Heat illness often happens when the body cannot cool itself fast enough, especially during high heat, humidity, or hard exercise. Cold illness often happens when the body loses heat faster than it can produce it, especially with wind, wet clothing, or long exposure. The most important actions are to stop activity, move to a safer environment, cool or warm the person safely, and get medical help for severe symptoms.
A useful rule is recognize, respond, and report.
Key Facts
- Heat exhaustion warning signs include heavy sweating, weakness, dizziness, headache, nausea, cool clammy skin, and a fast pulse.
- Heat stroke is a medical emergency when body temperature may reach 104°F or higher with confusion, fainting, seizures, or hot skin.
- For suspected heat stroke, call emergency services, move the person to shade or air conditioning, and cool rapidly with cold water or ice packs.
- Hypothermia can occur when body temperature drops below 95°F, causing shivering, confusion, slurred speech, clumsiness, and sleepiness.
- Frostbite warning signs include numbness, tingling, pale or waxy skin, hard skin, and loss of feeling in fingers, toes, ears, or nose.
- Use the clothing layer rule in cold weather: base layer wicks sweat, middle layer insulates, and outer layer blocks wind and rain.
- A simple hydration plan for activity is drink before exercise, drink regularly during exercise, and replace fluids after exercise.
- The first response rule is stop activity, move to a safer place, check symptoms, begin cooling or warming, and get adult or medical help when needed.
Vocabulary
- Heat exhaustion
- A heat illness caused by overheating and fluid loss that can lead to weakness, dizziness, heavy sweating, and nausea.
- Heat stroke
- A life-threatening heat emergency when the body cannot control its temperature and the brain or organs may be harmed.
- Hypothermia
- A dangerous drop in core body temperature below 95°F that can affect movement, thinking, and heart function.
- Frostbite
- An injury caused when skin and body tissue freeze, most often affecting fingers, toes, ears, nose, and cheeks.
- Wind chill
- The cooling effect of wind that makes the body lose heat faster than the actual air temperature suggests.
- Hydration
- The process of keeping enough water and fluids in the body so it can cool itself and function properly.
Common Mistakes to Avoid
- Ignoring early dizziness or headache during heat exposure is dangerous because these can be early signs of heat illness that may worsen quickly.
- Giving a confused person water to drink can be unsafe because confusion may mean a severe emergency and the person could choke.
- Rubbing frostbitten skin is wrong because frozen tissue can be damaged more by friction and pressure.
- Using very hot water or direct heat to warm cold skin is unsafe because numb skin can burn before the person feels pain.
- Wearing cotton as the main cold-weather layer is a mistake because wet cotton holds moisture against the skin and increases heat loss.
Practice Questions
- 1 A soccer practice lasts 90 minutes on a hot day. If a student plans to drink water every 15 minutes, how many drink breaks should they take during practice?
- 2 The air temperature is 34°F, but strong wind makes it feel like 22°F. Which number better describes the risk for cold stress, and why?
- 3 A hiker starts with 2 liters of water and drinks 0.5 liter each hour. How many hours will the water last if the drinking rate stays the same?
- 4 A classmate is shivering, confused, and moving clumsily after standing outside in wet clothes. Explain the safest first response steps and why they matter.
Understanding Heat & Cold Illness Prevention
Your body keeps its inner temperature within a narrow safe range. It does this by moving heat from the inside to the skin, then releasing that heat to the surroundings. Sweating is useful only when sweat can evaporate.
On a humid day, the air already holds a lot of water vapor, so evaporation slows down. A fan can help because moving air carries away humid air near the skin. Direct sun adds heat faster than shade, and dark or heavy clothing can trap more heat.
During exercise, working muscles produce a large amount of heat. This is why a practice that feels manageable at the start can become unsafe later.
Heat problems do not affect everyone equally. A person who is new to hot weather needs time to adjust. Over several days of shorter activity, the body becomes better at sweating and keeping salt balance.
This process is called heat acclimatization. Lack of sleep, illness, some medicines, dehydration, and prior heat illness can raise risk. Students may notice danger during marching band, outdoor games, gym class, construction work, crowded buses, or a long wait on a hot field.
Do not rely only on thirst. Thirst can appear after fluid loss has already begun. Pale yellow urine usually suggests adequate hydration, while darker urine can be a sign to drink more fluids.
Cold exposure works through several pathways. Wind removes the warm layer of air beside the skin. Water pulls body heat away much faster than dry air, which makes wet socks, rain, sweat, and snow especially serious.
The body responds by narrowing blood vessels near the skin to protect vital organs. This helps the chest and head stay warm, but fingers, toes, ears, and the nose receive less warm blood. Shivering creates heat through muscle activity, yet it uses energy and cannot continue forever.
Loose layers work because trapped air provides insulation. Cotton is often a poor choice for active cold weather because it holds moisture. Wool and many synthetic fabrics retain warmth better when damp.
Pay attention to changes in behavior as much as visible symptoms. Confusion, poor coordination, unusual quietness, irritability, or bad decisions can mean the brain is being affected by temperature stress. A teammate who insists on continuing may not be able to judge their own condition clearly.
Tell a coach, teacher, parent, or other responsible adult early. Avoid rubbing frozen skin or using very hot water to warm someone, since damaged tissue can be harmed further. Avoid giving drinks to a person who is confused, unconscious, or having trouble swallowing.
Prevention is mostly planning. Check the forecast, bring water, schedule breaks, use shade when possible, wear dry clothing, and change plans when conditions become unsafe. Stopping early is a smart safety decision, not a failure.