CHICAGO — Magician David Blaine took on a Zen-like appearance in the water tank as the minutes ticked by during his attempt to set a new breath-holding record. Oprah Winfrey, however, was anything but calm.

She fidgeted in her chair, pursed her lips, placed her head in her hands and kept seeking reassurance from the doctor at her side about Blaine’s persistently high heart rate.

“I’ll be glad when it’s over. I don’t like suspense,” she told the audience during a commercial break.

Soon enough, Winfrey – and Blaine – could breathe a lot easier.

Submerged in a water-filled sphere on the stage of “The Oprah Winfrey Show” during a live broadcast, Blaine held his breath for 17 minutes and 4 seconds. That bested the previous record of 16 minutes and 32 seconds, set Feb. 10 by Switzerland’s Peter Colat, according to Guinness World Records.

Blaine, 35, had a smile on his face soon after his head rose above the water and took several deep gulps of air. Within about a minute, he was able to hold a microphone and tell Winfrey, “I feel great,” later adding that breaking the record was a fulfillment of “a lifelong dream.”

Before his attempt, Blaine was allowed to inhale pure oxygen for up to 30 minutes, although he inhaled for only 23 minutes. A Guinness World Records judge was on hand to certify the feat.

Previously, the endurance specialist was buried alive for a week in a see-through coffin, spent more than a month suspended by the River Thames in London and was encased in a block of ice for 63 hours.

In May 2006 as a finale to a week spent in an aquarium with an oxygen mask at New York’s Lincoln Center, Blaine tried to set another type of breath-holding record. Without breathing pure oxygen beforehand, he tried to break the existing record of 8 minutes, 58 seconds for an attempt of that type.

But he had to be rescued shortly after 7 minutes when he was unconscious and having convulsions.

After Wednesday’s attempt Blaine was in much better shape. He walked unassisted down a set of stairs to join Winfrey for an interview, during which he told her he had doubted while in the water whether he’d be able to break the record because of his high heart rate.

The lower the heart rate, the less oxygen a human consumes.

Blaine had expected his heart rate to drop perhaps as low as under 20 beats per minute while he was in the water. But for most of the attempt, it was over 100 beats per minute, then started dropping and fluctuating rapidly during the last 2 1/2 minutes.

While training, Blaine said he would meditate to lower his heart rate. But amid the hubbub of a live studio audience, and with a record at stake, Blaine admitted he had trouble forgetting his surroundings.

Earlier in the show, Winfrey noted that Stedman Graham, her boyfriend, was making a rare appearance in the audience because he’s such a fan of Blaine’s work.

For Winfrey, however, the endurance feat was “nerve-racking to witness,” she told Blaine.

Blaine joked about coming back on her show again and again to get used to the surroundings, lower his heart rate and set new breath-holding records.

But first, Blaine said he plans to try to break the world record for staying awake. The current record is 11« days, he said. However, Guinness said it no longer acknowledges such attempts because of health concerns.