Smoked, snorted or injected, the drug cocaine gives its users a sense of euphoria that can lead them to conclude falsely that they are doing very well, particularly if the use continues over an extended period, according to scientists for the National Institute on Drug Abuse.

In the case of a professional athlete, continued drug use will probably curtail performance drastically, according to John Grabowski, a staff scientist with the institute.

"All it does is make you feel better, but it doesn't really make you perform better or help the team," Grabowski said. "Many people are not aware of the difference between really doing better and feeling they are doing better."

Charles R. Jackson Jr., assistant director of security for the NFL and a veteran in narcotics enforcement, said most players who become regular cocaine users lose their aggressiveness. "They become very aware of pain," he said. "You get a guy who may have been a real hard charger and he begins to hold back."

Illegal use of cocaine has been an intermittent issue in the sports community for several years. It gained public attention again last week with Sports Illustrated's publication of a first-person account by Don Reese, a former defensive lineman with the Miami Dolphins, New Orleans Saints and San Diego Chargers.

Cocaine, Reese contended, "now controls and corrupts the game because so many players are on it." He estimated that half the 1980 New Orleans Saints used cocaine.

Reacting to Reese's story, Rep. Leo C. Zeferetti (D-N.Y.), chairman of the House Select Committee on Narcotics Abuse and Control, announced that the panel will hold hearings in Washington, probably in mid-July, on the issue of drug abuse in pro football.

"The image of all the league's players has been besmirched," Zeferetti said in a press release. "Obviously they are not all drug abusers. It seems to me that since the league and the players have not been able to solve the problem, it is time that Congress stepped in."

A spokesman for Pete Rozelle, the NFL commissioner, said Rozelle and Zeferetti met Monday, and the league will cooperate in the hearings.

Bobby Beathard, general manager of the Washington Redskins, said he does not believe the Redskins have a drug problem.

In 1977 Beathard was on the staff of the Miami Dolphins and in May of that year he was having dinner with Coach Don Shula when Reese and teammate Randy Crowder were arrested on charges of selling cocaine to an undercover agent. "It was a shock," Beathard recalled.

Still, he said, "It wasn't the big deal then that it seems to be now."

Although some people suggest that Reese's account exaggerates the extent of cocaine use in the NFL, there seems little doubt that use of the drug has increased in recent years.

Since January 1981, Jackson said, 17 NFL players have voluntarily enrolled in the league's confidential program to help players with drug or alcohol related problems.

The number of participants may not indicate the extent of the problem, Jackson said, because players usually don't seek professional help until they are desperate.

Jackson said that since the program began several players have been treated for cocaine dependency and have returned to the NFL.

Last year, the National Basketball Association entered into a working agreement with the Life Extension Institute. The aim of that program was to provide confidential counseling for players; approximately 15 percent of the NBA players have used the service, according to Steven DuVall, who heads the program.

Marital and family difficulties were the No. 1 problem among players using the program, DuVall said, but drug and alcohol abuse was tied with mental health issues for second. The institute, at the request of the league, set up a special program for guard John Lucas of the Washington Bullets after Lucas admitted last winter to having had a cocaine problem.

If cocaine abuse is increasing among professional athletes, that parallels what is happening elsewhere, according to the Institute on Drug Abuse.

Since 1977, according to a survey by the institute, cocaine-related admission to federally funded drug treatment clinics has tripled.