There is substantial literature attesting to the positive relationship between human health and natural landscapes ^[1][2][3][1,2,3]. Beil and Hanes [4] examined the effect of visitation to different types of environments ranging between “very natural”, “mostly natural”, “mostly built”, and “very built” on levels of stress-related hormones and catalysts including cortisol and α-amylase. Their findings supported the contention that natural settings, such as forest landscapes, were more effective than built settings in reducing levels of stress when measured using cortisol and α-amylase. Ewert and Chang’s [5] study also using the biomarkers of cortisol and α-amylase found support for the effectiveness of natural landscapes in reducing levels of stress. Although not specific to stress reduction, another research team found that visiting different forest types (wild forest versus a tended forest) for patients suffering from metabolic syndrome (MetS) produced marked differences in acute insulin response, pulse rate, and oxidative stress markers, with the wild forest being associated with more positive health outcomes [6]. Evaluating the physiological and psychological effects of viewing forest landscapes on young women, one study found that, compared with viewing city areas, viewing forest landscapes was associated with significantly higher parasympathetic nervous activity and lower sympathetic nervous activity and heart rate [7]. Moreover, scores of the comfortable, relaxed, and natural parameters and vigor subscales of the profile of mood states scale were significantly higher with forest viewing.

2. Adventure-Based Activities and Health

One of the interesting behaviors practiced by citizens across the globe is the pursuit of outdoor recreational activities featuring elements of personal risk and danger with these types of activities now becoming a global mainstay for many individuals and organizations. For the purposes of this study, researchers defined outdoor adventure recreation (OAR) OAR, borrowing from Ewert and Sibthorp’s definition, as non-motorized activities and experiences usually carried out in a natural or outside environment that involves elements of challenge and either real or perceived risk, in which the outcome is uncertain but influenced by the skill and ability of the participant [8]. Moreover, a growing corpus of literature has suggested that OAR often involves specific types of both mental states and psychological aspects such as emotions, cognitions, perceptions, and motivations ^[9][10][9,10]. OAR activities offer myriad outcomes and benefits from participation that involve recreational and leisure experiences that present physical and emotional challenges often involving natural settings, such as forest landscapes, with participants engaged in activities such as mountaineering, whitewater boating, caving, rock climbing, sea kayaking, rappelling, and scuba diving. Over two decades ago, Ewert and Hollenhorst [11] mentioned the growing popularity of OAR activities occurring in a variety of outdoor and forest landscapes. Specific programs that involve OAR activities and experiences can often be characterized by several features, including the following: (a) they take place in an unfamiliar natural physical environment; (b) they consist of challenging activities with authentic and clear consequences that usually involve cooperation with others; (c) they take place in a small-group social setting; (d) and they are often guided by experienced, skilled instructors who ensure physical safety and emotional support during the program. The assumed psychological change process is based on the concept of experiential learning [12]. Moreover, the number of participants in these types of activities is impressive, as illustrated in a recent study involving over 20,000 online interviews and illustrated in Table 1 [13]. Beyond other recreational activities falling under the rubric of outdoor recreation, such as fishing, hunting, sight-seeing, walking, enjoying the scenery, and bicycling, because of the attendant components of potential risk and challenge, OAR activities involve a “blending” of physical, psychological, and setting attributes that often combine to form a unique experience that can produce powerful and long-lasting benefits to human health.

