Ambulances took longer to respond to emergencies after more people gained health insurance under Obamacare and began using medical services they otherwise wouldn't have, according to a study published Monday in the National Bureau of Economic Research.

The estimates show that ambulance response times slowed by almost two minutes, or approximately 19 percent, after Obamacare was implemented.

People facing a medical emergency could die as a result of having to wait too long for medical help, note the authors, an economist from Georgia State University and three others from University of Colorado in Denver.

To assemble the study, researchers used data from the Fatality Analysis Reporting System from 2010 to 2015; they aimed to determine whether more insurance coverage led to a higher demand for medical services.

"Expanding health insurance coverage should, in theory, increase the amount of medical care demanded by reducing its out-of-pocket price," the authors note in the paper.

Obamacare reduced the number of uninsured in the U.S. by more than 21 million people through several provisions, including by mandating that citizens purchase insurance or pay a fine. It allowed low-income people to sign up for government-funded Medicaid, a provision the majority of states enacted, and subsidized private plans sold on the exchanges for low- and middle-income people. The plans all had to cover a range of medical services, including emergency services like those provided by an ambulance.

The study concluded that ambulance response times "increased substantially" with the implementation of Obamacare. Researchers noted in the paper that they did not find evidence that the slowed response time could be attributed to traffic congestions or economic conditions.

They also noted that emergency medical providers may not have had enough time or money to increase the number of ambulances they operate in the short term, but could still make changes moving forward to accommodate greater demand.

"In the long-run, providers could, in theory, respond to increased demand by employing more EMS workers and ambulances," they wrote.