During a game in her junior year, Ithaca College field hockey player Sarah Gibble knew something wasn’t right.

“I started to feel very out of sorts, almost to the point of getting confused,” she said. “Nothing was really working for me. I kept fumbling with the ball.”

Gibble, who has type 1 diabetes, left the game and tested her blood sugar level - well below normal. Some juice and a granola bar got her back on the field.

She continued to play through her senior year, dealing with the challenges faced by thousands of athletes with diabetes. While exercise is beneficial for diabetics, helping to stave off complications and control blood sugar, it takes planning and care to participate safely.

Former NBA center Chris Dudley, golfers Scott Verplank and Kelli Kuehne, Olympic swimmer Gary Hall Jr. and Hockey Hall of Famer Bobby Clarke are among a long list of accomplished diabetic athletes.

Around 800,000 people have type 1, or juvenile, diabetes in which the pancreas produces none of the blood-sugar regulating insulin. Type 1 diabetics need to take daily injections or use an insulin pump.

Most of the nation’s 18 million diabetics have type 2, or adult-onset diabetes in which insulin is still present, but isn’t used properly by the body. Obesity, High cholesterol, high blood pressure, physical inactivity and family history are all risk factors for type 2. Treatments include diet, oral medication and insulin shots.

The most common problem for type 1 diabetics is hypoglycemia, or low blood sugar.

During exercise, the body depletes its stores of sugar, then cuts insulin production to compensate for the lower sugar levels. But in people taking insulin shots or using a pump, that doesn’t happen. Instead, hypoglycemia sets in, causing symptoms including dizziness, sweating, confusion and nervousness. Untreated, a person can lose consciousness, become comatose or even die.

Taking too little insulin can cause problems for an athlete too, said Dr. James Desemone, director of the Goodman Diabetes Service at Albany Medical Center. During physical activity, the body releases hormones like adrenaline that counteract insulin. That increases bloodstream levels of glucose and ketones, byproducts formed when fat is burned for energy, which can be dangerous.

Diagnosed with type 1 diabetes 30 years ago, Desemone works with many athletes with diabetes, from hockey players to cyclists.

The key, he says, is setting up a regimen using insulin injections or a pump to mimic the functioning of a normal pancreas during exercise, adjusting how much insulin is given to the body and when. Drinking enough liquids is also important to maintain correct blood sugar levels, he said.

Paula Harper, 61, started the Diabetes Exercise and Sports Association in 1985, a nonprofit group with about 3,000 members in North America and Europe. A longtime runner and nurse who has competed in 35 marathons, Harper was frustrated trying to come up with the right formula to keep her blood sugar level up over long distances.

“When I started, it was all trial-and-error,” said Harper, a diabetic since 1972. “And trial-and-error can get you in trouble sometimes.”

She recalled races when she ate a Fig Newton every two miles to keep her blood sugar up, and with the help of her husband, pricked her finger every five miles to test it.

A recent National Institutes of Health study showed that 58% of people with pre-diabetes - where blood sugar is elevated but not to the level of type 2 diabetes - staved off type 2 diabetes by exercising moderately 30 minutes a day and by cutting their weight by 5 to 10%.

“I so firmly believe exercise is important for everybody, but especially for diabetes,” Harper said. Her organization is “trying to help people with type 1 exercise safely and give those with type 2 the motivation to get off the couch.”