Heatwaves: What impact does extreme heat have on our bodies?

With heatwaves being reported from parts of India, here's everything you need to know about prolonged exposure to extreme heat.

After a media report suggested that heatwaves had killed nearly a hundred people in eastern India since late last week, Union Health Minister Mansukh Mandaviya chaired a high-level meeting today to review public health preparedness for the same.

Given rising temparatures, Deccan Herald explains what impact prolonged exposure to extreme heat has on our bodies:

When the body is exposed to extreme heat, it struggles to regulate its internal temperature, leading to various health risks and potential heat-related illnesses. These may be more severe for vulnerable populations, including the elderly, young children, pregnant women, those with chronic illnesses, and those who do manual labour outdoors.

Research suggests that extreme heat may lead to the following conditions (in order of progression and severity):

Dehydration: Excessive sweating due to heat may lead to a rapid loss of water from the body. Not drinking enough fluids to compensate for this loss may cause dehydration, which, among other symptoms may express itself as dizziness, fatigue, having a dry mouth, and decreased urine discharge. Severe dehydration can be life-threatening.

Heat cramps: Heat cramps are painful muscle contractions that typically affect the legs, arms, or abdomen. They may cause weakness, headache, and nausea. Heat cramps can be an early warning sign of more severe heat-related illnesses.

Heat exhaustion: Heat exhaustion is a more serious condition than heat cramps. It can occur when the body loses a significant amount of fluids and electrolytes through sweating. Symptoms include heavy sweating, weakness, dizziness, nausea, headache, and a rapid heartbeat. If left untreated, heat exhaustion can progress to heatstroke.

Heatstroke: Heatstroke is a life-threatening condition that requires immediate medical attention. It happens when the body's internal temperature rises to a dangerously high level, typically above 104°Fahrenheit (40°Celsius). Heatstroke can damage multiple organs and the central nervous system, causing confusion, ataxia, delirium, or seizures. Symptoms include a high body temperature, altered mental state, confusion, seizures, rapid breathing, and a rapid heartbeat. Heatstroke can be fatal if not treated promptly.

Respiratory distress: Extreme heat can worsen existing respiratory conditions, such as asthma and chronic obstructive pulmonary disease (COPD). Additionally, high temperatures can irritate the airways and lead to breathing difficulties.

Cardiovascular strain: Heat puts stress on the cardiovascular system as the body tries to cool itself down. The heart has to work harder to circulate blood and maintain core temperature. This increased workload can be problematic for individuals with heart conditions, leading to heart attacks, strokes, or other cardiovascular complications.