As the four humors/horsemen of the climate apocalypse- crazy storms, rising oceans, CO2 everywhere and higher temperatures impact all of our health, let us dive into some of the climate change outcomes that lead to disease. Sorry if a wee bit dramatic, remember there is hope, that is the whole point of working this problem just like a super sick patient. Understanding these eight core areas of our changing climate impacting health outcomes will help us comprehend the solutions. Extreme heat, air pollution, mental health, vector borne disease, water borne illness, food scarcity, wildfires and extreme weather compose our areas of focus of climate impacting health. Summer is nearly over but the hot days are not yet behind us. There is more than just heat stroke to be worried about with higher temperatures, in fact summer time is not when the living is easy any more.
Extreme temperatures is the most approachable topic, living in the desert and treating heat exhaustion most shifts in the summer. Higher temperatures for longer days lead to more heat related illness. Whether you are a weekend warrior, farmer worker, unhoused person, exercise enthusiast or construction worker, outdoor heat exposure may be a part of your daily life. Tolerance to heat is theorized to be a solution but people who live and work in the desert everyday for years can still be at risk. This risk is compounded by certain diseases such as diabetes with high sugars, viral gastroenteritis, and chemotherapy. Conditions that lead to a dehydrated state or decreased consumption of water lessen the body's defense against the dark hot arts skill set. Despite more attention recently, the number of heat related deaths each year continue to climb, with about a third directly related to climate change. Heat related death is the number one environmental cause of death. Hooray we're number 1?
Understanding who is affected used to be easy, look at those people who live in the hottest areas of the world. Temperature is a factor but humidity needs attention as well because sweating is our body's best defense other than the rational part of our brains that tells us to move to cool locations on hot days. Yes, humans can be stubborn and override this mitigation technique. Higher humidity blunts our cooling mechanism leading to even more dangerous conditions in hot and humid parts of the world. Migration or living in cooler parts of the world used to be a way to avoid heat illness but now high temperatures are hitting all parts of the northern hemisphere routinely thought to be cooler regions. There is no safe place, we all must find ways to help reduce this excessive energy in our planet and enact heat mitigation strategies.
Human migration patterns over time place most of us in cities which are prone to a heat island effect secondary to our urbanization actions. Removing trees and covering up fields with non permeable hardscape and buildings that absorb heat energy during the daylight hours with re-emission of heat at night, leads to a temperature difference of up 10 C compared to surrounding countryside. Many individuals who live in cities affected by this heat island effect are low-income, unhoused, and those marginalized by discriminating lending practices of the 1900’s. Lack of tree canopies, infrastructure investment or energy efficient housing magnifies this impact of heat on these communities which are predominately communities of color. In Tucson, if you take overlays of maps looking at greenspace, temperature, socioeconomic status and ethnicity, all these factors align in hurting our patients who have the least resilience to heat.
Mapping like this helps us identify not just social determinants, but climate determinants of health. Factors such as race, income level, extremes of age, medically compromised, mental illness, and outdoor exposure are at highest risk for extreme heat effects. Add in substance use, medications or pregnancy and you capture the highest risk groups for health harms. Many pharmaceuticals interfere with our thermoregulation system from decreasing thirst response or sweating to loss of water in urine. Children’s immature thermoregulatory system makes them more physiologically stressed by extreme heat leading to higher mortality, especially mixed with their inability to move independently to cooler locations at certain ages. Pregnant patients have higher stillbirths, higher premature births and lower birth weights with extreme heat exposure. Mental fatigue, aggression, decreased cognition, sleep disturbance and higher suicide rates occur with extreme heat and studies show this leads to higher ER visits. Air conditioning is the most commonly used adaptation strategy we employ for extreme heat but our power grid is taxed by peak demand usages. Unfortunately, this leads to blackouts which stops usage of air conditioning and medical devices requiring power including refrigeration, ventilators, nebulizers, oxygen concentrators and mobility vehicles. We take electricity for granted in Western society, but most of our medical care is dependent on power. Once in Guam, power and the back generator went down on shift and we were left with 8 outlets in the ER. What would you plug in?
Extreme heat and health are so interrelated including our patients' medical conditions, locations they live and work, the medications and climate health determinants and our power grid and urban planning. Sometimes it seems the problem is too complex, but not for us. We own complexity and the solutions in our pocket to enact change. Primary prevention for extreme heat includes green infrastructure in cities to increase shade, transpiration from plants, and removing hardscape to decrease the heat island effect. Efforts such as these decrease daytime temperatures in high population centers, part of why Tucson has less heat island effect than Phoenix. Secondary prevention includes increasing access to cooling areas for all people to reduce heat wave mortality. This can include programs to help install or fix AC units to independent cooling centers to improved communications regarding where cooling centers are located. Tertiary prevention may include asking our patients about their work or activities, advising them to avoid outdoor exposures and offer alternatives. We can employ these strategies in our backyard, our community, our work place and make these conversations daily with others about the health benefits of heat mitigation strategies.
Heat is here to stay for a while and we will continue to work the problem. Summer is fading but the monsoon rains led to beautiful sunsets that give each of us hope. Next month we will chat about the effects of water security and illness on health, as this essential molecule is life but too much can cause disease.
