By Nick Childs BBC correspondent in Washington

President George W Bush has used his weekly radio address to urge Americans to do more to keep fit and healthy.

As part of his health initiative, he led aides and administration officials on a three-mile run.

If just 10% of adults began walking regularly, Americans could save $5.6 billion in costs related to heart disease

President George W Bush

Recent statistics suggest that nearly two-thirds of all Americans are overweight.

So, the commander-in-chief became jogger-in-chief for a day.

Mr Bush led several hundred aides and staff on a brisk run around an army base in Washington.

It was part of a Healthier US initiative he launched earlier this week, to try to raise US health levels and cut health care costs.

'Take small steps'

And it was a theme he took up in his weekly national radio address. Even small steps, he said, could make a big difference.

Mr Bush, 55, follows a rigorous fitness regime

"If just 10% of adults began walking regularly, Americans could save $5.6 billion in costs related to heart disease," Mr Bush said.

"And research suggests that we can reduce cancer deaths by one-third simply by changing our diets and getting more exercise."

Mr Bush reeled off some alarming statistics:

• Almost two-fifths of all Americans take no exercise

• It is also reported that nearly two-thirds of Americans are overweight

And that all translates into massive medical bills, Mr Bush said.

The president's recipe for better health: daily exercise, better eating habits, medical checks, cutting out smoking and drugs, and cutting down on alcohol.

This is an initiative Mr Bush is well qualified to lead from the front: at 55 he follows a rigorous fitness schedule himself.

And to get others started, this weekend he has waived all entrance fees to national parks as an encouragement to exercise.