Heat exhaustion and heat stroke symptoms
Heat exhaustion can cause heavy sweating, weakness, headache and nausea. Move to a cool place and cool the body. Confusion, collapse or seizures in the heat can signal heat stroke even when skin is sweaty: call 911 and begin rapid cooling. Do not give fluids to someone confused or unable to swallow.
Also called: heat stroke signs · overheating · heat illness
Medically reviewed by Dr. Ikechukwu Ogbu, MD
MD · Board-Certified, Internal Medicine · Last reviewed
Seek urgent care or the ER if you have:
- Symptoms that are sudden, severe, or rapidly worsening
- High fever (over 103°F / 39.4°C) that doesn't respond to treatment
- Chest pain, trouble breathing, fainting, or confusion
- Signs of dehydration — dizziness, dark urine, unable to keep fluids down
- Symptoms in someone who is pregnant, immunocompromised, or over 65
Conditions related to heat exhaustion and heat stroke symptoms
These conditions may be associated with this topic. They are not a diagnosis or a ranked list of causes; follow the urgent-care guidance below.
Nausea and vomiting
Nausea and vomiting is related to this topic. Its presence here does not establish the cause of heat exhaustion and heat stroke symptoms or that acute symptoms can be treated online.
When to see a clinician
- Symptoms have lasted more than a few days without improving, or keep coming back
- You're not sure if this needs antibiotics, prescription treatment, or watchful waiting
- You have a chronic condition (diabetes, heart disease, immunocompromised) that raises the stakes
- You want guidance on whether your symptoms need an online evaluation or in-person care