Hyperthermia: What are the Symptoms and Causes of Overheating?


Climate change and rising global temperatures can impact our health in several ways, and it leaves certain individuals more prone to hyperthermia and heat-related illnesses.

According to the World Health Organization (WHO), exposure to extreme heat can cause heat illness, hospitalization, and even death.

Heat exposure can also disrupt the economy by affecting health services, transport systems and productivity, and increasing the risk of workplace accidents.

Individuals most at risk of hyperthermia include infants, athletes, the elderly, and people with heat intolerance.

To keep yourself and your loved ones safe, you should know who is most at risk of hyperthermia and what to do during emergencies.

In this article, we’ll explain what hyperthermia is, the different types that exist, and which steps to follow after being exposed to extreme heat.

What is Hyperthermia?

Hyperthermia occurs when your body temperature exceeds its normal range, reducing the body's capacity to operate effectively.

It serves as a collective term for various heat-related illnesses, including heat stroke, heat rash, heat exhaustion, and heat stress.

Hyperthermia can vary from mild to life-threatening. Similarly, excessive cold is also harmful, leading to hypothermia, where the body fails to maintain sufficient warmth.

Hypothermia is the opposite of hyperthermia, but both conditions illustrate the body's critical need for temperature regulation.

What are the Different Types of Hyperthermia?

Heat-related illness includes a range of conditions, such as heat rash, heat exhaustion, heat syncope, and heat stroke, each varying in severity and requiring specific treatments.

Conditions like heat stress and heat cramps also fall under this category, highlighting the diverse impact of excessive heat on the body.

Heat stress

Heat stress occurs when individuals face discomfort from engaging in physical activity in hot weather, especially in temperatures exceeding the typical room temperature range of 68°F to 77°F.

This condition, often experienced during extreme heat, leads to an abnormally high body temperature, resulting in excessive sweating, overall fatigue, and difficulty concentrating.

Treatment for heat stress

Heat stress is not a serious condition and does not require any treatment.

Simple measures such as relocating to a cooler environment or using a fan, can offer immediate comfort and help lower the body's abnormally high temperature to safer levels.

Key Point: What is Occupational Heat Stress?

Manual laborers who are required to wear protective gear have a higher risk of experiencing heat stress.

Such workers frequently undertake demanding physical tasks and must operate potentially hazardous machinery in high temperatures, elevating the risk of severe injury.

Miners in particular illustrate this scenario, where the combination of demanding physical activity and the use of hazardous equipment significantly increases their risk.

Statistics from the U.S. Bureau of Labor Statistics show that, on average, 38 work-related deaths from heat exposure occur each year.

Heat syncope

Syncope refers to a brief loss of consciousness, or fainting. Heat syncope occurs when exposure to high temperatures causes one to faint.

The primary mechanism behind fainting, in general, is vasodilation — the widening of blood vessels. This process reduces blood pressure, potentially leading to hypotension (low blood pressure), which can cause fainting.

In hot weather, our body attempts to maintain its core body temperature for optimal safety and functionality. This regulation involves the widening of blood vessels (vasodilation) to facilitate cooling.

However, this necessary response can lead to lowered blood pressure, resulting in heat syncope (fainting).

Treatment for heat syncope

If you experience heat syncope, you should immediately remove yourself from the hot environment and find a place to sit.

It's important to hydrate by drinking water. However, sports drinks are preferable when available, as they effectively replenish lost electrolytes.

Heat cramps

Heat cramps typically affect individuals engaged in manual labor or intense physical activities in hot weather.

These cramps happen when excessive sweating leads to a significant loss of electrolytes, which are crucial for muscle function. A deficiency in electrolytes can cause muscle spasms and cramps.

Although this form of hyperthermia is common during strenuous activities in the heat, where one sweats profusely over extended periods, it's not exclusive to hot environments.

Even individuals exercising in air-conditioned settings can experience heat cramps if they sweat heavily and lose a substantial amount of electrolytes.

Treatment for heat cramps

Stop all strenuous physical activity and sit down. Hydrate with water, juice, or sports drinks every 15 to 20 minutes, and complement your hydration with a light snack, such as a cookie.

While you might consider taking salt tablets to quickly restore electrolytes, it's advisable to avoid them.

Salt tablets absorb slowly and may not offer immediate relief. They can also irritate the stomach and potentially elevate blood pressure, a concern for individuals managing hypertension.

If your cramps persist for more than an hour, seek medical advice.

Heat exhaustion

Heat exhaustion happens when you lose too much water and salts from excessive sweating, especially in hot weather.

This can make your body struggle with controlling muscle and nerve functions and staying hydrated.

