Everyone is susceptible to health problems, especially those with a family history of disease or illness. The 2016 Olympics has brought over 10,000 athletes from 206 countries to Rio De Janeiro, Brazil, where the world’s top athletes will compete for a gold medal or recognition.

Spectators all over the world respect Olympic athletes for their dedication, pushing their bodies to the limits and health standards unlike anyone else in the world. Even world-class athletes, however, have serious health problems in which they have been forced to work around and treat in order to continue competing. Here are 10 American Olympic athletes who have surprised us with health problems.

Wilma Rudolph: American Track and Field, Polio

Wilma Rudolph had a tough childhood, suffering paralysis from polio as a young child, scarlet fever and double pneumonia. Doctors were not certain Rudolph would be able to even walk, let alone become an Olympic athlete later in her life.

Her 1956 Melbourne Games Olympic debut at the young age of 16 tokened her achievement with a bronze medal, and she went on to compete at the 1960 Rome games as well. She broke an astounding three world records in her relays, claiming the nickname “The Black Gazelle” for her intense speed, beauty and grace.

Peggy Fleming: American Figure Skater, Breast Cancer

Peggy Fleming fell in love with figure skating at a young age of nine, and quickly learned she had a competitive drive within her, which ultimately left her with a spot in both the 1964 Austria Olympic games and the 1968 Mexico City games, where she took home her first gold medal.

Just a few years later, Fleming was diagnosed with breast cancer. Now cancer-free, she is an active advocate for early prevention and treatment, sharing her 15-year journey with breast cancer at events such as the Pink Ribbon Symposium in 2012.

Greg Louganis: American Diver, HIV

Greg Louganis, the first diver to ever win a perfect score in the 1982 Olympics, has won 13 world championships during his diving career, but his journey getting there wasn’t easy. As an adopted child, he had an abusive father and bullied for dyslexia and experienced racial discrimination.

At the 1984 Los Angeles Olympics, Louganis earned two gold medals despite learning that he was HIV-positive prior to the games. He retired in 1989, working as an actor, author and actively speaking on issues such as dyslexia, domestic violence and overcoming hardship.

Lance Armstrong: American Cyclist, Testicular Cancer

Lance Armstrong began training as a professional triathlete at an early age of 16, training for the U.S Olympic cycling team while still in high school. During the 1982 Barcelona Olympic games, Armstrong finished 14th and immediately turned pro, eventually winning a stage at the 1995 Tour de France.

In 1996, Armstrong was diagnosed with testicular cancer, spreading to his lungs, lymph nodes, brain and abdomen. After multiple surgeries, doctors successfully removed all cancer from Armstrong. He has since continued racing, and has raised over $500 million to support cancer survivors with the LIVESTRONG Foundation.

Gary Hall Jr.: American Swimmer, Diabetes

Gary Hall Jr. had no family history of Type 1 Diabetes. In fact, his father Gary Hall Sr., grandfather, and uncle were also Olympic swimmers. He earned a spot in the 1996 Atlanta Olympic games, receiving a silver medal.

His quest for gold for the 2000 Sydney games came to a halt while training the year prior after Hall experienced extreme thirst and fatigue to the heart. Hall found a diabetes specialist endocrinologist, Anne Peters, M.D, who helped him manage the incurable disease, which allowed him to win a gold medal in the 2000 Olympic games!

Pat Summitt: American Basketball Player and Coach, Dementia

Pat Summitt was engrossed in her passion for basketball, competing for the women’s team in the 1976 Olympic games and winning a gold medal as the coach of the 1984 American Women’s team. During her career, she is best known for transforming the University of Tennessee team into a powerhouse, with the most wins and best record in NCAA history.

In 2011 at age 59, she was diagnosed with Dementia, but continued coaching with a dedicated passion. She died at age 64, but her name lives on, as she started The Pat Summitt Foundation to raise money to find a cure for Alzheimer’s disease.

Venus Williams: American Tennis Player, Sjogren’s Syndrome

Growing up playing tennis in street courts with her sister, Serena Williams, in Los Angeles, Venus Williams has won several Grand Slam titles and an Olympic gold medal in her career. She began breaking records at an early age of 10, receiving her pro card in 1994.

In 2011, Williams was diagnosed with Sjogren’s Syndrome, an autoimmune disease that left her muscles easily fatigued and sore. She converted to eating a vegan diet and transformed her training schedule, which proved successful as she is still competing today in the 2016 Rio Olympics.

Dana Vollmer: American Swimmer, Long QT Syndrome
Dana Vollmer was the youngest competitor in the 2000 U.S Olympic swimming trials, a young passionate swimmer with a massive family support system. Vollmer had experienced “dizzy spells”, which proved to be much more serious than low blood sugar or dehydration as expected.

Vollmer’s parents took her to a cardiologist as a precaution, but learned that Dana had Long QT Syndrome, a cardiac electrical disorder that can lead to arrhythmia. Vollmer continued to swim despite medical advice, always having a defibrillator on site and ready to activate. Today, Vollmer enjoys a life free of disease, as she outgrew her Long QT and is learning to manage unexpected food allergies.

Carrie Johnson: American Kayaker, Crohn’s Disease

Carrie Johnson, an American Kayaker, was training for the Athens Olympics Games in 1986 when she began suffering from extreme fatigue, weight loss and anemia. Johnson was unable to train during this time, and had no idea what could be wrong. Fortunately, she later was diagnosed with Crohn’s disease, a disease where doctors could help her manage her disease so she would continue training and competing. She competed in the 2008 Beijing Olympic games.

Phil Dalhausser: Beach volleyball, blood clots

Phil Dalhausser, also known as the “Thin Beast” began his career as a beach volleyball player in high school in Florida. His career blossomed during his studies at the University of Central Florida, where he received multiple awards and MVPs.

Dalhausser, with partner Todd Rogers, won the gold medal at the 2008 Beijing Olympics, but faced his biggest challenge in 2012 while training for the London Olympics when doctors discovered a blood clot in his subclavian vein. The condition is also known as Axillosubclavian Vein Thrombosis, or ASVT. Like Venus Williams, Dalhausser isn’t letting his condition stop him from competing as he is playing in the 2016 Rio Olympics.

What can we learn? These athletes’ health issues are proof to watch out for unusual health signs, go to your checkups, and to implement preventative measures into our lives by living a healthy lifestyle. Listening to our own bodies’ feedback is one of the most responsible things we can do for ourselves. From exercising to eating a healthy diet – What have you done recently that has proven advantageous for your health?