Visual Stimulation by Viewing a Seascape from a High-Rise Window Increases Subjective Relaxation and Left–Right Differences in Prefrontal Cortex Activity

Stress states are increasing with global urbanization, but evidence on the physiological impact of urban blue-space exposure remains limited compared to green spaces. In this randomized within-subject crossover study, we examined the physiological effects of seascape viewing from the 29th floor of an office building in 44 healthy young adults. Each participant underwent visual stimulation with a seascape window view (blue space) and a blind-covered window (control) for 90 s each after a 60 s rest. Prefrontal cortex activity was recorded using near-infrared spectroscopy, and the left–right difference (LRD) in Δoxy-Hb concentrations was used as an indicator. Autonomic nervous system activity was assessed using heart rate variability, and psychological outcomes were measured using a semantic differential scale and the Profile of Mood States—2 short form. Seascape viewing significantly increased LRD, indicating left-dominant prefrontal activation relative to the control. It also increased comfort and relaxation and improved mood states. Correlation analyses showed that LRD was positively correlated with comfort and relaxation. These findings suggest that intentional window-view design, including exposure to high-rise blue-space views, represents a promising environmental approach to support occupants’ well-being and provide practical implications for window-view design and operation in high-rise office environments.