Physical health discrepancy between individuals with Severe mental illness (SMI) and the general population is a cause for public health and ethical concern [1] . In those with SMI, increased incidence of concurrent health conditions, such as cardiovascular disease, type 2 diabetes, obesity and metabolic disturbances, is reported [2] - [4] and a reduced life expectancy of 10 - 20 years has been identified [5] [6] . Furthermore, physical disorders have been cited as the cause of up to 70% of premature deaths for people diagnosed with schizophrenia [7] . Reasons for the discrepancy in physical health between people with SMI and the general population are multifactorial and interconnected [8] - [10] . Lifestyle factors, namely physical activity, diet, dental care, sleep, smoking and misuse of drugs and alcohol are commonly cited explanations [9] - [11] . Reduced physical activity and increased sedentary behaviour are widely reported in individuals with SMI [12] - [14] . Dietary intake in this population is higher in saturated fat and sugar, lower in fibre, fruits and vegetables and there is an increased tendency towards daily eating of highly processed “fast foods” compared to the general population [15] - [20] .

The combination of physical inactivity and poor diet contributes to increased obesity rates and metabolic abnormalities [16] [21] . Physical health is also impaired by the low nutritional quality of food consumed, increasing the risk of micronutrient deficiencies [22] . Furthermore, SMI symptoms can increase unhealthy behaviours, such as night eating and snacking, and are associated with higher incidences of eating disorders [18] [23] - [26] . Increased consumption of high sugar foods and drinks combined with poor oral hygiene seen in SMI individuals (due to low motivation, anxiety and cost barriers to dental services) presents a further physical health risk through the association between oral disease and cardiovascular disease [10] [25] [27] .

Important interconnections between sleep quality and physical and mental health exist [11] [28] [29] . Disordered sleep is frequently reported by those with SMIs [30] . Sleep duration of less than six hours per night has been identified as a risk factor for metabolic syndrome [31] and sleep disorders may present an increased risk of obesity [32] . Poor subjective sleep quality in individuals with schizophrenia has been associated with lower physical health [33] . Sleep problems are associated with increased suicidal ideation [11] , impair social relationships and reduce the ability to engage in positive health and wellbeing behaviours [33] - [35] .

Smoking rates in people with schizophrenia have been reported to be between two and a half to six times higher than the general population [36] [37] . The use of illicit injectable drugs has been recorded as eight times higher, and 32% of men and 50% of women with SMI reported misusing alcohol [38] [39] .

Understanding why there is an increased prevalence of unhealthy lifestyle behaviours is key to addressing the physical health discrepancy experienced by individuals with SMI. Symptoms of mental illness such as suspiciousness, hallucinations, stress, depression, negative self-belief and social withdrawal are barriers to healthy behaviours [25] [40] - [44] . Anxiety and low confidence may be especially relevant in preventing young people (16 - 25 years) with SMI from taking part in sport [45] . Disrupted sleep patterns may accentuate the problem by reducing energy and motivation [35] [44] .

Cognition is a factor that may impact prevalence of unhealthy lifestyle behaviours. Altered cognition in SMI may reduce individuals’ ability to learn, plan and maintain new healthy behaviours [25] [46] [47] and dysfunctional reward mechanisms may hinder healthy eating habits [21] [48] . Poor cognitive performance may be associated with increased waist circumference and cardiovascular risk scores leading to the suggestion that cognitive deficits impair understanding of the importance of health check-ups and healthy lifestyle behaviours [49] .

Practical barriers to healthy lifestyle behaviours have been identified and these include difficulties around the cost of transport, activities, food and cooking equipment [40] [43] [50] . SMI is associated with low socioeconomic status reducing access to healthy food, opportunities for physical activity, and safe exercise spaces [16] [51] . Lack of support in overcoming these barriers, combined with feelings of stigma associated with mental illness, contribute to the complexity of the problem, reducing the likelihood of those with SMI to participate in mainstream physical activities, adopt a healthy diet and seek appropriate medical help [52] - [55] .

Medications used to treat SMI add further complication. In addition to directly inducing cardiovascular and metabolic disturbances and weight gain [56] - [59] , antipsychotics can disrupt appetite, cause feelings of drowsiness and amotivation, and induce extrapyramidal symptoms (such as incontrollable movements and tremors) which collectively hamper healthy lifestyle behaviours [21] [41] [52] [60] - [62] . However, medication may not always be a barrier and has been reported as helpful for promoting physical activity through making individuals with schizophrenia feel better in themselves [44] .

Interventions to improve lifestyle behaviours have the potential to enhance physical health [63] [64] . For such interventions to be effective in the SMI population, dedicated care and planning is essential given the complexity of challenges faced by these individuals [2] [9] [40] [46] [65] - [68] . Further, lack of time, resources and support can make implementing healthy lifestyle interventions into healthcare systems difficult [68] - [74] .

