Play and the Feel-Good Hormones: What the Science Shows

Originally published: 23 June 2016
Updated 18 August 2026
Reviewed and updated by Darryl Edwards MSc, FCIMSPA (Chartered), FBSLM, DFSEM(UK), DipExMed, ACSM-CES®

Movement can change how you feel within a single session.

Research shows that acute exercise can improve mood and reduce feelings of anxiety and depression. Longer-term exercise also has meaningful effects on depression and anxiety symptoms. [1,2]

The biology behind these changes is more interesting than the familiar idea of simply “boosting your happy hormones”.

Your brain and body use interacting systems involving endocannabinoids, endogenous opioids, dopamine, serotonin, norepinephrine, GABA, oxytocin and other signalling molecules. Movement can influence several of them.

Active play adds another dimension. It can combine physical activity with enjoyment, challenge, novelty, choice and social connection.

So what actually happens when you move and play?

What Are the “Feel-Good Hormones”?

“Happy hormones” and “feel-good hormones” are useful popular terms, rather than scientific categories.

The chemicals usually placed under this label actually do different jobs.

Endorphins are endogenous opioid peptides.

Dopamine, serotonin, norepinephrine and GABA act primarily as neurotransmitters.

Oxytocin acts as both a hormone and neuropeptide.

Endocannabinoids such as anandamide are lipid-signalling molecules.

They form part of complex biological systems that regulate motivation, pain, reward, mood, stress, arousal, learning and social behaviour.

Exercise can influence several of these systems at the same time.

That interaction probably gives us a better explanation for why movement can make us feel good than any single “happiness chemical”.

Endorphins, Endocannabinoids and the Runner's High

Endorphins have been associated with exercise for decades.

Human brain-imaging research has shown endogenous opioid activity following prolonged running, with changes associated with reported euphoria. [3]

Yet the familiar explanation that endorphins alone produce the runner's high is now incomplete.

A double-blind human experiment involving 63 runners found that 45 minutes of moderate running increased euphoria and reduced anxiety even when opioid receptors were pharmacologically blocked. Running also increased the endocannabinoids anandamide and 2-AG. [4]

This makes the endocannabinoid system a particularly interesting part of the runner's-high story.

Endocannabinoids can influence mood, anxiety, reward and pain processing. They may help explain why sustained rhythmic movement can leave you feeling calmer or more positive afterwards.

For active play, the intensity and duration vary far more than during steady running. We therefore cannot assume every playful activity produces the same neurochemical response.

The useful principle is broader:

Movement can activate systems involved in pleasure, pain regulation and emotional state, and those effects are produced by several interacting pathways.

Dopamine: Motivation, Reward and the Desire to Continue

Dopamine is often called the brain's “pleasure chemical”.

Its role is much richer.

Dopamine contributes to motivation, learning, reward prediction, behavioural activation and how willing you are to exert effort to obtain something you value. Modern neuroscience therefore treats dopamine as part of motivational circuitry rather than simply a chemical that creates pleasure. [5]

This has particular relevance to play.

A game provides immediate information:

Did I catch the ball?

Can I avoid being tagged?

Can I solve this movement problem?

Can I improve?

Challenge, feedback, anticipation and success can all make an activity behaviourally rewarding.

That provides a plausible mechanism through which enjoyable movement can encourage repetition.

The strongest evidence supports dopamine's role in motivation and reward-related behaviour. Evidence that a specific form of adult play produces a particular dopamine response remains much more limited.

Serotonin: Mood, Sleep and a More Complex Story

Serotonin contributes to a wide range of functions including mood regulation, sleep, appetite, cognition and behaviour.

Exercise can influence serotonergic signalling, although measuring neurotransmitter activity inside the living human brain is difficult.

One idea needs updating.

Depression cannot be adequately explained as simply having “too little serotonin”. Research examining the serotonin hypothesis has challenged this familiar chemical-imbalance explanation, and the relationship between serotonin, mood and antidepressant effects is considerably more complex. [6]

This does not make serotonin irrelevant.

It means the biology of mood involves interacting neural, psychological, inflammatory, metabolic and social processes.

Exercise acts across many of these systems simultaneously.

Norepinephrine: Alertness, Arousal and Attention

Norepinephrine, also called noradrenaline, helps regulate arousal, attention, alertness and the physiological response to challenge.

Physical activity engages catecholamine systems, including norepinephrine and dopamine.

