Health insurer Humana Inc. and the nonprofit cycling group Bikes Belong partnered with bicycle manufacturers and others to offer 1,000 bikes. They can be checked out from 7 a.m. to 7 p.m. Aug. 25-28.

They're doing the same thing during the Republican National Convention in St. Paul, Minn., beginning Sept. 1.

Adults can visit one of seven downtown bike stations in Denver and present a photo ID and credit card to check out a bike and helmet free. They return the bikes at a station in the evening.

More than 20 bike mechanics took part in bike building sessions as part of a program to showcase the advantages of cycling during the political conventions

Humana has had a bike sharing program since 2007. McCallister said the timing to expand the program during the national party conventions was right, as obesity rates, pollution and gasoline prices rise.

McCallister didn't disclose what Humana's financial investment was for the program.

"It's good for us to be associated with wellness and activity and doing something from the standpoint of helping people do something for their own health," McCallister said. "Everybody wins on that one."

Denver Mayor John Hickenlooper led a group of riders to one of seven pick-up stations Sunday in downtown Denver.