When our physiology becomes our psychology

During the recent Paris Olympics, mental wellbeing was openly discussed once more: in recent years there have been several high-profile cases of athletes going on record to discuss their issues. However, whilst the media attention goes some way to lift the stigma, we believe our collective understanding of mental health in elite sport is still vastly underdeveloped; in particular, our understanding of chronic anxiety and mental health. 

Our experience working in sport suggests that anxiety is a common emotion there; that it can become a clinical issue when it is persistent; and that adopting a traditional mental skills approach with some anxious performers seemed to have a limited impact on their behaviour. Whilst the pressures of competition are a factor, is it possible that some athletes are physiologically predisposed to chronic anxiety, largely irrespective of the demands of their environment?

Physical characteristics

In over 20 years of working with various groups of athletes, we have noticed that a particular physical characteristic was present in the majority of elite performers – hypermobility. Whilst hypermobility is almost a prerequisite for success in sports such as gymnastics or swimming, it's hard to think of many sports where athletes cannot gain a competitive advantage from the extended reach and range of motion that hypermobility can give them over non-hypermobile populations.

Hypermobility is almost a superpower when it comes to sport – think football, cricket, trampoline, hurdles, high jump and more – but it also comes with several potential downsides. These include recurrent myalgias, osteoarticular problems, cardiovascular and gastrointestinal issues. Research also suggests that individuals with hypermobility are up to 16 times more likely to suffer from anxiety and panic disorders (Eccles et al., 2012). So why would hypermobility predispose you to anxiety disorders?

Anxiety and hypermobility

Comparative fMRI studies have found that the brain circuitry activated when exposed to a certain threat is similar to the circuitry recruited when experiencing uncertain threat anticipation; the latter state being associated with pathological anxiety (Hur et al., 2020).

Anxiety is a natural response to threat, involving a complex interaction between the nervous, endocrine, and immune systems. This response occurs in two stages: an immediate reaction through the sympathetic-adreno-medullary (SAM) axis and a slower, secondary response via the hypothalamus-pituitary-adrenal (HPA) axis (Chu et al., 2022). When the SAM axis is activated, it triggers the release of epinephrin and norepinephrine, which results in extensive cardiovascular changes, changes in respiration and reduction in intestinal motility. Along with these physical effects, we also experience heightened alertness, sharper thinking, and altered pain perception. These changes increase our chances of survival when faced with immediate danger or threat.

Activation of the HPA axis leads to the release of cortisol, a hormone that prepares the body for longer-term threats. The presence of cortisol has several effects on the body, including an increase in blood pressure, which increases cardiac output to ensure a ready supply of blood to the large muscles of the body. Cortisol also acts to boost circulating levels of glucose in the blood which offers a primary energy source.

Cortisol is essential to the maintenance of normal homeostatic function. If it becomes dysregulated, it can have a profound effect on essential physiological functions such as metabolic balance, autoimmune response, cognition and behaviour. Whilst cortisol is widely recognised as an anti-inflammatory, and is noted for its moderating effect on immune response, overexposure can results in immune system resistance and an increase in proinflammatory cytokine production.

But what does this have to do with hypermobility? As previously mentioned, people with hypermobility often suffer with gastrointestinal problems (Sharp et al., 2021). The intestine is lined with epithelial cells, offering a semi-permeable barrier to facilitate the transfer of nutrients from the gut into the bloodstream and lymphatic system. However, hypermobility is associated with excessive gut permeability which can result in endotoxins and food fragments crossing this semi permeable barrier (Do et al., 2021). When this happens, the immune system will react, causing an inflammatory response which stimulates the HPA axis to produce cortisol.

Excessive gut permeability is a chronic condition, so the HPA axis will be triggered to produce cortisol more frequently. However, because the immune system has become resistant to the moderating effect of cortisol, the HPA axis remains active for longer, thus creating a persistent physiological state of fight or flight. This cycle is not limited to athletes, although they often experience it. Hypermobility affects more than 20 per cent of the general population, and even those who aren't hypermobile may face similar issues due to inflammatory diets or overuse of antibiotics.

Three inter-connected domains

Our knowledge and experience in sport led us to develop the Domain Loop model that revolves around three domains: internal (interoceptive), external (exteroceptive) and our inner voice (narrator). These domains interact with each other to build our picture of the world. However, when these domains become discordant, it can result in physiological or psychological distress. Specifically, if the interoceptive domain is signalling threat because it detects the physiology of fight or flight, but the exteroceptive cannot see, hear, smell (etc) a threat, then the narrator is likely to create a justification for the threat. It typically does this by catastrophising, which reinforces the sense of threat thereby creating a 'locked in loop'.

We would argue that emotions are not initiated in the theatre of the mind; they happen in the crucible of the body. The theatre of the mind then creates a narrative that we use to make sense of what we are feeling. This sense checking often results in us interpreting these feelings as a reaction to exteroceptive, rather than interoceptive information, because we do not consciously process interoceptive information. As such, interoceptive change effectively alters our conscious perception so, even if your exteroceptive senses are telling you that your environment is safe, it's hard not to be fearful if your body is telling you that you are under attack. There are numerous physiological conditions that can create an internal sense of threat – hypermobility just happens to be one of them. Our conscious thoughts sit at the crossroads between our interoceptive and exteroceptive domains, working to create a reality that correlates with the information we are being given.

