DENVER -- A new study's data shows riding your bike to work could be harmful to your health. As the number of people who commute to work increases, apparently so does the severity of their injuries.

According to the UC Denver School of Medicine, there was a 15 percent increase in chest injuries among bike commuters and the number of abdominal injuries has tripled over the past five years. The research also showed the amount of time patients spent in the ICU increased as well. Approximately 30 percent of injuries were head injuries.

"Bikes are great, but for instance, in Denver, the Cherry Creek bike trail doesn't help people who want to commute to work. Once they get off the Cherry Creek bike trail, our data would suggest that they are putting themselves in significant danger," said Dr. Jeffry Kashuk, associate professor of surgery at the UC Denver School of Medicine.

Data was collected from 329 bike injuries occurring from 1995 through 2006 at Denver Health Medical Center's Rocky Mountain Regional Trauma Center.

Dr. Kashuk and Zach Hartman, a third-year medical student, mapped out the accidents and discovered that the major concentration of collisions took place in the downtown urban area and the majority of riders were older males, suggesting a greater frequency of urban commuters opposed to recreational riders.

"So we think that the combination of the fact that the average age was greater, with the clusters of injuries in the central urban area away from the bike paths and more severe injuries, we're hypothesizing this could reflect the trend that we're all aware of, that more people are using the bicycle for commuting to work," said Kashuk.

The doctor admits the study sample is small but is in the process of expanding the research to more cities around the country. Even with the risk, bike groups like Bikes Belong in Boulder claim bike accidents are rare, saying the average accident rate for commuter cyclists is one accident every 8.7 years.

Kashuk believes the study data will be a wake-up call to local, state and the federal governments about the need for changes in the way cities look at the way bike riders use the same roads vehicles do.

"There's much more emphasis on bicycle as a method of transportation, but the infrastructure in the United States has really lagged behind, for instance, Europe. We think that this data could suggest that more of an emphasis on infrastructure, dedicated bike lanes will help improve the safety."