Exploring the association between self-reported and objective measures in search of the restorative quality of natural environments: a systematic review

The benefits of nature contact for psychophysiological restoration have sparked a surge of scientific attention in recent years. The diverse psychophysiological mechanisms of stress recovery make assessment with a single marker impractical. The majority of restoration research employs a holistic approach, including subjective psychological and objective physiological measures concurrently. However, this association has not been decisively supported by empirical studies. The purpose of this systematic review is to determine the degree to which subjectively experienced restoration, as measured by self-reported scales, is associated with actual physiological changes. Searches for peer-reviewed primary research articles were conducted in SCOPUS and PubMed, returning 216 papers; the final synthesis includes 21 empirical studies published between 2008 and 2022. Findings show that there is a strong association between subjective and objective measures of restoration. Further analysis verified that using concurrently self-reported and objective measures in measuring restoration, notably the associations of Profile of Mood States (POMS), Perceived Restorativeness Scale (PRS), and Positive and Negative Affect Scale (PANAS) with Blood Pressure (BP) and Heart Rate (HR), resulted in the highest degree of consistency. However, there were negligible inconsistent associations, which were mainly reported by Restoration Outcome Scale (ROS) in psychological indicators and Salivary Cortisol (SC) and Electroencephalography (EEG) in physiological indicators. This suggests that the results of research that uses these measures simultaneously should be interpreted with caution.