U.S. Olympic swimmer Natalie Coughlin, World Food Programme (WFP) ambassador, carries a South Sudanese displaced by fighting child at Imvepi settlement in Arua district, northern Uganda, April 4, 2017. Picture taken April 4, 2017. REUTERS/James Akena 

U.S. Olympic swimmer Natalie Coughlin, World Food Programme (WFP) ambassador, visits South Sudanese refugees displaced by fighting at Imvepi settlement in Arua district, Uganda, April 4, 2017. Picture taken April 4, 2017. REUTERS/James Akena 

Swimmer Natalie Coughlin poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 7, 2016. "I really like '90s hip hop but I actually don't listen to music when I train or before a race," said Coughlin. "I like the quiet in my own head." REUTERS/Lucy Nicholson SEARCH "THE WIDER IMAGE" FOR ALL STORIES. 

Swimmer Natalie Coughlin poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 7, 2016. "I really like '90s hip hop but I actually don't listen to music when I train or before a race," said Coughlin. "I like the quiet in my own head." REUTERS/Lucy Nicholson SEARCH "THE WIDER IMAGE" FOR ALL STORIES. 

Swimmer Natalie Coughlin poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 7, 2016. "I really like '90s hip hop but I actually don't listen to music when I train or before a race," said Coughlin. "I like the quiet in my own head." REUTERS/Lucy Nicholson SEARCH "THE WIDER IMAGE" FOR ALL STORIES. 

Swimmer Natalie Coughlin poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 7, 2016. "I really like '90s hip hop but I actually don't listen to music when I train or before a race," said Coughlin. "I like the quiet in my own head." REUTERS/Lucy Nicholson SEARCH "THE WIDER IMAGE" FOR ALL STORIES. 

Swimmer Natalie Coughlin poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 7, 2016. "I really like '90s hip hop but I actually don't listen to music when I train or before a race," said Coughlin. "I like the quiet in my own head." REUTERS/Lucy Nicholson SEARCH "THE WIDER IMAGE" FOR ALL STORIES. 

Swimmer Natalie Coughlin poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 7, 2016. "I really like '90s hip hop but I actually don't listen to music when I train or before a race," said Coughlin. "I like the quiet in my own head." REUTERS/Lucy Nicholson SEARCH "THE WIDER IMAGE" FOR ALL STORIES. 

U.S. Olympic swimmer Natalie Coughlin speaks at a news conference at en event to unveil the new line of Speedo LZR Racer X swim suits in the Manhattan borough of New York City, December 15, 2015. REUTERS/Mike Segar 

Olympic swimmers Ryan Cochrane of Canada (L) and Natalie Coughlin of the U.S. model the new line of Speedo LZR Racer X swim suits during an event held by Speedo to unveil the suits in the Manhattan borough of New York City, December 15, 2015. REUTERS/Mike Segar 

REFILE- ADDING ADITIONAL INFORMATION- (From L to R) Megan Romano, Shannon Vreeland, Natalie Coughlin and Missy Franklin of the U.S. pose with their gold medals at the women's 4x100m freestyle victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona July 28, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

(From L to R) Megan Romano, Shannon Vreeland, Natalie Coughlin and Missy Franklin of the U.S. pose with their gold medals at the women's 4x100m freestyle victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona July 28, 2013. REUTERS/Albert Gea (SPAIN - Tags: SPORT SWIMMING)

(From L to R) Megan Romano, Shannon Vreeland, Natalie Coughlin and Missy Franklin of the U.S. pose with their gold medals at the women's 4x100m freestyle victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona July 28, 2013. REUTERS/Albert Gea (SPAIN - Tags: SPORT SWIMMING)

(From L to R) Missy Franklin, Natalie Coughlin, Shannon Vreeland and Megan Romano of the U.S. wave before their women's 4x100m freestyle final during the World Swimming Championships at the Sant Jordi arena in Barcelona July 28, 2013. REUTERS/Gustau Nacarino (SPAIN - Tags: SPORT SWIMMING)

