Murray Grant wakes ready to exercise and rests only long enough to get to the next activity.

After a rigorous morning regimen of calisthenics, an early-morning tennis match and a four-mile walk with his wife, Grant relishes afternoons of more tennis and often robust games of pickup soccer.

Forget heat advisories, forget sports injuries, forget his age: Grant is muscular, bald and 79. He plays in extreme heat or cold, with knee and collarbone injuries that haven't fully healed.

"It doesn't bother me a bit," Grant said, jogging onto a soccer field recently in nearly 100-degree midday conditions.

Nothing stops Murray from exercising, strapping on cleats or swinging a racket.

"You need to do something," said Grant, a doctor specializing in public health and preventive medicine who advises seniors to stay active. "This is nothing new for me."

Grant traded his role as director of the D.C. Public Health Department and later chief medical adviser to the U.S. Government Accountability Office to become a leader on the field. For more than two decades, Grant has been organizing soccer leagues through the county's recreation department. When he's not playing sports, he keeps a foot in the medical field, working part-time as director of medical education at Holy Cross Hospital in Silver Spring.

About 25 years ago, Grant founded a soccer team for men over 35. Since then, the devoted group of soccer mates has been playing every week. As they aged, Grant created new teams. He founded a league for men 45 and older, which has grown to 18 teams. Six years ago, Grant started the "golden" division, for men 55 and older. It has five teams.

Grant, affectionately known as "Doc" on the field, still plays with both the 45-and-older and the 55-and-older teams, and is the oldest player.

In black shorts, a white T-shirt and black baseball cap, Grant weaves among 35 teammates during a recent pickup game at Layhill Park in Wheaton.

"Soccer is a wonderful game," he said, reluctantly taking a break to explain his league. With remnants of his English accent apparent, he talked about watching the Glasgow Rangers, a world-renowned soccer team when he was a young boy.

He was hooked on the game then and he named his first soccer team in the county the Rangers. The team still plays together and is regarded as a tough opponent.

League play starts up again in September, with games in Rockville and Silver Spring on Sunday mornings. Between seasons, league members play pickup games on Wednesday afternoons.

Horacio Hasse, 61, a member of the Garrett Park team, has been playing in Grant's league for 15 years.

"I recognize I am old, but I am enjoying the game," Hasse said. He said he relishes the game more now than he did in his pressure-filled 20s. In his homeland of Guatemala, Hasse played professional soccer and made it to the 1968 Olympics.

"Soccer is great," said Hasse, who squeezes in games between the demands of his Rockville computer job. "Here, you forget about work."

The players come from a range of countries -- France, Jamaica, Armenia, Italy, Chad, El Salvador -- and count on the weekly games to socialize and connect with other immigrants.

"This is my life," said Lucio Marchegiani, 65, who travels from Dayton, west of Columbia in Howard County, to play in Murray's league. "My wife knows that my first wife is soccer."

Grant's wife, Trudy, is the center of his social life. The couple recently celebrated 54 years of marriage. But on the field, it's strictly sports for Grant.

"I do like the camaraderie," Grant said, "but I depend on this for my soccer."

Avid theater and classical music buffs, the Grants spend much of their time together attending plays and concerts. They have five children and 11 grandchildren.

Grant remembers that when they married, his wife gently suggested he find another activity, because soccer was consuming much of his not-so-free time.

" 'Why don't you take up a nice sport like tennis,' " he remembers his wife saying. He took his wife's suggestion to heart, playing tennis twice a day, every day.

She doesn't regret it, though. "He's in better shape than some of his partners," Trudy Grant said. In fact, Murray Grant has aided some of his teammates. He remembers dashing across the net at a recent tennis match after noticing his partner suffering from heat exhaustion.

"I got him to lie down and put his head lower than his legs," said Grant, whose nickname on the tennis court is "Ironman."

Grant and his wife recently moved from Bethesda to the Leisure World retirement community in Silver Spring. Clearly, retirement has a different meaning for the Grants. They're not ones to sit around and take it easy.

"Neither my wife nor I will ever do that," Grant said. "You have to keep active, keep doing things, keep busy."

Grant still plays with both a 45-and-older and a 55-and-older team. "You have to keep active, keep doing things, keep busy," he said.About 25 years ago, Murray Grant founded a soccer team featuring men over age 35.For more than two decades, Murray Grant has been organizing various soccer leagues. Grant, a doctor, also works part-time at Holy Cross Hospital.