Hugh D. Jascourt, 70, a Washington lawyer whose passion for running lasted a lifetime, died July 27 after he returned from an extended speed walk around Greenbelt Lake on one of the hottest days of the summer. He was found on the back patio of his Greenbelt home, which borders the lake park.

The cause of death has not been officially determined.

Mr. Jascourt, a cross-country star at the University of Pennsylvania in the 1950s, became a running advocate and a race promoter at a time when it was something of an anomaly to see men and women of all ages, shapes and sizes, clad in skimpy running shorts and lightweight running shoes, jogging on city streets or in such places as Rock Creek Park or on the Mall. Organized races were almost nonexistent.

"I know of no better way to take care of your body, especially your heart, than running regularly," he told The Washington Post in 1962, when he was 27. "Studies have shown that the hearts of old men who ran regularly throughout their lives were strong hearts, just like those of young men."

He organized the first Road Runners clubs in Philadelphia in 1956 and in Detroit in 1958, while he was studying law at Wayne State University. He moved to Washington in 1959, organized the D.C. Road Runners Club in 1961 and immediately began promoting local races year-round.

Thirty-seven people showed up at Hains Point on June 21, 1961, for the first event put on by the D. C. Road Runners Club. By 1980, according to the National Running Data Center, Washington had the most race finishers per capita in the nation.

Today, the Road Runners Club of America boasts more than 670 running clubs across the nation, with 160,000 members. An estimated 37,310,000 Americans run.

Mr. Jascourt competed in the races he organized, and he helped coach the U.S. track and field team at the 1964 Southern Games in Trinidad and at the 1966 International Cross Country Championship in Morocco.

Hugh Donald Jascourt was born in Philadelphia and started running in junior high school. He received his bachelor's degree, with honors, in political science from the University of Pennsylvania in 1956 and his law degree from the Wayne State University Law School in 1960. He was editor in chief of the Wayne Law Journal.

He was an attorney and adviser with the U.S. Department of Labor from 1960 to 1964, an assistant director of employee-management relations for the American Federation of Government Employees in 1964 and 1965 and an attorney and adviser with the National Labor Relations Board in 1965 and 1966.

Among other positions, he was executive director of the Federal Bar Association in 1966 and 1967; house counsel for the American Federation of State, County and Municipal Employees from 1967 to 1969; assistant solicitor for the Department of the Interior from 1974 to 1982; and senior labor law counsel for the Department of Commerce from 1982 to 1990.

A labor lawyer who represented both unions and management, his real love was arbitration, mediation and dispute resolution.

When he retired from government service in 1991, he became founder and president of the Agency for Dispute Resolutions and Synergistic Relations, a nonprofit mediation service based in Greenbelt. He was still active in the organization when he died.

He investigated equal employment opportunity complaints and mediated labor relations disputes at the Department of Agriculture, the Department of Justice, the Department of the Interior and other agencies.

He was a member of the mediation committee of the American Bar Association section on dispute resolution.

He was named to the Road Runners Club America Hall of Fame in 1986 and was a master official honoree of the Penn Relays in 2000. He was a Penn Relays official for more than 30 years.

Survivors include his wife of 42 years, Resa Jascourt of Greenbelt; two sons, Stephen Jascourt of College Park and Leigh Jascourt of Gilbert, Ariz.; and a grandson.