Heat-related illnesses and sunburns - Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP): data blog:

Types of sun- and heat-related injuries and illnesses

Heat-related illnesses are usually caused by exposure to unusual or lengthened amounts of heat and humidity without adequate fluid intake or relief. They can come on quickly and have serious consequences such as long-term health problems or even death. Overexposure to UV radiation can cause sunburns, skin aging, eye cataracts and skin cancer. Some of the most common types of heat-related illnesses and injuries are^{Footnote 3Footnote 11Footnote 12Footnote 13Footnote 14}:

• Heat stroke: This heat-related illness is the most severe. It is caused by a rapid increase in body temperature and problems regulating the sweating mechanisms.
• Heat exhaustion: A disproportionate loss of water and salt caused by exposure to heat (usually due to heavy sweating). People affected may experience a fast and weak pulse rate, dizziness, nausea and muscle cramps.
• Heat syncope: A fainting episode that is caused by low blood pressure when heat causes the dilation of blood vessels.
• Heat cramps: Painful muscle spasms caused by a salt imbalance due to sweating.
• Heat rashes: Skin irritation usually caused by an inflammation of clogged sweat glands accompanied by red spots.
• Sunburns: This injury is characterized by red, painful and unusually warm skin after overexposure to UV radiation. More severe cases can be accompanied by swelling of the skin, blisters and fever.

Emergency Departments (CHIRPP database)

Between April 1, 2011, and January 12, 2023, there were 734 sun and heat-related cases^{Footnote +} reported in CHIRPP, representing 39.7 cases per 100 000 CHIRPP records. Males accounted for 57.1% of cases (n = 419). Individuals aged 19 years and younger represented 71.8% of sun- and heat-related cases (n = 527) (Table 1).

Type of Injury

As presented in Table 2, sunburns were the most common type of injury, representing 55.4% of all cases (n = 407). The most frequent body parts affected by sunburn injuries were the shoulders (27.0%), followed by the face (25.1%) and the back (13.5%). Over a quarter of all cases (27.5%; n = 202) were diagnosed with a form of heat-related stress or systemic overexertion, ranking this health outcome as the second most common type of injury (Table 2). Nine percent of cases (9.0%; n = 66) were diagnosed with other injuries (e.g., open wound, concussion, dislocation).

When do sun- and heat-related illnesses and injuries happen?

Sun- and heat-related illnesses and injuries generally occur during the warmer months. More specifically, 90.3% of sun- and heat-related cases took place during the months of May to August.

What were people doing?

Where reported, Table 3 shows the event circumstances associated with the two most common types of injuries noted above, namely sunburns and heat stress/systemic overexertion. With respect to sunburns, the most common circumstances were sport participation (33.1%; n = 84), followed by playing outdoors (23.2%; n = 59) and sitting, lying, sleeping and suntanning (13.8%; n = 35)(Table 3). Similar to sunburn injuries, the most common circumstances associated with heat stress/systemic overexertion cases were sport participation (33.1%; n = 56), followed by playing outdoors (14.8%; n = 25) and working (14.8%; n = 25).

A closer look at the circumstances:

• Sunburns
  • Sports and recreational activities: Among the sunburn cases, the four most frequent sports and activities were swimming (53.6%), non-motorized boating (9.5%), water slides (4.8%), and fishing (4.8%).
  • Leisure activities: This category contained an array of activities like woodworking, watching a sports game and going to an outdoor music festival.
• Heat stress/systemic overexertion
  • Sports and recreational activities: Among the heat stress/overexertion cases, the three most frequent sports and activities were swimming (17.9%), water slides (14.3%) and soccer (10.7%).
  • Working: Various occupations were reported, including firefighting, landscaping, construction work, paramedic work, and lifeguarding.
  • In car or vehicle: All 13 cases in this category occurred among children 4 years of age or younger, who were inadvertently left in or locked in a car.

