The cosmologist Carl Sagan once said: "Science is an attempt, largely successful, to understand the world, to get a grip on things ..." And Tupac Shakur once rapped, "Gotta get a tight grip, don't slip ..."

Researchers from Michigan Medicine agree.

They tracked more than 1,200 middle-age and older adults for eight to 10 years and found that muscle weakness — measured by grip strength -- accelerates aging.

The researchers looked at biological clocks known as DNA methylation that can track, on a molecular level, whether you are defying age or aging prematurely. Their conclusion: Older men and women showed an association between weak grip strength and biological age acceleration across those DNA methylation clocks.

This confirms another study that found grip strength is a better predictor of the risk for a heart attack than systolic blood pressure.

If you have trouble carrying grocery bags for more than a few minutes without putting them down for a break; if your hands and forearms get tired when you're shoveling snow, walking your dog, or typing on the keyboard; or if your hands often cramp, your grip is subpar. 

How do you maintain and improve grip strength?

Use a squeeze ball or grippers (a handheld spring device) to perform contractions — 10 squeezes in each hand, three times daily.

In addition, you should work to build overall muscle strength by doing strength-training exercises twice a week, as well as moderate and vigorous aerobics five days a week to combat age-related muscle weakness.

That way, you can get a grip on your health.