DUBLIN, Ireland - Though the Philadelphia Orchestra's current tour of European festivals leaves little time for the players do anything but travel, rehearse, and perform, some of them believe they'll burn out, stress out, or suffer some other unpleasant consequence if they don't find a way to break that routine during their few free hours in any given city.

Counterpoint is one key to equilibrium. Several musicians are in training for athletic events. Some are collectors and hunt for local treasures. On Monday, a quartet of musicians headed for the Irish mecca of beer drinkers, the Guinness brewery, known here as the Guinness Storehouse.

They took their instruments with them.

"I was signing up for tickets for a tour of the brewery on the website, and there was something that said 'Perform at the brewery!' " said concertmaster David Kim. "They had a YouTube clip of some high school band . . . so I wrote and said, 'Hey! We're the Philadelphia Orchestra. We'd like to try and play there.' And they said, 'We'd be delighted to have you!' "

On Monday afternoon, Kim led a quartet consisting of himself, violinist Daniel Han, violist Anna Marie Ahn Petersen, and cellist Yumi Kendall into the top level of the brewery, known as the Gravity Bar, where visitors enjoy pints of Guinness and panoramic views of Dublin. They played the first and last movements of Schubert's String Quartet No. 14 ("Death and the Maiden").

At this venue, the Fabulous Philadelphians probably weren't on anybody's radar as they launched into the lively first movements of this most beloved of Schubert's string quartets. But within moments the crowd had quieted - some people looking entranced, others setting aside their harp-emblazoned glasses to take pictures of the unusual sight.

"This takes a little bit more concentration, I have to say," cellist Kendall observed. "And in the quality of the playing, everything is up a decibel level."

Their official hosts were pleased. "We've had a lot of quartets. Last year we had a quartet from, oh, some part of Sweden," said Teresa Tuite, the bar's manager, before rhapsodizing, "It's beautiful. I love it!"

She turned to one of the players and asked, "Did you like the bar here? You need a pint now - to get ready for tonight!"

At most, the quartet members did a little sipping (one abstained completely, noting privately that the beverage "looks like something I'd pour into my car") in recognition of Monday evening's concert at the National Concert Hall, where pianist Jean-Yves Thibaudet would be filling in for the indisposed violinist Janine Jansen.

The concert marked the orchestra's Dublin debut, and at the morning rehearsal, in which chief conductor Charles Dutoit rehearsed Ravel and Stravinsky in minute detail, the players were delighted with the hall's lively but mellow acoustics, not to mention its unconventional light-green color scheme.

After rehearsing, they dispersed. Carol Jantsch set off to run laps around nearby St. Stephen's Green, Dublin's flower-and-sculpture-filled park, as if lugging her tuba around Europe wasn't enough exercise. Most wind players are big on cardiovascular training for the breath-control benefits. But Jantsch, 26, is in training for November's Philadelphia Marathon. She saves her longest runs for days when the orchestra doesn't have a concert.

"In Vienna [last week], I went to the island in the middle of the Danube that was all pedestrians, bicycles, and runners," she said. "I meant to do 12 miles but got a little lost and did 13."

And in running (as in music), "I don't like getting lost. I study the map a lot before I go."

Meanwhile, at subterranean health club at the Hotel Conrad, violinist Herold Klein - a 40-year veteran of the orchestra - was on a stationary bicycle turned up to top speed. He planned to stay that way for an hour, preparing for two multiple-sclerosis-related charity bicycle rides, the big one being October's MS Great 8. Covering eight states in eight days, and roughly 75 miles a day, it has been part of his life since 2007 - in part because of his love of bicycling, in part because of his commitment to the MS charities.

Normally he rents a road bike, often with cellist Derek Barnes, but such things sometimes aren't available, even in major European cities. "I think we got the only two road bikes in Vienna," he said. And just as Jantsch has studied different running techniques, retooling her own and finding exactly the right shoe to accommodate it, Klein, 66, is used to his bicycle back home, whose materials, weight, and size are as closely tailored to his needs as his instrument.

Still, he brought his own pedals on tour, and swears by the psychological benefits that he says come with any two-wheeled vehicle. "There's something about getting on a bike and just riding and riding and riding . . . that if you have a stressful problem to solve, you can do it," he said.

There's a bit of that going around. Cellist Richard Harlow maintains his sense of balance by keeping a blues harmonica in his pocket - an emotional outlet that takes on particular poignance amid the orchestra's current bankruptcy reorganization, a situation Harlow says "leaves a pit in the stomach."

"I try not to think about it. Performing in Europe is like being in the World Series. We have to be at our best," he says, adding firmly, "and we are."

Contact music critic David Patrick Stearns at dstearns@phillynews.com.