Good managers understand vacations are well-deserved breaks, not a sign that an employee is not a hard worker.

Every year, two out of three Americans take a vacation, but most feel like they still have to answer work emails or phone calls while they're out of the office. This vacation-work culture is unhealthy and unsustainable and I believe it's the responsibility of today's business leaders to fix it. Managers should set a good example and actively take steps to address the problem.

Why does this vacation-work culture persist? Because the majority of working Americans believe being unavailable on vacation could negatively affect their career. In fact, nearly 80 percent of workers think that working more hours is the key to being promoted. Two in three fear they will look replaceable if they take time off. Taken together, these concerns have produced a deeply unhealthy work culture.

Related: Workers resort to lying to avoid checking in on vacation