Tu and colleagues isolate a question often blurred in active-travel research: whether the environment through which walking occurs produces effects beyond walking itself. Synthesising 55 intervention studies, the review compares natural and artificial urban walking settings across psychological and physiological outcomes. Natural environments significantly improve positive affect and reduce anxiety, while differences in heart rate, blood pressure, cortisol, mood and cognitive performance are not consistently significant. Distance and duration matter, and the review identifies thermal comfort and adequate walking space as underintegrated environmental conditions. The methodological importance lies in separating movement as physical activity from environmental exposure as a concurrent causal field. This creates a bridge between transport research and environmental psychology: walking is simultaneously mobility, exercise and situated exposure. The urban implication is that pedestrian infrastructure cannot be evaluated by connectivity or step counts alone; the qualitative conditions encountered along the route participate in what walking does to the body and mind.