and competitions.
As athletes are expected to push themselves physically, the line between acceptable levels of exertion and dangerous levels of exertion during heat may be blurred. CDC's guide on Recognizing, Preventing, and Treating Heat-Related Illness can be useful in protecting athletes from heat.
A range of organizations offer information about the risk heat poses to athletes. While many athletes have suffered from complications due to overheating, the death of Korey Stringer, who was participating in a National Football League training camp in 2001 when he suffered heat stroke, led to the creation of an eponymous institute at the University of Connecticut for the prevention of such deaths in the future. This is one organization that conducts research and issues guidance for the prevention of heat-related morbidity and mortality in athletes.
Older Adults
For older adults, health complications such as cardiovascular issues can exacerbate the effects of extreme heat. Adults who require life-sustaining devices may be disproportionately affected during power outages that commonly accompany extreme heat events. Additionally, those who need constant access to oxygen, prescription drugs, or other consumable medical resources may not feel comfortable leaving their homes during a heat wave. Some older adults may also be using prescription drugs that affect their capability to thermoregulate or that block nerve impulses,2 both of which increase vulnerability to thermal extremes. Additionally, certain conditions, such as different types of dementia, can also affect a person's reactions and choices related to taking self protective actions, increasing risk of harm during a heat event. The CDC offers information to help you recognize the signs of heat-related distress in older adults, and find tips you can offer to help them keep cool.
Older adults are also more likely to be socially isolated than some groups, as they are less likely to have occupations and may lack other community involvement. Empirical studies have documented the increased risk of morbidity and mortality due to extreme heat among older people.2 Older populations may be concentrated in retirement communities in states such as Florida or Colorado (where the Colorado Climate Change Vulnerability Study predicts a 125 percent increase in such populations by 2030). Such dense clusters of older residents may put extra pressure on early responders and health care facilities during extreme heat in these areas. Finally, urban settings, with high rise structures and the urban heat island effect, may increase the risk of heat illness substantially, yet rural settings have factors such as social isolation and lack of transport or services which can also increase risk.
The first step in addressing the risk of heat illness among older adults is understanding where they live. The U.S. Environmental Protection Agency’s EJSCREEN tool helps decision makers examine demographic variables that may influence environmental health outcomes. For example, users can produce maps showing “percent of population over age 64." Additionally, the U.S. Department of Health and Human Services' emPOWER Map can show where Medicare beneficiaries or those who rely upon electricity-dependent medical and assistive equipment reside. Older residents may also be less likely to have or use air conditioners because of the expense of electricity. The HHS Low Income Home Energy Assistance Program (LIHEAP) can assist with this issue.
Tips for older adults include:
- Do not stay home alone during a summer power outage or an extreme heat event.
- Make sure a trusted friend or relative has an extra key to your home, knows where you keep your emergency supplies and can use lifesaving equipment or administer medicine.
- Drink fluids regularly to avoid getting dehydrated and overheated. Talk to your doctor about whether you need fluids with extra electrolytes in the heat.
- Be careful with the amount of time you spend outdoors. Take frequent breaks to come back inside, cool off, and drink fluids that don’t have caffeine.
Pregnant People
For pregnant people, extreme heat can be quite uncomfortable. Discomfort occurs not only because pregnant people tend to experience a general increase in their core body temperature regardless of the air temperature, but also because extreme heat events can increase the likelihood of common challenges during pregnancy, such as excessive sweating and heat rash. Importantly, extreme heat also poses health risks for a pregnant people and her developing fetus. There is increasing evidence that extreme heat can increase the risk for preterm birth, low birth weight, fetal death, and infant mortality.
Emergency Responders
Emergency responders put themselves in danger repeatedly in the line of duty, and heat waves are no exception. Police officers, firefighters, paramedics, and the many others who protect people during heat waves need information to understand how to find and help those who are most disproportionately affected, while ensuring they are protected themselves. In order to support this population, the Federal Emergency Management Agency (FEMA) U.S. Fire Administration and the International Association of Fire Fighters (IAFF) developed the Emergency Incident Rehabilitation (PDF) report to inform decision makers of heat exposures that firefighters and other emergency responders face. The IAFF also hosts the Emergency Incident Rehabilitation Program, which contains training resources and other information.
Before an extreme heat event, emergency responders must prepare themselves to tend to members of groups experiencing disproportionate impacts. The CDC tool Assessing Health Vulnerability to Climate Change: A Guide for Health Departments guides health departments in assessing local vulnerabilities to the health hazards associated with climate change. It's also important to assure the continuity of operations of vital health care resources during extreme heat events. The Sustainable and Climate-Resilient Health Care Facilities Toolkit provides information to build resilience of healthcare organizations.
