Table 2.
Summary meta-analysis results table: the pooled effect sizes between simulated nature and non-nature exposure groups.
| Outcome | Outcome test | Number of studies (participant) | Effect MD or SMD | 95% CI | Heterogeneity I2 | p value | Summary |
|---|---|---|---|---|---|---|---|
| Self-reported psychological outcomes | |||||||
| Positive affect | PANAS, ZIPERS, single-item scale | 11 (849) | 0.40 | (0.22, 0.58) | 37% | <0.0001* | Improved |
| Negative affect | PANAS, ZIPERS, POMS | 10 (848) | −0.09 | (−0.23, 0.05) | 0% | 0.20 | No effect |
| Perceived stress | single-item scale | 2 (146) | −0.38 | (−0.71, −0.06) | 0% | 0.02* | Improved |
| TMD | POMS | 2 (188) | −0.87 | (−1.17, −0.57) | 0% | <0.00001* | Improved |
| Tension | POMS, AD ACL | 8 (767) | −0.70 | (−0.99, −0.41) | 73% | <0.00001* | Improved |
| Fatigue | POMS | 5 (380) | −0.60 | (−0.91, −0.28) | 55% | 0.0002* | Improved |
| Vigor | POMS. SVS | 5 (518) | 0.58 | (0.30, 0.86) | 55% | <0.0001* | Improved |
| Anxiety | STAI | 4 (444) | −0.72 | (−1.43, −0.02) | 91% | 0.04* | Improved |
| Depression | POMS | 5 (438) | −0.33 | (−0.52, −0.14) | 0% | 0.0006* | Improved |
| Confusion | POMS | 3 (248) | −0.79 | (−1.19, −0.40) | 54% | <0.0001* | Improved |
| Anger | POMS | 4 (318) | −0.54 | (−0.76, −0.31) | 0% | <0.00001* | Improved |
| Happiness | VAS | 2 (284) | 0.26 | (0.00, 0.51) | 0% | 0.05 | No effect |
| Calmness | AD ACL, VAS, single-item scale | 3 (378) | 0.54 | (0.17, 0.92) | 63% | 0.004* | Improved |
| Arousal | Nitsch’s Personal State Scale, single-item scale | 3 (161) | −0.10 | (−0.41, 0.21) | 0% | 0.54 | No effect |
| Valence | UWIST-MACL, Nitsch’s Personal State Scale, single-item scale | 3 (206) | 0.40 | (−0.67, 1.48) | 92% | 0.46 | No effect |
| Psychophysiological outcomes | |||||||
| SBP | / | 3 (189) | 0.86 | (−3.88, 5.61) | 54% | 0.72 | No effect |
| DBP | / | 3 (189) | −0.49 | (−2.71, 1.73) | 0% | 0.67 | No effect |
| HR | / | 4 (188) | −0.10 | (−0.40, 0.20) | 5% | 0.08 | No effect |
| LF power | HRV | 2 (88) | 0.22 | (−0.20, 0.64) | 0% | 0.31 | No effect |
| HF power | HRV | 3 (148) | 0.24 | (−0.15, 0.63) | 24% | 0.22 | No effect |
| LF/HF | HRV | 2 (80) | −0.10 | (−0.54, 0.34) | 0% | 0.66 | No effect |
| RMSSD | HRV | 2 (131) | 0.11 | (−0.23, 0.45) | 0% | 0.53 | No effect |
MD, mean difference; SMD, standardized mean difference; TMD, total mood disturbance; SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; LF, low frequency; HF, high frequency; RMSSD, root mean square on successive differences; PANAS, positive and negative affect schedule; ZIPERS, Zuckerman’s inventory of personal reactions scale; POMS, profile of mood states (including its short form and translated form); AD ACL, the activation-deactivation adjective check list; SVS, subjective vitality scale; STAI, state–trait anxiety inventory; VAS, visual analogue scale; UWIST-MACL, the University of Wales Institute of Science and Technology Mood Adjective Checklist; HRV, heart rate variability.
*p < 0.05. Bolded fonts indicate MD, non-bold fonts indicate SMD. Summary describes the effect of exposure to simulated nature on outcome measures.