That music can bring happiness is obvious. But is it also the key to a long life?

Pianist Artur Rubinstein retired from the concert stage after his 89th birthday. Mieczyslaw Horsowski played his final concert at age 99 and taught a lesson the week before he died in 2003, just one month before his 101st birthday. But the world’s oldest living Holocaust survivor, Alice Herz-Sommer, trumps both of these legendary artists.

On Tuesday, she turns 110. Ms. Herz-Sommer no longer plays Bach and Schubert at concert level. Some days, her arthritic fingers fail to cooperate. And she must rely on her prodigious musical memory, as she can no longer see to read a score. But the woman who made her debut as a soloist with the Czech Philharmonic before her 21st birthday in 1924 still plays.

Ms. Herz-Sommer was well on her way to an international career when the Nazis invaded Prague, the city of her birth, on March 15, 1939. Forbidden as a Jew from playing public concerts, she continued to practice long hours in her apartment until the day in July 1943 when she, her husband, Leopold Sommer, and Rafi, their 6-year-old son, were deported to the Theresienstadt concentration camp.

Having heard rumors of concerts in the camp from Leopold, who worked for the Prague Jewish Community Organization, she faced the imprisonment with cautious optimism. “How bad can it be if we can make music?” she remembers thinking.

But from the moment she was herded inside the camp’s gates at age 40, Ms. Herz-Sommer confronted the horrific reality of life in Hitler’s waiting room for Auschwitz. Thousands disappeared, only to be replaced with new shipments of human cargo. In September 1944, Leopold was shipped to Auschwitz. She would never see her husband again.

Before Hitler came to power, it had been a common practice in Germany to hold concerts in factories. Many of the managers in the factories were elevated to positions of authority in the Nazi regime, and so encouraging music in the concentration camps must have seemed a logical step—even if it meant being entertained by musicians slated to be murdered.

“Once one commandant had a prisoner orchestra and concerts, others proudly followed suit,” Anita Lasker Wallfisch, the only cellist in the Girls’ Auschwitz Orchestra, once told me. The Nazis exploited the concerts for publicity, most prominently in a 1944 propaganda film, “Hitler Gives the Jews a City.”

Yet Jewish prisoners were forbidden to bring sheet music or instruments into Theresienstadt. The one piano used for concerts was in extremely poor condition, the buildings were unheated, and the Nazis rarely permitted rehearsals. But as best they could, the performers shared the eternal sounds of Mozart, Bach and Dvorak with those trapped in Hitler’s “model” camp. Ms. Herz-Sommer played more than 100 concerts during her 21 months in Theresienstadt for an audience of fellow prisoners.

“Music was our food,” Ms. Herz-Sommer has said often since those days. “Through music we were kept alive.” She greets visitors today in her tiny London flat with the same radiant smile that must have given much comfort to her fellow inmates as she performed.

After the war, Ms. Herz-Sommer fled the Communist regime in Czechoslovakia to raise Rafi, who had also survived the camp, in the new state of Israel. She eked out a living teaching there at the Music Academy of Jerusalem, before settling in England in 1986. Despite all she has endured, Ms. Herz-Sommer seems joyful when practicing piano or listening to classical music programs on the radio. “I think, no I am sure,” she says, “I am one of the happiest people in the world.”

Ms. Stoessinger, a pianist, is the author of “A Century of Wisdom: Lessons From the Life of Alice Herz-Sommer” (Spiegel & Grau, 2012).