Seven days before the test, Stephanie Yeh stood in her sorority house and cried.
An electrical engineering and computer science major, she was set to graduate near the top of her MIT class next month and start a six-figure job as a Wall Street analyst.
Just one test, terrifying to her, remained. She, like scores of undergraduates at Massachusetts Institute of Technology, had been putting it off for nearly four years. But Yeh and the others have to pass this exam to graduate.
She had to swim 100 yards, four lengths of a pool, without stopping.
The problem: Yeh never learned how to swim.
''Just having my face in the water really, really freaks me out," Yeh said the day before the test. ''So I never learned, I never really wanted to."
Hundreds of college seniors nationwide are similarly in deep. At Cornell, Dartmouth, and Columbia, where swim proficiency also is required, it is time to sink or swim. For students like Yeh, who has aced virtually every exam in her 22 years, it is time to face demons under the surface.
College swim requirements, which sprang up after World War II, have been in decline since the 1970s. One criticism: The test was biased against those who grew up away from the water.
Among the colleges dropping it: MIT's cross-town rival, Harvard. By 1997, just 14 percent of schools had a swim test, according to a North Carolina State University survey. And more schools have dropped the test since, though college is one of the last chances for mass instruction, said Frank Ormond III, an associate professor of physical education who conducted the North Carolina State survey.
Much to Yeh's chagrin, MIT has stayed the course. Carrie Moore, director of physical education at MIT, calls it ''a critical survival skill that everyone should have."
And for students who are scared of the water?
''This is a great opportunity for them to get over it," Moore said.
For the procrastinators, there were plenty of warnings. About half of the 1,000-member freshmen class usually takes the test by their second week in Cambridge. Typically, about two dozen do not pass. ''It's their first test at MIT, and they fail," said Ben McElhiney, MIT's assistant aquatic director. ''And these are kids who aren't used to failing anything."
From that point the students have a choice: Take the exam or enroll in a beginning swim class to fulfill the requirement.
Lifeguards at the pool say many students who struggle with the test are from Middle Eastern and Southeast Asian countries where they have had little access to oceans or pools or swimming lessons. Among them: senior Mahreen Khan, whose father had not let her swim in public pools in her native Bangladesh because he said they were dirty.
On April 21, Khan jumped in the MIT pool for her test, squealed because the water was cold, and splashed through her first of four lengths of the pool. Halfway across the second, she began struggling to lift her arms out of the water, and then she got scared.
''I started thinking, 'It's too deep here, I can't just stand up,' and I panicked," said Khan, who had never swum four lengths without stopping. She tried to grab onto the lane line, missed, and started to go under. A lifeguard jumped in and grabbed her.
At poolside, Yeh watched, painfully. Yeh had an aversion to the water for as long as she could remember. Her parents were overprotective, she said. They feared she would hurt herself. Because she had no interest in the water, she simply never learned to swim.
On visits to the beach, the Chicago native waded out only until the water touched her waist. If she canoed or sailed, she wore a life jacket. During her MIT career, she signed up twice for beginner classes. Both times she bailed.
''I was busy," she said, adding: ''I kept thinking I'll be the only one in the class who can't swim."
Surveys indicate that about a third of Americans are afraid to put their heads under water. Nearly half are afraid of deep water in pools, and nearly two thirds are afraid of deep ocean water.
Yeh's little bubble of denial popped last month when an e-mail gave a deadline to pass the test. No test, no graduation. That's when she cried. ''It just seemed unfair," she said. ''I mean, who cares if you can swim?"
Once she finally grasped the situation, she enlisted friends who had volunteered to teach her. The time, she told them, had come.
On Day One, she clutched a kickboard in 3-foot-deep water and learned to trust her buoyancy. Day Two, she tried without the board, making it a half a length before standing, exhausted.
Each spring, MIT lifeguard Jimmy Carlson sees plenty of anxious seniors, some with instruction manuals. ''They over-think it," said Carlson. ''When I teach them, they want to learn what angle to hold their arms. I just tell them to go ahead and try it; don't worry about the numbers."
Wearing her roommate's bright blue swimsuit and smoked goggles, Yeh began to make real progress by Day Three. Her housemate, Melanie Michalak, realized Yeh did not have the physical stamina to swim three lengths of crawl, so she taught her the breast stroke. The day before the test she had completed four lengths but had to rest in between each one
On test day, she jumped in the deep end, scrunched up her face and began kicking and moving her arms like a windmill. It was not pretty, but she was moving. The first length went well. By length two, a tiring Yeh switched to breast stroke, then to crawl, her arms barely moving over her head.
For the fourth, she rolled onto her back and finished. She touched the edge of the pool breathing heavily and grinning broadly. ''The hardest test I've ever taken at MIT," she said. Was it worth it? ''Not really," Yeh said. She has no plans to swim again.
Douglas Belkin can be reached at email@example.com.