The Interleaving Trails of Lifestyle and Wilderness

Abstract

Wilderness medicine (WM) and lifestyle medicine (LM) both aim to use creative methods to promote health. The purpose of this review is to elucidate the effects of wilderness environments on health and elaborate on the intersections of WM and LM. The three theories describing potential mechanisms of health promotion in the wilderness environment—biophilia theory, stress reduction theory (SRT), and attention restoration theory (ART)—are presented. Activity in the wilderness environment is associated with improved cardiovascular fitness and cognitive performance, better sleep/wake cycles when not at altitude or extremely cold weather, better stress management, positive social interactions, and avoidance of risky substances. Wilderness is medicine and may be used as such to promote vigor and vitality in our patients.

“For one to have a wilderness experience, it may take place outside of a federally designated and protected wilderness area and may even be a state of mind.”

The Wilderness Environment

One definition of wilderness in the Oxford dictionary as, “an uncultivated, uninhabited, and inhospitable region.” Another perspective of this word from National Geographic is “an area of land that has been largely undisturbed by modern human development. ¹ ” From the Wilderness Medicine Society, wilderness is referred to as any environment with “difficult patient access, limited equipment, and environmental extremes; decision making, creative thinking and improvising. ² ” Some see the wilderness as a place that they wouldn’t like to be–uncultivated, inhospitable; while others take on the perception of nature’s beauty—undisturbed by development; but each organization sees the wilderness as it pertains to their duties—not the same as in urban society.

Wilderness areas can be small or large, rural or suburban. The US Government recognizes and protects 803 ³ different wilderness areas in all 50 states, just over half of these are in Alaska. The largest is 36 740 square kilometers (Wrangell-Saint-Elias Wilderness Alaska) and the smallest is .02 square kilometers (Rocks and Island Wilderness California). For one to have a wilderness experience, it may take place outside of a federally designated and protected wilderness area and may even be a state of mind. Wilderness experiences may allow for clarity of mind by removing the mental clutter of “human development” and focusing on the world that’s right in front of you.

Effects of the Wilderness Environment on Health

For much of the population, the wilderness is not accessible on a daily basis. However, there are mental benefits to bringing the wilderness to you. The remote wilderness locale is not required for nature-based activities to occur, for example, they can take place in a city park. Nature-based activities have verifiable positive effects on mental and physical health. ⁴ Further evaluation is needed to substantiate this claim based purely on nature-based activities alone.

There are three predominant theories describing the mechanism that wilderness activities exert such positive effects on our bodies—biophilia theory, stress reduction theory (SRT), and attention restoration theory (ART). The biophilia hypothesis describes that because our human ancestors relied on the environment for survival and our evolution occurred in the wilderness, we have a drive to connect with nature and the wilderness. Stress reduction theory explains that nature reduces our stress levels, allowing us to focus our mental energies on more important things. Lastly, ART argues that exposure to nature is enjoyable and restores our ability to concentrate and pay attention. It is unlikely that only a single theory individually effects personal health promotion in the wilderness.

In a recent meta-analysis ⁴ examining the effect of nature-based activities on mental health, they found decreases in depressive mood −.64 (95% CI: 1.05 to −.23), anxiety −.94 (95% CI: .94 to −.01), negative affect −.52 (95% CI: .77 to −.26), and increases in positive affect .95 (95% CI: .59 to 1.31). Other findings were that wilderness adventure therapy has significant effects on the mental health of adolescents in a 10-week program in Australia, specifically showing significant improvements in psychological resilience and social self-esteem. ⁵ Further research is needed to determine whether this effect is due to the mental “escape” that wilderness and nature allow from the persistent chore of work and city life, or if there is some unseen element present in the natural environment.

Cognitive Function

Cognitive function improves executive functions and lower level cognitive functions ⁶ and is also improved by simply being physically active. ⁷ Nature experiences provide psychologic benefit ⁸ to patients and it has been shown that study participants who walked, improve their trail making test scores and profile of mood states after walking in the forest, whereas it did not after walking downtown. ⁹ Additionally, participants’ mood was positively influenced during and after walking in the forest. This improvement may be defined by ART or SRT, but is attention or stress the primary factor?

