The impact of heat on the human body

The heatwaves can make the days unbearable and even dangerous. With rising temperatures, the body undergoes various changes that could lead to heat exhaustion or even heatstroke. It is crucial to stay cool and safe during these hot days!

Manuela Băbuș
Medical Writer
The impact of heat on the human body

The first step in staying safe during the heatwave is knowing how the body reacts to increased temperatures. The human body's normal temperature is around 37°C

When exposed to hot weather, the body sweats, regulating its temperature. However, the body's mechanism may not work correctly in sweltering conditions, increasing the internal temperature. This may lead to heat exhaustion, which includes symptoms such as dehydration, fatigue, headaches, and muscle cramps. Therefore, it is important to keep an eye on your body's changes and take steps to cool off when necessary.

One way to prevent overheating is to choose the right clothes. Opt for light-colored and loose-fitting clothing to help with ventilation and reflect the sun's rays. 

Hats and sunglasses are also beneficial for protecting the head and eyes from the sun. 

But drinking plenty of water is crucial for preventing dehydration, which is a common problem during heat waves.

While everyone can be affected by excessive heat, certain populations are more susceptible to its adverse effects (elderly people, children, individuals with chronic illnesses, outdoor workers, homeless individuals, athletes, pregnant women, etc).

While everyone can be affected by excessive heat, certain populations are more susceptible to its adverse effects (elderly people, children, individuals with chronic illnesses, outdoor workers, homeless individuals, athletes, pregnant women, etc).

Elderly Individuals

The elderly have a diminished ability to regulate body temperature due to age-related changes in thermoregulation. They may not sense temperature changes accurately, making them prone to overheating. Chronic health conditions and medications further exacerbate their vulnerability.

Children and Infants

Young children and infants have underdeveloped thermoregulatory systems. They produce more metabolic heat per unit of body weight than adults, which can lead to rapid dehydration and overheating.

Individuals with Chronic Illnesses

Chronic conditions like cardiovascular diseases, diabetes, and respiratory disorders reduce the body's capacity to cope with heat stress. Medications can also interfere with temperature regulation.

Outdoor Workers

Individuals employed in outdoor occupations face prolonged exposure to high temperatures. Their risk is compounded by physical exertion, which increases body heat production and diminishes hydration levels.

Homeless Individuals

Limited access to air conditioning and safe shelter leaves these groups highly vulnerable during heat waves. They often lack resources to stay cool and hydrated, putting them at greater risk of heat-related illnesses.


Physical activity elevates body heat production. Athletes and those who engage in strenuous exercises are prone to dehydration and heat exhaustion if not adequately hydrated.

Pregnant Women

Pregnancy alters thermoregulation and increases heat sensitivity. The added stress on the body's circulatory system makes pregnant women more susceptible to heat-related complications.

Individuals with Mental Health Conditions

Mental health conditions can impair the individual's ability to recognize and respond to heat stress, potentially leading to neglect of necessary precautions.


Heatstroke is the most serious heat-related illness. It occurs when the body's temperature regulation system fails, leading to a rapid rise in body temperature. This malfunction disrupts the body's ability to cool itself, making the sweating mechanism ineffective. The result is a rise in body temperature to 40°C or higher in just 10 to 15 minutes. The repercussions of heat stroke can include irreversible disability or even death if immediate emergency intervention is not administered.

Signs and symptoms:

  • Confusion, altered mental status, and slurred speech
  • Loss of consciousness, often leading to coma
  • Skin that is either excessively hot and dry or wet with profuse perspiration

A body temperature that rises to dangerous heights

The criticality of timely care; rapid response is paramount, as delayed treatment could prove fatal.

First-aid measures

If a patient succumbs to heat stroke, follow these steps:

  • Move the individual to a cool, shaded area and remove outer clothing.
  • Call 911 if medical assistance is not available and stay with the patient until help arrives.
  • Initiate rapid cooling using the following techniques: 
  • Use cold water or ice bath if possible.
  • Moisturise the skin.
  • Apply cool, damp cloths to the skin.
  • Saturation of clothes with cold water.
  • Improve cooling by facilitating air circulation around the affected individual.
  • Strategically place cold, wet washcloths or ice on critical areas such as the head, neck, armpits, and groin. Alternatively, wet the clothes if these areas are not accessible.

Heat exhaustion

Heat exhaustion is the body's response to an excessive loss of water and salt, usually through excessive sweating. Heat exhaustion is most likely to affect:

  • The elderly
  • People with high blood pressure
  • Those who work in a hot environment

Symptoms and signs of heat exhaustion include:

  • Headache
  • Nausea
  • Dizziness
  • Weakness
  • Irritability
  • Thirst
  • Profuse perspiration
  • Increased body temperature
  • Decreased urine production

First-aid measures

  • Remove the people from the hot area and give them fluids to drink.
  • Remove unnecessary clothing, including shoes and socks.
  • Cool the patient with cold compresses or have the worker wash their head, face, and neck with cold water.
  • Encourage frequent sips of cold water.


Sunburn is another common health issue during the summer. 

Overexposure to ultraviolet rays can cause skin damage and even skin cancer. Wearing sunscreen with at least an SPF of 30 and reapplying it every two hours is crucial when spending time outdoors. 

You could also avoid outdoor activities during peak sun hours, typically between 11 am to 5 pm. The shade is also your ally. 

Staying under a tree or umbrella reduces direct sunlight and provides relief from the heat.


Prevention for heat-related diseases is key, but knowing the signs and treatment for these conditions could be lifesaving. The signs for heat exhaustion and heatstroke could be similar, but heatstroke is a severe condition that requires emergency medical attention

If you or someone you know is experiencing symptoms of heatstroke, immediately call for medical help. Meanwhile, move the affected person to a cooler location, apply cool water, and loosen tight clothing.

Please note that the information provided on this blog is for educational and informational purposes only. It is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.

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Manuela Băbuș.
Medical Writer