Heat Waves and Health: The Rising Threat of Climate Change
Written by May Myo Myint, MS, and Melissa Schenkman, MPH, MSJ
Have you felt like it is absolutely sweltering every time you have stepped outside during the summer the past few years? Feel like you would like to jump in a cold swimming pool if you could? Well, you are not alone.
Excessive heat waves have become a common thread around the country and world. In fact, you would be hard-pressed not to find someone talking about how hot they feel on a daily basis.
Climate change—the long-term change in the average weather patterns that have come to define Earth’s local, regional, and global climates—has led to rising global temperatures throughout the year. Most noticeably in the summertime.
For the foreseeable future, rising temperatures and extreme heat are here to stay. So, it is important for us to understand heath impacts of extreme heat, including overheating symptoms, heat sickness, and heat injuries.
Together, with Environmental Specialist May Myo Myint, MS, we explore the science behind and realities of climate change, its impacts on our health, and how to navigate them.
Understanding extreme heat events
According to The Weather Channel, a heat wave is defined as “a prolonged period of excessively hot weather as compared to average temperatures.”
While in years past they were a rare occurrence, that has all changed. Just look at the numbers.
Major cities across the United States now experience an average of six heat waves per year. When looking at a little over 60 years of weather data, the United States Environmental Protection Agency finds that today’s heat waves are three times more frequent compared to the 1960s.
Heat waves are also increasing in duration, lasting one day longer on average compared to the 1960s as well, with increasing intensity. So, it’s not just you not being accustomed to the heat, the heat feels even warmer because it truly is more intense than when we were growing up.
If you live in a major city, you are most certainly dealing with even more warmth than surrounding rural areas because of what’s called the urban heat island effect.
The heat island effect makes urban areas about 1–7°F hotter during the day and about 2–5°F hotter during the nighttime.
The U.S Census data states that 80% of the American population is living in an urban area, making climate change and specifically, heat waves, one of the most important public health issues of our time.
Direct health effects of extreme heat
The impacts of heat waves should not be taken lightly as they can lead to serious health issues and even death.
On average, there are 1,220 heat-related deaths each year in the US, according to the Centers for Disease Control and Prevention.
It’s crucial that everyone knows what the symptoms of heat injuries are and that we act fast if we notice anyone with the symptoms. Overheating symptoms and their related conditions include one of more of the following:
Heat exhaustion- heavy sweating, dizziness, headaches, weak, rapid pulse, weakness, fatigue, nausea and vomiting
Heat stroke – the most severe form of heat illness. Primary symptoms are a very high core body temperature above 104 degrees Fahrenheit (40 degrees Celsius), altered mental status, and confusion.
Dehydration – headache, dizziness, dry mouth, chills, high heart rate, but low blood pressure; constipation, loss of appetite but maybe craving sugar, weakness.
Cardiovascular stress- dehydration from sweating stresses the heart and increases heart rate
Respiratory problems- the heat and humidity make the air more stagnant making it more difficult to catch your breath, especially when air pollution or smog is also at play.
Kidney issues- dehydration leads to decreased kidney function and low blood pressure. When body temperatures are higher than 104 degrees Fahrenheit, they cause significant problems for the kidneys. If not caught and treated, the breakdown of muscle will lead to kidney failure.
Additionally, heat stress can exacerbate underlying medical conditions such as cardiovascular disease, asthma, and diabetes.
It is also noteworthy that humid heat waves (i.e., hot and humid days) are more dangerous than dry heat waves. High humidity makes it harder for sweat to evaporate from our skin, causing our body to struggle with getting rid of excess heat and cooling down.
Vulnerable populations
Some people are more affected by extreme heat due to their age, health issues, socioeconomic status, and environmental conditions. Populations that are especially vulnerable to heat-related illnesses include:
Elderly (generally those over age 65)
Children
Pregnant women
People with chronic illnesses
Outdoor workers (such as farm and construction workers) face higher risks due to their prolonged exposure to heat.
