Hutchinson-Gilford Progeria Syndrome is a genetic disease that causes premature aging. It affects one in 4 million newborns, making it one of the rarest genetic diseases we know about.

While such rare conditions may not (at least yet) be preventable, the millions of people who have a genetic predisposition to everything from diabetes to heart disease, stroke, breast and prostate cancers, and dementia can do a lot to stop the risk from becoming a reality.

That's because the lifestyle choices you make can reduce your familial risk by turning off potentially harmful genes and switching on health-boosting ones.

A study published in the British Journal of Sports Medicine found that people with a high genetic risk for Type 2 diabetes had a 2.4 times greater chance of developing the disease than those with a low genetic risk. But when the at-risk people engaged in moderate- to vigorous-intensity physical activity regularly, their risk for developing Type 2 diabetes was the same as that of low genetic risk people who got comparable exercise.

The researchers considered running, aerobic dancing, cycling uphill or at a fast pace, and heavy gardening to be preventive activities.

So don't sweat it if diabetes or another chronic condition runs in your family. Instead, get sweating. Five days a week of aerobic exercise and two days of strength-building are optimal.