Forest Yoga vs. Studio Yoga: Differential Effects on Cortisol Levels and Immune System Markers in Healthy Adults

Abstract

Background: Yoga is widely recognized for its stress-reducing and immune-enhancing benefits. Environmental settings, especially natural surroundings, may further augment these benefits.
Objective: This study investigates the differential effects of yoga practiced in a forest environment compared to a traditional indoor studio on cortisol levels and immune system markers in healthy adults.
Methods: Forty healthy adults (age 25–45) were randomly assigned to either a forest yoga group (n = 20) or a studio yoga group (n = 20) for 4 sessions over two weeks. Pre- and post-intervention salivary cortisol and immunoglobulin A (IgA) levels were measured.
Results: The forest yoga group showed a significantly greater reduction in cortisol (p = 0.008) and a larger increase in IgA levels (p = 0.012) compared to the studio yoga group.
Conclusion: Yoga performed in a natural forest environment yields stronger physiological stress-reducing and immune-enhancing effects than studio-based yoga. Nature-based yoga could be a cost-effective and accessible public health tool.