Heat Exhaustion Symptoms: What You Need to Know
Heat exhaustion is a heat-related illness that occurs when the body overheats due to prolonged exposure to high temperatures, especially when combined with dehydration and physical exertion. While it is less severe than heatstroke, it still requires immediate attention to prevent complications.
In this article, we’ll explore the early and advanced symptoms of heat exhaustion, how it differs from heatstroke, risk factors, and prevention tips. Recognizing the signs early can save lives.
What Is Heat Exhaustion?
Heat exhaustion happens when the body loses too much water and electrolytes through sweating, making it difficult to regulate its core temperature. It’s a warning stage that the body is struggling to cool down, and if left untreated, it may progress to heatstroke, a life-threatening emergency.
Common Symptoms of Heat Exhaustion
The signs of heat exhaustion can vary from person to person, but the following are the most commonly reported symptoms:
Heavy Sweating
- The most prominent sign; your body is trying hard to cool down.
- Clothing may become soaked quickly.
Cool, Moist, Pale Skin
- Despite the heat, the skin may feel clammy due to excessive sweating.
- Goosebumps may appear, even in high temperatures.
Dizziness or Lightheadedness
- Caused if you don’t have enough blood flow to the brain.
- May result in fainting or temporary vision changes.
Fatigue or Weakness
- Physical exertion becomes difficult or unsafe.
- The body feels drained and heavy.
Muscle Cramps
- Especially in legs, arms, or abdomen due to electrolyte loss.
- Often an early indicator of developing heat-related illness.
Rapid, Weak Pulse
- Also known as a “thready” pulse.
- A sign that the heart is working harder to regulate temperature.
Nausea or Vomiting
- A warning that the body is under significant stress.
- May be accompanied by lack of appetite.
Headache
- Ranges from mild pressure to severe throbbing pain.
- Can worsen with continued heat exposure.
Fainting (Syncope)
- In severe cases, the person may briefly lose consciousness.
- Typically triggered by sudden standing or movement.
Low Blood Pressure on Standing
- Known as orthostatic hypotension.
- Causes sudden dizziness or imbalance upon rising.
When Heat Exhaustion Becomes Dangerous?
- Symptoms persist beyond 1 hour despite cooling and hydration.
- Confusion, disorientation, or aggressive behavior is observed.
- Body temperature rises above 104°F (40°C).
- Fainting, slurred speech, or seizures occur.
What Causes Heat Exhaustion?
Heat exhaustion is triggered by a combination of high environmental temperatures, excessive sweating, and inadequate fluid intake. Contributing factors include:
- Hot, humid weather
- Intense physical activity without acclimatization
- Inadequate hydration
- Wearing heavy or non-breathable clothing
- Alcohol or caffeine use
High-Risk Groups
Anyone can develop heat exhaustion, but risk increases in:
- Infants and young children (less efficient thermoregulation)
- Elderly adults (slower physiological response)
- People with diabetes and heart disease
- Athletes and outdoor workers
- Those on medications like diuretics, beta-blockers, or antipsychotics
Prevention Tips
- Hydrate regularly: Drink water or electrolyte solutions even before you feel thirsty.
- Avoid peak sun hours: Stay indoors between 11 am and 4 pm when possible.
- Dress appropriately: Wear loose, light-colored, breathable clothing.
- Take breaks: Especially during physical activity or outdoor work.
- Protect against sunburn: Use sunscreen, hats, and seek shade.
First Aid for Heat Exhaustion
If you or someone near you shows signs of heat exhaustion:
- Move to a cooler environment (shade or AC).
- Lay down and elevate the legs slightly.
- Loosen or remove excess clothing.
- Apply cool compresses
- Take a cold shower
- Sip cool water slowly — avoid alcohol or caffeine.
- Monitor closely — seek emergency help if no improvement in 30–60 minutes.
Heat Exhaustion vs. Heatstroke
| Feature | Heat Exhaustion | Heatstroke |
| Body Temp | <104°F (40°C) | ≥104°F (40°C) |
| Sweating | Present | Often absent |
| Mental Status | Clear or mildly confused | Severely impaired |
| Skin | Cool, moist | Hot, dry, or flushed |
| Danger Level | Serious | Medical emergency |
Final Thoughts
Heat exhaustion is a serious but preventable condition. By recognizing its early symptoms and responding promptly, you can protect yourself and others from potentially fatal heatstroke. As temperatures rise globally, awareness and prevention of heat-related illnesses have never been more important.
If you found this guide helpful, share it with others and take proactive steps to stay safe during the summer heat.
