If employers want more alertness and productivity on the job, they should follow the example of elementary school teachers, says New Jersey cardiologist George Sheehan.

"When kids get restless, bored and unteachable, we schedule recess so they can run their heads off for 20 minutes," the 60-year-old marathon runner told a group of about 75 corporate administrators at a symposium on employe health and fitness in Gaithersburg.

"The kids come back docile and ready to learn. The same principle applies to the workplace. When a person has the opportunity to exercise during the day, energy is restored. There's no better way to inspire creativity and loosen up brain cells. That's why employers have to get their employes moving."

Co-sponsored by the YMCA, the Washington Board of Trade and the President's Council on Fitness and Sports, the symposium outlined other benefits of employe health programs, including reduced absenteeism, heightened productivity and improved morale.

Richard Warner, supervisor of Exxon Corporation's physical-fitness laboratory, presented six model employe-fitness plans, based on programs currently in use around the country.

They are listed here in order of cost. (Compare these expenses to the estimated $50,000 it costs to replace a key employe who dies of a heart attack, suggests Richard Keelor of the President's Council on Fitness and Sports.)

1. Education program. The company encourages fitness at minimal cost by providing pamphlets and showing films on subjects such as nutrition, obesity and exercise. They also might sponsor exercise clubs, or provide space for lunchtime runners. Boeing Aircraft in Seattle, for example, turned some underground tunnels into jogging tracks.

2.Employer-employe shared costs. The company pays part of the employe's membership in an outside fitness facility or health club, and the employe pays the rest. Or the company might subsidize a yoga or dance class, taught at the workplace, and charge employes a small fee. The employer can expect to pay anywhere from about$100 to $550 per participating employe per year. In Milwaukee the YMCA provides programs for 15 local companies.

3. Non-supervised facility. The employer provides an on-site equipped exercise room for employes to use on their own time. The employe recreation association may opt to run the room. Depending on the space available, the exercise and locker room, equipment and showers might cost about $45,000. Texas Instruments has a 34-acre employe "playground" run by their recreation association.

4. Supervised facility. The company provides a supervised exercise facility. Employes exercise on their own time and may share some of the expense. The operating cost would run a minimum of about $30,000 per year, not including salaries. Branches of Metropolitan Life Insurance have such facilities.

5. Cardiovascular conditioning program. The employer provides a supervised exercise facility and the employe pays some costs for cardiovascular screening and conditioning. The fastest growing program, this plan works well at companies that have flexitime since employes exercise on their own time. Some companies allow families to use the facilities. Operating costs can run from about $20,000 to several hundred thousand dollars per year. Xerox in Connecticut has this type of program.

6. Total fitness plan. The employer provides a comprehensive in-house program, complete with exercise room, medical testing and uniforms. Often limited to top executives, participants may work out on company time. Operating costs can run from about $35,000 to several hundred thousand dollars per year. Several New York banks, including Chase Manhattan, offer executives this plan.