The positive impact of naturally soundscaping a noisy urban space on same-night sleep in working adults

Previous research has demonstrated that short-term, nature-related breaks can support psycho-cognitive restoration. In practice, urban green spaces such as rooftop gardens offer such restorative effects; however, these benefits are often undermined by urban noise. Research further suggests that adding natural sounds, such as birdsong, can improve the self-assessed pleasantness of these spaces and enhance psychophysiological recovery. We extend this line of research by examining the immediate and medium-term (same-day, same-night, and next-day) (objective) physiological benefits of a natural soundscape intervention in a sample of working professionals. In a controlled field experiment in Singapore, working professionals took a 30 min break at a rooftop biophilic gazebo exposed to heavy traffic noise. The intervention and control groups received identical instructions and experience, except that the intervention environment was covertly enhanced using a validated system broadcasting natural sounds, including bird calls. Heart rate variability (HRV), a physiological marker of recovery, was continuously measured via wearable devices from before the gazebo visit through overnight sleep and the following morning. Participants exposed to the natural soundscape exhibited significantly higher HRV after the visit, indicating improved psycho-physiological recovery. Critically, this benefit persisted for up to two hours after sleep onset on the same night but was no longer evident the following day. These findings suggest that even modest, low-cost acoustic interventions can temporarily cushion the physiological toll of urban noise. The study highlights the potential for integrating scalable soundscape design into urban planning to enhance mental recovery in public spaces.