Ocean waves fall within the water sounds category that showed the strongest positive affect improvement in the Buxton et al. (2021) PNAS meta-analysis of 18 studies.
What makes ocean waves distinct from other water sounds is their rhythmic amplitude cycle (6-12 seconds for wind-generated waves). This cycle aligns with human respiratory rhythms (12-20 breaths per minute) and the 0.1 Hz Mayer wave (arterial blood pressure regulation), supporting parasympathetic entrainment and relaxation.
Kaplan's Attention Restoration Theory (1995) identifies four components of restorative environments: being away, extent, fascination, and compatibility. Ocean waves provide all four, making them one of the most complete natural soundscapes for attention recovery between focus sessions.
No ADHD-specific ocean study exists. Included based on the strong general-population evidence for water sounds and the unique rhythmic entrainment properties.