A record-breaking heat wave that enveloped British Columbia over the last five days is believed to be linked to hundreds of deaths and counting.
The B.C. Coroners Service said Wednesday it has tallied 486 sudden deaths across the province from Friday to Tuesday.
Over a normal five-day period, 165 people die a sudden death, chief coroner Lisa Lapointe said. Many of the dead coroners are finding are those who live alone in unventilated homes.
But it鈥檚 not just old or infirm that are hit by heat death.
鈥淓ven young people die in the heat: football players, long-distance runners,鈥 said the B.C. Centre for Disease Control鈥檚 Dr. Tom Kosatsky, who as medical director of environmental health, is in charge of everything from health inspectors and food safety to the knock-on effects of climate change. As he puts it: 鈥淓verything the environment can do to hurt you.鈥
Heat is on his radar. It鈥檚 already the No. 1 cause of weather-related death in the United States. In Canada, where climate change is warming some areas up to four times faster than the global average, many are just coming to grips with its deadly potential.
鈥淭his, frankly, took many of us off guard,鈥 Lapointe said Wednesday. 鈥淚 think it鈥檚 very likely many of us misunderstood the extreme risk.鈥
What does too much heat do to the human body? In a word: hyperthermia.
How heat kills
Death by heat starts slow. Too much time under the sun or stuck in a hot apartment has made you tired, and at times, dizzy.
If you are an outdoor worker 鈥 a firefighter, a farmer or a construction worker 鈥 you face bigger risks when heat waves hit. Genetics matter less than age and the ability to get out of a wheelchair or bed, Kosatsky said.
Those over 65, who are overweight or have pre-existing medical conditions, like heart disease or high blood pressure, tend to have a harder time avoiding the worst heat illnesses, he said.
Medication, such as diuretics, or recreational drugs like cocaine and amphetamines, can interfere with your body鈥檚 ability to compensate for the heat. Alcohol only accelerates dehydration. Alone under punishing heat and with little water, those factors set the stage for a devastating spiral.
Heat stress
As you begin the march toward hyperthermia, you might have a headache, feel tired or dizzy.
When heat stress hits you, you know you鈥檙e thirsty. You need water.
Heat fatigue
Your palms sweat. You don鈥檛 want to do anything.
You got too much sun 鈥 a heat rash has flared up in your armpits and elbow creases.
Or maybe you forgot to put on sunscreen at the beach. You are burned.
Heat cramps
The mercury rises, your dehydration deepens. Painful muscle spasms come and go due to a lack of electrolytes.
All that sweating has depleted your body of vital minerals like potassium, sodium and calcium 鈥 Gatorade, basically 鈥 that help fire the chemical reactions in your muscles.
Anyone working hard in hot conditions is especially vulnerable, and heat cramps are known to hit hikers and people working under the sun.
鈥淚t can occur any time you鈥檙e dehydrated,鈥 said Kosatsky. 鈥淏ut it鈥檚 much more likely to occur in the heat.鈥
At this point, finding a cool place and restoring fluid with electrolytes can bring a person back. But if you鈥檙e stuck in an apartment or caught under the sun, things can turn quickly.
鈥淧eople can go one way or another,鈥 said Kosatsky.
Heat syncope
The other way? Heat syncope.
You speak in broken words, unable to string together full thoughts.
A lack of water has reduced the volume of blood in your body. As the blood thickens, your body fights to keep your temperature down by pushing blood to the skin to induce sweating.
An adult can lose a litre of water an hour this way; if they don鈥檛 drink more, the blood continues to thicken in a vicious cycle, drawing blood from the brain and sending your head spinning in dizziness.
You faint.
Heat exhaustion
Your heart, your body鈥檚 biological pump, is pounding to drive blood toward the skin 鈥 to sweat.
You have a fever. You鈥檙e irritable. Sweat pours out of your body as it works to stay in the range where human life is possible. Dizziness has escalated to disorientation. You are confused, can鈥檛 see straight and want to vomit.
You need cold compresses, an ice-cold shower or a jump in the lake to regulate your body temperature. You need water.
鈥淧aradoxically, they deny thirst, they get so far along they don鈥檛 feel thirsty anymore,鈥 said Kosatsky.
Heat stroke
Your sweat runs dry, spiking your fever to over 41 C.
Your body wants to move into damage control, it wants to move blood to the organs keeping you alive. But without enough of it to go around, your blood pressure plummets, the vital fluid now a thick sludge.
As blood retreats from your organs, blood vessels begin to collapse.
You start to hallucinate.
Then your organs shut down 鈥 maybe the kidneys first.
The mud-thick blood now clogs in your blood vessels, perhaps triggering a stroke.
Your heart fails.
鈥淭hat鈥檚 lethal,鈥 said Kosatsky.
How many more dead
Dying of heat is never a straight line. Medical experts usually pay attention to heat cramps, heat exhaustion and heat stroke.
鈥淭here鈥檚 a trigger temperature,鈥 said Michael Brauer, a researcher who studies the health effects of extreme heat at the University of B.C.鈥檚 School of Population and Public Health.
鈥淥nce you get beyond that, things can go up after that exponentially.鈥
Experts say there鈥檚 a three- to four-day documented lag time between death and a heat wave鈥檚 peak.
鈥淭he worst is not over,鈥 said Armel Castellan, a warning preparedness meteorologist with Environment Canada.
The worst is also hard to measure. Deaths are expected to rise beyond the tragic cases of seniors left alone in an apartment without air conditioning.
Brauer said researchers have documented spikes in everything from suicides and homicides to workplace accidents and drownings as more people flock to the water.
Most of those haven鈥檛 been traditionally tallied by agencies like the B.C. Coroners Service, which relies on a medical model to determine the cause of death. The heat wave and the decades of anthropogenic climate change that 鈥渄efinitely has its fingerprints on this event,鈥 according to Castellan, don鈥檛 appear on the death certificate.
鈥淲e know every year in the world, there are like four million deaths linked to air pollution,鈥 said Brauer,
鈥淚t鈥檚 the same issue here. You can just hear the sirens at night. There are a lot of people dying. This is due to the heat. But we just don鈥檛 put that on death certificates.鈥
In the same way a Royal Society of Canada task force recently found evidence that roughly 6,000 COVID-19 deaths 鈥渕ay have been missed鈥 across Canada, it will likely take months of research to determine just how many people died because of heat.
Whatever the results of the B.C. Coroners Service investigation, Brauer said he hopes this heat wave will reinforce for British Columbians just how deadly heat can be.
鈥淲e鈥檝e been saying this. We鈥檝e known this for decades,鈥 he said. 鈥淭he depressing thing is the train has already left the station鈥. It鈥檚 now about adaptation. So that in the next heat event, how do we avoid what we鈥檙e seeing now?鈥