To determine this, we must look at studies that have addressed both attention and stress simultaneously. Hartig used blood pressure measurements to assess psychophysiological stress differences in groups of varying levels of fatigue in urban or natural environments and found that nature experience groups showed significantly decreased stress, improved mood, and had better performance on attention tests. ¹⁰ Hartig was also able to demonstrate that stress and attention impacts happened at different times during the walk. In other studies, attention and stress-related theories are studied separately. For example, participants in an urban environment increased their attentional load induced by a proofreading task more than in a natural environment ¹¹ and were also found to have a decreased ability to shift attention between two types of attention demands. ¹² Laumann gathered stress reduction data by showing participants nature or urban videos and then measured their heart rates with an electrocardiogram (EKG). The nature group had significantly lower heart rates than the urban group, but was not able to increase the ability to switch attention from voluntary to involuntary. ¹¹ Therefore, the results support SRT, but do not provide compelling evidence for ART. As individuals seek to improve cognitive function through wilderness experiences, one should be cautious to not push it too far to the extremes, as acute cold exposure begins to deteriorate working memory, reaction time, and executive function skills at 10°C. ¹³

Stress Management

The benefits of physical wilderness activities, such as hiking, gives immediate benefits; ¹⁴ such as decreased blood pressure, decreased stress levels, enhanced immune surveillance, and restored attention. Some benefits may also be delayed; weight loss, decreased depression, and improved overall wellness. Each of these immediate and delayed benefits has a positive impact on the stress management capacities of individuals. Wilderness studies clearly demonstrate that being in a forest environment has positive physiological and psychological effects including decreasing blood pressure, heart rate, anxiety, and stress. People find forest environments more desirable than urban environments, ¹⁵ and they can also enhance stress recovery and restoration in a way that urban scenes cannot.^16-19 Warber found that nature immersion in a camp setting increased relaxation and positive emotions, decreased stress and negative emotions, and increased the sense of social interaction, a sense of wholeness, and experience of transcendence. ²⁰

Vigor

Compared with exercising indoors, exercising outside in wilderness environments is associated with greater feelings of revitalization, positive engagement, and increased energy. ²¹ Natural environments have also been shown to be associated with decreases in tension, confusion, anger, and depression. During the studies, feelings of calmness tended to decrease during the exercise, but after the bout of running, calmness exceeded baseline scores in the nature group. This is likely due to stresses placed on the body by the changing environment, physiologic challenges, excitement, or other factors. SRT and ART may both be accurate descriptors because after wilderness exposure, stress is reduced, attention is restored, and individuals can feel more calm and relaxed. Participants in these studies are more likely to report greater enjoyment and satisfaction with outdoor activity and intent on repeating the activity at a later date. Meta-analyses ²² on wilderness activities continue to report the full-spectrum of mental health benefits; improved well-being, cognition, resilience, and restoration as well as decreased levels of anxiety, depression, and stress.

Transcendence and Awe

The Transcendence and Sublime Emotion toward Nature (SEN) scale includes 18 items, distributed into awe (6) and inspiring energy (12) ²³ categories. Awe was defined by feelings of fear, threat, vulnerability, fragility, and respect for nature, which is perceived as vast, powerful, and mysterious. Inspiring energy was defined by feelings of vitality, joy, energy, oneness, freedom, eternity, and harmony with the universe. This is the first statistically valid and reliable method to operationally define sublime emotion toward nature.

Awe, according to the Matryoshka model demonstrates hierarchical changes in 4 broad areas which all contribute to the feeling of awe; electrical changes, immediate psychological changes, neuroendocrine-psychological changes, and existential perspective changes. Some of the specific contributions under each of these umbrellas, respectively, include increased parasympathetic activation, broader attention focus, decreased proinflammatory cytokines, enhanced meaning of life, and numerous other contributions. ²⁴ The Matryoshka model functions well in the context of major depressive disorder (MDD) because elements of MDD are directly counteracted by positive changes seen with awe.

