People report that their minds wander at work 37% of the time, and stress increases mind-wandering by 2-3 times, according to The Mind at Work study by Potential Project, a global research, leadership development and consulting firm. By Friday, people who feel stressed report that their minds wander for nearly 60% of the workday.

The Mind at Work study polled people in 44 countries across 15 industries to assemble 225,000 data observations on employee focus, resilience and engagement. It found that unfocused employees and absent-minded leaders cost the U.S. economy alone nearly $30 billion annually.

The study sheds light on what helps us to be our best selves at work. Employees whose work is purpose-driven are 30% less stressed and 50% more focused on their day-to-day tasks, and employees who get a good night’s sleep come to work with 15% more focus, 20% less stress and feel 25% more in control.