Activity	Number of Participants in 2018 (000’s)	Percent of U.S. Population
Backpacking	10,540	3.5%
Climbing	5025	1.50%
Kayak (Sea)	2805	0.90%
Kayak (Whitewater)	2562	0.90%
Rafting	3404	1.10%
Scuba diving	2849	0.90%
Canoeing	9129	3.00%

3. OAR in Natural and Forest Landscapes

Both historical and recent literature support the belief that OAR activities can contribute to human health. While a great deal of anecdotal literature has described the reasons for engaging in OAR activities, there is a growing body of more formal research studies focused on why people engage in OAR. One early study used the responses from 266 members of the Alpine Club of Canada, Calgary Section, the results indicated a mosaic of motives for climbing including a social experience, health and fitness, excitement, relaxation, achievement, to be expressive, and love of nature [14]. A study on visitor motivations and satisfaction at Pirongia Forest Park, New Zealand, noted a link between satisfaction and those attributes generating a sense of relaxation, such as the mountain scenery [15]. The views from high up allowed for a sense of perspective and the vistas had a calming effect on those who climbed to the tops of the Park’s peaks. Using backpacking and wilderness camping activities with adolescent youths, researchers found significant improvement in the variables of reduced stress, subjective well-being, self-efficacy, and mindfulness [16]. Moreover, the effects were of considerable magnitude with moderate–large effect sizes. Based on these findings, Mutz and Müller argue that outdoor adventures, particularly in forest and other types of natural landscapes, can have direct positive impacts on an individual’s subjective well-being and perceived stress including psychological resilience, well-being, and good health, most notably, self-efficacy and mindfulness. Buckley [17] supports this contention by suggesting that adventure tourism can provide experiences that provoke powerful psychological effects and could even be considered “therapeutic”. In addition, several researcheuthors extended this concept by suggesting that OAR activities such as adventure tourism can be associated with numerous benefits which can lead to improved family functioning and cohesiveness ^[18][19][18,19]. Boyes [20] found that participation in OAR can be instrumental in developing successful ageing strategies. OIn this study, outdoor adventures are seen as positive leisure experiences that include challenging physical activity, social engagement, and the natural environment. The benefits of engagement for health, well-being, and successful ageing were identified through the physical, social, and psychological domains. Buckley [21] added to this supposition by developing research findings within the context of aging and adventurous nature sports. Of particular significance, both enjoyment and opportunities for euphoria persisted despite ageing and can temporarily override chronic pain, stress, and fatigue. Buckley suggests that by providing opportunities for euphoria as well as exercise, adventurous outdoor nature sports can make substantial contributions to the physical, mental, and social health of older individuals and reduce the costs of care for the aged. Zwart identified six attributes that contribute to the effectiveness of OAR in promoting individual health [22]. Based on a sample of 288 college students, the following attributes were generated: the natural environment, opportunities for restoration, the aesthetics and beauty of nature, solitude, social group, and sense of community, and providing a cultural hub. Cleary, OAR involves a matrix of physical, psychological, emotional, and social aspects. Moreover, the literature suggests that OAR promotes health through several avenues. First are the aspects of prevention. That is, participation can be influential for reducing the possibility of negative health outcomes such as diabetes, managing blood sugar, weight gain, heart attack, illness, or premature death, often as a function of the physicality often associate with OAR activities. Second, from an enhancement perspective, participation in OAR can relate to improving health outcomes such as overall fitness, overall health, muscle strength, and flexibility. Past research has also suggested that participants identified their OAR activities as involving more whole-body workouts; engaging not only the body but also engaging the mind, with participants reporting that this one factor is often lacking when participating in a more formal workout setting such as a gym, on a bike trainer, running track, etc. [22]. Because of the variety of OAR activities available both between and within specific activities, these activities can often be tailored to match the abilities and skills of the participant to the extent that they become lifelong engagements, rather than simply physical activities limited to specific age groups or specific abilities. In addition, previous research has shown that OAR participants are able to identify, perceive, and accurately report the effects and benefits of their participation ^{[1][23][24][25]}[1,23,24,25]. The health benefits of outdoor experiences are active, such as those involving physical activity and movement [26], and inactive, such as enjoying an aesthetically pleasing scenery ^[27][28][29][27,28,29]; both have been researched well. Blonna [30] identifies six forms of health and well-being: emotional, environmental, intellectual, social, spiritual, and physical. Research in the health and wellness field synthesizes these forms into two primary categories predominantly, physical or physiological, and mental or psychological.