For example, the reduced vagal control, hyperactive amygdala, and enhanced default mode network activity seen in patients with MDD are directly countered by a sense of awe with concomitant decreases in default mode network activity and increasing parasympathetic activation. There is also a high self-focus in MDD and awe tends to create a small self-image with a broader attention focus. The fixed expectations and rumination one experiences with MDD is counteracted by creative thinking and the expansion of mental frames. Finally, addressing the profound hopelessness that these patients feel, the Matryoshka model describes that awe enhances meaning in life, satisfaction with life, nature connectedness, and generosity/prosocial behaviors.

Awe can be described by a wide range of titles, including admiration, astonishment, beauty and may also be associated with confusion, surprise, or wonder. These experiences can be either positive or negative, but do have common threads—the vastness or power of the experience and accommodation to that awe-related state. One’s attempts to understand and accommodate to the awe-related state are a determining factor as to whether the experience is viewed as either terrifying (negative) or enlightening (positive). ²⁵ The different types of awe-related states are threat, beauty, ability, virtue, and supernatural causality. One’s health will likely be benefitted by experiencing awe. One mechanistic model of how awe experiences impact health ²⁶ by Monroy and Keltner demonstrates that awe typically decreases sympathetic arousal, inflammation, sense of self. Awe is also found to increase vagal tone and individuals’ sense of meaning of serving a larger purpose, social integration, and prosocial responsibility. All of these factors promote mental health by improving wellbeing, and decreasing stress, anxiety, depression, and PTSD. Physical health is also promoted with decreasing frequency of headaches, body aches, and improving cardiovascular health and longevity.

In the wilderness, one may experience positive or negative awe-related states, due to an individual’s ability to understand or cope with the experiences. The wilderness is vast, truly awe-inspiring, and full of admiration, astonishment, beauty, confusion, surprise, and wonder. There is still much research to do to determine the effects of specific types of awe-related experiences in the wilderness. Future studies which might be explored in the future include foraging, meditative reflection, survivalism, animal communication, and others.

Cardiovascular Fitness

Because wilderness activities promote physical movement, we can expect that cardiovascular health will improve. Movement improves lymphatic return, ²⁷ promotes energy balance ²⁸ –pertaining specifically to calorie intake vs output, and cardiovascular fitness. ²⁹ Among hikers with metabolic syndrome on a 3-week hiking vacation at either moderate or low-altitude, those at both altitudes improved parameters of cardiac function; systolic, diastolic, and mean arterial pressures, and circadian heart rate profiles. The cardiovascular benefits achieved in this population are likely to be the result of regular physical activity rather than an altitude-specific effect of the mountain environment.

Although physical activity is promoted more in the wilderness environment, we want to identify specific changes that wilderness environments have on the cardiovascular system. Some of which are an immediate fall in systolic blood pressure (SBP) on standing when at altitude vs at sea level ³⁰ and a sympathetic predomonance. ³¹ We also see increased sleeping blood pressures in hypertensive individuals at high altitude. ³² These studies demonstrate the stresses that the wilderness environment can put on the body, but we must also remember that numerous studies have been completed which show the blood pressure lowering effects.^14,15,30-32 Surely, there will be physiological stresses in different environments, but is SRT, ART, of the physiological stressors more predominant? Further research is needed to elucidate the overall effects of the wilderness on the cardiovascular system.

Sleep/Wake Cycles

Humans have a 24-hour biological circadian clock, which supports the biophilia theory. In contemporary life, natural sleep/wake cycles are interrupted by electronics and artificial light, which are associated with emotional, psychological, and physical consequences including heart disease, cancer, and diabetes. Interestingly, nature exposure at extremely high altitudes or extremely cold weather ³³ causes too much physiological stresses for our bodies, and the sleep/wake cycles are disrupted with exposure to these elements. At moderate altitudes, sleep stages 3 and 4 decrease and stage 1 time increases with little change in stage 2 ³⁴ sleep.

