He was just 22 years old.

According to an obituary written by family members, the 6-foot-3, 241-pound defensive end was training in a weight room on Nov. 21 "doing what he loved" ... when he suddenly went into cardiac arrest.

The family says school officials began life-saving measures ... and after they regained the football player's pulse, he was rushed to the ICU. Sadly, he passed away seven days later.

Ryan's family explained in their obituary the medical emergency was all due to "an undetected genetic heart condition and a large, loving heart."

"Reed had a contagious smile and lived life to the fullest in his short years," Reed's family wrote. "Reed loved people, he could talk to anyone and prided himself on being surrounded by friends, family, mentors, and being part of a team."

Reed starred at Waunakee High School in Wisconsin before he accepted a full-ride to North Dakota State University. He played four seasons for the Bison before he transferred to the University of Minnesota Duluth. In his one year for the Bulldogs, Ryan logged eight total tackles and one sack.

"Our staff and players are devastated about Reed's passing," UMD head football coach Curt Wiese said in a statement. "Reed aspired to be better every day at whatever task was at hand. He helped bring out the best in others with his positive attitude, infectious smile, and genuine care for the people around him."

NDSU football added in a statement on X on Wednesday that Ryan was "the ultimate teammate, a constant source of joy, a genuine selfless spirit, and a beloved friend."

"We'll miss you, Reed," the Bison wrote. "Your legacy will live on."