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Countdown to Rio: How Olympic athletes train to acclimate to Brazil's hot, humid climate

After years of dedicated preparation, over 10,000 of the world's top athletes will soon compete in more than 40 sports for the 2016 Summer Olympics in Rio de Janeiro.

While much has been said about the threat of the Zika virus or the polluted waterways that will be the home for many competitions, the heat and humidity will present an inherent challenge, especially for endurance athletes.

The games, which take place Aug. 5-21, will be held during Rio's winter season. Despite that, temperatures will likely run in the middle 80s to near 90 F (29 to 32 C) throughout the event, according to AccuWeather Meteorologist Rob Miller.

Jessica Kutz, associate professor of exercise science at Shenandoah University in Winchester, Virginia, said becoming acclimated and staying properly hydrated are two of the biggest keys to avoiding any type of heat illness.

Heat illness is a spectrum of disorders that includes heat exhaustion, heat cramps or heat stroke.

Since Olympians are in such elite physical condition and have some of the world's best trainers constantly by their side, they understand the need to be vigilant with regards to warning signs of heat stroke, she said. However, while heat stroke is unlikely, other ailments aren't improbable.

"I think you'll see plenty of heat cramps in Rio because of the higher temperatures and especially because of that humidity," Kutz said, adding that the weather could trigger some cases of heat exhaustion.

Some athletes may use a pre-cooling method before their events, a practice that involves wearing a vest filled with ice packs. This technique is common for runners, triathletes and cyclists.

This helps lower an athlete's core temperature, making it take longer for their core temperature to rise to dangerous levels, Kutz said.

Changes to diet can be helpful as well. As they acclimate to Brazil temperatures, athletes may consider adding salt to their foods to help them reabsorb fluids and stay hydrated, Kutz said.

With the amount of pressure put on athletes to perform their best at Olympic events, some countries go to great lengths to determine the best measure of training for different climates.

In 2015, a group from the University of Technology at Sydney, Australia, and members of the French National Institute of Sport, Expertise and Performance (INSEP) examined the adaptation of athletes to different climates with the goal of helping French athletes prepare for this year's games.

In the study, they had a group of French triathletes train for one month in their home city, before dividing the group into two. One part of the group was sent to train in Guadeloupe, a French island in the Caribbean where temperatures were around 86 F (30 C), while the rest remained in Paris.

Christophe Hausswirth, a professor with INSEP, said in a UTS release that after the Caribbean group returned to Paris with temperatures around 50 F (10 C), performance improved.

A moderate increase in performance was noted five days after their return and a large increase was observed after 12 days.

In the U.S., the Olympic Committee (USOC) employs sport physiologists to work with athletes to improve training methods at the organization's flagship training center in Colorado Springs, Colorado.

At the facility's High Altitude Training Center, members of Team USA are able to train and sleep in different altitudes, air temperatures and relative humidity. Air temperature can be altered anywhere from 5 below zero to over 100 F, while relative humidity ranges from 5-100 percent.

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According to Randy Wilber, USOC senior sport physiologist, altitude training provides physical benefits that will result in enhanced performance upon return to sea level in Rio de Janeiro.

"Because Rio de Janeiro will be a hotter and more humid environment versus Colorado Springs (and other altitude training areas), athletes need to do heat and humidity pre-acclimatization via layered clothing, etc., during their altitude training block prior to competing in Rio this summer," Wilber said during the training center's media day in May.

Kutz said the process of acclimating can take one to two weeks of exercising lightly to moderately, whether it's a 30- to 45-minute jog, bike ride or similar practice for another sport.

"You're just taking that time to allow your body to go through some of those processes to adapt so your body begins sweating sooner, you reabsorb some electrolytes sooner within that sweat so all things are going to promote cardiovascular health and at the end of the day promote their performance," Kutz said.

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