Bill Pennington / New York Times News Service

In February, hundreds of youth sports safety advocates convened at a Washington hotel. They were determined to talk about something other than concussions, a counterintuitive ambition considering the rampant worry about the effects of head trauma in young athletes.

But the group knew something most do not: the No. 1 killer of young athletes is sudden cardiac arrest, typically brought on by a pre-existing, detectable condition that could have been treated. Another substantial yet hidden lethal threat is heat stroke, a condition considered completely preventable.

Concussions are receiving attention nationwide, but death from a blow to the head is exceedingly rare. In contrast, a young athlete dies from a cardiac incident once every three days in the United States, researchers say.

In hot months like August, heat stroke often causes the death of a young athlete every other day on average.

“Concussion victims almost always get a second chance,” said Laura Friend, an attendee at the Washington summit whose 12-year-old daughter, Sarah, died of sudden cardiac arrest while swimming at a Texas community pool in 2004. “When your heart fails from something that could have been treated — which happens all the time — you don’t have another chance.”

Heat stroke, also known as exertional heat illness, has been a focus of sports safety advocates because of simple, common-sense preventive measures, like introducing gradual levels of exercise at the beginning of a sports season in hot temperatures.

“When my son died, people treated it as a freak thing,” said Rhonda Fincher, whose 13-year-old son, Kendrick, died in 1995 from heat stroke sustained during a season-opening football practice in Arkansas.

Leaders of youth sports acknowledge that concussions have long been overlooked and that the injury deserves a period of heightened awareness, especially because of the potential for long-term consequences. But as the focus of the February conference organized by the National Athletic Trainers’ Association suggests, there is a mounting worry that more hazardous health concerns are being disregarded because of the intense emphasis on brain injuries.

A sudden heart-related death is “so incredibly tragic and stunning that people aren’t comfortable putting it into the everyday conversation,” said Dr. Jonathan Drezner, the president of the American Medical Society for Sports Medicine.

One factor that may be inhibiting the conversation is a widespread disagreement about suitable precautionary measures for young athletes.

The physical examination that virtually every athlete in the United States must pass to play a school sport includes listening to the heart, checking blood pressure and reviewing family medical history. But many doctors strongly advocate adding an electrocardiogram, or EKG, to the pre-participation exam. They say it would detect about two-thirds of the deadly, concealed heart trouble aggravated by exercise in competition.

In other countries, most notably Italy, young athletes are required to have EKGs to play sports, but adopting the practice in the U.S. could cost $25 to $150 per EKG, which may not be covered by insurance.

The cost of giving an EKG to each of the country’s 7.7 million high school athletes has led to skepticism of whether EKGs are a prudent, practical medical procedure. Many attendees felt that the focus on universal EKG screening was a distraction from more pertinent goals, like having lifesaving automatic external defibrillators, or AEDs, in every school in the country.

Prevention efforts contrast with decades of belief that the best way to get a team into shape during the preseason is a series of punishing workouts. Advanced research and better investigation of sports-related deaths have revealed the danger of two-a-day workouts common at football camps. Any overly strenuous sessions in hot weather before athletes have had time to acclimate to an increased level of exercise can be dangerous, especially outdoors.