INDIANAPOLIS—The downtowns of the nation's core cities have increasingly become beehives of around-the-clock activity as many younger people have decided the suburban lifestyle isn't for them. But this penchant for downtown living has truly become a national phenomenon, and spread into secondary cities—especially those in the Midwest, such as Indianapolis—which have seen a surge in mixed-use urban development and population growth, according to a new study by CBRE Group, Inc.

“It's primarily younger professionals who are moving into downtown Indianapolis,” Dan Richardson, senior vice president of CBRE in Indianapolis, tells GlobeSt.com. According to CBRE's study entitled “Resurgence in Midwest Secondary Markets: Implications for Occupiers,” Indianapolis' urban core has seen a 59.7% population increase in the last ten years, and currently boasts $1.4 billion worth of commercial real estate under construction.

The company surveyed 11 Midwest cities for the study and found a slew of investment activity taking place, with both Fortune 500 companies and new industries like high tech relocating into the region's CBDs in order to attract and retain all that youthful talent. CBRE also noted that many local governments have recognized the opportunities and have invested in downtown areas to make them more accessible and walkable.

“Indianapolis has done a good job of keeping entertainment options in the downtown area,” Richardson says. This includes several sports stadiums and arenas in addition to a host of restaurants and retail.

In 2005, about 16,900 residents lived in the city's downtown, but by 2015 about 27,000 called the area home. This growth was mirrored in most of the other cities in the study, which included Kansas City, Cincinnati, Columbus, Cleveland, Minneapolis, Milwaukee, Detroit, St. Louis, Pittsburgh and Louisville.

Richardson said that the recent decision by Rolls-Royce to move thousands of office jobs into downtown Indianapolis was a good example of the recent migration. The British company manufactures jet-engines throughout central Indiana, but decided to consolidate many of its engineers and other white-collar employees into what had been a vacant downtown campus, spending millions of dollars in the process to renovate the structures on S. Meridian St.

Other major downtown projects include Cummins' $40 million Global Distribution Headquarters currently under construction. The 95,000 square-foot office building will have main floor retail and restaurant space and will open in late 2016. And the $22 million CityWay YMCA, an 87,000 square-foot facility will open in December at the downtown's CityWay—a $155 million mixed-use development.

CBRE found that all of the cities in the survey have seen increased construction spending, particularly on mixed-use projects meant to attract millennial residents. Cleveland, Detroit, Pittsburgh and Minneapolis all currently have more than $1 billion worth of new construction projects underway.

“We don't predict any slowdown in this activity in the near future as these trends have steadily increased for the past decade,” says John Merrill, managing director of CBRE's Indianapolis' office. “It looks like the future is bright for these growing urban cores.”