It's more serious than just feeling overheated but not as dangerous as a heat stroke.

People who are more likely to get heat exhaustion include those with high blood pressure, older adults, and anyone working or spending a lot of time in the heat.

Treatment for heat exhaustion

If someone shows signs of heat exhaustion, such as elevated body temperature or other heat-related symptoms, immediately take action to cool them down.

Follow these steps:

  • Move them to a shaded or air-conditioned space away from the heat.

  • Loosen or remove unnecessary clothing, including socks and shoes, to help reduce their body temperature.

  • Offer them water or a sports drink for hydration and apply ice packs or cold compresses to their body to further cool them down.

  • If they're capable, escort them to a medical facility for further evaluation. If they're too weak, call emergency medical services. Always ensure they're not left alone while awaiting help.

Heat rash

Heat rash — also known as miliaria, sweat rash, or prickly heat — is a skin irritation caused by excessive heat and moisture.

Characterized by clusters of small red bumps, it develops gradually as body temperature rises.

It typically emerges in areas prone to sweat accumulation such as armpits, elbow and knee creases, the groin, under the breasts, and within skin folds.

Treatment for heat rash

To alleviate heat rash, remove yourself from the hot and humid conditions. Gently dry the affected skin area and sprinkle some baby powder on it to keep it dry.

Avoid the application of creams or ointments, as their moisture content can hinder the healing process. Generally, heat rash is not severe and typically resolves within a few days.

Heatstroke

Heatstroke is a critical and potentially fatal condition where the body loses its ability to regulate temperature, having depleted its cooling mechanisms.

This leads to the body's temperature rising to dangerous levels, potentially reaching 107°F within just 10 to 15 minutes.

Heatstroke is a medical emergency. Without immediate medical intervention, this swift and severe overheating may cause lasting harm, including permanent disabilities or even death.

In the U.S., more than 1,300 heat-related deaths are reported each year.

Treatment for heatstroke

If you are around someone who is experiencing heat stroke, immediate action is required.

Call an ambulance and do not leave the person alone while waiting. Then, try to cool them down using the following methods:

  • Soak them in an ice bath

  • Keep their skin wet

  • Remove their clothes

  • Place ice packs/bags of frozen vegetables on their body

  • Ensure that they’re in a well-ventilated place

  • Position them near a fan

What are the Symptoms of Hyperthermia?

The symptoms of hyperthermia or heat-related illnesses are all quite similar, but they differ in intensity and medical management.

Below is a table summarizing the unique symptoms associated with each form of hyperthermia:

Hyperthermia type

Symptoms

Heat rash

Small, red blisters clustered on the skin. Common in areas where sweat builds up and there are skin folds such as in the elbow creases, groin, under the breasts, and neck.

Heat stress

General discomfort, impaired concentration, a feeling of general weakness.

Heat exhaustion

Headache, dizziness, general weakness, excessive sweating, muscle cramps, nausea, and faint but fast pulse.

Heat cramps

Muscle cramps and/or spasms.

Heat stroke

A body temperature of 103°F or higher, dry and hot skin, headache, dizziness, nausea, confusion, loss of consciousness, and a strong, fast pulse.

How Can I Prevent Hyperthermia?

There are some simple ways to keep yourself safe from overheating and prevent hyperthermia:

  • Wear loose, lightweight clothing

  • Decrease the intensity of physical activity

  • Stay hydrated, especially in hot and humid weather

  • Work in a cool space in your home or a public building with air conditioning

  • Always check the weather before planning outdoor activities

  • Complete appropriate employee training on heat-related illnesses and how to respond during emergencies

Where Can You Learn More About Preventing and Treating Hyperthermia?

Do you work in an environment where extreme heat is prevalent? Have you experienced the symptoms outlined in our article?

If you belong to one of the high-risk groups for hyperthermia, including those with high blood pressure, LifeMD can help.

LifeMD can connect you to a team of medical professionals who can offer advice on staying safe in extreme heat, as well as assist in managing conditions like hypertension to enhance your overall health and reduce the risk of hyperthermia.

Book your appointment today to safeguard your health.

Joslin Ruiz, APRN, FNP-C

Joslin began her healthcare journey as an ER nurse, where she fine-tuned her expertise in both pediatric and adult care over the years. She’s spent years in family practice and telemedicine, finding immense joy and fulfillment in her work. Joslin is all about embracing the great outdoors and can often be spotted hiking with her two pups or venturing to new travel destinations. She's a true foodie at heart, jumping at every chance to savor new culinary experiences.

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This article is intended for informational purposes only and should not be considered medical advice. Consult a healthcare professional or call a doctor in the case of a medical emergency.

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