XXX POLYVAGAL THEORY XXX SENTENCE ON VAGAL FUNCTION XXX the GENIAL model builds on well established theories of vagal function which include polyvagal theory.
Finally, our updated model emphasises the environmental
context within which individual health and wellbeing is promoted and communities reside. Glenn Albrecht \cite{albrecht2019} provides a solid foundation for understanding the link between human emotion and the environment, coining numerous words to emphasise the negative and positive 'psychoterratic' states that have important implications for the health and wellbeing of individuals, communities and societies now and into the future. Environmental contributors include negative and positive psychoterratic states such as solastalgia (chronic place-based distress) and soliphila (a neutral political term for combatting solastalgia) \cite{albrecht2019}. A review of the literature on potential mechanisms linking nature to health identified 21 potential pathways empirically linked to nature \cite{Kuo_2015}. These pathways included environmental factors including phytoncides - antimicrobial volatile organic compounds with physiological effects - and vegetation filtering of pollutants, physiological factors such as elevation of vagal function and immune function, psychological factors involving positive emotions and attention restoration, and behavioural factors including positive health behaviours such as the promotion of physical activity and social ties. Interestingly, this paper suggested that enhanced immune functioning might reflect a central pathway for mediating the beneficial effects of nature on health. It is apparent however, that vagal function plays a regulatory role over immune function via the cholinergic anti-inflammatory response \citep{Pavlov_2003}. Thus, we suggest here that vagal function will play a key role in not only regulating the beneficial effects of positive psychological experience, positive health behaviours, positive social ties, but also, the beneficial effects of nature on human health and wellbeing.
In conclusion, our updated GENIAL model (fig \ref{div-162276}) summarises individual, community and environmental contributors to human health and wellbeing. Our model also characterises the major clinical targets for potentially improving the wellbeing in people living with a host of chronic conditions and disorders, a topic to which we turn next. Clinical targets include psychological experience, health behaviour, social connections and outdoor nature-based activities to which the tools from positive psychology and behaviour change may be applied. We examine how clinicians might implement and sustain positive change in our discussion on facilitating behaviour change in section \ref{225494}.