There is a zero-cost, zero-calorie, instantly available stress management tool that requires no equipment, no subscription, and no dedicated time in your calendar. It works within seconds, has measurable effects on cortisol and brain chemistry, and most senior professionals dramatically underuse it partly because somewhere along the way, leadership got quietly associated with looking serious.

That tool is laughing. And its slightly more restrained colleague, smiling.

Before you dismiss this as the least useful entry in a stress management series: the mechanism is genuinely interesting, and there’s a specific detail about smiling that most people don’t know and that actually changes how you use it.

Not all smiles are doing the same job

Here’s the detail worth knowing. There are essentially two kinds of smiles, and your brain treats them very differently.

A polite smile, the one you produce in back-to-back meetings, in photographs you didn’t ask to be in, or when a colleague explains something for the third time, uses only the muscles around your mouth. Your brain recognises this immediately for what it is: a social performance. It produces no particular neurological benefit, which may explain why you can smile through an entire day and still feel exhausted by it.

A Duchenne smile, named after the French neurologist Guillaume Duchenne, who apparently spent a remarkable amount of his career investigating what made smiles look genuine , is different. It engages not just the mouth but the muscles around the eyes, creating the small creases at the corners that are genuinely difficult to fake. More importantly, it sends a direct signal to the brain that something good is happening. Cortisol drops. Endorphins release. Your nervous system receives a clear message that the threat level has lowered.

The quickest way to find yours: think of a memory that makes you genuinely happy a moment that still makes you smile without any effort. Something ridiculous a friend did. A time you laughed until it hurt. The look on someone’s face when something went unexpectedly right. When the smile arrives from that place rather than from social obligation, you’ll feel the difference in your body almost immediately. Tension eases. The shoulders drop slightly. Something loosens.

If you’re currently attempting to smile while reading this to check whether your eyes crinkle, that’s entirely normal and counts as a good start.

From smiling to laughing, a short but worthwhile journey

Laughter is essentially smiling with commitment. And when it arrives genuinely, the neurological response is considerably more pronounced a rapid release of endorphins, dopamine, and serotonin that collectively do what most people spend significant money trying to achieve through other means.

The interesting thing about laughter at the senior professional level is that the barriers to it are often self-imposed. There’s an unwritten rule in many professional environments that serious work requires serious people, and that laughing too readily signals that you aren’t quite taking things seriously enough. This is, to be blunt, both neurologically incorrect and a significant waste of one of your best stress regulation tools.

Research consistently shows that people who laugh regularly not performatively, but genuinely, report lower stress, better resilience under pressure, and stronger relationships with colleagues. None of those outcomes are soft. They are directly relevant to how well you lead and how sustainably you perform.

You don’t need to schedule a comedy evening or develop a stand-up routine. What works is considerably simpler: a genuinely funny clip watched without guilt during a break. A conversation with the colleague who reliably makes you laugh. Actively recalling a ridiculous memory when the afternoon is grinding. Allowing yourself to find something funny in the small absurdities of professional life — and there are many, if you’re looking.

The Duchenne smile and the genuine laugh are not luxuries you earn after the work is done. They’re part of how the work gets done well.

Your face knew this before your diary did.