College-age individuals experience mental health benefits after spending as little as 10-20 minutes in natureA concern addressed in this review of the literature relates to the unprecedented levels of stress, depression, and other psychologically debilitating conditions experienced by American college and university students. While an increasing body of evidence demonstrates that spending time in nature can support mental health and well-being, it's not clear how much time ("dose") is needed to experience such benefits. This study aimed “to define a ‘dose’ of time in nature that could be prescribed to college-age students, as a preventative and supportive mental health and well-being intervention.” Nature was defined as green spaces, including urban parks and woods, and relatively undisturbed natural sites.
Studies were included in this review if they (1) included subjects of average college age, (2) examined a treatment of time in nature, (3) examined change in measures of mental health and well-being before and after time in nature, (4) compared participants across at least two environments (e.g., city street and natural area), and (5) were published in English or French within the last 20 years. Fourteen studies met these inclusion criteria. Ten of the studies took place in Japan, one in Sweden, and the remaining three in the United States. All of the included papers were published in peer-reviewed journals. The “dose” of nature evaluated in the included studies ranged from 10 to 50 minutes.
Findings reported in the included studies show statistically significant differences in physiological and psychological health associated with time in nature. Specific indicators of positive effect of time in nature included short-term changes in physiology, affect, and attention. Physiological health markers of stress associated with time in nature included decreased heart rate, salivary cortisol, blood pressure, and sympathetic nervous system activity, and increased parasympathetic nervous system activity. Psychological indicators of reduced stress associated with time in nature included assessment scores showing less depression, anxiety, and fatigue, and increased vigor, positive affect, and feelings of calm.
Overall findings of this review indicate that as little as 10 - 20 minutes in nature may serve as a preventative measure for stress and mental health strain for college-age individuals. Six specific foci for more research in this area are presented.
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