While several studies have shown that physical activity reduces body mass index and insulin resistance - an early stage in the development of diabetes - this is the first study to estimate the effects of long-term changes in daily step count on insulin sensitivity.
A popular guideline is to do 10,000 steps every day, though a more recent recommendation is 3,000 steps, five days a week.
The research, by the Murdoch Childrens Research Institute, Melbourne, involved 592 middle-aged adults who took part in a national study to map diabetes levels across Australia between 2000 and 2005.
At the start of the study, participants completed a detailed diet and lifestyle questionnaire and underwent a thorough health examination. They were also given a pedometer and instructed how to use it. Participants were monitored again five years later.
Other lifestyle factors, such as diet, alcohol and smoking were taken into account.
A higher daily step count over five years was associated with a lower body mass index, lower waist to hip ratio, and better insulin sensitivity.
These associations were independent of dietary energy intake and appeared to be largely due to a change in adiposity (fatness) over the five years, say the authors.
The authors estimate that, in their setting, a sedentary person who takes a very low number of daily steps but who was able to change behaviour over five years to meet the popular 10,000 daily step guideline would have a threefold improvement in insulin sensitivity compared with a similar person who increased his or her steps to meet the more recent recommendation of 3,000 steps for five days a week.
They conclude: "These findings, confirming an independent beneficial role of higher daily step count on body mass index, waist to hip ratio, and insulin sensitivity, provide further support to promote higher physical activity levels among middle-aged adults." (EurekAlert/ January 2011)