Despite the reelection of an octogenarian as president of the AFL-CIO, there are stirrings of new life in the American labor movement.

Although George Meany is 83, even his critics concede that he is still vigorous and mentally keen. He presided over the just-concluded convention of the AFL-CIO at Los Angeles not only with his customary aplomb, but in such a way as subtly to suggest that he is not insensitive to the growing influence of younger and less conservative union leaders who are eager to get labor on the march again.

The reelection of Meany should be seen not so much as an unqualified endorsement of his policies as the continuation of an unbroken no-retirement tradition: In the long history of the AFL there have been, besides Meany, only two other presidents, both of whom died in office.

Samuel Gompers was 74 when he died in 1924 after serving 38 years as the organization's first president. He was followed by William Green, who served 28 years, dying on the job at 79. John L. Lewis, first head of the CIO, was president of the United Mine Workers for 40 years, serving into his 80s.

The best evidence that Meany is far from senility is the way he has been shifting ground on positions he has rigidly adhered to in the past, especially on foreign policy, which in recent years has seemed to supersede his interest in labor.

There is little doubt, for instance, that his angry hawkishness in almost obsessively backing the Vietnam war, even after the nation turned against it, marred his leadership, divided labor as a whole and shrank its political power.

Yet, he didn't hesitate to say that "foreign policy is too damned important to be left to the Secretary of State." Even as late as the spring of 1975 he wanted the United States to rush back into Vietnam with mass aid to save the corrupt and collapsing Saigon regime. "If Congress," he said, "does not live up to its responsibilities to Vietnam, the American people will ultimately pass judgment upon it, and that judgment will not be flattering." More recently, however, the AFL-CIO chieftan has been saying, "If I knew then what I know now, I would have been against the Vietnam war."

Another encouraging sign that Meany may be having some second thoughts about his chronic chauvinism is his surprising support of the controversial Panama Canal treaties. It's a sharp break with his long-time cold warrior allies, but, as he knows, it is in line with the thinking of other prominent labor figures.

The rising generation of union leaders has not forgotten how Meany exerted his despotic power to torpedo the presidential hopes of dovish, but pro-union, George McGovern and help pave the way for the victory of former President Nixon, a lifetime enemy of organized labor.

Neither, however, have they forgotten the great contributions of an earlier Meany, who helped merge the AFL and CIO, and then, as its first president, cleaned out the Communists and expelled the corrupt Teamsters. Nobody did more to shore up labor's good name with the public.

Another reason for Meany's unopposed reelection for a 12-th two-year term is the virtually unanimous expectation that it will be his last one, for he will be 85 at the next convention. Meanwhile, just below "Old George," the aging leadership of the AFL-CIO has been notably rejuvenated. In the last two years, half the 35-man executive council, the chief policy-making body, has been replaces with new and younger members.

Also, if anything should happen to Meany, the organization has in Lane Kirkland, its secretary-treasurer, an already well-groomed probable successor. Although a Meany loyalist, the able Kirkland is seen as a younger (55), broader and more flexible figure than his boss. In any case, whoever follows Meany will have to rule by consensus, and that consensus is that the AFL-CIO must get on with a rebuilding program.

Meany's weakness has always been his indifference to growth of membership. His own union, the plumbers, operated as an exclusive closed shop. Over the years, he showed little interest in recruiting young people or minorities. Above all, he seemed largely oblivious to the onrush of 40 million women into the work force.

Since the last convention of the federation in 1975, it has lost 500,000 members. As a percentage of the total work force, union membership has dropped from 35 per cent in the 1950s to around 25 per cent today. It's easy to understand why the Los Angeles convention resolved to launch an aggressive organizing campaign.

An important step is a legislative change in the labor-relations law aimed at making it easier to recruit new union members. Meany now has a mandate to make this the first order of business, and the reports from Capitol Hill are that he is doing his utmost.

As to his pursuit of the goal, some think that Meany, prodded by the up-and-coming white-collar unions, is even ready for a rapprochement of sorts with the political liberals he has so often scorned. Necessity is sometimes the mother of reconciliation.