Researchers say they can finally answer the question of whether you really are as old as you feel.

A new method to determine biological aging could be a breakthrough in therapies that slow aging and help prevent age-related diseases before they occur, New Zealand researchers at the University of Otago said on Tuesday.

The international study tracked, from birth to the present, more than 1,000 people born in the South Island city of Dunedin from 1972 to 1973.