Chris Dudley sets to dunk the ball

Chris Dudley sets to dunk the ball (Rocky Widner/NBAE/Getty Images)

Former NBA center Chris Dudley was 16 when he exhibited the classic signs of Type 1 diabetes. "I was incredibly thirsty and going to the bathroom all of the time," said Dudley. His uncle, a diabetic, recognized what was going on, and after a home test kit showed Dudley's blood sugar was sky high, he went to the hospital.

"I was scared because I didn't know what diabetes was," recalled Dudley, who went on to play 16 seasons in the NBA. The first question he asked his doctor was if he'd be OK; the second was whether he'd be able to play basketball.

"The doctor said 'yes' and 'yes,'" said Dudley, whose foundation advocates and educates about Type 1 and sponsors clinics and basketball camps for kids with Type 1. "You can live a long life, and you can play if you take care of yourself."

Former NFL player Jay Leeuwenburg was a sports-crazed 12-year-old when he started losing weight and had "an unquenchable thirst." Leeuwenburg's doctor diagnosed him with Type 1 diabetes. He went on to a nine-year NFL career.

Of the 26 million Americans with diabetes, an estimated 3 million have Type 1, according to the Juvenile Diabetes Research Foundation (JDRF), including Philadelphia Flyer Nick Boynton, Chicago Bears quarterback Jay Cutler and Olympic cross-country skier Kris Freeman, who like the pro athletes before them, work hard to balance training and competition with the disease.

Often referred to as juvenile diabetes, Type 1, according to JDRF, occurs when the body's immune system destroys beta cells, which produce the hormone insulin. Insulin moves the glucose (sugar) in food into the body, where it's used as fuel. Without insulin, glucose stays in the blood. High blood sugar levels left untreated can lead to ketoacidosis, which can result in coma and death. Type 1 diabetics must take insulin to survive.

Lifestyle is more important in controlling Type 2 diabetes, which is on the rise due to an increasingly obese population. "In this form of diabetes, the pancreas still produces insulin, but the body does not produce enough or is not able to use it effectively. Treatment includes diet control, exercise, self-monitoring of blood glucose, and, in some cases, oral drugs or insulin," according to the JDRF.

Are there limitations?

Whether or not they're encouraged to keep competing — ultramarathoner Missy Foy was told by four doctors that if an athlete could qualify for the Olympic marathon trials, it already would have been done — Type 1 takes lots of trial and error to control. "Exercise changes a lot of things, including your requirements for fuel," explained Dr. Andrew Ahmann, professor of medicine and director of the Harold Schnitzer Diabetes Health Center at Oregon Health & Science University.

"While you need insulin to get glucose into tissues, you also become much more insulin-sensitive when you exercise and have a greater risk of having low blood sugar when exercising, so it's always a complex balance."

Three-time Olympian Gary Hall, Jr., for example, thought his swim career was over when he was diagnosed with Type 1 just before the 2000 Olympics, but with the help of a nutritionist and medical professionals, he adjusted his diet and medication, was able to continue a grueling training schedule and won gold in 2000 and 2004.

Knowing your body

Symptoms of low blood sugar can include trembling, accelerated heart rate, sweating and increased hunger — all of which can be confused with how the body reacts to working out. In a study on athletes ages 9 to 17 at the York University Diabetes Sports Camp in Canada, researchers found that low blood sugar levels decreased basic sports skills an average of 20 percent.

Low blood sugar can also impair cognitive skills. "It's helpful to have somebody you know who recognizes what's going on and says, 'I think your blood sugar's low,'" said Dudley, whose wife can quickly sense when Dudley needs food.

A big part of managing diabetes is testing blood sugar, explained Dudley, who on game days would test 14 to 15 times (six to eight on nongame days.) "You have to get to know your body and how it reacts to exercise and food."

Foy learned she had Type 1 at age 33, just as she was launching her professional road running career. She then became the first diabetic athlete to qualify for the Olympic marathon trials.

Foy practiced her marathon runs on a 1.5-mile course with her coach to figure out when and what she needed to eat. "We'd come up with a plan for race day, and sometimes it wouldn't go right," she said. "Twice I had to drop out of a race because my blood sugar went higher and higher and I couldn't take in carbs. If you don't have enough insulin on board, you can't take in carbs," she explained. "You have to have enough insulin to get the sugar out of the bloodstream and into the cells, but not too much insulin that you end up with no sugar in your bloodstream."