Landmark research by The George Institute for Global Health has found that exercise can save lives, with an increase in the number of steps walked each day having a direct correlation with long term mortality.Study author Professor Terry Dwyer said this was the first time research had been able to make the link between exercise, measured directly through pedometers, and reduced mortality over time in people who appeared healthy at the outset.'Inactivity is a major public health problem, with conditions like obesity costing the economy tens of billions of dollars every year,' Prof Dwyer said. 'This shows more clearly than before that the total amount of activity also affects life expectancy.