Participatory and spectator sports have a pervasive influence on the lives of a vast majority of Americans, affecting the quality of marital relations, patterns of child rearing and the reading and television watching habits of millions, according to a major survey released yesterday.

The survey, based on a random, nationwide questioning of 1,319 men, women and teen-agers last October and supplemented by interviews with 410 coaches, sports physicians, sportswriters and broadcasters, found only 3.7 percent of the population is uninvolved in sports, either participating or watching less than once a month.

Done by the New York-based Research & Forecasts Inc. for Miller Lite Beer, the survey represents one of the most extensive inquiries ever into the role of sports in America. Among its major findings:

* Seventy-four percent of the population watches sports on television at least once a week, and almost 70 percent watch, read about or discuss sports at least once a day.

* Forty-four percent of all Americans participate in a sports activity every day or almost every day, and 71 percent say they engage in sport or physical exercise at least once a week.

* In terms of numbers, swimming is the most popular participatory sport in America, with 33 percent of the population swimming at least once a week. Thirteen percent of the population swims almost every day. Swimming is followed by calisthenics, jogging, bicycling and baseball in terms of frequency of participation. Sports participants said football, baseball, basketball and tennis were their favorite sports after swimming.

(The fact that the poll was done in October, when many participants could be expected to have been swimming frequently during the summer months, could account for some of swimming's popularity.)

* Top spectator sports are football, baseball, basketball and gymnastics, in that order.

* Couples with similar levels of sports interests appear to be more satisfied with their marriages, and 75 percent of American parents encourage their children to participate in sports. Eighty-five percent watch their children compete and cheer them on, and 46 percent feel as if they are participating in their children's games.

John Crowthers Pollock, president of Research & Forecasts and the principal author of the survey, said its findings disprove the myth that sports in America involve only a few participants and a large numbers of spectators. "We're very involved in sports as a country," said Pollock, adding that most sports participants in America are attracted for reasons other than competition.

"Americans are much more interested in enjoyment and health than they are in competition," said Pollock.

Pollock also said the survey indicated that American families "are involved in sports in a way that is very important . . . We see little evidence of the sports widow. We see involvement. What we don't see is the stereotype of the American father sitting home alone on Sunday afternoon or Monday night watching a football game."

One out of every four Americans surveyed said participating in or watching sports events brought his family closer together. But, said Pollock, "most Americans (57 percent) do not think sports activities have any effect on family life . . . Our evidence suggests that they do--the shared interest in sports, the satisfaction that couples derive . . . "

In terms of leisure activity, the survey found that 59 percent of those families who share a high interest in sports express a high degree of satisfaction with their overall leisure time, compared with 32 percent of those who share a low interest in sports.

Alan G. Easton, a vice president of Miller, said the $250,000 survey was commissioned because "it was about time for somebody to do something like this . . . Honestly, it's also true that the sports fan and the beer consumer are essentially the same."

In terms of attitudes towards children's participation in sports, a majority of the survey participants agreed that competition is good for children because it teaches them to try to do their best. But an even larger majority also agreed that sports leagues for children are sometimes taken too seriously.

Eighty percent of the survey participants agree that teams with children 12 or younger should allow all to participate equally, and 86 percent agreed that in children's sports leagues there is too much emphasis on winning.

At the college level, 68 percent of the survey participants said intercollegiate sports involve the proper degree of professionalism. But college graduates are much more likely (33 percent) to say that college sports are too professional than are high school graduates (20 percent) or those with an eighth-grade education or less (12 percent).

The survey also noted that interest in sports, both as a participant and as a fan, tended to increase with the level of education and with annual income.