Many things can affect how your body responds to a symptom and what kind of care you may need. These include:

• Your age. Babies and older adults tend to get sicker quicker.
• Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
• Medicines you take. Certain medicines, herbal remedies, and supplements can cause symptoms or make them worse.
• Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
• Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.

Exposure to a hot environment can cause many problems. Problems can be mild, like a heat rash, swelling in the hands or feet, or heat cramps. But heat can also lead to more dangerous situations like confusion, seizures, or passing out.

Symptoms of heat exhaustion may include:

• Weakness, dizziness, or fatigue.
• Headache.
• Nausea.
• Skin that is pale, cool, and moist. 
• Raised body temperature.

Heat exhaustion may occur when you are sweating a lot (typically, while working or exercising in hot weather) and do not drink enough to replace the fluids you've lost.

Symptoms of difficulty breathing can range from mild to severe. For example:

• You may feel a little out of breath but still be able to talk (mild difficulty breathing), or you may be so out of breath that you cannot talk at all (severe difficulty breathing).
• It may be getting hard to breathe with activity (mild difficulty breathing), or you may have to work very hard to breathe even when you’re at rest (severe difficulty breathing).

Severe trouble breathing means:

• You cannot talk at all.
• You have to work very hard to breathe.
• You feel like you can't get enough air.
• You do not feel alert or cannot think clearly.

Moderate trouble breathing means:

• It's hard to talk in full sentences.
• It's hard to breathe with activity.

Mild trouble breathing means:

• You feel a little out of breath but can still talk.
• It's becoming hard to breathe with activity.

Severe trouble breathing means:

• The child cannot eat or talk because he or she is breathing so hard.
• The child's nostrils are flaring and the belly is moving in and out with every breath.
• The child seems to be tiring out.
• The child seems very sleepy or confused.

Moderate trouble breathing means:

• The child is breathing a lot faster than usual.
• The child has to take breaks from eating or talking to breathe.
• The nostrils flare or the belly moves in and out at times when the child breathes.

Mild trouble breathing means:

• The child is breathing a little faster than usual.
• The child seems a little out of breath but can still eat or talk.

If you have symptoms of heat exhaustion, try the following first aid to cool off:

• Stop what you are doing and rest.
• Get out of the sun and heat.
• Remove any extra clothing.
• Spray or mist the body with cool water.
• Use a fan if one is available.
• Drink plenty of cool water or rehydration drinks.

Signs that heat exhaustion is becoming severe include:

• Blurred vision.
• Fast breathing and fast heart rate (more than 120 beats per minute when you are at rest).
• Severe belly cramps.
• Very heavy sweating (sweat is pouring off you and soaking through your clothes).

Some other symptoms of heat-related illness include:

• Muscle twitching or spasms.
• Muscles that feel hard and lumpy.
• Sore muscles.

Symptoms of heatstroke may include:

• Feeling or acting very confused, restless, or anxious.
• Trouble breathing.
• Sweating heavily, or not sweating at all (sweating may have stopped).
• Skin that is red, hot, and dry, even in the armpits.
• Passing out.
• Seizure.
• Nausea and vomiting.

Heatstroke occurs when the body can't control its own temperature and body temperature continues to rise.