8:00am Sunday: You glance over and notice an email from your boss while you’re eating breakfast and reading the paper. Ok, you think, I’ll respond later, maybe after my run.

8:10am: Ping! A text arrives. “I have a question about the project.” Ok, you think, it’s Sunday, but sure, I’ll get back to him after breakfast.

8:20am: The phone rings. It’s him. “I’ll need that slide for tomorrow’s presentation. How soon can you get it to me?”

You are a valued professional, a team player. But, there goes your morning run. Or the game of catch with your child. Or reading that book you can’t put down.

Health care professionals have always understood the need for coverage around the clock. It took the form of “being on call” — with specific people designated to respond to middle of the night emergencies — one of the responsibilities of the profession.

But you were not always on call. You had time away from the pressures and demands of the job to re-energize.

Fast forward to today and “24/7″ has become a badge of honor for knowledge workers everywhere. People boast about working more hours in a week than they should (for health, sanity, and safety) even be awake. The Sunday-interrupting boss is not an outlier tyrant, but rather the norm. Suddenly, however, recent news brings some well-intended efforts to reverse this tide.

Perhaps you’ll disagree, but pushing back against overwork is a crucial leadership issue. Leaders must create a culture where sane work hours are not only accepted, they’re respected. They must strive to build a culture where everyone respects people who get things done — for patients, for the world — and perhaps even worry a little, and express concern, about those unable to get their work done within the constraints of sane, safe work hours.

Insane work hours are the result of an unfortunate intersection between new communication technologies that allow us to find employees at any time, any place and the sheer difficulty of assessing the quality of knowledge work and the contribution of individual knowledge workers. Assessing someone’s availability or hours is easy, so bosses everywhere start to equate this with performance. Who are the good workers? Those who work around the clock!

Really? Of course not.

Reversing the tide of overwork

Here are three reasons why we’ve got it wrong, and why leaders in every organization must help people reverse this powerful tide of overwork.

1. Activity does not equal productivity. Intuitively we know this. We can be incredibly busy and get little done. Distraction is a new and growing epidemic… Email, well, don’t get me started. More work hours do not automatically produce more or better work. Henry Ford famously experimented with longer and shorter workweeks and found that 40 hours produced maximum productivity. More hours didn’t produce more cars, while fewer hours produced fewer cars. Hence, the weekend was born.

2. Sleep deficits irrefutably lead to harm, including bad decision-making. They also lead to professional burnout.

3. Norms about availability ratchet up, never down. The more a boss thinks he or she can reach you 24/7, the more she will, in fact, reach you 24/7.

Some pioneers have started to take action. For example, Goldman Sachs instituted a new policy to banish the defacto 100-hour workweek that had become embedded in the culture. Boston Consulting Group asked consultants to turn off their smartphones, one night a week. New studies on multitasking, sleep and cognition, and overwork and burnout, resoundingly support this new take on what it means to be a good employee.

It seems to me that banishing the culture of addiction to 24/7 presents a golden opportunity for any leader, in health care or elsewhere, to make a difference — for employees, their families, and their clients. Of course physician call systems for emergencies remain critical to the profession.

However, those not on call need to recharge and refresh. And who better to speak up about and model healthy work-life practices than leaders in the industry in which a bad decision made by an over-tired nurse or doctor can lead to harm for a patient?

Amy Edmondson is the Novartis professor of leadership and management, Harvard Business School. This article originally appeared in athenahealth’s Health Care Leadership Forum.