4 things to watch out for in extreme heat

With the forecast predicting the hottest day of the year so far, the risk of heat-related illnesses is high.

A heat warning from Environment Canada is in effect, with a forecast high of 33 C Thursday and an overnight low approaching 20 C, providing little relief.

"Extreme heat affects everyone," Environment Canada warns. "The risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors."

• RELATED: Four places to cool off in Ottawa this week

Ottawa Public Health says that early heat waves can be especially dangerous because our bodies have yet to acclimate.

"It takes our bodies up to two weeks to adjust to hot weather," OPH says. "Take it easy until your body has adjusted by drinking more water & taking extra precautions."

Just two weeks ago, Ottawa was dealing with frost advisories. The low on May 18 was -3.1 C.

After a long winter and some colder weather earlier this spring, it's natural to want to get outside and enjoy hot, sunny weather, but there are ways to do so safely.

There are four major problems to watch out for in the hot, sunny weather: dehydration, heat exhaustion, heat stroke, and sunburn.

Here are the signs to look out for in yourself and others:

DEHYDRATION

Signs include:

• Thirst
• Dry skin
• Fatigue
• Light headedness
• Confusion
• Dry mouth
• Increased heart rate
• Increased breathing rate
• Less frequent urination

Dehydration is caused by the excessive loss of water and salts from the body due to illness or from prolonged exposure to heat. Severe dehydration can easily become a life-threatening condition for infants and the elderly.

It can be prevented by drinking fluids, such as water, juice or sports drinks, and by avoiding strenuous activity outdoors during intense sunlight hours of 10 a.m. to 3 p.m.

If you or someone you know is experiencing dehydration, move to a cool, dry place, lie down and rest, and drink plenty of fluids.

HEAT EXHAUSTION

Signs include:

• Headache
• Blurred vision
• Nausea or upset stomach
• Vomiting
• Sluggishness or fatigue
• Thirst
• Profuse sweating
• Moderate increase in body temperature

Heat exhaustion is a non-life-threatening condition caused by the excessive loss of water and salts from the body due to prolonged exposure to extreme heat. Continued exposure may lead to heat stroke, which is life-threatening.

Children and the elderly are most susceptible to heat exhaustion.

It can be prevented by taking frequent breaks from the heat. If you're outside, wear light-coloured clothes and a hat and avoid strenuous activity between the hours of 10 a.m. and 3 p.m. when the sun is the hottest. Drink plenty of fluids through the day, but avoid caffeine and alcohol.

If you or someone you know is experiencing signs of heat exhaustion, move to a cool, dry place and lie down, apply cool water to the skin and reapply often and have a fan. Keep hydrated and apply ice to areas such as the head, neck, armpits and groin.

HEAT STROKE

Signs include:

• Headache
• Dizziness
• Disorientation, agitation or confusion
• Sluggishness or fatigue
• Seizures
• Hot dry skin
• Increased body (inner) temperature
• Loss of consciousness
• Rapid heart beat
• Hallucinations

Heat stroke is a life-threatening condition. It occurs when the body cannot cool itself, usually by sweating and the body's core temperature becomes too high.

It can be prevented by taking frequent breaks from the heat. If you're outside, wear light-coloured clothes and a hat and avoid strenuous activity between the hours of 10 a.m. and 3 p.m. when the sun is the hottest. Drink plenty of fluids through the day, but avoid caffeine and alcohol.

If you or someone you know is experiencing signs of heat stroke, call 9-1-1 immediately and move to a cool, dry place and lie down. Apply cool water to the skin and reapply often and have a fan. Keep hydrated and apply ice to areas such as the head, neck, armpits and groin.

SUNBURN

Signs include:

• Skin is red, tender and warm to touch
• Blisters
• Severe reactions such as fever, chills, nausea or rash
• Fever or chills
• Peeling skin several days later

Sunburn occurs when skin cells that are not protected from direct exposure to the sun are burned. Damage can range from a mild burning sensation to severe blistering of the affected area, depending on how long unprotected skin is exposed.

Research shows that repeated overexposure to the sun may lead to various forms of cancer including melanoma.

Sunburns can be prevented by wearing sunscreen that protects against UVA and UVB rays with a sun protection factor (SPF) of 30 or more (do not use sunscreen on babies under 6 months of age), by wearing a wide-brimmed hat and tightly-woven clothing such as long-sleeved shirts and pants, and by avoiding sun exposure between 11 a.m. and 4 p.m., when the UV index is 3 or higher.

Sunburns can take several hours to a day before the full effects are apparent.

If you get a sunburn, treat it with cool compresses or by taking a cool bath to help minimize pain and swelling. You can apply aloe gel if needed; avoid use of creams or lotions that can hold heat inside the skin or contain numbing medication. Pain medications may help to reduce pain and swelling.

Severe sunburns require medical attention.