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The Impact Of Heatwaves On Human Health

In an environment where rising temperatures are a concern to the world today, the impact of heatwaves is increasingly becoming common due to global warming (i.e. increasing high temperatures). Which may pose a notable threat to food security and more importantly human health. As temperatures continue to rise, so does the occurrence and human exposure to extreme heat. The impact of heatwaves has become an issue for several countries in the world. It’s becoming one of the biggest challenges that farmers and humans are complaining about today.

Impact of heatwaves on human health.
Extreme Heat on Humans: Freepik

What is A Heatwave?

A heatwave is an extended continuous period of extremely hot and unbearable high temperatures that exceed 40°C. It usually lasts for 3 days to weeks. It’s usually associated with relatively high dry air. You can feel the air burning your skin or while sitting outside on a paved area, it feels extremely hot like you are sitting on the surface of the sun or a hot plate stove. The more the temperatures continue to rise, we will experience severe weather conditions like this for quite some time. They are considered more dangerous when they are combined with high humidity. They have become a major concern due to their negative impact on human health, food security or production in agriculture, the environment, and animals. The focus of this study will be the impact of heatwaves on human health.

What is a heatwave?
Heatwave: Pixabay

How do Heatwaves Form?

Heatwaves form when there are high-pressure systems in a specific location in the atmosphere. A high-pressure system means there is more air pressure pushing the air away from the surface. The systems trap warm air underneath without allowing the cool air to come beneath or in. So, the air just sits there and gets hotter and hotter. While the air gets hotter, the sun’s rays beat down, adding more heat to the air. That is how a heatwave is formed.

They occur anywhere where there is high-pressure air that creates the environment to form a heat dome. Climate change is also making heatwave conditions worse for humans. In South Africa, heatwaves occur during the El Nino. An El Nino is a climate event that occurs when there is high sea or ocean surface temperatures in the equatorial Pacific. Furthermore, it is usually associated with low rainfall causing problems for farmers and vulnerable communities.

High pressure systems causing heatwaves
High-Pressure Systems Causing Heatwaves: SciJinks

Impact of Heatwaves on Human Health

The impact of heatwaves has become one of the most severe weather events that the world is facing today. Although they impact other sectors in several ways, they have a significant impact on human health. The impact and common effects of heatwaves on human health include:

Increase in Heat Stroke

When temperatures are extremely high, the body cannot cool down through sweat. The person might experience heat exhaustion, which could potentially lead to a heat stroke. There is a vast combination of factors that can lead to heat stroke also called “sunstroke”. This includes anything from high temperatures (i.e. the body temperature can increase to 104°F or 40°C in minutes), air movement/flow, underlying health conditions, lack of water, to lack of access to natural cooling mechanisms like trees or urban areas aircon. All these conditions exist as a result of climate change and the inability of humans to use sustainable measures to put less pressure on natural resources.

Increased Respiratory Conditions

Respiratory problems caused by heatwaves coupled with increased air pollution can affect the airway and breathing for Individuals with lung problems such as asthma, chronic obstructive pulmonary disease (COPD), or Tuberculosis (TB). Additionally, increases in pollen due to rising temperature cause more problems for individuals sensitive to these conditions.

Heatwaves can place additional strain on the heart, and the body’s circulatory systems. This worsens cardiovascular diseases, resulting in hypertension, high cholesterol, and low blood pressure among individuals.


Heatwaves cause shortages in water around the world. However, it becomes even worse for vulnerable communities with elderly, children, and pregnant women without proper access to clean safe water and sanitation. Therefore, these communities are usually faced with heightened or high risks of dehydration, which in some cases leads to death or health problems if the conditions persist for too long.

According to World Vision Australia, about 785 million people around the world do not have access to safe clean water. About 2.2 million of the population comes from the United States (US), the richest economy in the world. Moreover, children die every day from cholera or diarrhea caused by contaminated dirty water and poor hygiene or sanitation.

Heatwaves impact on water shortages
Demand to End Water Crisis in South Africa: Green Peace

Mental Health Impacts

Heatwaves are becoming a significant contributing factor to mental health conditions. Zhang et. al., 2023, iterated that the frequent occurrence of heatwaves, reduces physical activity, increases stress, and affects the overall individual psychological and spiritual well-being. Individuals with mental health issues are at high risk of fainting, dizziness, memory loss, and depression. It can increase the consumption of substance abuse which leads to domestic abuse, and suicide. According to the World Economic Forum, mental health-related deaths increase by 2.2% for every 1°C increase in temperature.

