Does Outdoor Play ‘Keep the Doctor Away?’

Altru Health System, Grand Forks, ND

Dr. Feldman reports no financial relationships relevant to this field of study.

SYNOPSIS: A survey of more than 29,000 Canadian youth 11 to 15 years of age revealed a correlation between physical activity and lower rates of psychosomatic complaints in girls, and a correlation between valuing connection to nature and lower rates of psychosomatic symptoms in boys and girls.

SOURCE:Piccininni C, Michaelson V, Janssen I, Pickett W. Outdoor play and nature connectedness as potential correlates of internalized mental health symptoms among Canadian adolescents. Prev Med 2018;112:168-175.

“It’s been proven by quite a few studies that plants are good for our psychological development. If you green an area, the rate of crime goes down. Torture victims begin to recover when they spend time outside in a garden with flowers. So we need them, in some deep psychological sense, which I don’t suppose anybody really understands yet.” Jane Goodall, 2013

Jane Goodall’s words from 2013 ring true today — our understanding of the healing power of the outdoors remains incomplete.¹ However, the medical field is beginning to recognize that a “breath of fresh air” may have healing or preventive powers. Studies examining the relationship between open space and health are becoming more numerous, but thus far have shown only weak evidence for health benefits. These studies predominately were conducted among adults, mostly were observational, and were burdened with confounding variables.²

Noting both the weaknesses of previous studies and the opportunity to analyze data from a large-scale population study of youth, Piccininni et al designed a study to investigate if outdoor play and a perception of a strong connection to nature relate to the prevalence of psychosomatic symptoms in young teens. They attempted to control for historic confounders, including sex, age, socioeconomic status, and geographical location. All data were obtained from the 2013/2014 Health Behavior in School-Aged Children (HBSC) survey, which is conducted every four years in Canada; the 29,784 responses are weighted to represent public school children between 11 and 15 years of age.³

Piccininni et al selected the prevalence of psychosomatic symptoms as a measure because they believed it to be one indicator of mental health status (although this relationship was not investigated in this study). The symptoms were ranked in the survey on a scale from 1 to 5 and included the following eight self-reported items: feeling depressed, bad temper, nervousness, sleep problems, stomachache, headache, backache, and dizziness. A score of 1 reflected daily symptoms, while a score of 5 indicated rare symptoms. Thus, the total score could range from 8 to 40, with lower numbers indicative of more frequent symptoms. High psychosomatic symptoms was defined as a total score < 28.

The quantification of outdoor play was covered by two items in the survey — one asking about time spent in weekday outdoor play and the other asking the same about weekends. Responses were in 0.5-hour to one-hour increments, with a range from “none at all” to more than seven hours daily. For purposes of this study, Piccininni et al converted the responses from hours of exposure daily to hours of exposure weekly.

Two additional survey items involved relationship to nature; the authors combined these responses to calculate “nature connectedness.” One question asked, “How important is it for you to feel connected to nature?” while the other asked “How important is it for you to care for the natural environment?” Allowable responses fell on a numerical scale linked to responses such as “not at all important” to “very important.”

All data were self-reported, and raw data were obtained from the HBSC survey. Some noteworthy results follow:

• The sample size was reduced from 29,874 to 20,697 participants after eliminating all respondents with missing or incomplete data.
• A mean outdoor play per week of 15 hours was calculated for the entire sample, with slight differences by gender (16.8 hours for males and 13.4 hours for females).
• Mean outdoor play per week decreased from 15.8 hours in grade 6 to 14.1 hours in grade 10.
• 8.9% of participants reported no outdoor play.
• 59.2% of participants indicated connection to nature as “important” (57.2% of males and 61% of females.)
• Perception of connection to nature as “important” decreased from 72% in grade 6 to 50.3% in grade 10.
• Psychosomatic symptoms: 18.9% of males and 37.5% of females indicated high levels of psychosomatic symptoms.

After adjustment for multiple variables (including age, ethnicity, geography, family support, and socioeconomic status), total outdoor play > 0.5 hours weekly was associated with a decrease of about 24% in prevalence of some specified psychosomatic symptoms in girls when compared with girls who did not report outdoor play. This decrease became more pronounced with more outdoor play, but even a minimal change from almost no outdoor play to > 0.5 hours weekly suggested an effect. The symptoms showing a decline were feeling depressed, bad temper, feeling nervous, and sleep problems. The relationship appeared to peak at 34.5 mean hours per week of outdoor play and perhaps reversed in those reporting
> 35 hours per week of outdoor play. There was no such relationship identified among the boys in the sample. The somatic symptoms, such as stomachache and headache, did not show such an association in either boys or girls (only the psychological symptoms in girls). No P values were available for review. (See Tables 1 and 2.)

Connection to nature and psychosomatic symptoms: In both males and females, responding positively to the two survey items measuring connection to nature was associated with a 23% decline in males and 29% decline in females in the prevalence of reports of high psychosomatic symptoms.