During active movement, this can help prepare your brain and body to respond rapidly to changing demands.

Think about a game of tag.

You track another person.

You change direction.

You react.

You make decisions quickly.

You repeatedly shift attention between your body, another person and the surrounding environment.

Norepinephrine is part of the neurobiology that supports this state of arousal and readiness.

The relationship between exercise, norepinephrine and cognition remains more complicated than “more norepinephrine equals better concentration”. Intensity, fatigue, fitness and the cognitive task all influence the response.

GABA: Exercise and the Brain's Inhibitory System

GABA, or gamma-aminobutyric acid, is the brain's principal inhibitory neurotransmitter.

It plays an important role in regulating neural excitability and is involved in processes related to anxiety, learning, motor control and sleep.

Human magnetic resonance spectroscopy now allows researchers to examine changes in brain metabolites following exercise.

A 2023 systematic review found only nine eligible studies examining acute physical activity using this technology. Across those studies, GABA tended to increase following exercise, although the evidence base remains small. [7]

This is much more precise than claiming that play simply “releases GABA”.

Physical activity appears capable of influencing GABAergic activity. Researchers are still establishing how different exercise types, intensities and populations affect that response.

Oxytocin: Social Connection Is the Interesting Part

Oxytocin is strongly involved in social behaviour, attachment and stress regulation.

Calling it simply the “love hormone” misses much of that complexity.

Human research on naturally occurring oxytocin and social interaction shows links between oxytocin and social behaviour, while also highlighting substantial differences between studies and difficulties measuring oxytocin reliably. [8]

This matters for active play because play is often social.

You make eye contact.

You cooperate or compete.

You laugh.

You synchronise movement.

You touch, chase or respond to other people.

Research on synchronised dancing, for example, has found increased social bonding alongside increased pain thresholds. The latter has been used as an indirect marker consistent with endogenous opioid activity, although the study did not directly measure brain endorphin release. [9]

Social play therefore offers something solitary exercise cannot fully reproduce: movement combined with interpersonal interaction.

Oxytocin may form part of that biology, but it should not be presented as a simple equation in which playing with somebody automatically “boosts oxytocin”.

Does Exercise Really Improve Mood?

Here the evidence is much stronger than the evidence for individual neurotransmitter explanations.

A 2024 meta-analysis examining single bouts of exercise found improvements in general mood alongside reductions in anxiety and depressive symptoms. [1]

The longer-term evidence is stronger again.

Exercise produced meaningful reductions in both depression and anxiety symptoms. The effect was moderate for depression (SMD −0.61, 95% CI −0.69 to −0.54) and smaller for anxiety (SMD −0.47, 95% CI −0.59 to −0.36). [2]

SMD means standardised mean difference. It allows researchers to combine studies that measured symptoms using different scales. In plain English, an SMD of −0.61 means the exercise groups improved by about six-tenths of a standard deviation more than the comparison groups, which is generally considered a moderate effect.

Group and supervised exercise were associated with particularly strong reductions in depressive symptoms.

This last finding is interesting in the context of active play because many forms of play naturally combine movement with interaction.

It strengthens the case for considering the experience of movement, alongside physiological dose.

Why Play May Add Something to Exercise

Exercise science tells us that the body requires sufficient stimulus and repetition to adapt.

Behaviour determines whether that stimulus happens repeatedly.

Play can provide several features associated with positive movement experiences:

choice, challenge, immediate feedback, enjoyment, novelty and social connection.

This creates a simple pathway that sits at the centre of my work:

Positive movement experience → engagement → repetition → sufficient movement dose → adaptation

The neurochemistry provides part of the explanation.

The experience itself matters too.

You do not need to chase a dopamine spike, maximise serotonin or “hack” your happy hormones.

Find movement you enjoy enough to repeat.

Run.

Dance.

Climb.

Play tag.

Lift.

Walk with someone.

Invent a game.

The physiological benefits of movement accumulate through repetition. Enjoyment can give you another reason to come back.

So, Does Play Boost the Feel-Good Hormones?

Active play activates a network of neurobiological systems that help regulate mood, motivation, reward, stress and social connection. These include endorphins, endocannabinoids, dopamine, serotonin, norepinephrine, GABA and oxytocin.

Play can combine those effects with enjoyment, choice, challenge and social connection.

That combination is what makes active play particularly interesting.

Movement changes your physiology.

How movement feels may help determine whether you choose to do it again.

References

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