Mark A. Wieder began playing chess at age 8. Now the owner of a consulting firm in New Jersey, Wieder, 65, played competitively throughout high school and college. According to the U.S. Chess Federation, he is among the top 5 percent of federation members age 65 and older.

During the last two summers, Wieder has flown to Missouri to spend four days at the Chess Club and Scholastic Center of St. Louis watching even better players compete. “It’s like sending your brain to the gym,” he said.

Wieder plays in tournaments in Ridgewood, New Jersey, and at the Marshall Chess Club in New York’s Greenwich Village, where he’s eligible for a reduced-rate senior membership of $225. He said he hoped to eventually join tournaments abroad once his children were on their own.

As people age, ways to keep the mind sharp are becoming one of their latest obsessions. A Brain Health Research study released in 2014 by AARP found that those questioned believed maintaining mental acuity (37 percent) was second only to a healthy heart (51 percent) in sustaining a healthy lifestyle.

While many older people are attracted to mind challenges and computer games, others like Wieder embrace competition in tried-and-true games like bridge, poker and chess.

“Computer games don’t offer the same opportunity for social engagement,” said Cynthia R. Green, founder and president of Memory Arts, a company in Montclair, New Jersey, that provides memory fitness and brain training to organizations. Experts say besides social engagement and rewards for winning, tournament participants reap intellectual and travel benefits.

Research released in 2014 from the University of Wisconsin-Madison found that “participants who engaged in cognitive activities like card games have higher brain volume, in specific regions, compared with peers who played fewer or no games,” said Ozioma C. Okonkwo, an assistant professor of medicine at the university and the study’s senior author.

Ursula M. Staudinger, director of the Robert N. Butler Columbia Aging Center at Columbia University in New York, said competition conferred other benefits. “A competitive tournament is another type of unpaid work,” she said. “It’s serious, has purpose or meaning.”

Calculating how many older people play these games seriously is difficult. Many play recreationally with friends at home or in community and senior centers. But there is evidence from associations devoted to tournament play that senior interest in competition as a way to sharpen their skills is growing as well.

The American Contract Bridge League, based in Horn Lake, Mississippi., estimates that 95 percent of its more than 167,000 members are older than 55. About 12,000 new members join annually.

The U.S. Chess Federation, based in Crossville, Tennessee, says its membership has grown to 85,000, from 75,000, in the past five years, and the number of those over 55 increased to 16,300 from 14,500. Membership rates range from $40 to $122.

And participation in the main World Series of Poker event in Las Vegas by those 50 and older increased to 4,193 players in 2015, from 2,707 players in 2009. Buy-ins to the various World Series of Poker competitions vary, from as little as $75 at satellite tournaments to as much as $10,000 for some competitions. Typically, the top 10 percent take home some winnings.

While tournament poker is limited to states where gambling is legal, like Nevada and New Jersey, an avid bridge player can play at some 3,300 local clubs or travel to three-day sectionals and seven-day regional events, all under the auspices of the American Contract Bridge League.

The group also conducts three 10-day annual tournaments called the North American Bridge Championships, each held in a different city. This year 5,000 participants descended on New Orleans in the spring and 6,500 signed up for a summer event in Chicago. The fall competition is wrapping up this weekend in Denver. The tournaments offer group rates for lodging and sightseeing. Players compete for master points, not cash.

Peggy Kaplan, 64, a real estate agent who lives in Minnetonka, Minnesota, registered for all three bridge tournaments this year. She holds the designation of Grand Life Master, the highest level of achievement, having earned 10,000 master points.

“You never stop learning,” she said. “There are all sorts of people I would have never met or known, if not for bridge.”

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Kaplan said she usually stayed at a tournament hotel for convenience, at times socializing past midnight, but she forgoes tourist attractions. She goes to the tournaments “to compete and see friends,” she said.

Margaret Mitchell, 66, who recently retired from a financial service company, has about 2,400 master points and takes a more restrained approach to competition. For the Chicago tournament Mitchell, of Minneapolis, stayed at a friend’s condominium in nearby Evanston, Illinois, and played for four days.

At regional events, she enjoys meeting with people she has competed against before. But it’s the constant challenge of the game that excites her most. “You’re building a language for use at the table, a combination of positive and negative inference, determining a line of play and how well you interpret the language of bidding,” she said.

Denise C. Park, research director at the Center for Vital Longevity at the University of Texas at Dallas, says competition allows participants to engage with opponents and respond to strategy. “There is value in being matched with an opponent at the appropriate skill level,” she said.

Stephen Zolotow, 70, considers himself a professional games player, but the Las Vegas resident notes that there are drawbacks to the organized competitions. In duplicate bridge tournaments, “the games are very regimented,” he said. “You play on their schedule.” (In bridge he has amassed about 2,500 master points.)

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For those who want to avoid the confines of organized competitions, online play is an attractive alternative.

In chess, one of the largest sites is the Internet Chess Club, with 30,000 users. It offers chat rooms, message centers and paid instruction with teachers. It also live-streams most top events.

“If they are a chess addict, this is chess heaven,” said Martin Grund, vice president of online operations for the Internet Chess Club, which is based in Pittsburgh. “They won’t miss any major tournaments.”

The website www.bridgebase.com draws 100,000 daily users. The flexibility of online play is appealing to players like Kaplan.

“You can get online, play at any hour of the day and night, anywhere in the world,” she said. “Everything you do in real life.” She estimates she plays from 45 minutes to three hours, four to five evenings a week.

Wendeen H. Eolis, 71, founder of Eolis International Group in New York City, a legal recruiting and legal management consulting firm, was the first woman to finish in the money at the main event World Series of Poker, in 1986, and is considered a pioneer in bringing more women into the game. She has stepped away from the intensity of competing at the highest levels but is confident that the benefits endure. “Negotiation is a way of life,” she said.

As for Wieder, he looks forward to playing chess as long as he can. “Age plays almost no part in chess,” he said. At a recent tournament he was paired against an 11-year-old opponent. The game was a draw.

© 2015 The New York Times Company