Leroy (Satchel) Paige, a masterful pitcher and baseball showman who once told his fans how to stay young with the advice, "Don't look back, something might be gaining on you," died yesterday in Kansas City after suffering a heart attack. He was believed to be 75.

Mr. Paige did not pitch in the major leagues until he was 42 because of baseball's unwritten policy of not allowing blacks to play. In recent years, he had heart trouble and emphysema. He had experienced discomfort in his home after a Monday storm knocked out power, preventing the use of an air conditioner.

"I said, 'Are you too warm?' " his wife Lahoma related to the Associated Press. When her husband said he was chilly, Mrs. Paige put her jacket around him. The Paiges' daughter noticed he looked "lethargic" and began to fan him. Paramedics were summoned and, along with Mrs. Paige, tried to revive her husband with cardiopulmonary resuscitation.

Alex George, Mr. Paige's longtime friend, said he was dead on arrival at the hospital.

Mr. Paige spent the first 22 years of his career in baseball's Negro leagues, pitching perhaps as many as 125 games a season. Records of those years are sketchy, so his statistics remain as clouded as his real age. Mr. Paige's birthdate was listed as July 7, 1906, in the Baseball Encyclopedia, but when Bill Veeck signed him for the Cleveland Indians in 1948, his age estimates ranged from the 40s to the 50s.

He enjoyed the debate over his age, feigning innocence when pressed to divulge the real number.

Born Leroy Robert Paige in Mobile, Ala., the lanky right-hander began pitching in the mid-1920s for the Chattanooga Black Lookouts. He went on to play for a long list of bush and Negro league clubs, establishing himself as an energetic and entertaining legend.

Art Carter, sports editor of The Washington Afro-American newspaper and former publicity man for the Homestead Grays of the Negro leagues, recalled a game in the 1930s when Mr. Paige summoned his outfielders to the infield, then struck out the next two batters.

Mr. Paige pitched 42 games for the Pittsburgh Crawfords in 1933, and won 31 games, 21 in a row, and had 62 consecutive scoreless innings.

Veeck wanted Mr. Paige to beef up his team's drive toward the 1948 American League pennant and he was not disappointed. At 42, Mr. Paige had a 6-1 record and Cleveland went on to win the pennant.

Although he played against major leaguers in numerous unofficial barnstorming games, Mr. Paige spent only five seasons in the big leagues, with Veeck's Cleveland and St. Louis Browns teams. He compiled a 28-31 record, with 32 saves and a 3.29 earned run average.

In 1965, he signed with the Kansas City Athletics: at age 58, he was the oldest man to play major league baseball. He worked the first three innings of one game and allowed one base hit.

Mr. Paige finally was admitted to baseball's Hall of Fame when a special committee to honor Negro league players elected him in 1971.

Mr. Paige offered a list of half a dozen "Masters' Maxims" to young players, in a effort to keep the world youthful. Besides the admonition not to look back, Paige urged everyone to: "Avoid fried meats which angry up the blood.

"If your stomach disputes you, lie down and pacify it with cool thoughts.

"Keep the juices flowing by jangling around gently as you move.

"Go very lightly on the vices, such as carrying on in society. The social rumble ain't restful.

"Avoid running at all times."

"Satchel was a nice fellow, he was always jolly and liked to tell a lot of jokes," said Buck Leonard, 74, another Hall of Famer from the Negro leagues, from his Rocky Mount, N.C., home. "I never saw him angry at anybody, even the umpire, which pitchers usually are. He always had something funny to tell. He was the fastest thing I have ever seen."

Baseball Commissioner Bowie Kuhn said in a prepared statement, "It's too bad major league fans never had a chance to see him in his prime, for he was one of the greatest pitchers of all time. Some fine athletes are forgotten when they're gone. Satch will never be."