Many Washington area schools scrapped all outdoor activities through the weekend, several tour groups canceled plans to visit the capital, and home-delivery services thrived yesterday as people tried to protect themselves from a deadly sniper they feared could strike again.

The impact of a week of shootings on daily routines could be felt almost everywhere in the region, but particularly where children were involved. Northern Virginia school districts canceled all outdoor athletic events, including varsity football games, through Sunday, and Prince George's and Anne Arundel counties moved their weekend football games to Monday. The association that governs sports in D.C. public schools was to make its decision today.

Montgomery County school officials said today's football games would be played tomorrow and all other weekend events would go on as scheduled.

Many youth recreational leagues also took unscheduled mid-season breaks, despite concerns from some league officials that it might be an overreaction.

"It's not an easy decision," said Howard Kohn, commissioner of the Takoma Park Neighborhood Youth Soccer League, which has 2,000 players and canceled all games through the weekend. "As a practical matter, once you cancel, when do you resume? Do you wait for an arrest? Then there's the question of what we're telling our kids with these decisions. There are parents on both sides, and even within the league, the officers were split."

The annual Washington Area Girls Soccer League tournament, which had been held last year despite the Sept. 11 terrorist attacks, was abruptly canceled Wednesday night. This weekend's tournament involved 372 teams, most of them from outside the region. Local hotel operators said the cancellation would cost them hundreds of thousands of dollars in lost revenue.

"Nobody's happy about it, but you've got some choices, and first and foremost we cannot guarantee [players'] safety," said league president Kathie Diapoulis. "Wouldn't it be a coup for this guy to set up in the woods around one of the locations and pop off one at my players, parents or tournament officials? I'm not willing to take that chance."

Even the mundane, such as picking up lunch, wasn't being left to chance. At Mario's Pizza House in Arlington, manager Boo Chauhan said only two or three people came in yesterday, a stark contrast to the long lines that usually snake out the door. Delivery orders, on the other hand, were nearly double the average, something that couldn't be pinned solely on yesterday's rain.

Pizza Hut in Rockville has been delivering about 20 more pizzas a night since the shootings began. And A La Carte Express, which delivers food from 90 different restaurants to homes in the District, has had such a large spike in business that owner Russell Winter has had to make some of the deliveries himself.

Chauhan's conclusion: "People are definitely scared to go outside."

Other activities that might be considered optional -- such as exercise -- also provide evidence of the sniper's effect on lifestyles. There is less traffic on running trails throughout the region, and some health clubs report that treadmills are picking up the slack. At Fitness First in Rockville, treadmills are usually available even during peak hours, trainer Theresa Dunn said. But not this week. Now customers must sign up in advance and face up to a 20-minute wait.

"My wife told me, for example, that until this thing blows over, she's running on the treadmill," said Brian Tresp, president of the Montgomery County Road Runners Club. "There are definitely fewer people out. If you go to Rock Creek Trail or to Capital Crescent Trail, it's much, much lighter than, say, two or three weeks ago."

Some whose businesses depend on tourists say the nervous reaction to the shootings has resulted in a dip in revenue. The Doubletree Hotel and Executive Conference Center in Rockville was expecting 200 people for a high school reunion banquet this weekend, but by yesterday, half of those had canceled, said Ed Proenza, general manager of the hotel.

October is traditionally an active time for school tours in Washington, but the sniper attacks have trimmed the schedules of some operators. At Classic Tours in Auburn, Ind., a tour of 35 Michigan eighth-graders who were to come to the District next week was canceled. So was the tour of 112 Indiana eighth-graders planning to come Nov. 30. The status of the company's remaining trips, worth about $4,000 each, is growing more precarious with each gunshot, said the tour company's owner.

"We think we're about to lose them all," Carole Seavers said. "The schools are getting call after call from parents saying they are afraid their children are going to get killed."

One company, Educational Tours Inc. of Deerfield, Ill., sent letters to school officials noting that the shooter "has been operating in wooded/shaded areas many miles away from D.C. historical monuments and memorials." The approach seems to have worked: Of 500 students scheduled to arrive here next week from Chicago, only about a dozen have pulled out, and the trip will go on as planned, company president Mitchell Slotnick said.

But closer to home, AAA Mid-Atlantic suspended its school safety patrols in the Washington area for the first time in at least two decades. In the program, older elementary school students assist younger ones in getting on and off school buses and crossing intersections.

Taste of D.C., a three-day outdoor food festival, will open on Pennsylvania Avenue NW, stretching from Seventh Street to 14th Street, as scheduled tomorrow. It is expected to draw up to a million people.

"As there is every year, there'll be a police presence," said Victoria Isley, a spokeswoman for the Washington DC Convention and Tourism Corp. "Safety's in the hands of the professionals."

Cpl. Tammy Sparkman, a spokeswoman for the Prince George's County police, said extra precautions will be taken for Sunday afternoon's Washington Redskins game at FedEx Field in Landover, about 10 miles from Benjamin Tasker Middle School, where a 13-year-old boy was shot and critically wounded Monday.

"We do have security measures in place, but we're not disclosing any of the plans at this time," she said. "We do encourage everyone to attend the game."

For those who decide to stay inside and limit their exposure, could such lifestyle changes really prevent more killings? 

Gregg McCrary, a retired FBI profiler from Fredericksburg, said the spread of fear around the area is creating "hardened targets" for the killer.

"It's going to be harder for him to find communities that aren't as vigilant," he said. "The more he does this in different areas, the greater the caution among residents, and the greater the vigilance among law enforcement."

Several people said that until the shooter is caught, they would rather err on the side of caution than court unnecessary risk.

"I think everyone hopes to return to normal, but I'm not sure what it will take to get there," said soccer commissioner Kohn. "An arrest would certainly bring us back to normal, but short of that -- I don't know."

Staff writers Manny Fernandez, Christina A. Samuels, Annie Gowen, Allan Lengel, Debbi Wilgoren, Michael Barbaro, Michael E. Ruane, Justin Blum, David Cho, Judith Evans and Greg Sandoval and special correspondent Brian Straus contributed to this report.