Additionally, exposure to extremely high temperatures can affect mood or sleeping patterns, leaving individuals exhausted due to lack of sleep. Pregnant women mostly struggle with sleep during a heatwave. For this reason, it can adversely affect their entire pregnancy journey or complicate and worsen pregnancy labour and delivery.

moving forward

In conclusion, all these impacts affect and increase mortality and morbidity rates, particularly for people with pre-existing health conditions. In the grand scheme, heatwaves pose a significant risk to human health and governments globally need to make people aware of these climate conditions and the severe consequences they could have.

Communities and public and private entities need to unite to form proactive, preventative measures to keep society safe from these catastrophic or disastrous weather events. To ensure, healthy lives and promote well-being for all, all parties (policymakers, community leaders, etc.) involved need to raise awareness, implement mitigation or adaption strategies, provide resources such as access to safe clean water, medical assistance, shelter or air cooling systems in disadvantaged communities and prioritise mental health support services to mitigate the adverse impacts of heatwaves on well-being and minimise exposure to air pollutants.

achieving the United Nations Sustainable Development Goals (SDGs) and how they link to The Impact Of Heatwaves

Heatwaves and their effects on human health can slow down the achievement of sustainable development goals (SDGs). Here are some key sustainability goals that demonstrate how heatwaves in various ways slow down the world’s progress to sustainability.

  • Good Health (SDG 3): Heatwaves can give rise to the spread of several diseases due to poor air quality and worsen current health problems for people who are already in vulnerable situations (infants, pregnant women, elderly, and low-income communities, people with health problems). This leads to higher death rates, widens health disparities, undermines or hinders the progress or efforts to promote health equity, and increases inequalities (SDG 10).
  • Clean Water & Sanitation (SDG 6): Heatwaves, due to their association with high temperatures, can evaporate water quickly from dams, reservoirs, etc. They lead to water shortage and availability. Therefore, it affects human access to clean water and hygiene.
  • Affordable Energy (SDG 7): With heatwaves, there is a high demand for energy for cooling buildings and homes. This puts pressure on energy-producing sources and hinders progress toward clean affordable electricity.
  • Sustainable Cities & Communities (SDG 11): Heatwaves can lead to more wildfires damaging infrastructure. Consequently, making the building of safe, resilient, and sustainable cities difficult.
  • Life below Water & on Land: High temperatures linked to heat waves affect water (SDG 14) and land (SDG 15) ecosystems. This leads to animal and plant (crop) losses and leaves no food for people. This worsens food security and increases hunger (SDG 2) and possible poverty (SDG 1) in the long run. Therefore, heatwaves can reduce productivity in the agriculture, mining, and construction sectors, leading to the loss of decent work and economic growth (SDG 8).
  • Climate Action (SDG 13): Heatwaves make drought conditions more prominent or prolonged, making it a challenge to implement climate action strategies.

A Thrivable Framework

The Thrive Framework raises global awareness of heatwave-driven catastrophic fires and droughts through research and education. It also advocates for governments to implement preventative measures against climate change, aiming to reduce the severity and frequency of climate crises. An urgent collective organisational collaboration is necessary to ensure individual survival, and prevention of biodiversity loss and species during these conditions.

To learn more about the THRIVE project Thrivability matters, register for our webinar events to discuss all things sustainability with experts in the field. You can sign up for our free newsletter, follow our podcast series, and informative monthly blog posts. Further educational videos can be found on our YouTube Channel.


  • Letlotlo Dlamini

    Letlotlo Dlamini is a scientist and leader with experience in Sustainable Agriculture, Climate Change, Science & Technology Investments. She worked at a Science Institution in South Africa, where she promoted Research & Development (R&D) activities through the use of tax incentives in the private sector. She completed her MBA at Edinburgh Business School (EBS) in the United Kingdom. She joined the Thrive Project as a Researcher to help tackle all issues related to Sustainability and Climate Change. She is interested Sustainable Finance and making an impact by solving sustainability and climate change challenges faced by world today.