When planning for extreme weather events that could knock out power and/or reduce transportation options, the emPOWER Map can be used to understand where Medicare beneficiaries or those who rely upon electricity-dependent medical and assistive equipment reside. People with mental health conditions (including older adults and those taking prescription medications that impair the body's ability to regulate temperature) can also be at increased risk of disease and death in extreme heat: the Substance Abuse and Mental Health Services Administration provides helpful information for serving these populations. Finally, a range of forecasting tools can keep you apprised of upcoming heat events on many time scales.
Outdoor and Indoor Workers
People who work outdoors—in agriculture, fishing, construction, or other service areas—or in situations where they don't have access to air conditioning are at risk for heat-related illnesses and injuries. These workers may have job tasks requiring great physical exertion, and the use of personal protective clothing and equipment may trap heat and prevent cooling. Many of these workers, particularly farm workers, may not have easy and quick access to water and shade. Lack of acclimatization in new workers and during heat waves also puts workers at higher risk. Some outdoor workers may also suffer from increased temperatures in cities due to the urban heat island effect, which can increase temperatures by 18 to 27°F (10 to 15°C) during the day, and 9 to 18°F (5 to 10°C) at night in urban areas compared to rural areas.
Photo courtesy of OSHA
People with Disabilities
Many people with disabilities are at a higher risk of heat-related illness during periods of high daytime and nighttime temperatures. Approximately one in four adults in the United States has a disability, and extreme heat can cause them significant adverse impacts, and even death. People with disabilities are two to four times more likely to be injured or killed in a natural disaster, and heat waves triple the risk of death for people with preexisting psychosocial disabilities.
During chronic or acute heat events, people with physical, sensory, mental, or cognitive disabilities are disproportionately affected. The increase in heat events across the nation impacts people with disabilities’ ability to recover and adapt after an extreme weather event. Additionally, heatwaves can affect many populations over a short period of time, which may overwhelm healthcare and emergency response capacity and disrupt transportation and communications systems. Because disruption to these systems can seriously impact people with disabilities, it is important to include people with disabilities as central stakeholders and community members when planning for them.
It is important to note that individuals with disabilities are protected from discrimination by civil rights laws including the Americans with Disabilities Act and the Rehabilitation Act. These laws require government agencies and many of their nongovernmental partners to affirmatively plan for and meet the needs of individuals with disabilities in disasters. These obligations typically include ensuring programmatic and effective communication access for individuals with disabilities and providing reasonable modification of policies, practices, and procedures to ensure access.
What heat related concerns can people with disabilities experience?
- Exposure to heat may result in more severe health risks or death because it exacerbates preexisting conditions, including cerebral, respiratory, and cardiovascular diseases
- Heat has an impact on those who are taking medications that may affect the body’s ability to regulate its temperature (for example: antidepressants and mood stabilizers)
- Emergency warnings and other important public messaging may not be accessible or consider the needs of people with disabilities. Inaccessible public warnings and information that doesn’t include information regarding people with disabilities may make it difficult for people with low vision or blindness, hearing loss, or mobility issues to receive actionable information and plan for extreme weather events.
- People with disabilities may rely on long-term services and supports, such as personal assistance services (PAS), meal delivery, or other in-home supports, which can be disrupted before, during, and after a natural disaster or extreme weather event.
- Extreme heat events can force people to leave their residences to seek cooling relief, or can cause people to be stranded in their homes unexpectedly where they may, in some situations such as a blackout, experience deadly indoor temperatures.
- Some people with disabilities may need accessible public transportation to access cooling centers and cooling center facilities to be accessible.
- Dementia is a risk factor for hospitalization and death during heat waves.
- People with disabilities experience disproportionately higher rates of social risk factors, such as poverty and lower educational attainment, that contribute to poorer health outcomes during extreme events or climate-related emergencies.
Heat and Spinal Cord Injuries
People with spinal cord injuries are especially at risk during high temperatures because of their inability to control their body temperature. Spinal cord injuries can lead to reduced sweating capacity, the body's natural way to cool itself off. Prolonged periods without water or sustained periods of intense heat could accelerate adverse reactions to extreme temperatures in someone who lacks the ability to naturally thermoregulate. Equitable access to cooling systems during recovery, including water, is the only way to reduce risks to persons with spinal cord injury or disease.
