Exposure to forests and birdsong may reduce physiological stress among college students

Introduction The escalating mental health crisis among college students presents a global challenge that may be exacerbated by isolation from nature. Previous research, largely conducted in laboratory settings, indicates that exposure to nature and birdsong improves mental and physiological health. We built on this work with an outdoor experiment testing for independent and potentially additive effects on physiological stress associated with exposure to natural landscapes (i.e., forests) and soundscapes (i.e., birdsong). Methods We engaged 95 participants from North Carolina State University in a randomized, four-treatment, within-subjects design to evaluate the effects of adding different sounds (birdsong vs. traffic) to landscapes (forest vs. gray space) on measures of physiological stress: heart rate (HR) and heart rate variability (HRV) (measured as RMSSD). We started each sample with 5 min of silent control, followed by 10 min of recorded birdsong or recorded traffic noise. Participants listened to each recording in both settings. We modeled HR and HRV using linear mixed models with a random intercept to account for participant effects and fixed effects for soundscape, landscape, their interaction, age, and gender. Results Forest exposure had reduced HR relative to gray space (b = 0.65, p = 0.007). Birdsong exposure increased HRV relative to traffic noise (b = -1.38, p = 0.049). We did not detect a significant soundscape × landscape interaction for either outcome (all p > 0.16). Discussion These findings indicate that visual and auditory nature cues may support physiological recovery through partially independent pathways, with forest landscapes associated with reduced cardiovascular arousal and birdsong soundscapes associated with increased autonomic recovery. Results highlight the different ways that green infrastructure on college campuses can improve students’ mental health outcomes.