Natalie Coughlin of the U.S. reacts during training for the World Swimming Championships at the Sant Jordi arena in Barcelona July 26, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

Michael Phelps and Natalie Coughlin of the U.S. swimming team chat during a promotional event in London July 25, 2012. Picture taken July 25, 2012. REUTERS/Damir Sagolj (BRITAIN - Tags: SPORT OLYMPICS SWIMMING) 

Natalie Coughlin of the U.S. swimming team claps her hands as she joins her team mates during a promotional event in London July 25, 2012. Picture taken July 25, 2012. REUTERS/Damir Sagolj (BRITAIN - Tags: SPORT OLYMPICS SWIMMING) 

Natalie Coughlin of the U.S. swimming team arrives to join her team mates during a promotional event in London July 25, 2012. Picture taken July 25, 2012. REUTERS/Damir Sagolj (BRITAIN - Tags: SPORT OLYMPICS SWIMMING) 

Natalie Coughlin of the U.S. swimming team talks to reporters during a promotional event in London July 25, 2012. REUTERS/Damir Sagolj (BRITAIN - Tags: SPORT SWIMMING OLYMPICS) 

Natalie Coughlin of the U.S. swimming team talks to reporters during a promotional event in London July 25, 2012. REUTERS/Damir Sagolj (BRITAIN - Tags: SPORT SWIMMING OLYMPICS) 

Natalie Coughlin of the U.S. swimming team talks to reporters during a promotional event in London July 25, 2012. REUTERS/Damir Sagolj (BRITAIN - Tags: SPORT OLYMPICS SWIMMING) 

Michael Phelps and Natalie Coughlin of the U.S. swimming team chat during a promotional event in London July 25, 2012. REUTERS/Damir Sagolj (BRITAIN - Tags: SPORT SWIMMING OLYMPICS) 

Member of the U.S. national Olympic swimming team Natalie Coughlin is seen at the Aquatics Centre before the start of the London 2012 Olympic Games in London, July 23, 2012. REUTERS/David Gray (BRITAIN - Tags: SPORT OLYMPICS SWIMMING)

Natalie Coughlin starts her women's 100m freestyle heat during the U.S. Olympic swimming trials in Omaha, Nebraska, June 29, 2012. REUTERS/Jeff Haynes (UNITED STATES - Tags: SPORT SWIMMING SPORT OLYMPICS)

Natalie Coughlin swims her heat in the women's 100m backstroke during the U.S. Olympic swimming trials in Omaha, Nebraska, June 26, 2012. REUTERS/Jeff Haynes (UNITED STATES - Tags: SPORT SWIMMING)

Natalie Coughlin swims her heat in the women's 100m backstroke during the U.S. Olympic swimming trials in Omaha, Nebraska, June 26, 2012. REUTERS/Jeff Haynes (UNITED STATES - Tags: SPORT SWIMMING)

Natalie Coughlin swims her heat in the women's 100m backstroke during the U.S. Olympic swimming trials in Omaha, Nebraska, June 26, 2012. REUTERS/Jeff Haynes (UNITED STATES - Tags: SPORT SWIMMING)

Natalie Coughlin swims her heat in the women's 100m backstroke during the U.S. Olympic swimming trials in Omaha, Nebraska, June 26, 2012. REUTERS/Jeff Haynes (UNITED STATES - Tags: SPORT SWIMMING)

Natalie Coughlin swims her heat in the women's 100m backstroke during the U.S. Olympic swimming trials in Omaha, Nebraska, June 26, 2012. REUTERS/Jeff Haynes (UNITED STATES - Tags: SPORT SWIMMING)

Natalie Coughlin swims from the pool after winning the women's 100m butterfly semifinal during the U.S. Olympic swimming trials in Omaha, Nebraska, June 25, 2012. REUTERS/Jeff Haynes (UNITED STATES - Tags: SPORT SWIMMING)

