Legacy.com Joseph Pedrotti
Around midnight a few weeks ago during spring break vacation, college senior Joseph Pedrotti and some friends gathered at the pool of their hotel in Panama City Beach, Florida.
Pedrotti "was betting he could hold his breath long enough" to go around the perimeter of an island within the pool at Spring Hill Suites, according to a police report obtained by PEOPLE.
About a minute after he entered the water, Pedrotti's friends spotted the 21-year-old floating facedown, unconscious; they pulled him out and started CPR before police and rescue workers took over, according to police, who arrived on the scene shortly after midnight on March 30.
Pedrotti was rushed to a hospital in critical condition, and on April 2 he died of a deadly and little-known condition called "shallow water blackout," according to his obituary.
Video: Newlyweds drown on island honeymoon
"Please educate yourself and others about the cause of Joe's death, Shallow Water Blackout, at www.shallowwaterblackoutprevention.org and help save someone's life," his obituary says.
Shallow water blackout is an underwater "faint" caused by holding your breath continuously for a long time underwater, the site says.
The body is starved of oxygen and decreased carbon dioxide levels cause the brain to block the signal to breathe, causing a swimmer to faint underwater with no other symptoms or awareness of a need to breath, according to the site.
"Drowning is silent and immediate," and is the major cause of drowning death in experienced swimmers, says Dr. Alan Lake, M.D. in a PSA video on the website. Olympic swimmer Michael Phelps and his coach, Bob Bowman, are also part of the PSA.
At greatest risk of shallow water blackout are accomplished swimmers at the end of a training session, swimmers attempting an underwater swim who are oftentimes competing to see who can go the furthest, and swimmers who are alone.
Because the swimmer has a low level of oxygen at the time of fainting, "brain damage occurs within a couple of minutes and death is very likely unless immediate resuscitation is undertaken," says Lake.
Bowman and the site give tips on how to prevent shallow water blackout:
Never swim alone and never ignore the urge to breathe while underwater.
Never repeatedly hold your breath as repetitive breath-holding increases risk.
Never compete with other swimmers to see who can swim the furthest underwater or play breath-holding games.
Don't attempt long or repetitive underwater swims or kicks for any reason.
Only perform underwater training under the guidance of a certified swim coach.
If hyperventilating, never start an underwater swim or kicks.
The site urges pool owners to post signs that ban breath-holding drills and games.
RELATED VIDEO: Scientist Ron Davis Is Fighting to Cure His Son's Chronic Fatigue Syndrome: 'It's Like a Living Death'
Pedrotti — an outstanding high school athlete from Fairway, Kansas who won numerous state championship awards in basketball and football — was a standout student at the University of Missouri majoring in mechanical engineering, according to his obituary.
"Joe was always loving, kind, humble, patient, self-assured, funny and hardworking," his obituary says, noting he was an organ donor, and four different people received his organs.
"Many of us find it easy to do the right thing when others are watching; however, Joe was the person who did the right thing when no one was watching," Pedrotti's obituary says. "He loved his friends and cherished all the time he spent with them."