Abstract

Understanding the effects of exposure to forest environments requires attention not only to subjective experience, but also to the physiological processes through which restoration, stress regulation, and well-being may be expressed in the body. Although participants in guided forest therapy sessions often report feeling calmer, lighter, more grounded, mentally refreshed, or even sleepy, such experiences may also be accompanied by measurable biological changes. For this reason, physiological markers have become an important focus in research on forest-based interventions.

This chapter examines physiological markers as one means of understanding how the body responds to stress, relaxation, environmental exposure, and emotional regulation in the context of forest therapy. Particular attention is given to hormonal markers associated with the stress response, especially adrenaline, noradrenaline, and cortisol; inflammatory markers such as interleukins, tumor necrosis factor, and C-reactive protein; and autonomic indicators, including heart-rate variability. The chapter also considers the interaction between the hypothalamic-pituitary-adrenal axis, the autonomic nervous system, and inflammatory processes, highlighting their relevance for understanding recovery and adaptive regulation.

Rather than reducing the forest therapy experience to biological measurement alone, this  article situates physiological markers within a broader psychophysiological framework. These indicators do not capture the full meaning of well-being or the therapeutic encounter in the forest, yet they offer valuable insight into how the body may shift from states of heightened activation toward regulation, recovery, and balance. In this way, the chapter aims to bridge subjective reports of restoration with measurable physiological processes, contributing to a more integrated understanding of forest therapy and its potential relevance for human health and well-being.