Katie Ledecky won the 800 freestyle final in 8:10.32 to qualify for a third individual event at the Rio Olympics. (Al Bello/Getty Images)

After hoisting herself out of the competition pool at the U.S. Olympic trials for the final time Saturday night at the conclusion of the 800-meter freestyle final, her face and body language betraying the slightest hints of the toll of six straight days of all-out racing, Katie Ledecky’s countdown to Rio de Janeiro officially began. When she wakes Sunday morning, having already begun the process of switching her body clock over to Brasilia time, it will be exactly 36 days until her first swim of the 2016 Summer Olympics.

Unless it is 35 days.

As she spoke to the media following her latest runaway victory — a nearly 10-second win in the 800 free, with a time of 8:10.32, securing her place in a third individual event in Rio — her words reflected a sense of satisfaction, but her tone was of the opposite, as if she thought she could have been better here. And there was also a thread of determination, as if she was resolved to be better in Rio.

“I got the job done,” said Ledecky, a 19-year-old from Bethesda. “I would’ve liked to have been faster, but I could tell throughout the race it wasn’t all that much faster than [Friday’s preliminary time of 8:10.91]. I would’ve liked to have brought in the legs a little more, but the legs just weren’t there tonight and it made my arms a little tired. But I got through it, and I can’t complain about an 8:10.

“I did what I needed to do here to do what I want to do in Rio.”

What is known about Ledecky’s ambitious Olympic program is this: She will be swimming the 200 free, 400 free and 800 free. At the world championships in Kazan, Russia, last August, she swept those three events, plus the 1,500 free (which isn’t contested for women in the Olympics) — an unprecedented feat now known as the Ledecky Slam. She also set three world records along the way.

The world will be expecting a similar show of dominance in Rio.

She will be an overwhelming favorite in the 400 and 800, as the world record holder in each, and a slight favorite in the 200, in which she is the top-ranked swimmer in 2016 — by twelve-hundredths of a second over Italy’s Federica Pellegrini — as she seeks to become the first woman since Debbie Meyer in 1968 to sweep all three in an Olympics. She will also anchor the 4x200 freestyle relay, another gold medal possibility, giving her the opportunity to join Amy Van Dyken (1996) and Missy Franklin (2012) as the only American women to win four golds in a single Olympics.

Those are the four Olympic events for which Ledecky qualified at the Olympic trials, and the four events most likely to keep alive her streak of having never lost a final at a major international meet.

She also remains a potential member of the 4x100 free relay — which comes Aug. 6, the opening day of the Rio swim meet — even after finishing outside the top six, which typically determines the relay’s personnel. That’s because the U.S. coaching staff has the leeway to make substitutions up until the night before the race, and a potential scheduling conflict involving 28-year-old Dana Vollmer — who has the 100 butterfly on the same day as the 4x100 relay — could create an opening for someone else.

And who better to fill it than the premier freestyler in the world — who, for what it is worth, has no other swims on that day, with her first individual race Aug. 7, the following day?

“If they want me for that relay,” she said Saturday night, “I’ll be ready.”

But even for Ledecky, who seems so indefatigable and appears to power through the water with such ease, there is a price to pay for swimming extra events. Asked Saturday night whether the three 100s she swam over the previous two days — a prelim heat, a semifinal and a tension-packed final — may have compromised her in the 800, she said, “Probably.”

“It was a different week, a different set of events than I’ve done in the past,” she said. “Take three rounds of the 100 out, and my schedule gets a little easier in Rio.”

It was an open secret in Omaha this past week that Ledecky, with the unusual luxury of knowing she would still make the Olympic team in her core events at something less than full power, did not take a full taper — or extended period of rest — ahead of the trials, the way almost every other swimmer does. The assumption is that, with a full taper ahead of Rio, there are still faster swims and lower times within her for the Olympics.

“I’m really excited to get back to work this week and see if I can get a little faster,” she said, “then taper down and get ready for Rio.”

Minutes before the start of the 800 final, the giant video board above the pool replayed highlights of Ledecky, then 15, winning the same race four years earlier at trials — in 8:19.78. In the “ready room” where swimmers wait to enter the pool deck, Ledecky watched it on a television and was struck by the change in her stroke and the improvement in her turns from four years ago.

“It gives you perspective to look back at how much I’ve improved over the last four years,” she said, “and the time shows that.”

Amazingly, four years later, she is still the youngest swimmer — at least so far, with one day left in this meet — on the U.S. Olympic swim team for Rio. But in terms of both status and experience, with one Olympic gold medal and nine world championship golds, she will be looked to as a veteran.

“Hopefully I can bring a little bit of something to the team,” she said. Her advice to younger swimmers, she said, would be, “Just to enjoy the Olympic experience. Do as much as you can, but also do everything you need to do to swim your best.”

One by one, as they have finished their meets this past week, those swimmers who have clinched Olympic spots have been switched to a new, Olympic training schedule, one that accounts for both Rio’s time zone — which is one hour ahead of Eastern daylight time — and the bizarre meet schedule for the Olympic competition, in which, to accommodate television, preliminary heats will start at 1 p.m. and evening finals at 10 p.m. Rio time.

So, instead of a daily schedule involving early-morning and late-afternoon practices — typical of swimmers — Ledecky, like her Team USA teammates, will begin training in the late morning and night and adjust her body clock to account for, say, 2 a.m. lights-out and 10 a.m. wake-ups.

But by now it is clear that time is no enemy for Ledecky. She is still so young and still so fast, to where time, at least in the sport of swimming, must adjust itself to her, and not the other way around.