The Canadian summer: BBQs with friends, patio cocktails after work and the occasional sweltering heat wave that has the sweating masses desperately searching for clever ways to cool off.
Temperatures in the high thirties are oppressing parts of Eastern and central Canada this week, and earlier this month B.C. saw record summer temperatures during its own heat wave. But Canadians without air conditioning need not simply sweat and fret about the heat.
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There's a multitude of novel, and in some cases downright outlandish, tips and tricks to stay cool during heat spells. Many should probably be left to the nether reaches of the internet, but some are for real.
Here are a few lesser-known but effective ways to keep yourself and your home cool during the searing days of summer.
Hug a tree
Not all shade is created equal. If you can find a big, leafy tree on a hot day, then you’ve potentially hit the shade jackpot.
Shade cast by a tree is usually much cooler than cover coming from, for example, high rises in the downtown of a city.
The reason is that trees, being alive and sensitive to temperature just like humans, can cool themselves off.
During the day leaves transpirate. Essentially, it's tree sweat: water moving through a tree is evaporated into the atmosphere through the leaves. It helps to cool the tree down, among other things, and keeps the surrounding air slightly cooler as well.
"If you looked at a building with trees around it through an infrared camera, a camera that shows you the heat signatures of objects, you'd see that the trees are significantly cooler than the building," says Danielle Way, a plant physiologist and assistant professor at Western University in London, Ont.
Concrete, asphalt and stone absorb the sun's energy constantly, becoming progressively warmer as temperatures peak. The heat energy is radiated outwards, which is why you can often feel the heat of hot sidewalk or concrete building before you even touch it, Way says. Even in the shade you'll feel the building's heat, so it's unlikely to provide much cooling effect.
"Part of the balance of how you warm up or cool off is the temperature of the things around you," Way says. "If these objects are cold, then you emit energy towards them and feel that as a reduction in temperature. If they’re as warm or warmer, it won’t help much."
The caveat is that on really humid days the wet air can't take up any more moisture, so tree sweating slows down considerably.
Old-school 'swamp coolers'
Americans living in the hot, dry southwestern states have a way to keep your pad inhabitable that was figured out long before the advent of air conditioning. Nicknamed 'swamp coolers,' you can make your own if you have a window or two.
The principle is the same as leaves evaporating moisture to keep a tree's temperature down. In this case, the leaf is a wet bed sheet and the tree is your home or apartment.
'So opening windows at the top and opening the windows at the bottom will create a chimney effect — cool air being sucked in and hot air leaving through the top floor.'—James Drummond
You simply dampen a sheet with cold water and then hang it over an open window. Hot air passing through evaporates the water in the sheet "creating a cooling airstream," says James Drummond, a professor at atmospheric science and Canadian Research Chair in remote sounding of atmospheres at Dalhousie University in Halifax.
If you live in a multi-storey dwelling, you can take your swamp-cooler to the next level by strategically selecting the best windows to keep open. Open windows on the top floor that have the most sun exposure, and open bottom story windows with the least exposure, then place the sheet over the coolest window.
"The upper floor of your house is going to be hotter than the lower floors because hot air rises. So opening windows at the top and opening the windows at the bottom will create a chimney effect — cool air being sucked in and hot air leaving through the top floor," says Drummond.
"The sheet may simply add to the cooling effect of the air stream," he says.
Unfortunately, this is another technique that suffers when it's really humid outside. More humidity means less evaporation and therefore a lower cooling effect from the dampened sheet.
Cooling down your body using ice sounds like a no-brainer, but the key to getting the most out of a bag of cubes is location, location, location.
One of the many ways the human body reduces its internal temperature is to send blood to the skin. It's why we become flushed when exercising.
Blood near the surface of your skin can transfer heat into the surrounding atmosphere, and it circulates back a bit cooler than it was before, says Stephen Cheung, Canada Research Chair in environmental ergonomics at Brock University in St. Catharines, Ont.
"The blood vessels open near the skin and that allows us to cool down deeper tissues throughout the body," he says.
The head, neck and wrists — all parts of the body with lots of blood vessels close to the skin's surface — are particularly good places for the blood to let off steam.
Cheung points out that on really hot days, the outside temperature can encroach on the body's normal internal temperature of 37 degrees Celsius, and therefore the transfer of heat is minimal. But if you take a few ice cubes and keep them on pulse points in your neck and wrists for a few minutes, the temperature difference of the ice and your blood will amplify the transfer of heat.
Rice in a tube sock
An alternative to ice, which can be uncomfortable on skin or melt away too quickly, is a clean tube sock stuffed with plain, dry white rice.
Fill up the sock, tie it at one end, and throw it in the freezer for a few hours. It's an ice pack on a budget, and you don't have to worry about melting and leaks.
While rice itself doesn't have any "magical thermal properties," says Cheung, "rice is useful because, even when cold or frozen, it's pretty easy to mould it to fit your body."
A rice-filled sock can be particularly helpful if you're trying to sleep during a hot, humid night and need some extra help cooling off.
"It's essentially identical to using a bag of frozen peas," Cheung says, "only with the benefit that a sock full of rice isn't going to get all mushy once it thaws."
You can also warm the rice sock up in the microwave – being careful not to zap it for too long – to get an instant hot pack once the heat wave has passed.
Watch what you eat
As it turns out, you might want to rethink that 16-ounce sirloin paired with a couple of tall, frosty beers at your next weekend BBQ. What you eat, and how much, has an impact how hot you feel.
Heat generated during digestion is one of the key sources of internal heat, says Ira Jacobs, professor and dean of the faculty of kinesiology and physical education at the University of Toronto.
"Proteins and some carbohydrates are associated with higher metabolic heat production for every gram of food that's digested," says Jacobs. "Proteins are complex molecules that simply take longer for the body to digest properly."
So that big steak and the carbohydrates in the beer are going to put your stomach into overdrive. Plus, the alcohol in the brewskis acts as a diuretic, robbing your body of moisture that it needs for cooling.
Cheung points out that it's better to munch on several smaller snacks over the course of the day, rather than two or three large protein- and carbohydrate-heavy meals. More food requires more metabolic energy to break it down, increasing how hot we feel as a result of the meal.
Spice things up
If you're a daredevil who can handle feeling a bit hotter before cooling down, consider adding a few hot chilies to your next summer dish.
Diners in the southern climes figured out a long time ago that capsaicin, the molecule responsible for 'heat' in hot chilies, could be your best friend on hot days.
Capsaicin binds to pain receptors in your mouth and creates a sensation of heat without actually increasing the temperature. Your brain is tricked into thinking your mouth is heating up, and the body starts sweating in response, says Paul Bosland, a professor of horticulture at New Mexico State University, where he is known as the 'chileman.'
As the sweat evaporates, you feel cooler.
So next time you're downing a Szechwan hot pot on a sidewalk patio, don't wipe that sweat from your brow. Let it flow and feel the sweet, sweet cooling sensation.