That was the finding in the Gwinnett County medical examiner's report provided to The Gazette on Tuesday.
Dowis died from blunt-force trauma to the left side of the chest, examiner Dr. Carol A. Terry concluded. Dowis was not wearing a seat belt and separate samples tested by the state crime laboratory showed blood-alcohol levels of .210 and .233. The legal limit in Georgia is .08 percent. The blood specimen tested negative for amphetamines, cocaine, barbiturates and other drugs.
Dowis was traveling the wrong way on Interstate 85 in a white 2014 BMW at about 5 a.m. on Aug. 29 when he entered the median and began to back up, according to the report. As he backed up he was struck in the driver's side door by a silver Subaru. The driver of the Subaru was taken to a hospital with minor injuries. Dowis expressed to a friend shortly before his death that he feared he was "losing his mind due to the concussions he suffered while playing football," the report states.
The 1989 Heisman Trophy finalist and the all-time leading rusher in Air Force history was pronounced dead at the scene, and Dowis' football past was immediately discussed as part of the investigation.
Jay Cox, a longtime friend of Dowis, spoke to investigators on behalf of the distraught Dowis family on the morning of the crash.
"Mr. Cox stated that (Dowis) was a running quarterback and that the decedent took a lot of hits to his head," the report says. "Mr. Cox stated the decedent sustained several concussions during his playing days."
Cox also said that a year earlier Dowis was at a South Carolina hotel and suffered an episode that the family believed to be a stroke but was later proven to be the cause of dehydration.
"Mr. Cox stated prior to that incident the decedent would start to forget things and that he and the decedent had discussions about him losing his mind due to the concussions he suffered while playing football."
Cox told The Gazette Tuesday afternoon that he never told investigators that Dowis used the term "losing his mind," but Cox did say Dowis indicated to him that he "felt like he was experiencing symptoms of CTE (chronic traumatic encephalopathy)," a degenerative disease of the brain due to repeated head trauma.
At the request of his family, Dowis' brain was sent for study to the Mayo Clinic in Jacksonville, Fla.
Dowis, 48, is survived by his wife, Tracie, and two children. The Air Force Academy honored Dowis -- who wore No. 6 -- the week after his death, placing his initials at the 6-yard line of Falcon Stadium.
Dowis had two alcohol-related arrests in South Carolina in recent years. He was arrested for driving under the influence on March 5, 2015 and was cited on Aug. 12, 2014 for public intoxication.
Editor's note: A previous version of this story stated that the Dowis family had received results from the test for CTE and opted not to share them. The family has not received the report, according to an email from Cox on Tuesday evening.