Ochsner Health Systems in Louisiana offers reductions of up to $2,000 from health-care premiums, depending how much employees exercise. The company is one of more than 120 employers that hire Virgin HealthMiles, owned by Richard Branson's Virgin Group, to monitor employees' daily exercise. HealthMiles distributes devices such as accelerometers so employees can prove they're exercising. Certain benefits--beyond a lowered risk for heart disease and diabetes--kick in if employees walk an extra 3,500 steps per day, doubling what they'd walk naturally. Every dollar invested in a reward program yields $3 to $6 in health-care savings, says Virgin HealthMiles Chief Executive Officer Chris Boyce.