Why We Yell: Swearing, Grunting and Pain

Stub a toe and the words come out on their own.

Psychologists have tested what that yell does. In lab studies, swearing helped people put up with pain for longer, and grunting tennis players hit the ball a little faster. The effects are real, modest and come with some surprising catches.

Updated 15 October 2026 · 6 sources

Swearing can blunt pain
Overuse dulls it
Grunts add a little power
Save it for when it counts

Check a yell

THE SHORT ANSWER

A yell can help,
a little.

Three findings from lab studies
of swearing, grunting and shouting.

PAIN

Swearing in ice water

Keele University studies found repeating a swear word increased how long people could keep a hand in icy water, compared with a neutral word.

Check a yell

POWER

The tennis grunt

In a small study of 10 college players, grunting increased ball speed by 3.8% without raising the oxygen cost of hitting.

See the numbers

THE CATCH

Use it sparingly

People who swore more often in daily life got less pain benefit from swearing, suggesting the effect wears off with overuse.

Why it works

A tennis player seen from behind striking a forehand on an outdoor hard court in bright sunshine — AI-generated image, not a photograph of a real person or place.

FOUR THINGS THE STUDIES SUGGEST

What a yell
seems to do.

The researchers are careful about mechanisms. These are the explanations they found best supported, and the ones they ruled out.

It sparks a fight-or-flight response
The 2009 study found swearing raised heart rate, and suggested it may trigger fight-or-flight and break the link between fear of pain and feeling it.
It is emotional, not just distracting
In 2020, distraction seemed of little importance, while emotional arousal was flagged as worth further study.
It wears off with overuse
Heavy everyday swearers got less benefit, consistent with the idea that the effect depends on an emotional jolt.
Sound shapes how others see you
In tennis studies, an extra sound at contact slowed viewers' responses, and louder grunts made shots seem to travel further.

TWO NUMBERS WORTH KNOWING

Modest effects,
measured carefully.

One figure from the ice-water test,
one from the tennis court.

33%

Rise in pain tolerance when repeating a swear word

Compared with a neutral word, repeating a conventional swear word at a steady pace and volume raised tolerance of icy water by 33% in 92 volunteers.

PAIN · FRONTIERS IN PSYCHOLOGY 2020

3.8%

Extra ball speed when grunting

Grunting players averaged 83.4 km/h against 80.3 km/h without grunting, in a study of 10 university tennis players.

TENNIS · J STRENGTH COND RES 2014

In the first swearing study in 2009, the effect did not appear in men who tended to catastrophise about pain. Small samples mean these figures are best read as signs, not settled facts.

A QUICK YELL CHECK

What did the
yell actually do?

Pick a situation that researchers tested to see what they found. The bar shows roughly how big the measured effect was.

Small laboratory studies with healthy volunteers. They show average effects in a test setting, not a way to manage pain. This is general information, not medical advice.

Yell check

Choose a situationRepeating a swear word in icy waterRepeating a made-up swear wordSwearing if you swear a lot anywayGrunting while hitting a tennis ballHearing a louder grunt from your opponent

Repeating a swear word in icy water+33% tolerance

In a 2020 study of 92 people, a common swear word raised pain tolerance by 33% and pain threshold by 32%, compared with a neutral word.

Repeating a made-up swear wordNo change

The invented words 'fouch' and 'twizpipe' felt more emotional and funnier than a neutral word, but did not change pain threshold or tolerance.

Swearing if you swear a lot anywaySmaller benefit

The more often people swore in daily life, the less extra pain tolerance swearing gave them in the test.

Grunting while hitting a tennis ball+3.8% ball speed

Ten college players hit faster groundstrokes when grunting, with no rise in oxygen use, heart rate or effort ratings.

Hearing a louder grunt from your opponentBalls seem longer

Players watching clips judged the ball would travel further when the grunt was louder, a sign the sound feeds into how we read the shot.

Sources: Stephens and colleagues, NeuroReport (2009), Journal of Pain (2011) and Frontiers in Psychology (2020); Callison and colleagues, Journal of Strength and Conditioning Research (2014); Müller and colleagues, PLoS One (2019).

A hand held in a glass bowl of water and ice cubes on a white table, as in a cold pressor pain test — AI-generated image, not a photograph of a real person or place.

THE GRUNTING DEBATE

Is it fair
on the other player?

A 2010 study played clips of tennis shots with or without a brief extra sound at contact. When the sound was there, viewers were slower and less accurate at saying which side the ball was going.

A 2019 study tested why. Louder grunts made players expect longer shots, but did not increase their errors in a way that pure distraction would predict, suggesting the brain blends the sound with what it sees.

In conversation

Questions people ask

Does swearing really reduce pain?

In lab studies at Keele University, repeating a swear word let volunteers keep a hand in icy water for longer than repeating a neutral word. A 2020 study found a 33% increase in pain tolerance.

Do made-up swear words work?

Not in the 2020 study. The invented words 'fouch' and 'twizpipe' were rated more emotional and funnier than a neutral word but had no effect on pain threshold or tolerance.

Why do tennis players grunt?

One study of 10 college players found grunting increased ball speed by 3.8% without raising oxygen cost. Other studies suggest sound at contact can also affect how opponents read the shot.

Does swearing more make it work better?

No, the reverse. A 2011 study found the more often people swore in daily life, the smaller the pain benefit of swearing in the test.

Should I swear to manage pain?

These are small lab studies of short-term pain in healthy volunteers, not treatment advice. Anyone with ongoing pain should follow guidance from a health professional.

Sources

Each figure on this page comes from the sources below.

Let it out.
Science says so.