Effects of Heat Waves: Health Risks and Precautions

Tuesday, 27 May, 2025

As global temperatures rise, heat waves have become more frequent and intense, posing significant health risks. Understanding the effects of heat waves on humans is crucial, especially for vulnerable populations. This guide delves into how extreme heat impacts the body, identifies at-risk groups, and offers actionable precautions to stay safe during scorching temperatures.

How Heat Waves Impact Human Physiology

Heat waves challenge the body's ability to regulate temperature. Prolonged exposure to high temperatures can overwhelm thermoregulatory mechanisms, leading to dehydration, electrolyte imbalances, and heat-related illnesses. The body’s cooling mechanisms—such as sweating and increased skin blood flow—may not be enough in extreme heat, especially when the humidity is high.

This thermal imbalance can cause serious symptoms including faintness, heat cramps, and fatigue. The risk increases dramatically when individuals are engaged in physical activities, work outdoors, or remain in poorly ventilated indoor spaces. In extreme cases, this thermal stress may lead to long-term damage to internal organs, especially the brain and kidneys.

Heat Wave Trends in India

India has witnessed a surge in heat wave incidents over recent years. States like Rajasthan, Gujarat, Maharashtra, and parts of Karnataka have recorded temperatures soaring above 45°C during peak summer. Urban areas, due to the "urban heat island" effect, experience intensified heat, exacerbating health risks for city dwellers.

The India Meteorological Department (IMD) has indicated that climate change is contributing to longer and more intense heat waves. This makes it critical for local governments and individuals to adopt summer precautions for students, workers, the elderly, and other susceptible groups. Increased public awareness campaigns, improved access to cooling centers, and government heat action plans are becoming more critical with every passing year.

Critical Health Risks of Heat Waves

Heat Stroke: The Most Serious Effect of Heat Waves

Heat stroke is a medical emergency characterized by a core body temperature exceeding 40°C. It may be accompanied by symptoms such as confusion, altered mental state, dry skin, and even unconsciousness. Without immediate emergency treatment for heat stroke, the risk of fatality or long-term complications increases substantially.

Always take preventive steps like staying hydrated and avoiding peak sun hours, especially for individuals with underlying health conditions. In case of symptoms, cool the body using wet cloths or ice packs while waiting for emergency medical help.

Heat Exhaustion and Dehydration

Heat exhaustion is more common than heat stroke and typically develops after prolonged exposure to high temperatures and insufficient fluid intake. Symptoms include heavy sweating, weakness, dizziness, nausea, and headache. These are classic signs of heat fatigue and should not be ignored.

Prompt cooling, hydration, and rest can help prevent progression to heat stroke. Consuming electrolyte-rich fluids and avoiding overexertion in extreme heat can serve as effective first-line defenses.

Cardiovascular Strain

When exposed to high heat, the body diverts blood to the skin to facilitate heat dissipation. This puts extra pressure on the heart, increasing the risk of heart attack or stroke, especially in those with pre-existing cardiovascular conditions. Older adults and people with hypertension are particularly at risk.

Increased heat also leads to higher blood viscosity due to dehydration, which can cause clotting issues. Patients with heart conditions must take extra care and avoid stepping outdoors unless necessary.

Neurological Effects of Extreme Heat

Heat waves can impair neurological function, leading to confusion, lack of coordination, seizures, and even loss of consciousness. These extreme heat effects are more severe in individuals who do not have access to cooling facilities or who are already suffering from other health issues.

Children and elderly patients are particularly vulnerable to heat-induced neurological complications. Long-term cognitive effects, such as memory loss or mental fatigue, may also result from repeated episodes of severe overheating.

Vulnerable Populations During Heat Waves

Effects of Heat Waves on Elderly People

Older adults are less efficient at thermoregulation and often have underlying conditions that elevate their risk during heat waves. Medications for blood pressure or heart disease can further impair their ability to respond to high heat, leading to heat-related medical conditions.

Monitoring their hydration and ensuring they stay in cool environments is essential. Family members or caregivers should check on elderly individuals frequently during summer.