Where there is a disconnect between the interoceptive and exteroceptive domains, the narrator will create a reality to bridge the gap in order to make sense of it. The greater the disconnect between the interoceptive and exteroceptive domains the harder it becomes for the narrator to reconcile the differences. This leads to an altered sense of reality that is prone to catastrophic thoughts, a need to control its environment and potentially obsessive in nature; all characteristics of elite performers. This only acts to reinforce and amplify the sense of anxiety. Furthermore, the communication between these domains is multi- directional so they can further loop and act to underpin our beliefs, behaviours and our reality.

Take a cricketer who is worried about their performance, despite having good bowling figures. Even though their coach regularly reassures them that they're doing well (exteroceptive domain), the cricketer is 'stuck in their own thoughts', imagining worst-case scenarios and convincing themselves they won't perform (narrator domain). In this situation, it would be easy to assume that their environment is the problem, and to focus on the 'top two inches' in order to alter their appraisal of the situation. However, we argue that their anxiety is being driven by the interoceptive domain and a persistent breakdown in homeostasis. As such, they are constructing a narrative to rationalise the threat signalling of the interoceptive domain, even though the threat does not really exist.

Managing chronic anxiety

Whilst Domain Loop offers a model to explore how anxiety might become persistent, it also offers an integrated framework for intervention whereby professionals, organised around the three domains, can work collaboratively. As such, in order to reduce the harmful state of clinical anxiety, a planned inter-disciplinary strategy can be developed that optimises synergy and reduces dissonance between the domains. 

In our applied work, educating performers about the nature of their anxiety and adopting a multi-dimensional approach to treatment, the Domain Loop Model has experientially produced very encouraging results. However, we accept that the model lacks empirical evidence and would suggest two possible areas for future research. Firstly, a case control study to identify biomarkers for threat response in a population with intestinal permeability. Secondly, a study to explore the efficacy of integrated interventions, using the model as a framework for practice, in communities of elite athletes.

Broader applications of the model

Whilst this article has largely focused on the physiology of Domain Loop, the model is both integrated and multi directional. As such, actions in any domain can impact across the whole model; this means that it has multiple applications. 

For example, in today's media driven world, it's hard to read an article, watch the news or listen to politics without getting the sense that you're being forced to pick a side. This is often presented as a binary option, and often relies on fear-based thinking to encourage you to pick one option over the other. Once we choose an option, we create a narrative to support it and look for confirmation amongst our peers. However, we can become trapped in a physio- psychological loop whereby, an activated physiological threat response, drives the narrative to rationalise and justify the sense of threat, even though the threat is not real. This state can repeat over and over, powerfully overriding a more reasoned and logical approach to thinking. At his 1933 inauguration, Franklin D Roosevelt stated that 'the only thing we have to fear is fear itself'. The Domain Loop Model suggests that this statement could be more accurate than he could ever have imagined, and we speculate it could help us make sense of the polarising challenges that we face in the 21st century.

Stephen Hartshorn (BSc Ost, MBA), Retired Lecturer in Osteopathy at Swansea University and practicing Osteopath registered with the General Osteopathic Council

Michael O'Brien (BSc, MSc), Lecturer in Psychology - Gower College Swansea; Accredited Performance Psychologist with the British Association of Sport & Exercise Sciences

References

Do T, Diamond S, Green C, et al. Nutritional Implications of Patients with Dysautonomia and Hypermobility Syndromes. Curr Nutr Rep. 2021;10:324-333. doi:10.1007/s13668-021-00373-1.

Eccles JA, Beacher FD, Gray MA, Jones CL, Minati L, Harrison NA, Critchley HD. Brain structure and joint hypermobility: relevance to the expression of psychiatric symptoms. Br J Psychiatry. 2012 Jun;200(6):508-9. doi: 10.1192/bjp.bp.111.092460. PMID: 22539777; PMCID: PMC3365276.

Chu B, Marwaha K, Sanvictores T, et al. Physiology, Stress Reaction. [Updated 2021 Sep 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. 

Hur J, Smith JF, DeYoung KA, Anderson AS, Kuang J, Kim HC, Tillman RM, Kuhn M, Fox AS, Shackman AJ. Anxiety and the Neurobiology of Temporally Uncertain Threat Anticipation. J Neurosci. 2020 Oct 7;40(41):7949-7964. doi: 10.1523/ JNEUROSCI.0704-20.2020. PMID: 32958570; PMCID: PMC7548695

Sharp HEC, Critchley HD, Eccles JA. Connecting brain and body: Transdiagnostic relevance of connective tissue variants to neuropsychiatric symptom expression. World J Psychiatr. 2021 Oct 19;11(10):805-820.