Minnesota Vikings star Korey Stringer died Wednesday of heat stroke a day after collapsing at a practice session during which the heat index reached 110 degrees.

Stringer, 27, vomited at least three times during Tuesday morning's practice, but he didn't alert a trainer until the session was over. Then the football star developed symptoms of heat stroke, including weakness and rapid breathing.

The 335-pound Pro Bowl tackle was unconscious when he arrived at Immanuel St. Joseph's-Mayo Health System in Mankato, Minn. His temperature was more than 108 degrees.

Stringer never regained consciousness and his heart failed at 1:50 a.m. CDT.

The Pro Bowl star's death came less than a week after University of Florida freshman Eraste Autin, 18, died after collapsing of heat stroke. Figures from the University of North Carolina show that 18 high school or college players have died of heat-related causes since 1995.

The only other NFL training camp fatality is believed to be J.V. Cain, a tight end for the St. Louis Cardinals, who died of a heart attack on July 22, 1979, his 28th birthday. Chuck Hughes, a wide receiver for the Detroit Lions, died of a heart attack Oct. 24, 1972, during a game in Detroit against the Chicago Bears.

The Vikings worked out in full pads Tuesday, the second day of training camp, despite temperatures in the low 90s and stifling humidity that pushed the heat index as high as 110 degrees.

Trainer Chuck Barta said that five other Vikings had heat-related problems that day. Barta didn't speak specifically about what was done to aid Stringer, but said in general, "You recognize you have the heat, you recognize you have to force fluids down them, you also use ice towels to keep them cool on the outside so they don't sweat as much."

Barta said he sometimes recommends toning down the practice intensity because of heat, but said there's no magical point for that and it wasn't clear if he did so on Tuesday. Head coach Dennis Green isn't known for running tough practices, and many NFL teams hold longer training camps than the Vikings. Players have access to lots of fluids and iced towels, but no water-misting devices or fans were on hand this week.

Tuesday's session had one-on-one drills with intense hitting, then later had scrimmages that afforded players more break time as second-teamers got their work. The morning session ran from 8:45 a.m. to 11:10 a.m., a bit longer than usual.

Players, coaches and team officials kept a vigil into the night for Stringer, one of the most popular players on the team.

Barta, offensive line coach Mike Tice and medical services coordinator Fred Zamberletti were at the hospital for much of the day and evening. Quarterback Daunte Culpepper, receivers Randy Moss and Cris Carter and the entire offensive line also went to the hospital.

Stringer had struggled with weight problems early in his career before slimming down and having a breakout Pro Bowl season last year. He reported to training camp at 335 pounds and said he was in the best shape of his career, but also had difficulty on Monday, the first day of camp, when he was taken off the practice field on a cart.

Drafted by the Vikings during the first round of 1995 picks, Stringer started every game at right tackle the past two seasons.

He was popular with fans as well as teammates. He lived in the Twin Cities year-round and had established community service programs at local schools and with the St. Paul public library.

Fans who gathered at the Vikings' camp as early as 6 a.m. Wednesday were stunned to hear of Stringer's death.

"I bought a picture of him to get signed," said Scott Westphal, 17, who drove up from northwest Iowa with friends to watch camp. "I wouldn't be able to ask for any autographs now. It's just not right."

University of Florida coach Steve Spurrier, stung by the death of one of his players, spoke Sunday at the annual meeting of Florida college football coaches about changes in his team's conditioning philosophy that he hopes will someday save a life, the South Florida Sun-Sentinel reported.

"I think the one thing we've learned as coaches, I know I've learned — even though this is not that situation at all — is that when we do drills in the future and a guy is really tired and so forth, you can't push him," Spurrier said, according to the Sun-Sentinel.

"We used to do this all the time, as has every coach around the country, when guys are struggling to make their runs across the field or something like that. I think we're to the point where you've got to say, 'Now, give it your best shot, but if you're feeling queasy or feel like you can't make it ...'"

The Associated Press contributed to this report.