Swimmer Natalie Coughlin poses for a portrait during the 2012 U.S. Olympic Team Media Summit in Dallas, Texas May 14, 2012. REUTERS/Lucas Jackson (UNITED STATES - Tags: SPORT OLYMPICS HEADSHOT PROFILE PORTRAIT SWIMMING) 

Swimmer Natalie Coughlin poses for a portrait during the 2012 U.S. Olympic Team Media Summit in Dallas, Texas May 14, 2012. REUTERS/Lucas Jackson (UNITED STATES - Tags: SPORT OLYMPICS PROFILE PORTRAIT SWIMMING) 

Swimmer Natalie Coughlin poses for a portrait during the 2012 U.S. Olympic Team Media Summit in Dallas, Texas May 14, 2012. REUTERS/Lucas Jackson (UNITED STATES - Tags: SPORT OLYMPICS PROFILE PORTRAIT SWIMMING) 

Natalie Coughlin competes in the women's 100m freestyle event during the USA Swimming Grand Prix Charlotte Ultra Swim at the Mecklenburg County Aquatic Center in Charlotte, North Carolina May 13, 2012. REUTERS/Davis Turner (UNITED STATES - Tags: SPORT SWIMMING) 

Natalie Coughlin competes in the preliminaries of the women's 100m backstroke event during the USA Swimming Grand Prix Charlotte Ultra Swim at the Mecklenburg County Aquatic Center in Charlotte, North Carolina May 12, 2012. REUTERS/Davis Turner (UNITED STATES - Tags: SPORT SWIMMING) 

Dana Vollmer (L) is congratulated by Natalie Coughlin after Vollmer won the women's 100m butterfly event during the USA Swimming Grand Prix Charlotte Ultra Swim at the Mecklenburg County Aquatic Center in Charlotte, North Carolina May 11, 2012. REUTERS/Davis Turner(UNITED STATES - Tags: SPORT SWIMMING) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

U.S. swimmer and 11-time Olympic medalist Natalie Coughlin appears at a news conference in New York, January 26, 2012, where she announced a partnership with Pantene, the world's leading haircare brand, which will support Coughlin and 10 other elite female athletes as its newest beauty ambassadors. The group will be featured in Pantene's first global marketing campaign to support the Olympic Games. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT SWIMMING PROFILE) 

Natalie Coughlin of the U.S. starts the Women's 4x100 meter Freestyle during the Mutual of Omaha Duel in the Pool swimming competition at the Georgia Tech Aquatic Center in Atlanta, Georgia December 17, 2011. REUTERS/Tami Chappell (UNITED STATES - Tags: SPORT SWIMMING) 

Natalie Coughlin of the U.S swims in her leg of the women's 4x100 meters medley relay, during which her team set a world record, in the Mutual of Omaha Duel in the Pool swimming competition at the Georgia Tech Aquatic Center in Atlanta, Georgia December 16, 2011. REUTERS/Tami Chappell (UNITED STATES - Tags: SPORT SWIMMING) 

Natalie Coughlin of the U.S looks on after her leg in the women's 4x100 meters medley relay, during which her team set a world record, in the Mutual of Omaha Duel in the Pool swimming competition at the Georgia Tech Aquatic Center in Atlanta, Georgia December 16, 2011. REUTERS/Tami Chappell (UNITED STATES) 

Missy Franklin of the U.S. (in water) shakes hands with teammate Natalie Coughlin (C), who swam the first leg of their race, after they set a world record in the women's 4x100 meters medley relay during the Mutual of Omaha Duel in the Pool swimming competition at the Georgia Tech Aquatic Center in Atlanta, Georgia December 16, 2011. Rebecca Soni, who swam the second leg of the relay, stands on the left of Coughlin. REUTERS/Tami Chappell (UNITED STATES - Tags: SPORT SWIMMING) 

