The risk in staying reachable after hours isn't the interruption. It's the exhaustion it loads onto tomorrow.

It is 8:47 on a Sunday night. Your operations manager sends you a two-line message asking you to confirm a number before the Monday forecast call. You answer in ninety seconds because it is faster than making her wait until morning. You do not think about it again. She does not go back to what she was doing before your message arrived — she goes back to work mode, because that is what answering you required.

A study published this year in the Journal of Occupational and Organizational Psychology looked at exactly that moment, repeated over and over across a working population. Angela Grotto (Montclair State University and Manhattan University), Rui Sundrup (University of Louisville), and Maura Mills (The University of Alabama) tracked 176 working adults across a five-day workweek, collecting 679 daily reports on off-hour interruptions, sleep, and exhaustion at work. This was not a lab exercise: it was a daily diary design, meaning everything in it — the interruptions, the sleep duration, the exhaustion — is self-reported, and the design shows association, not proof that any single interruption caused any single bad day. I could not get past the publisher's paywall, so I am working from the abstract and the journal's own metadata. That means I cannot tell you how the sample breaks down by industry, company size, or seniority, or whether the paper reports it at all — and I am not going to guess.

What the study does show: when a job carries the expectation that you are reachable after hours, that expectation produces more off-hour interruptions, and those interruptions carry over into exhaustion at work — because each one forces a switch back into work mode during the exact hours meant for recovery. The one lever the researchers found that changed the outcome was sleep duration. People who slept more across the workweek showed a weaker version of that chain, even after the researchers controlled for how well they slept, not just how long.

"These findings suggest that prioritizing sleep can help accrue resources needed for work, shifting the perspective from sleep as a reactive restorative process to a proactive protective mechanism."— from the study's abstract, Journal of Occupational and Organizational Psychology

Here is why this lands differently for the person at the top than for anyone else in the building. You are probably the person least affected by your own after-hours messages. You are up anyway. You are already thinking about the business at 9 p.m., so answering your own question does not cost you a switch back into work mode — you never left it. The person you texted did leave it, and she is also the person least likely to tell you that answering you cost her something, because you sign the checks.

The part the research doesn't say, but that I'll say plainly: the timestamp on your messages is a policy, whether or not you meant it as one. Nobody in your company needs to read an employee handbook to learn when they are expected to be reachable. They read your send times. If you text at 9 p.m. and your best manager sees it, she now has two choices — answer, or explain later why she didn't — and neither of those is a choice you actually offered her out loud. That is a cost you are handing down without ever deciding to.

The study also doesn't say the fix is "never message after hours." But it never tested restraint either. The only buffer it put to the test was sleep duration, and that one worked. What you control is something the study never measured: how much of the interruption is actually necessary. Most after-hours messages are not urgent; they are just top of mind for the person sending them.

One thing to do this week: pull up your last ten after-hours messages to employees — not clients, employees. For each one, ask whether it needed to land that night or whether you sent it because you happened to be thinking about it then. If most of them could have waited, use your email or chat tool's delayed-send feature so the thought leaves your head now and the message lands at 8 a.m. You keep the same clarity of mind; the interruption cost moves off someone else's evening.

This is a small habit, but it sits inside a bigger pattern: leaders set norms through their behavior far more than through anything they say in a meeting. If you want a clearer read on which of your own habits are quietly setting expectations you never intended, the Leadership Profile is built to surface exactly that.