Where do heat-related illnesses and sunburns happen?

Where reported, Table 4 presents the locations concerning the two most common types of sun- and heat-related injuries (sunburns and heat stress/systemic overexertion). Among sunburn injuries, the most frequently reported locations were natural bodies of water, such as a beach, lake, or river (35.8%; n =78), residential settings (23.9%; n = 52), and public parks (12.4%; n = 27). With respect to heat stress/systemic overexertion cases, the most frequently reported locations were public spaces, including sidewalks, streets and parking lots (17.3%; n =23), aquatic recreation facilities (12.8%; n = 17), and residential settings (12.8%; n = 17).

What level of in-hospital treatment was needed?

Table 5 shows the level of in-hospital treatment for all reported sun- and heat-related cases. Out of the 734 sun- and heat-related cases, 60.0% required medical treatment in the ED. Additionally, 20 patients (2.7%) were admitted to the hospital, of which, just over half (55.0%) were among males, a quarter (25.0%) were among adults aged 65 years or older and 20.0% were among infants younger than 2 years of age.

Sample narratives

Sample narratives of the sun- and heat-related cases entered in CHIRPP charts are listed below. These include:

• Sunburn
  • Touch football. Put on sunscreen in the morning but was outside all day. Sunburn to face and arms.
  • Playing outside for long period – no sunscreen or hat – has sunburn to face.
  • Homeless, outside without shirt for most of last 2 days, sunburned shoulders.
  • Fell asleep in the sun.
  • Got sunburnt while on vacation. Sunscreen was being used.
  • Watching baseball game, got sunburn on leg.
• Heat stress/systemic overexertion
  • Playing at water-park - outside for 5 hours - 23 degrees weather.
  • Friend found patient sitting in apartment, apartment too hot.
  • Attending soccer camp, 29 degree Celsius temperature, running a lot, complains of heat exhaustion.
  • Landscaping for 48 hours. Did not hydrate well while outside.
  • Patient was accidentally locked in family car, in car seat for about 15 mins with all windows closed in the sunlight (overheated).
  • While at summer school, felt nausea and dizziness. Air conditioning in school not working.
  • Patient was roofing for couple of hours in the sun and developed headache, nausea and dizziness.

Prevention

It is important to keep in mind that too much sun or heat can be harmful. Here are a few general, sun- and heat-related safety tips:

• It is important to protect yourself from UV rays all year round – even during the winter, on cloudy days or when you are in the water.
• Apply sunscreen with an SPF of at least 30, wear loose-fitting, light-coloured clothing and a wide brimmed hat made of breathable fabrics, and use sunglasses that protect from both UVA and UVB rays.
• Never leave people or pets alone in a parked vehicle, even if a window is cracked.
• Reduce the time you spend in the sun and heat. If you can, reschedule outdoor activity to a cooler part of the day or another day.
• Drink plenty of liquids before you feel thirsty to stay hydrated and avoid heat-related illnesses – water is best.
• Spend a few hours in a cool place. It could be a tree-shaded area, swimming facility or an air-conditioned spot.
• Some medications and illnesses (e.g., cardiac, respiratory and psychiatric conditions) may make you more vulnerable to extreme heat. Ask your healthcare provider if you are at risk.

For more information on extreme heat and sun safety tips, you can visit the following websites:

• Sun safety basics -Canada.ca
• Sun safety tips for parents - Canada.ca
• Extreme heat events: how to protect yourself - Canada.ca
• It's much too hot! Protect yourself from extreme heat - Canada.ca
• Keep children cool! Protect your child from extreme heat - Canada.ca
• You're active in the heat. You're at risk! Protect yourself from extreme heat - Canada.ca
• Three ways to protect you and your loved ones during an extreme heat event - Canada.ca
• Staying healthy in the heat infographic - Canada.ca
• Staying healthy in the heat video - Canada.ca
• Health and Safety: Hot Work Environment - Canada.ca