According to new study from the Joslin Diabetes Center, published in the journal Nature Metabolism, all your efforts to get into shape may not add up to the victory you're hoping for if you have a high glucose level.

It turns out that elevated glucose (even in the prediabetes range) dampens the benefits of aerobic exercise — such as improved cardiovascular health, stress reduction, lower levels of inflammation, reduced risk of some cancers, and gastrointestinal problems.

This happens, the researchers suggest, because elevated glucose keeps muscle fibers from becoming more efficient at using oxygen during exercise.

In the lab, the researchers found that the muscles of animals with elevated glucose levels have bigger fibers and fewer blood vessels. And looking at young adult humans, they found that those who had higher blood sugar levels also showed the lowest aerobic exercise capacity.

If you're battling elevated glucose and trying to become more fit, your best bet is to keep your blood sugar in the normal range through diet and, if needed, medication while gradually increasing your aerobic capacity through interval training with walking, biking, swimming, or jogging.

Don't overspend energy on aerobics if you aren't controlling your blood glucose levels. Tackling both together is how to get fit and stay healthy.