Get fit, stay fit - or else

A new study by Mercedes Carnethon, PhD, of Northwestern University, and colleagues reported online in Diabetes Care that twenty-somethings who aren't physically fit may be at an increased risk of developing diabetes in middle age, researchers said.
The evidence shows that patients with low aerobic fitness levels in their 20's were 2-3 times more likely to develop diabetes than those that maintained their physical fitness.

"[Patients] who have low fitness in their late teens and 20s tend to stay the same later in life or even get worse," Dr. Carnethon said. "Not many climb out of that category."

The finding suggests that the "mechanism by which fitness decreases risk for diabetes is through the regulation of body mass."

Physical fitness may protect against diabetes via weight loss, improved muscle insulin sensitivity, improved endothelial function and autonomic function, or reduced inflammation and oxidative stress, the researchers said.