COMMENTARY

Making no claims to neutrality, Piccininni et al introduced their paper with the following statement, “Exposures to outdoor environments have great potential to be protective factors for the mental health of young people.” While this inherent bias may not have affected the data analysis, it certainly can lead to examination of the group’s final interpretation with a healthy degree of skepticism. On the other hand, Piccininni et al appeared to expose the limitations of the work quite carefully and avoid any firm conclusions by stating: “For female adolescents, spending time outdoors may … promote mental well-being and buffer against developing poor mental health,” and for both boys and girls, “… nature contact may promote mental well-being ….”

The strength of this work lies in the availability of large-scale, weighted, cross-sectional representational data covering youth 11 to 15 years of age. A major limitation is that all responses were self-reported by young teens. Among other items, the respondents were asked to report hours usually spent playing outside on weekdays and during weekends and to rank how often psychosomatic symptoms occurred. These responses are subject to recall bias.⁴ The responses also may be affected by more subtle factors, such as the youth’s perception of socially desirable or “correct” choices to these queries. These both unwittingly may affect the measures and results.

Another inadvertent bias in the study may have come from the wording of the question itself and connotations with using the word “playing” in regard to the outdoors. Older adolescents may perceive unstructured outdoor time as “hanging out” rather than playing per se, and also may not associate the word “playing” with more serious pursuits and activities, such as hiking, rock climbing, biking, etc. This could have led to an underestimation of time spent outdoors and may help explain the drop in outdoor “play” time noted in the older age groups.

Further questions emerge regarding the reports of psychosomatic symptoms as a measure of mental health. Piccininni et al noted that the reports of these symptoms did not correlate directly with mental health disorders, but may be one measure of mental health in general. This relationship was not explored directly in the study. Although intuitively this rings true, more robust and controlled studies are needed to verify and quantify this relationship.

On a similar note, one neglected potential confounder in the data analysis was the presence of mental health or any medical disorders. For example, a young teen with a depressive disorder may report frequent psychological symptoms and avoid outdoor play because of a lack of energy and motivation, whereas a teen with asthma may have fewer psychological symptoms but may avoid outdoor play because of allergens. An understanding of the complexity of this subject requires more specific studies controlling for such variables. However, the prospect of conducting a rigid, randomized, controlled trial regarding outdoor play in teens presents significant ethical and logistical challenges.⁵

It is important to note that the authors provided no evidence or claims regarding causality, but simply reported correlation. Examining and clarifying the nuances of these relationships may need to wait until clearing the barriers to conducting a methodologically sound randomized, controlled trial in the field.

It is unclear why the results differed for boys and girls when looking at time spent outdoors and the prevalence of psychosomatic symptoms. The overlap of premenstrual symptoms (such as mood changes, stomachache, and headache) and psychosomatic symptoms could be relevant. Notably, girls reported a higher prevalence of psychosomatic symptoms at baseline (37.5% compared to 18.9% for males). It may have been that the difference in baseline numbers was powerful enough to affect results. It is even more interesting to understand why the gender differences vanish when comparing the prevalence of high psychosomatic symptoms and valuing nature. Again, more studies are needed to fully investigate these associations.

Even with the study limitations, this article regarding time spent outdoors, perceived connection to nature, and reports of psychosomatic symptoms holds significance to providers working with families and adolescents. Popular literature aimed at parents indicates a rising concern regarding the decline of outdoor activity among children and teens.⁶ Providers are well-situated to educate families that spending time outdoors may have a protective effect on psychological symptoms (at least in girls). Extending the message to note that feeling connected with nature is associated with lower prevalence of such symptoms in all teens can strengthen an argument for outdoor life and spark interesting discussions about health, wellness, and prevention. In this age of pervasive and compelling indoor entertainment,⁷ signs of the potential and power of the outdoors can serve as well-needed reminders of the importance of balance in life and in health.

REFERENCES

1. Stromberg J. Interview: Jane Goodall on the Future of Plants and Chimps. Smithsonian.com. Available at: https://www.smithsonianmag.com/innovation/interview-jane-goodall-on-the-future-of-plants-and-chimps-24872217/. Accessed Aug. 22, 2018.
2. Van den Berg M, Wendel-Vos W, van Poppel M, et al. Health benefits of green spaces in the living environment: A systematic review of epidemiological studies. Urban Forest Urban Green 2015;14:806-816.
3. Government of Canada. Health Behaviour in School-Aged Children. Available at: https://www.canada.ca/en/public-health/services/health-promotion/childhood-adolescence/programs-initiatives/school-health/health-behaviour-school-aged-children.html. Accessed Aug. 20, 2018.
4. Hassan E. Recall bias can be a threat to retrospective and prospective research designs. Available at: http://ispub.com/IJE/3/2/13060. Accessed Aug. 21, 2018.
5. Klinker CD, Schipperijn J, Kerr J, et al. Context-specific outdoor time and physical activity among school-children across gender and age: Using accelerometers and GPS to advance methods. Front Public Health 2014;2:20.
6. McCarthy C. 6 reasons children need to play outside. Available at: https://www.health.harvard.edu/blog/6-reasons-children-need-to-play-outside-2018052213880. Accessed Aug. 20, 2018.
7. Twenge JM, Joiner TE, Rogers ML, et al. Increases in depressive symptoms, suicide-related outcomes, and suicide rates among U.S. adolescents after 2010 and links to increased new media screen time. Clin Psych Sci 2017;6:3-17.