Is it sunburn or heat exhaustion?

Sunburn is skin damage caused by ultraviolet rays. Heat exhaustion is the body's response to losing too much water and salt, usually through heavy sweating. A day outdoors can involve both UV exposure and heat, although the itinerary rarely lists them separately. Fatigue alone does not distinguish between them.14

ProblemSymptoms to look for
SunburnWarm, tender or painful skin, often pink or red. More severe burns can cause swelling or blisters. Tiredness, headache, fever and nausea can occur.
Heat exhaustionHeavy sweating, thirst, weakness, dizziness, headache, nausea, raised body temperature or less urine than usual.
Heat strokeConfusion, slurred speech, seizures, loss of consciousness or very high body temperature. Skin can be dry or heavily sweaty.
14

When does tiredness need urgent help?

Call 911 or your local emergency number for confusion, slurred speech, seizures, loss of consciousness or suspected heat stroke. Move the person to a cool or shaded place and cool them with wet cloths or water while help is coming. Stay with them. Do not give anything by mouth if they are vomiting or unconscious.34

Seek prompt medical evaluation for signs of heat exhaustion rather than trying to sleep them off. See a doctor for dehydration, a sunburn with fever above 101°F (38.3°C), serious burns covering more than 15% of your body, extreme pain lasting more than two days, or pus or red streaks around blisters. A whole back, a whole leg or both arms can represent a substantial burned area.14

What should you do now?

  1. 1Get out of the sun and into a cool place. Stop exercise or strenuous activity if you feel overheated.
  2. 2Cool the burned skin with a cool bath, shower or damp cloth. If heat illness is suspected, use cool wet cloths and a fan to help lower body temperature.
  3. 3Sip water if you are alert and not vomiting. Heat illness can involve salt loss as well as water loss; a sports drink is another option.
  4. 4Apply a moisturizer or aloe vera gel to soothe the sunburned skin. These are measures for skin discomfort, not treatment for heat stroke.
  5. 5Leave blisters intact and let peeling skin come away on its own. Get medical help for extremely large blisters.
23

How long will you feel tired?

There is no fixed recovery time for sunburn related fatigue. Mild sunburn usually heals within a few days to a week, while blistering burns can take weeks. Skin pain often peaks around 24 hours after exposure. Those skin healing times are not a countdown for tiredness: worsening exhaustion or new symptoms needs attention, particularly after heat exposure.23

Avoid another round while you recover

Stay out of the sun until the burn heals. For future outings, use shade, covering clothing and broad spectrum sunscreen. The sun's rays reach you on cloudy days, despite clouds looking like they have taken over the sky. Limit time in the heat and drink fluids. Children, older adults and people taking certain medicines are more vulnerable to heat illness; some medicines also increase sensitivity to sunlight.15

Where this answer comes from

  1. 1Preventing Sunburn | Skin Cancercdc.gov
  2. 2Sunburn: Symptoms & Treatmentmy.clevelandclinic.org
  3. 3Heat emergencies: MedlinePlus Medical Encyclopediamedlineplus.gov
  4. 4Heat-related Illnesses | Heatcdc.gov
  5. 5Heat Illness: MedlinePlusmedlineplus.gov