Effects of Wearing a Face Mask During Hot and Humid Temperatures

Masks are important to reduce the spread of COVID-19 and should be worn when adequate distance cannot be maintained, even when outdoors.

However, wearing a mask during hot temperatures can be dangerous, especially for some people who are at higher risk of heat-related illnesses. Heat illnesses, including heat stroke, heat exhaustion, heat fainting, heat edema (swelling of hands, feet and ankles), heat rash and heat cramps (muscle cramps) can affect you quickly and are mainly caused by over-exposure to heat or over-exertion in the heat.

During very hot weather, pay close attention and monitor any heat-related symptoms. Some symptoms include:

  • Dizziness or fainting
  • Nausea or vomiting
  • Headache
  • Rapid breathing and heartbeat
  • Extreme thirst (dry mouth or sticky saliva)
  • Decreased urination with unusually dark yellow urine

REMINDER: Children need additional attention and monitoring as they may not always recognize or be able to communicate the signs.

If you or someone is experiencing these effects, immediately move to a cooler area, loosen excess clothing, apply cold water to the skin or clothing to reduce the body temperature, fan the person and hydrate with water. Call 911 immediately if you notice that someone has a high body temperature and is either unconscious, confused or has stopped sweating.

Masking and precautions

During hot weather events, take the necessary precautions. If individuals must be outdoors or indoors where air conditioning is unavailable, plans should be in place to allow for adequate distancing to alleviate the need for masking.

Some precautions include:

  • Plan outdoor outings for the coolest times of the day (e.g., early morning or late evening).
  • Take frequent breaks in the shade or a cool environment.
  • Modify activities as needed.
  • When taking breaks to cool off, ensure you are able to adequately distance from others to allow you to remove your mask.
  • Stay hydrated by drinking plenty of cool liquids, especially water. Children may not feel thirsty but will still need to drink regularly.
  • Stay cool by dressing for the weather; wear a hat, loose fitting and light coloured clothing with breathable fabric.
  • Keep your home or environment cool; keep blinds and drapes closed, avoid using the oven, open windows at night to allow the space to cool.
  • Masks work in hot temperatures as long as they stay dry, keep a spare mask to change if your mask becomes wet.

Outdoor activities for childcare centres and schools

As per the Ministry of Education guidelines, masks must be worn when physical distancing cannot be maintained, even when outdoors. However, if a physical distance of 2m can be maintained outside, the mask can be removed.  

Here are recommendations to cope with the hot and humid temperatures:

  • Prepare activities that can be done while physically distancing outside (e.g., Simon Says or Freeze Dance).
  • Set up break stations (may use cones, flags, or other visual cues to maintain the 2m distance). Break stations should ideally be in a shaded area and have hand sanitizer to wash hands when removing or putting on mask.
  • Create small cohorts and have a mandatory rotation into the break area where the mask is removed to drink their water.
  • Practice low intensity physical activities preferably in the shade.
  • Avoid going outside between 10am and 2pm.
  • Ensure that children remain well hydrated. Each child should have their own individual bottle.
  • Bring 2 masks per child to allow change of mask if wet.
  • Use sprinklers or water activities to cool down. They must be used by one child at a time to ensure physical distancing. Reapply sunscreen afterwards.

Additional outdoor activities ideas that allows physical distancing and the removal of masks

To provide time without masks, plan outdoor activities that promote physical distancing:

Workers

For people undertaking physical exertion in heat, a mask can make the effort more difficult. Decreasing intensity/volume of work, more frequent rests, and more cooling and water breaks may be necessary. Discuss your health needs with your employer.

Please review the EOHU's Masks (Face Coverings) webpage for more details about masking.

HEAT-RELATED ILLNESSES
What to look for What to do
HEAT STROKE
  • High body temperature (103°F or higher)
  • Hot, red, dry, or damp skin
  • Fast, strong pulse
  • Headache
  • Dizziness
  • Nausea
  • Confusion
  • Losing consciousness (passing out)
  • Call 911 right away- heat stroke is a medical emergency
  • Move the person to a cooler place
  • Help lower the person's temperature with cool cloths or a cool bath
  • Do not give the person anything to drink

HEAT EXHAUSTION
  • Heavy Sweating
  • Cold, pale, and creamy skin
  • Fast, weak pulse
  • Nausea or vomiting
  • Muscle cramps
  • Tiredness or weakness
  • Dizziness
  • Headache
  • Fainting (passing out)
  • Move to a cool place
  • Loosen your clothes
  • Put cool, wet cloths on your body or take a cool bath
  • sip water
Get medical help right away if:
  • you are throwing up
  • your symptoms get worse
  • your symptoms last longer than 1 hour
HEAT CRAMPS
  • Heavy sweating during intense exercise
  • Muscle pain or spasms
  • Stop physical activity and move to a cool place
  • Drink water or a sports drink
  • Wait for cramps to go away bafore you do any more physical activity
Get medical help right away if:
  • Cramps last longer than 1 hour
  • You're on a low-sodium diet
  • You have heart problems
SUNBURN
  • Painful, red, and warm skin
  • Blisters on the skin
  • Stay out of the sun until your sunburn heals
  • Put cool cloths on sunburned areas or take a cool bath
  • Put moisturizing lotion on sunburned areas
  • Do not break blisters
HEAT RASH
  • Red clusters of small blisters that look like pimples on the skin (usually on the neck, chest, groin, or in elbow creases)
  • Stay in a cool dry place
  • Keep the rash dry
  • Use powder (like baby powder) to soothe the rash

Taken from the Centres for Disease Control and Prevention (CDC) - Warning Signs and Symptoms of Heat-Related Illness https://www.cdc.gov/disasters/extremeheat/warning.html

Eastern Ontatio Health Unit / Bureau de santé de l'Ontario