How should effective managers deal with complaints from employees that the workload is too heavy?

If it’s genuine that employees have extra work load then should create a new vacancy in the complained department in order to divide the work load or furnish to the existing employees with some extra benefits in term of cash, insurance, gift etc., to motivate their moral. 

When employed, every person would go through certain periods where the workload could be heavier than usual; like at the end of a month or when a deadline for a project looms or before the launch of a product, etc. These times call for an employee to walk the extra mile to get things done.

For other times, it’s a good sign that an employee can freely discuss workload issues with his/her manager. It would greatly help if the manager could guide the employee in analyzing his/her working style, i.e. peak performance time, downtime that could actually be used productively, etc. Once this is done, the manager could sit with the employee, go through the tasks together, reassign priorities and set goals. Once the employee feels that the workload is manageable, s/he would feel more confident about getting work done. And if there are genuine workload issues, like Mr. Naeem Bari said, it might get the manager thinking about hiring an extra person.

I will tell one thing , this is the business,if you don't like find other place