Heat and Mental Health
People with mental health and substance use conditions are especially susceptible to heat. Sleep loss during periods of prolonged, extreme heat may be a contributing stressor for mental health and substance use conditions. Psychotropic medications may increase risk, and use of alcohol and other substances also can place people at more risk of har. People with severe mental health conditions, such as schizophrenia, are at risk during hot weather because their medications may interfere with temperature regulation or even directly cause hyperthermia.
Heat and Cognitive Disabilities
Cognitive disabilities, such as intellectual disabilities, Alzheimer’s disease and, dementia, can impact a person’s ability to comprehend symptoms and/or communicate the effects they are experiencing. Certain cognitive disabilities can also affect a person's ability to take self-protective actions, increasing risk of harm during a heat event.
Impacts of Heat on Infrastructure and Power Outages
Extreme heat can damage or destroy critical infrastructure and facilities. The disruption to critical services disproportionately and negatively impacts people with disabilities and puts individuals at increased risk. Temperature increases and heatwaves can lead to brownouts or blackouts. Power outages can jeopardize the health and safety of people with disabilities, older adults, and people with serious health conditions, who often depend on equipment powered by electricity.
During a power outage, people with disabilities may lose access to medications, durable medical equipment, and alternate and assistive communication devices. Life- saving medications, such as insulin, need to be refrigerated. Power outages also affect life-sustaining medical equipment, such as oxygen or mobility equipment. Additionally, people who depend on electric medical devices, such as a ventilator, and people who require dialysis, or need power for wheelchairs are also at high risk during a power outage.
Tips for people who are dealing with loss of power during heat:
- Develop a plan to use caregivers, neighbors, family, and friends to address your heat-related needs. Communicate with them to let them know how they can best support you.
- Keep a cooler and cold packs nearby to help keep refrigerated medicine, like insulin, cool during a power outage.
- Know the phone numbers and locations for local medical facilities, such as hospitals or medical clinics, to create contingency plans if you cannot access a cooling center, lose power, or need more help.
- If a person is facing a barrier to accessing air conditioned or cooler environments (such as during a blackout), one good way to cool down is to take a bath or shower.
- If you are in need of medical care, call 911
Actions to take to decrease heat risk for people with disabilities:
- Consult your pharmacist or a professional to talk about the types of heat risks that could be a side-effect prescribed medications and self-protective actions to reduce your heat related risk.
- Prepare for an emergency, including heat-related emergencies by having an emergency plan and a kit with medication, food, water, first-aid supplies, and copies of medical records.
- Connect with your local emergency manager to make them aware of your functional needs and to identify resources that they have can you, if needed, during an emergency.
Access the links in the tab below for more resources, tips, and guides for people with disabilities.
People with Chronic Health Conditions
Extreme heat can be dangerous for anyone, but it can be especially dangerous for those with chronic medical conditions. High daytime and nightime temperatures can cause stress on the human body which exacerbates health conditions such as respiratory and cardiovascular diseases, diabetes, and renal disease. Some medical conditions, such as obesity and heart disease, increase people’s sensitivity to heat, putting them at greater risk of heat illnesses. In addition, some medications (such as some antidepressants, diuretics, and beta-blockers) taken for a chronic illness may increase an individual’s sensitivity to heat by interfering with the body’s ability to regulate temperature, fluids, or electrolytes.
Why are people with chronic medical conditions more disproportionately affected by extreme heat?
- They may be less likely to sense and respond to changes in temperature.
- They may be taking medications that can make the effect of extreme heat worse.
- Conditions like heart disease, mental illness, poor blood circulation, and obesity are risk factors for heat-related illness. Individuals who are overweight or obese tend to retain more body heat.
Heat and Cardiovascular Conditions
Prolonged heat exposure from extreme heat places an increased strain on the heart and may lead to heat-related illness if the cardiovascular system fails to properly thermoregulate internal body temperature. Individuals with already weakened cardiovascular systems have a heightened risk of heat-related morbidity and mortality, as their hearts may not be able to meet the increased demand required to rid the body of the excess heat. In older adults and those with pre-existing cardiovascular conditions (e.g., ischemic heart disease (IHD), coronary heart disease (CHD), heart failure (HF)), the heart is not as proficient at meeting the increased demand required to rid the body of the excess heat. Individuals that belong to these populations are more susceptible to adverse health outcomes from extreme heat exposure. Additionally, there is evidence of combined effects of air pollution and extreme heat on cardiovascular mortality, especially in urban areas
Heat and Mental Health
People with mental health conditions are particularly at-risk to heat-related illnesses. For example, some medications can increase a person’s risk for heat-related illness. Certain conditions, such as different types of dementia, can affect an individual’s judgment or reactions, increasing the risk of harm during a heat event. People with an existing mental health conditions are also more at risk for distress and other mental health effects following extreme heat. Medical conditions like Alzheimer’s disease can impair judgment and behavioral responses in crisis situations, which can place people with those conditions at greater risk. The risk of death also increases during event for people with psychosis, dementia, and substance misuse. Hospital admissions have been shown to increase for those with mental health conditions as a result of extreme heat, increasing ambient temperatures, and humidity.