Natalie Coughlin of the U.S. takes off her jacket as she prepares to swim the women's 100 meters butterfly during the Mutual of Omaha Duel in the Pool swimming competition at the Georgia Tech Aquatic Center in Atlanta, Georgia December 16, 2011. REUTERS/Tami Chappell (UNITED STATES - Tags: SPORT SWIMMING) 

Natalie Coughlin of the U.S. readies herself to swim the women's 4x100 meters medley relay during the Mutual of Omaha Duel in the Pool swimming competition at the Georgia Tech Aquatic Center in Atlanta, Georgia December 16, 2011. REUTERS/Tami Chappell (UNITED STATES - Tags: SPORT SWIMMING) 

U.S. swimmer Natalie Coughlin speaks to media as she promotes the new Speedo brand swimsuits "Speedo FASTSKIN3" at a news conference in New York November 30, 2011. REUTERS/Eduardo Munoz (UNITED STATES - Tags: SPORT SWIMMING FASHION ENTERTAINMENT) 

U.S. swimmer Natalie Coughlin models the new Speedo googles brand "Speedo FASTSKIN3" at a news conference in New York November 30, 2011. REUTERS/Eduardo Munoz (UNITED STATES - Tags: SPORT SWIMMING) 

U.S. Olympic gold medallist swimmer Michael Phelps (C), U.S. swimmer Natalie Coughlin (R) and Olympic Medallist Ryan Lochte model the new Speedo brand swimsuits "Speedo FASTSKIN3" at a news conference in New York November 30, 2011. REUTERS/Eduardo Munoz (UNITED STATES - Tags: SPORT SWIMMING) 

U.S. swimmer Natalie Coughlin models the new Speedo brand swimsuits "Speedo FASTSKIN3" at a news conference in New York November 30, 2011. REUTERS/Eduardo Munoz (UNITED STATES - Tags: SPORT SWIMMING) 

U.S. Olympic gold medallist swimmer Michael Phelps (R) and U.S. swimmer Natalie Coughlin promote the new Speedo brand swimsuits "Speedo FASTSKIN3" at a news conference in New York November 30, 2011. REUTERS/Eduardo Munoz (UNITED STATES - Tags: SPORT SWIMMING) 

U.S. Olympic gold medallist swimmer Michael Phelps (L) and U.S. swimmer Natalie Coughlin model the new Speedo brand swimsuits "Speedo FASTSKIN3" at a news conference in New York November 30, 2011. REUTERS/Eduardo Munoz (UNITED STATES - Tags: SPORT SWIMMING) 

Rebecca Soni (top) of the U.S. jumps in the pool past team mate Natalie Coughlin in the women's 4x100m medley relay final at the 14th FINA World Championships in Shanghai July 30, 2011. REUTERS/Carlos Barria (CHINA - Tags: SPORT SWIMMING IMAGES OF THE DAY) 

Natalie Coughlin, Rebecca Soni, Dana Vollmer and Melissa Franklin of the U.S. (L-R) pose with their gold medals for the women's 4 X 100m medley relay final at the 14th FINA World Championships in Shanghai July 30, 2011. REUTERS/David Gray (CHINA - Tags: SPORT SWIMMING AQUATICS) 

Natalie Coughlin, Rebecca Soni and Dana Vollmer (L-R) of the U.S. celebrate after winning the women's 4 X 100m medley relay final at the 14th FINA World Championships in Shanghai July 30, 2011. REUTERS/David Gray (CHINA - Tags: SPORT SWIMMING AQUATICS) 

Natalie Coughlin (front), Dana Vollmer and Rebecca Soni (R) of the U.S. cheer on their teammate Melissa Franklin during the women's 4 X 100m medley relay final at the 14th FINA World Championships in Shanghai July 30, 2011. The U.S. team won the event. REUTERS/David Gray (CHINA - Tags: SPORT SWIMMING IMAGE OF THE DAY AQUATICS)