Bodily systems break down. Extra padding accumulates. Memory dulls. For middle-aged men, the odds of developing heart disease, high blood pressure, prostate troubles and other issues increase exponentially.

To add insult to injury, low testosterone—and its running mate, reduced libido—can be another effect of aging, though it can also affect younger people. Men's bodies generally produce 1 percent less testosterone each year after age 40, according to the Mayo Clinic.

While low testosterone has a variety of effects and comorbidities, one phenomenon getting more attention is the link between low-T and yet another common disease for aging men: diabetes.

Low testosterone and why it matters

Most people generally understand that testosterone is a sex hormone