Low-income communities
Of all the groups mentioned, lower-income communities are the most significantly impacted by the urban island effect that we mentioned earlier.
Geographically, urban areas experience more severe heat waves than rural areas due to the heat island effect. This happens because urban environments, with their concrete, asphalt, and buildings, tend to keep more heat from the sun compared to natural landscapes. Socioeconomic factors further exacerbate this issue.
According to the U.S. Department of Energy, heat stress impacts poor communities more severely in 94% of urban areas.
People with lower income and communities of color are more likely to live in urban environments that lack access to parks and green spaces. Additionally, they also lack resources like air conditioning to cope with the heat, making the situation worse.
May Myo Myint, MS, is an Environmental Specialist with her Master of Science in an Environmental Policy and Management at University California, Davis.
Societal and economic impacts
Increased healthcare demand
Healthcare systems have a very important role in emergency preparedness, vulnerable population support, and monitoring and surveillance.
Climate change affects every aspect of the healthcare system in some way by putting a strain on it. Heat waves increase the number of people with health injuries, thereby increasing the amount of people needing medical care and causing healthcare costs to rise. It also exacerbates existing inequalities for people who do not readily have access to healthcare or quality care to begin with. Yet, at the same time, there health is effected far more.
Reduced worker productivity
Hot climates can pose significant health risks, especially for outdoor workers; but office workers face similar risks if heat prevention measures are not taken properly at the workplace. For this reason, employers and workplace managers should be educated about heat safety and heat illness prevention.
In industries with outdoor work, including construction and agriculture, excessive heat has led and continues to lead to reduced worker productivity.
Strain on infrastructure (e.g., power grids)
Excessive heat affects the power grids that provide basic services to meet our daily needs. This includes everything from air conditioning to internet access, and simply electricity as whole. For healthcare systems alone, this power outages can disrupt life-saving services, and the transportation needed to get a clinic in the first place.
Prevention and adaptation strategies
During extreme heat events, individuals can best protect themselves by following these tips:
Personal measures
Keep up with local weather updates and heat advisories to be aware of the conditions and take appropriate precautions.
Stay Hydrated. Even if you are staying indoors, drink plenty of water. Avoid alcohol and caffeine, as they can be dehydrating. If sweating excessively, drink sports drinks or take salt tablets.
Avoid going outside during the hottest parts of the day.
Wear Proper Clothing. Keep it lightweight, loose-fitting, and light-colored.
Protect Yourself from the Sun. When outdoors wear sunglasses, a hat, and sunscreen.
Avoid abrupt temperature transitions from hot to cold environments.
Community measures
Community-level interventions (cooling centers, early warning systems)
Urban planning and design (greenspaces and office and residential buildings that use sustainable materials and practices to operate them when it comes to energy use)
Healthcare system preparedness – have a pivotal role in educating the public about the dangers of heat waves, preventive measures, the signs of heat-related illnesses and coping strategies. This includes providing guidance on hydration, recognizing symptoms, and understanding the importance of staying cool.
Conclusion
Extreme heat waves have become a more common occurrence than ever before.
Between their direct health effects and the large number of people living in urban areas where temperatures climb the highest due to urban heat island effect, it’s more important than ever to be aware of the signs and symptoms of heat injuries and related illness, in order to take quick action and get proper treatment.
If we do not, it can lead to the severe consequences of heat exhaustion or heat stroke.
It is also important to recognize that the effects of heat waves on health are not ‘one-size-fits-all,’ but rather something that has more significant impacts on people of lower socioeconomic status and those with underlying medical conditions. That knowledge must be taken into account, as we advocate for efforts to combat climate change.
Excessive heat can be a thing of the past. But that cannot happen without taking individual and collective action at the community level to decrease and stop the changes to our environment and atmosphere.
We urge you to take action both for yourself and the planet, and in the meantime, make strategic choices in your daily life to adapt to the heat in your city. Your body will thank you.
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