A blazing hot sun was beating down on Hamilton. Chris Milburn, who grew up in the Maritimes and was living in the city attending school, had never adjusted to running in the summer weather of Steeltown, which left him struggling to reach the finish line of a 10K race.
"I nearly died," says Mr. Milburn, a 40-year-old emergency room doctor in Sydney, N.S. "I probably didn't hydrate well enough, I didn't know how to try to cool myself down when there was water or ice available. I was just used to blasting through a run."
The lessons of that race years ago taught Mr. Milburn a very valuable lesson, one that runners should heed in the coming months.
"I've always been a little more respectful of the heat since then," he says.
With Environment Canada predicting above-average temperatures this summer, runners will need to adjust their training accordingly. Otherwise, they risk suffering the kind of illness and injury that could sideline them come race day. And while making those adjustments is largely a matter of common sense, it is important to know the signs and symptoms of the toll that rising mercury can take.
"We think, statistically at least, the character, the personality of the summer, is going to be warmer than normal, and that's certainly something we haven't seen in the last two years," says Dave Phillips, senior climatologist at Environment Canada. This is going to be a season of heat, haze and humidity, a combination that can hurt runners, Mr. Phillips says. "It leads to stress and overheating," he says, adding that hot, humid days can easily lead to heat stroke depending on a person's health and age.
Joanne Merrett, who has completed 10 marathons since she took up running six years ago, has learned to change up her training when it's hot outside.
"Sometimes I will run earlier in the day, depending on the humidity," says the 43-year-old from Ottawa. "If it's just to the point where you can't do it, I'll go for a bike ride instead or go to the gym and do it on the treadmill in the air conditioning. There is a cutoff where it's just not sensible to be out there."
Runners with a "no pain, no gain" philosophy may not know when they've reached that cutoff point, says Samuel Gutman, medical director of the BMO Vancouver Marathon.
"Distance runners are not always ones to listen to their body, because if they did they wouldn't do it," he says. "There's a certain amount of discomfort and stress that you have to put your body through repeatedly in order to get to the distance and beyond." But things like dizziness, headache and nausea are clear signs runners are on their way to heat stroke and need to stop, Dr. Gutman says.
Training in the early morning or late evening, wearing breathable clothing and a hat and running with liquid is advisable, he says. "Reducing the distance isn't even that important, it's just staying well hydrated and going slower."
Jonathan Hooper, an Ottawa doctor involved with the Ottawa Marathon, recommends drinking between 400 and 800 millilitres of water an hour to prevent dehydration.
It is also a good idea for runners to gradually get used to running in the heat. The more time you have to acclimatize to hot weather before race day, the better.
"Your sweat glands are like muscles in the sense that they become more fit and more ready to deal with it, so there is definitely an advantage to starting [training]early," Dr. Gutman says.
Andrew Goss, a 40-year-old student in Kingston, Ont., has suffered through several races because of the heat, he says. At this year's Ottawa Marathon, he started pouring water over his head from the first aid station on.
"If you get dehydrated, there's not much you can do once you realize that. You have to stay on top of it right from the beginning of the race," he says.
And no matter how pumped up a runner might be on race day, if it's a scorcher, it's best to accept you're not going to be setting any records.
"If you've been training for 16 weeks and then it happens to be 35 degrees, well, guess what, you're not doing your personal best today, so don't try," Dr. Gutman says.