What is heat-related illness?
Heat exhaustion and heat stroke are two common conditions that result from excessive exposure to high temperatures. While heat stroke is a severe, life-threatening condition, responding to early signs of heat stress—such as excessive sweating, dizziness, weakness, or cramps—can help prevent more serious health issues. Heat-related illnesses are caused by prolonged exposure to high temperatures. These include:
- Heat Exhaustion
- Heat Stroke
Heat stroke, in particular, is a medical emergency that can be fatal if not treated quickly. Early recognition and prompt action are key. Symptoms of heat-related illness include excessive sweating, heat rash, dizziness, fatigue, and muscle cramps. If left untreated, these can escalate into heat stroke, which requires immediate medical attention.
What causes heat-related illness?
Heat-related illness occurs when the body is overwhelmed by heat stress, which can result from a combination of environmental and individual factors. These include:
- High ambient air temperature
- Radiant heat from sources like fires, equipment, or hot work environments
- Low air movement
- High humidity
- Physical activity or tasks requiring personal protective equipment
- Metabolic heat production
The human body is made up of approximately 60% water, and dehydration can set in with as little as 2% fluid loss. Symptoms of heat stroke may appear when dehydration reaches 5%. In high heat environments, we can sweat up to 3 litres per hour, making heat-related illness possible within 1-2 hours of exposure. Even in moderate heat conditions, staying hydrated and using preventative measures is essential.
Who is at risk?
Certain factors increase susceptibility to heat-related illness. People at higher risk include those who are:
- Overweight or obese
- Older adults
- In poor general health or with pre-existing medical conditions
- Taking certain prescription or illicit drugs
- Dehydrated
Dehydration can occur for several reasons, such as inadequate water intake, or consumption of fluids with diuretic effects (like alcohol or coffee).
How to prevent heat-related illness
Here are four key steps to protect yourself when exposed to high temperatures:
- Hydrate
- Start hydrating 2 hours before exposure to heat.
- Drink consistently to avoid feeling thirsty.
- Carry a water bottle and drink about 250ml every 15 minutes while working in the heat.
- Avoid caffeinated drinks, alcohol, milk, carbonated drinks, and fruit juices.
- Examine
- Be mindful of the early symptoms of heat stress and check in with others about how they’re feeling.
- Acclimatise
- Be aware of the weather and adjust your clothing to be lightweight and light-coloured.
- Prepare ahead of time by spending a little time outside before your shift to gauge the intensity of the heat and plan your hydration needs.
- Timing
- Pace yourself during physical work or exercise.
- Whenever possible, schedule strenuous activities for cooler parts of the day.
How to treat heat stress
If you encounter someone experiencing heat stress, it’s crucial to act quickly. Follow these steps:
- Get medical attention immediately
- Move the person to a cooler area
- Increase their water intake
- Loosen or remove clothing
- Fan and spray with cool water
Can you drink too much water?
While staying hydrated is essential, drinking excessive amounts of water can also be dangerous. Hyponatremia is a condition where too much water dilutes the sodium levels in your blood, causing cells to swell. Symptoms of hyponatremia include nausea, vomiting, fatigue, headaches, confusion, cramps, and irritability. In severe cases, it can lead to seizures or coma.
If you suspect hyponatremia, seek immediate medical help. It’s crucial to differentiate between heat-related illness and hyponatremia, especially in high-heat conditions where people tend to drink large amounts of water.
What is the best drink for optimal hydration?
For most situations, water is the best choice for staying hydrated, as it has no adverse side effects. However, if you’re engaging in prolonged physical activity or heat exposure for over 60 minutes, sports drinks may offer additional benefits. These drinks contain a balanced mix of electrolytes and carbohydrates that are lost through physical exertion. They are often easier to consume in larger amounts and are absorbed quickly without causing excessive fluid loss.
Avoid energy drinks, soft drinks, cordial, fruit juices, and alcohol for hydration. These beverages have inappropriate sugar and electrolyte concentrations, which can be detrimental to hydration and health in hot conditions. Additionally, alcohol is a diuretic and should be avoided before, during, or after heat exposure.
By understanding heat-related illnesses, staying hydrated, and recognising symptoms early, you can protect yourself and others from the dangers of heat stress.
Visit our Health & Lifestyle page to view our Heat Stress Training service.
