The Goal Is to Go Fast. Just Not Too Fast.

Smith has struggled with a range of issues, including depression, anxiety and memory loss, since retiring from competition in 2004. She cited the death of Adam Wood, a Canadian bobsledder who died by suicide in 2013, as a reason she has taken her symptoms seriously. An examination revealed damage to her brain.

“I completely believe that this is the hidden pandemic, the brain injuries in sports,” Smith said.

One problem, scientists and former athletes said, is that sliding-sports athletes often risk their own financial security to bankroll their Olympic dreams. As a result, there is little incentive for them to self-report injuries — and remove themselves from valuable training time or competitions. One symptom of concussions, those experts noted, is the reduction of choice-making ability, a lesson Snyder said she learned from her own experiences in skeleton.

Britain’s Amy Williams, 39, won a gold medal in women’s skeleton at the Vancouver Olympics in 2010. She recalled being taken aback by the track’s speed and pushing to the back of her mind the tragedy that had occurred only days before it was her turn to compete.

“You’re right on the edge of being in control and not being in control and finding the speed, but being in control of your sled, but then trying to push your limits,” Williams said. “It’s finding where those limits are, being fast or crashing.”

Williams retired after the Vancouver Games. In the years since, she has undergone four major knee operations, she said, and suffers from constant headaches and sharp pain down her legs.

“Sort of the pain of my life,” Williams said. “They’re quite regular in skeleton, unfortunately.”

For the next Games, which took place in 2014 in Sochi, Russia, designers of the Olympic track created three uphill sections that reduced speeds by about 10 m.p.h. from the ones recorded at the track in Vancouver, British Columbia.