Heart rate variability is enhanced by long-lasting pleasant touch at CT-optimized velocity.

INTRODUCTION: The present study explores whether long-lasting pleasant touch has positive effects on the stress response, reward sensitivity, mood, and interoceptive awareness.

METHODS: 40 participants received either 35min of brush stroking targeting C-tactile fibres (CT) or vibration on the forearm, and rated pleasantness and intensity. Prior and after, stress response (cortisol and heart rate variability), reward sensitivity, mood and interoceptive awareness were measured.

RESULTS: Pleasantness decreased over time for both groups, with brush stroking being perceived as more pleasant and intense than vibration. Heart rate variability (SDNN) increased for brush stroking only, and was related to the higher pleasantness and intensity. No significant effect of CT-optimal touch was observed on any of the other measures.

DISCUSSION: The beneficial effect of pleasant touch on heart rate variability suggests a neuronal link between CT-fibre stimulation and autonomic regulation, and highlights the potential of long-lasting touch to improve the physiological response.