Animal Comparison, Stress hormones, PTSD Heidi Oh Animal Comparison, Stress hormones, PTSD Heidi Oh

Empirical Support and Clinical Implications

Review research on play, stress recovery, vagal tone, somatic therapy outcomes, and clinical safety — exploring how play supports nervous system regulation and trauma healing.

The idea that play supports nervous system regulation isn’t just philosophical —

there’s meaningful evidence across animal research, human physiology studies, and trauma-treatment outcomes suggesting that play and play-like states can support recovery, flexibility, and social engagement (with important caveats about safety and context).

Animal research: play and stress recovery

In affective neuroscience, Jaak Panksepp identified PLAY as a primary emotional system in mammals, emphasizing that play is not “extra,” but biologically organized and evolutionarily conserved. Play is also consistently studied as a key driver of social learning and adaptive development. For example, research on juvenile rats shows that depriving animals of normal peer play can lead to socio-cognitive deficits in adulthood and measurable changes in prefrontal cortex neurons — a finding that links play to brain development in circuits relevant to flexibility and regulation. A major review of social play in rats describes play as rewarding and deeply tied to motivational and neurobiological systems, reinforcing that play is not simply a behavior but a neurophysiological process with downstream effects.

Human physiology: stress hormones, regulation, and play-like states

Direct adult “play” studies using HRV and cortisol are still emerging, but there is stronger evidence for play-adjacent states that involve the same ingredients: spontaneity, social engagement, laughter, and positive affect. A 2023 systematic review and meta-analysis in PLOS ONE found that spontaneous laughter is associated with greater reductions in cortisol compared with usual activities, supporting the idea that playful affect can shift stress physiology. (This doesn’t mean all play reduces stress — some play can be stimulating, competitive, or physiologically activating — but it does support that specific playful states can measurably downshift stress hormones.)

Somatic therapy outcomes

On the trauma-treatment side, there is published outcome data for somatic approaches. A randomized controlled study on Somatic Experiencing ® (SE) reported significant improvements in PTSD symptoms and depression compared to controls, suggesting SE can be effective for trauma-related symptoms. A separate scoping review found preliminary evidence of positive effects of SE on PTSD-related symptoms, while also emphasizing the need for more high-quality studies.

Clinical implications and contraindications

Clinically, “play as intervention” works best when it is voluntary, titrated, and recoverable — meaning it doesn’t push the nervous system past capacity. Play can become dysregulating when it is coercive, overly intense, shame-based, or socially unsafe. For trauma histories involving boundary violations, clinicians typically prioritize consent, choice, and pacing before introducing higher activation forms of play.

Takeaway:

the evidence supports play as biologically meaningful, potentially stress-buffering, and compatible with somatic trauma treatment — but the type of play and the nervous system context determine whether it becomes regulating or overwhelming.

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