Experts offer advice on performing endurance events in excessive heat
As the Tour de France gets underway in high temperatures, these tips can help amateur athletes excel in dangerous temperatures.
LONDON — As pro cycling teams have been preparing for the start of the Tour De France on Saturday, extreme heat has rolled across Western Europe, smashing temperature records, cracking infrastructure and taking a toll on the population.
However, these elite athletes have followed intensive programs as they prepare to compete in one of the toughest endurance events, the 3,000-kilometer, 21-day bicycle race.
The 113th edition of the world’s premier road cycling race begins on July 4 with a time trial stage at the French border with Spain, in the center of Barcelona, before returning to France. Across the route, temperatures have spiked to dangerous levels, with Barcelona reaching 41°C (106°F) and France reporting its hottest day ever on June 23.
Training to race in extreme heat has become a critical part of riders’ preparations, said Nathan Haas, a former pro cyclist who raced the Tour de France in 2015 and now head coach for Team EF Coaching, part of the Boston-based cycling team competing in this year’s Tour de France. “Pretty exciting new science” has helped today’s riders perform in extreme heat, he said.
Recreational cyclists and amateur athletes stepping out this summer to ride in high temperatures can take valuable lessons from what these elite athletes do, Haas said, and heed vital warnings.
Northeastern Global News spoke to several experts about performing efficiently and safely in the heat, including Mike McKenny, Northeastern University’s director of Athletic Training, and Rui Li, director of the Exercise Science Program at the Bouvé College of Health Sciences.
Cool down as you warm up
Staying cool as you warm up might sound like sending your body mixed messages, Haas said, but it works. Elite teams employ a combination of methods to lower body temperature before hot races.
“They’re wearing cooling vests and pants. They have all their main artery points (strapped) with very deep freeze ice packs to try and lower their core body temperature anywhere between one to two degrees,” said McKenny, who spent the first three years of his career working on USA cycling events.
Studies have shown that pre-cooling can significantly increase the time elite athletes can ride before experiencing exhaustion. Recreational athletes benefit from a similar effect, Li said.
“You can apply some ice packs or even have an ice bath to lower your core body temperature” before you start cycling, she said.
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Rehydrate with salty slushies
Before and after the race, Tour de France cyclists take slushy drinks both to cool down while replenishing key electrolytes. Tests have shown that cyclists and runners who receive electrolyte supplementation can push much further without hitting their limits, explained McKenny. “That’s a performance enhancement,” he said. “It’s not blood doping, it’s human physiology.”
Those electrolyte drinks contain large amounts of sodium along with potassium and magnesium. “Western diet habits have been taught that sodium is the enemy – that’s not true,” McKenny said. These salts might be your enemy if you’re spending your days sedentary but when you’re sweating a lot, they’re essential. There have been cases of high school athletes who have rehydrated with water or Gatorade, but without sufficient salts, cells can’t uptake water, and some have suffered serious health problems or died as a result, he said.
The American College of Sports Medicine, as well as road cycling associations, have useful guides for how to maintain hydration in the optimum range, said Li. Recreational athletes can find commercial sports drinks containing a good mixture of sodium and other electrolytes, she said.
Get salt tested
“My biggest advice for all athletes is to find out how much you sweat and what your sodium concentration rate is in sweat,” Haas said.
You can perform a basic test of how much you sweat by weighing yourself prior to exercise, monitoring how much you drink, and weighing yourself after, Li said. The amount of weight lost, plus the amount of water consumed, gives a good estimate for how much water you need to consume next time to replenish the fluid lost to sweat.
Sweat tests, designed to show how much you’re losing in perspiration, can cost as little as $100. This is a highly individualized trait that stays with people through life, said McKenny, who has advised Northeastern athletes to take them to understand how much sodium they need to replace.
Get data from your urine
Elite athletes are monitored throughout training and races with complex systems of sensors, even including ingestible thermometers, McKenny said. Such monitoring systems, along with round-the-clock medical care, allow these athletes to push their bodies beyond the bounds that are safe for most people.
For the rest of us, there are more straightforward ways of gathering useful data that will enhance safety and performance. There are three main ways of telling if you’re hydrated, Li said. They are heart rate, urine and thirst. If your brain is sending you a signal you’re thirsty, it’s usually a sign you’re overdue for a drink, Li said, while an increased heart rate is a quicker test to show you’re dehydrated. Urine can provide valuable warnings. “We can buy urine strips, online or at the drug store,” Li said. These come with a seven-step color comparison that shows hydration level. “You want to make sure your urine color is three or below.”
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Training for the heat
Tour de France training has changed a lot since around 2008, Haas said. Recent advances have led to intensive heat adaptation training that allows athletes to hit these critical heat levels and continue to perform. Similar to high-altitude training, such training has been shown to boost blood plasma volume, in addition to helping athletes disperse heat by sweat more effectively, he added. But for non-pros, it’s not easy to translate these lessons safely.
There is one key piece of guidance they can take from the elite athletes: heat training means training at lower intensity when adapting to heat. Even the professionals reduce their intensity by as much as half, when getting used to hotter temperatures, Haas said.
If regular athletes want to train for the heat, don’t head out in peak heats and ensure you know where there are safe spots to seek rest and get medical attention, Li said. “The safest way to do it is you just shorten your cycling and monitor your heart rate constantly,” she said. If it increases, reduce intensity and take breaks. “You want to take short breaks, for 15 to 20 minutes, and reset, get hydrated, take extra ice packs, bring down your core body temperature to prevent heat stroke.”
