How to stay safe in the summer heat

Jul 28, 2023

So far Summer 2023 has been one for the record books, breaking temperature records worldwide, while in Ontario a record-breaking wildfire season has sent air quality plummeting across the province and much of eastern Canada and the US for much of June and July. 


Extreme heat is a health risk. It’s important to plan ahead and take precautions so you stay safe and healthy in the heat. 

Recognize the signs of heat-related illness

Heat-related illness includes heat stroke, heat exhaustion, heat fainting, heat rash and muscle cramps. The signs of heat-related illness to watch out for include:

  • Dizziness or fainting
  • Nausea or vomiting
  • Headache
  • Rapid breathing and heartbeat
  • Extreme thirst
  • Decreased urination with unusually dark yellow urine.

If you experience any of these symptoms, move to a cool place and drink liquids. Cool water is best, not ice cold.

Heatstroke is a medical emergency

Heat stroke is a medical emergency. If you or someone you are with has a high body temperature, along with one or a combination of the following symptoms confusion, unconsciousness or has stopped sweating, call 911 immediately.

While you wait for help, cool the person right away by moving them to a cool or shady place, taking off excess clothing, and/or applying cool water to large areas of their skin or clothing.

Plan ways to stay cool in advance

The best way to avoid heat-related illness is to stay cool and hydrated by planning ahead:

  • Check the forecast for your area regularly so you can prepare for hot weather in advance.
  • Make sure your air conditioning, ceiling fans or other fans work properly.
  • If you don’t have air conditioning at home, plan ahead and find an air-conditioned spot nearby where you can cool off for a few hours on a hot day, like a mall or an air-conditioned coffee shop or public library. You can also check with your local public health unit about public cooling centres in your area.
  • Wear loose, light-coloured, breathable clothing, and wear a wide-brimmed hat when outdoors to keep the sun off your face and neck. You may also want to use a parasol or an umbrella to avoid the sun.
  • Plan your meals to avoid using your oven or stove, if possible, particularly if you don’t have air conditioning.
  • Keep your drapes and/or blinds closed to block out the sun during the day.
  • Schedule outside activities, like yard work or exercise for the cooler parts of the day (morning or evening).
  • Do not leave people or pets in a parked car.
  • Check with your doctor or pharmacist about any medications that may increase your risk of heat-related illnesses or dehydration, and
  • Drink plenty of cool water even before you feel thirsty.

Drink plenty of fluids

Dehydration occurs when your body loses more fluid than you take in. Dehydration can occur surprisingly quickly, especially in hot, humid weather, so don’t wait until you are thirsty to take a drink. It’s also a good idea to limit the amount of caffeinated and alcoholic beverages you drink in hot weather. Caffeine and alcohol are diuretics, which means they make you pee more frequently. This increases the speed at which you lose body fluid and salt, both of which are required for your body to function.

Infants and toddlers, the elderly and people with chronic illnesses like cystic fibrosis and diabetes, are at particular risk of dehydration. Outside workers and athletes also have a higher risk of dehydration and heat-related illness on hot days.

Avoid sugary drinks, caffeine and alcohol on hot days

Dr. Michael Sarin, a diabetes educator with Diabetes Canada, recommends that people exercising or performing vigorous activities outdoors on hot and humid days drink at least eight ounces (about 250 ml) of fluids every 20 minutes: 

On extremely hot and humid days drink plenty of fluids 30 minutes before exercise, and then drink at least eight ounces every 20 minutes. After exercise, drink enough to feel as if you have more than quenched your thirst. Avoid sugary drinks and full-strength fruit juices, caffeinated beverages and alcohol, which can all increase dehydration.

Recognize the signs of dehydration

Symptoms of dehydration include feeling thirsty, peeing less often than usual, dark yellow urine, feeling tired and feeling dizzy or light-headed. If you start to feel dehydrated, have a cool drink of water or diluted fruit juice.

People with cystic fibrosis lose more salt from their sweat than people without cystic fibrosis and they are less likely to feel thirsty. It’s very important if you have cystic fibrosis (CF) or you are caring for a child with CF that you have plenty of drinks and a salty snack on hand for hot days. Older people also have a lower thirst drive and should make a point to drink more fluids, particularly on hot days.

Check on elderly family, friends and neighbours

Finally, make a plan to check on your older family members, friends and neighbours during heat events – particularly if they live alone. The older we get, the more trouble our bodies have regulating our internal temperature. Older people are also more likely to have a chronic health condition, like cardiovascular disease, diabetes or lung disease. This is why seniors are more susceptible to the heat, and heat-related illnesses are more dangerous and more likely to be fatal for seniors.

Cool off in air-conditioned spaces or by taking a cool shower

If you or someone you are with does start to feel overheated, the best thing to do is find someplace air-conditioned. If air-conditioning isn’t available, a cool shower, spraying yourself with water, running an ice cube over your skin, or placing an ice pack on the back of your neck can help reduce your body temperature.

Extreme heat is the number one cause of weather-related death in Canada, so plan ahead, stay out of the sun, drink plenty of water, check on your elders and stay safe this summer.

To learn more about how to cope with the summer heat, please visit:

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For general questions:

Sarah Wood
Executive Director


315 Front St. West, 5th Floor
Toronto, ON
M7A 0B8

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