Risky Substance Use

Alcohol causes much morbidity and mortality in society, up to 3% (95 000) of all deaths may be attributed to alcohol in the general population. ³⁵ The risk of death when drinking alcohol is much greater in the wilderness; failsafes and guardrails don’t exist in wilderness environments. Epidemiologic studies of wilderness mortality in Pima County (Arizona) reviewed all of the deaths that occurred during the 13-year study and it was estimated that alcohol was a “probable” or “very probable” cause of death in 40% of the unintentional trauma deaths. ³⁶ To compare this across the United States, 200 955 accidental trauma deaths were reported in 2020, but only 30% were likely due to alcohol. ³⁷ Alcohol use in the wilderness increases death rates.

Wilderness Therapy Programs

Wilderness therapy programs (WTP) are typically prescribed or court-mandated for problematic substance use and aim to remove a person from an environment where there are dysfunctional or toxic relationships, technology overuse, or other drivers of high-risk behaviors. These WTP are led by teams of mental health professionals, field instructors, physicians, and activity trainers who provide ongoing assessment, goal setting, and personalized assignments to address each participant’s emotional, physical, psychological—and sometimes spiritual—needs.

In WTP, survival and safety are based primarily on cooperation, planning, follow-through, respect, and mutual understanding. With these programs taking place in the wilderness setting, the participants are encouraged to actively learn new ways of thinking, coping, and interacting in order to break unhealthy patterns. Unfortunately, when clients engage in a WTP without an aftercare plan, they tend to recidivate or continue drinking alcohol and/or using drugs. ³⁸ The aforementioned aims of WTP are all elements of LM and delivered in the wilderness setting. There is not much data regarding the success rates of WTP, but one meta-analysis has suggested that interventions 6 weeks or less were considerably less effective at achieving their aims than interventions lasting >6 weeks. ³⁹ Bedard conducted a meta-analysis to address the effectiveness of outdoor therapeutic programs ⁴⁰ with juvenile delinquents in a government-funded program, which showed significant effect sizes for behavioral (.50), non-behavioral (.53), and recidivism (.31) variables. It was seen that recidivism rates were reduced from 37% in the control group to 29% in the treatment group.

Nature Therapy

Nature therapy (NT) is a mechanism of treatment for a condition not yet recognized by medical manuals for mental disorders; Nature Deficit Disorder (NDD). Essentially, this condition is the idea that most human beings, and especially children, are spending less time outdoors now than they did in the past, and that this is in correlation with behavioral problems. Richard Louve first coined the term in his book “Last Child in the Woods: Saving our Children from Nature Deficit Disorder. ⁴¹ ” As described previously, NT (walking in a forest) shows improved short-term memory, concentration, lower cortisol levels, increased natural killer cell number and activity, decreased heart rate and blood pressure. NT can be split into eleven different subdisciplines, namely: adventure therapy, animal-assisted (pet) therapy, blue care, care farms rest bathing, green exercise, nature meditation/guided visualization, nutrition (herbal, botanical, floral), Therapeutic horticulture/horticultural therapy/gardening, and wilderness immersion. ⁴²

Conclusion

LM primarily focuses on prevention and overall health while WM is anchored on applying medical services in wilderness settings. The specialties of WM and LM are independent disciplines; yet, they overlap significantly. Numerous pillars of LM are represented in wilderness activity and LM can be applied in wilderness settings. This review suggests that physicians practicing LM might consider making a prescription for nature-based or wilderness activities to improve their patient’s cognitive function, stress management, vigor, transcendence and awe, cardiovascular fitness, sleep, diets, and risky substance use.

Limitations

This review is limited by the paucity of high-quality evidence. Large-scale recommendations cannot be made at this time. We need larger, long-term trials to evaluate the effect of different wilderness activities on health.