Understanding Heat-Related Illness: Heat Exhaustion vs. Heat Stroke

As global temperatures continue to rise and heat waves become more frequent and intense, it is increasingly important to recognize the signs of heat-related illness. Heat exhaustion and heat stroke are two serious medical conditions that result from the body’s inability to regulate its internal temperature in extreme heat. Understanding the differences between these conditions—and knowing how to respond—can prevent complications and save lives.

What Are Heat-Related Illnesses?

Heat-related illnesses occur when the body’s mechanisms for dissipating heat—primarily sweating—are overwhelmed. This can happen in high temperatures, high humidity, or when hydration levels are inadequate. Certain medications and health conditions can also increase susceptibility.

Heat Exhaustion: Early Warning Signs

Heat exhaustion is an early stage of heat-related illness. The body is still attempting to cool itself, but may not be doing so effectively. Symptoms can include:

• Profuse sweating

• Fatigue

• Nausea or vomiting

• Headache

• Dizziness or faintness

• Muscle cramps

• Cool, moist skin

Individuals experiencing heat exhaustion should move to a cooler environment, rest, hydrate with water or electrolyte fluids, and apply cool compresses or take a cool shower. Prompt attention can prevent progression to heat stroke. Think of it this way: would you rather be exhausted or have a stroke?

Heat Stroke: A Medical Emergency

Heat stroke is a life-threatening condition that occurs when the body’s temperature rises to 104°F (40°C) or higher. The body’s cooling system has failed, and urgent intervention is required. Symptoms include:

• High body temperature

• Hot, dry skin or cessation of sweating

• Confusion or altered mental status

• Rapid pulse

• Seizures

• Loss of consciousness

Heat stroke requires immediate emergency medical attention. Call 911, move the person to a shaded or cool environment, and begin active cooling using fans, ice packs, or immersion in cool water. Do not wait—begin these cooling measures while waiting for the ambulance to arrive.

Medication and Heat Sensitivity

Certain prescription medications can impair the body’s ability to regulate temperature or maintain hydration. These include:

• Diuretics (commonly known as water pills), which can cause dehydration

• Anticholinergics (such as Benadryl or several medications used for mental illness), which inhibit sweating

• Beta blockers, which affect heart rate and heat response

• Stimulants (like Adderall for ADHD), which elevate body temperature

Patients taking these medications should be especially cautious during heat events and consult with a healthcare provider about managing risk.

Emergency Cooling During Extreme Heat

In the event of a heat wave or “heat dome” and limited access to air conditioning, the following strategies may help reduce body temperature:

• Apply wet cloths to the skin and sit in front of a fan

• Use frozen towels or ice packs on the neck, wrists, and ankles

• Take cool (not cold) baths or foot soaks

• Stay hydrated and avoid alcohol or caffeinated beverages

• Visit public cooling centers if home conditions are unsafe

Recognizing and responding to heat-related illness promptly is essential, particularly for vulnerable populations such as older adults, those with chronic conditions, and individuals taking medications that affect thermoregulation. As climate conditions continue to shift, being prepared and informed is a critical component of personal and community health.