Biomarkers of stress and exercise-induced affect in connection with physical activity in nature
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- Master's theses (ILP) 
Psychosocial stressors can contribute to chronically stimulate the stress-response system, possibly leading to disease if not adequately “shut off”. Physical activity in nature, called green exercise, is often used a means of stress-relief. A literature review of scientific literature on benefits of green exercise was conducted, with special focus on cortisol and emotions. Twenty-six articles were included. Results showed low-intensity green exercise, such as walking, led to greater improvements in emotions than in built environments. The results regarding effects on cortisol were inconclusive. The second part of this study was based on a randomised controlled trial conducted in 2012. The objective of this study was to examine the effects of green exercise on the cortisol awakening response (CAR) of healthy adults, and explore a possible correlation with exercise-induced affect. Fourteen participants (7 male and 7 female, mean age 49±8 years) were assigned to a green exercise or indoor exercise setting. The intervention consisted of two exercise sessions on separate days, involving a biking and strength training part. The area under the curve with respect to the ground (AUCG) and area under the curve with respect to increase (AUCI) for the CAR was calculated, and analysed using between-subject analysis of covariance. The green exercise group had significantly lower AUCI for the CAR than the indoor exercise group. Difference for AUCG between settings did not reach significance. A significant positive correlation was observed between tranquillity and AUCG. No other significant correlations were found. Overall, the findings from this thesis are suggestive of beneficial effects of green exercise on emotions, and possibly of a lower physiological stress response. Further studies on larger samples are required.