Table 2.
Characteristics of included studies.
| Main Author, Year | Country | Study Design | Sample Size | Characteristics | Age | Gender | Intervention | Control | Duration | Quality |
|---|---|---|---|---|---|---|---|---|---|---|
| (Control) | Assessment * | |||||||||
| [27] Grazuleviciene, 2016 | Lithuania | RCT | 10 (10) | Coronary artery disease | 45–75 y | Mixed | Park walks | Urban walks | 7 days | Weak (II) |
| [28] Razani, 2018 | USA | RCT 2:1 ratio | 50 (28) | Low-income parents | Mixed | Facilitated park tours | No facilitated tours | 3 months | Moderate (III) | |
| [29] Niedermeyer, 2017 | Austria | RCT crossover | 42 (42) | Healthy individuals | M:32 y | Mixed | Mountain hiking | Treadmill/sitting | 3 h | Weak (II) |
| [30] Han, 2016 | South Korea | CCT | 14 (14) | Elderly with poor mental health | NA | NA | Horticultural therapy | Passive control | 10 weeks | Weak (II) |
| [31] Kjellgren, 2010 | Sweden | CCT | 9 (9) | Individuals suffering from stress | 37 y | Mixed | Relaxation in nature | Slideshow of nature | 30 min | Moderate (II) |
| [32] Mao, 2011 | China | CCT | 10 (10) | University students | NA | Male | Stay/walk in forest | Stay walk in city | 2 days | Weak (I) |
| [33] Largo-Wight, 2017 | USA | CCT | 18 (19) | University office staff | M:49 y | Mixed | Daily outdoor break | Daily indoor break | 4 weeks | Moderate (III) |
| [34] Lee, 2010 | Japan | CCT | 12 (12) | University students | M:21 y | Male | Sitting in forest | Sitting in urban park | 15 min | Weak (I) |
| [35] Olafdottir, 2017 | Iceland | CCT | 20 (24) | Inactive university students | NA | NA | Nature walk | Treadmill/nature videos | 40 min | Weak (I) |
| [36] Passmore, 2014 | Canada | CCT | 43 (41) | Undergraduate students | NA | Mixed | Own choice nature activity | Own choice activity | 2 weeks | Weak (I) |
| [37] Van den Berg, 2011 | Netherlands | CCT | 14 (16) | Allotment gardeners | 38–79 y | Mixed | Gardening | Indoor reading | 30 min | Weak (II) |
| [38] Fuegen, 2018 | USA | CCT crossover | 181 (181) | University students | M:22 y | Mixed | Green walk/green rest | Treadmill/rest | 15 min | Weak (I) |
| [39] Gidlow, 2015 | UK | CCT crossover | 38 (38) | Unstressed adults | M:41 y | Mixed | Green walk/blue walk | Urban walk | 30 min | Weak (II) |
| [40] Gladwell, 2016 | UK | CCT crossover | 13 (13) | Healthy individuals | M:39 y | Mixed | Nature walk | Campus walk | 30 min | Weak (II) |
| [41] Horiuchi, 2014 | Japan | CCT crossover | 15 (15) | Healthy volunteers | M:36 y | Mixed | Sit and view in forest | View a curtain | 15 min | Weak (I) |
| [42] Im, 2016 | South Korea | CCT crossover | 41 (41) | Undergraduate students | 18–35 y | Mixed | Forest exposure | Urban exposure | 2 h | Weak (I) |
| [43] Kobayashi, 2017 | Japan | CCT crossover | 408 (408) | Young individuals | NA | Male | Forest viewing | Urban viewing | 15 min | Weak (I) |
| [44] Song, 2015 | Japan | CCT crossover | 23 (23) | University students | M:22 y | Male | Park walk | City walk | 15 min | Weak (I) |
| [45] Stigsdotter, 2017 | Denmark | CCT crossover | 51 (51) | University students | 20–36 y | Female | View and walk in arboretum | View and walk in city | 55 min | Weak (II) |
| [46] Tyrväinen, 2014 | Finland | CCT crossover | 77 (77) | Workers in Helsinki | 30–61 y | Mixed | View and walk in woodland | View and walk in city | 45 min | Moderate (III) |
| [47] Berman, 2012 | USA | pre/post crossover | 20 (20) | Depressive disorder | M:26 y | Mixed | Park walk | Urban walk | 50 min | Weak (I) |
| [48] Li, 2016 | Japan | pre/post crossover | 19 (19) | Middle-aged | 40–69 y | Male | Guided walks in forest park | Urban guided walks | 1 day | Weak (I) |
| [49] Toda, 2013 | Japan | pre/post crossover | 20 (20) | Volunteers | 64–74 y | Male | Woodland walk | Sitting in office | 45 min | Weak (I) |
| [50] Bang, 2017 | South Korea | pre/post crossover | 51 (48) | University students | M:26 y | Mixed | Forest walk in lunch break | Passive control | 6 weeks | Weak (II) |
| [51] Marselle, 2014 | UK | pre/post 2 groups | 15 (16) | Adults | NA | NA | Group walks in nature | Passive control | 13 weeks | Moderate (III) |
| [52] Bird, 2015 | Australia | pre/post | 20 | Veterans | 31–61 y | Male | Outdoor therapy program | 6 days | Weak (I) | |
| [53] Duvall, 2014 | USA | pre/post | 98 | Veterans | 20–49 y | Mixed | Nature-based recreation | 4–7 days | Weak (II) | |
| [54] Hofmann, 2017 | Germany | pre/post | 85 | Volunteer gardeners | 25–70 y | Mixed | Urban gardening | 6 months | Weak (II) | |
| [55] Iwata, 2016 | Ireland | pre/post | 15 | Mental ill health | 32–72 y | Mixed | Forest walk | 13 weeks | Weak (I) | |
| [56] Marselle, 2016 | UK | pre/post | 935 | Elderly | 55–74 y | Mixed | Walk in nature | 13 weeks | Weak (I) | |
| [57] McCaffrey, 2016 | USA | pre/post | 195 | Adults with stress | N/A | Mixed | Garden walks | 6 weeks | Weak (II) | |
| [58] Ochiai, 2015a | Japan | pre/post | 9 | Normal-to-high blood pressure | 40–72 y | Male | Relax and walk in forest | 1 day | Weak (I) | |
| [59] Ochiai, 2015b | Japan | pre/post | 17 | Middle aged | 40–73 y | Female | Forest therapy program | 2 days | Weak (I) | |
| [60] Ohe, 2017 | Japan | pre/post | 43 | Office workers | 20–70 y | Mixed | Forest therapy program | 2 days | Weak (I) | |
| [61] Sahlin, 2015 | Sweden | pre/post | 57 | On sick leave due to stress | 45 y | Mixed | Nature-based therapy | 16 weeks | Moderate (III) | |
| [62] Yu, 2017 | Taiwan | pre/post | 128 | Middle-aged and elderly | 45–86 y | Mixed | Forest bathing program | 2 h | Weak (I) |
* The alternative quality assessment, which excludes the blinding parameter (Table 4), is included in the Quality Assessment column with the symbols I: low; II: medium; III: strong. Abbreviations. RCT: randomised controlled trial; CCT: controlled clinical trial.