Work anxiety is causing sleepless nights for employees, according to new survey results from global staffing firm Accountemps. More than 4 in 10 professionals (44 percent) in the nationwide survey of 2,800 workers said they often lose sleep over work. The three most common causes of restlessness are an overwhelming workload, a looming business problem and strained co-worker relationships. Among Des Moines employees surveyed, 40 percent said they often lose sleep over work issues. Nationwide, younger employees (ages 18 to 34) are more likely to lie awake at night. Additionally, more men (50 percent) experience sleeplessness over job-related issues compared with women (40 percent).