People taking certain psychotropic medications may experience more side effects than usual when temperatures increase. Psychotropic medications are drugs that affect how the brain works and cause changes in mood, awareness, thoughts, feelings, or behavior. These medications are used in mental health therapy and treatment and are taken by both children and adults. Types of psychotropic medications include antidepressants, anti-anxiety medications, stimulants, antipsychotics, and mood stabilizers. Some psychotropic medications can interfere with a person’s ability to regulate heat and their awareness that their body temperature is rising, which is associated with injury and death.
Heat and Diabetes
People who have type 1 or type 2 diabetes feel the heat more than people who don’t have diabetes. This is due to:
- Certain diabetes complications, such as damage to blood vessels and nerves, can affect your sweat glands so your body can’t cool as effectively. That can lead to heat exhaustion and heat stroke, which is a medical emergency.
- People with diabetes get dehydrated (lose too much water from their bodies) more quickly. Not drinking enough liquids can raise blood sugar, and high blood sugar can make you urinate more, causing dehydration. Some commonly used medicines like diuretics (“water pills” to treat high blood pressure) can dehydrate you, too.
- High temperatures can change how your body uses insulin. You may need to test your blood sugar more often and adjust your insulin dose and what you eat and drink
Tips for People with Diabetes
- Don’t store insulin or oral diabetes medicine in direct sunlight or in a hot car. Check package information about how high temperatures can affect insulin and other medicines.
- If you’re traveling, keep insulin and other medicines in a cooler. Don’t put insulin directly on ice or on a gel pack.
- Check your blood sugar before, during, and after you’re active. You may need to change how much insulin you use. Ask your doctor if you would like help in adjusting your dosage.
- Heat can damage your blood sugar monitor, insulin pump, and other diabetes equipment. Don’t leave them in a hot car, by a pool, in direct sunlight, or on the beach. The same goes for supplies such as test strips.
Tips for People with Chronic Health Conditions:
- Work with your support network if you have one - caregivers, neighbors, family and friends - to monitor and address your heat-related needs. Have them check in with you regularly to ensure you are safe and healthy.
- Read the side effects of medications and talk with your doctor about how heat exposure will interact with them.
- Keep a cooler and cold packs nearby to help keep refrigerated medicine, like insulin, cool during a power outage.
- Know the phone numbers and locations for local medical facilities, such as hospitals or nursing homes, to create contingency plans if you cannot access a cooling center, lose power, or need more help.
Pets and Service and Support Animals
Pet and service and support animal owners should take special precautions to safeguard the health of their animals during extreme heat. All animals have different thermoneutral zones (TNZs)—ranges of temperatures within which their bodies needn’t work to stay warm (for example, by shivering) or cool (for example, by sweating or panting). In some cases, the TNZs may be somewhat close to humans’ (domestic dogs), while in other cases the TNZs may be skewed higher (domestic cats) or lower. Small animals, such as rodents, may be at increased risk for the same reason as children—their metabolic rate is much higher than larger animals due to their small size. Additionally, some of the same characteristics that make some humans more vulnerable than others are also in play with other animals, such as older or very young pets and pets with existing health conditions. Watch for warning signs, such as heavy panting or glazed eyes, because animals cannot tell you when they are too hot. Another risk to pets and service animals is the potential for burns to their paws and pads as paved surfaces may become excessively hot during a heat wave.
An additional factor to consider regarding pet and service and support animal ownership is that having an animal may influence the behavior of people in maladaptive ways during heat waves. For example, reluctance to leave a pet behind while seeking medical care for oneself or uncertainty as to whether a pet will be accepted at a cooling center could cause pet owners to remain in a hot building when it is unsafe. As a precaution, consider calling cooling centers well in advance of heat waves or heat season to determine if those nearest you will accept pets.
Learn About Pets and Their Risk to Extreme Heat