As companies cut payrolls and hours worked to reduce costs during the weakest period of economic growth in seven years, U.S. worker productivity unexpectedly accelerated in the first quarter, Bloomberg reported.

Productivity, a measure of efficiency, rose at a 2.2 percent annual rate after a 1.8 percent gain in the fourth quarter, the Labor Department said today. Labor costs climbed at a 2.2 percent pace, down from a 2.8 percent pace in the last three months of 2007.

Slowing sales and rising expenses for raw materials, like fuel, provoked companies to cut staff hours by the most in five years last quarter. The weakening job market will probably limit increases in pay, indicating there is little risk that escalating wages will heighten inflation.

Economists had forecast productivity would rise at a 1.5 percent annual pace, according to the median of 69 projections in a Bloomberg News survey. Estimates ranged from gains of 0.5 percent to 2.5 percent.

Productivity measures how much an employee produces for each hour of work. Generally, as the economy slows, companies pull back production, hiring and other spending to try to increase efficiency and lower costs.