Healthy lifestyle interventions for people with SMI have demonstrated varied successes and systematic reviews highlight weak evidence, a lack of randomised control trials and risk of bias [66] [75] [76] . Positive outcomes for physical health parameters such as reduced BMI, body weight and waist circumference [2] [46] [53] [77] [78] and healthy lifestyle changes such as improved eating habits and increased physical activity are reported [79] - [83] . In addition, there is evidence of positive ripple effects for mental health with reduced depression, anxiety and social isolation and increased sense of achievement, motivation, confidence and adherence to treatment [43] [82] [84] - [87] . However, various group-based interventions have seen no significant weight loss or changes relating to physical activity, diet or substance abuse [86] [88] - [91] .

Programmes involving outdoor activities, peer support, non-stigmatising environments, flexible schedules and individualised approaches with collaborative participant-coach relationships have been found to improve engagement in SMI healthy lifestyle interventions [43] [69] [92] [93] . Those that start soon after initial SMI diagnosis and initiation of antipsychotic medications may benefit the most [87] [94] - [96] .

As the importance of self-management skills and personalised, holistic approaches are increasingly recognised, health coaches may play a key role in the successful delivery of SMI lifestyle interventions [35] [44] [45] [97] - [99] . Health coaching has been defined as “a goal-orientated, client centred partnership that is health-focused and occurs through a process of client enlightenment and empowerment” [73] . SMI individuals may benefit from this framework, where they are encouraged to make their own goals appropriate for their current health status and cognitive functioning, and are provided with professional, non-judgemental support to achieve them [80] [100] [101] .

The use of technology, such as telecoaching and wearable fitness tracker devices, may also enhance lifestyle interventions. Success in the general population has shown improved sleep duration and quality with software application supported online coaching [102] and a telenutrition programme was found to be effective for weight management [103] [104] . Controlled trials using a “Fitbit” wearable activity and sleep tracker device have increased physical activity in the general population [105] and in patients with type 2 diabetes [106] . With the increasing accessibility of mobile technology and trackers this approach offers an opportunity to provide scalable, individualised health interventions to those with SMI [52] [107] - [109] and “Fitbit” have been shown to offer a simple way of monitoring and promoting physical activity and weight loss [109] . Evidence from the general population suggests that combining these technologies with face-to-face health coaching (through increased personalisation) can further enhance an intervention’s impact and sustainability of behaviour changes made [103] .

Similar benefits for weight management in individuals with SMI and obesity have been found when wearable trackers were combined with a fitness trainer and lifestyle coaching from peers [65] [110] . The Well-Track intervention combines an activity tracker with three health coaching sessions over eight weeks [111] . Well-Track participants with psychosis described Well-Track as helpful for increasing awareness and motivation around exercise and positively influencing behaviours around sleep hygiene and physical activity [111] . Improvements in mood, self-management, motivation, confidence and social engagement were also recorded following Well-Track [112] . Further evidence suggests that Well-Track can improve general well-being and reduce insomnia in SMI individuals [113] .

The aim of this paper is to further assess the usefulness of the Well-Track intervention for those with SMI through qualitative assessment of participant experience. The impact on physical activity, sleep and weight management is investigated. Further, the paper seeks to understand potential benefits of Well-Track for physical, mental and emotional health, and the role of health coaching in supporting behaviour change in SMI.

The 15 participants comprised seven females, seven males, and one individual identifying as non-binary. The mean age was 42.93 years (SD = 14.72), ages ranging from 21 to 62 years.

The analysis revealed three overarching themes:

(1) Fitness tracker as a driver of healthy habits

(2) Holistic support and coaching for individualised change

(3) Positive impact associated with Well-Track

These themes illustrate how the Well-Track intervention facilitated behavioural change, motivation, and overall well-being. Further detail is presented in Figure 1 .

Qualitative analysis of in-depth interviews of individuals with SMI revealed insights into the benefits and mechanisms of action of Well-Track, supplementing quantitative data previously published showing enhanced well-being and improved sleep quality and reduced insomnia [113] . The activity tracker was identified as a helpful tool for making positive lifestyle changes. Improvements in physical activity levels, sleep hygiene and eating habits were described supporting evidence from other tracker-based interventions for SMI individuals [65] [109] [119] .

Evidence from the interviews suggests the activity tracker facilitated these improvements in three ways. Firstly, the activity tracker provided feedback and sense of achievement. Increasing motivation is recognised as an important first step for change in individuals with little or no initial engagement in health promoting habits [120] . The activity tracker may be of particularly value when people are first establishing new behaviours and have not yet experienced tangible health benefits to encourage consistent adoption as well as enabling longer term engagement through regular boosts in motivation.

Secondly, the activity tracker provided an increased awareness of overall physical health [112] [119] . Participants could see how their heart-rate and calorie expenditure changed in response to physical activity and gained valuable insights into the quality of their sleep. Autonomous motivation is key for the sustainability of healthy behaviours [121] . For those with SMI, an important balance is described between encouraging this motivation and applying too much pressure to achieve which may cause individuals to suffer disappointment and disengage from healthy lifestyle habits [121] . The personalised information Well-Track participants received from their activity tracker encouraged self-motivation as individuals made changes that were relevant and important to them.

Thirdly, by providing a practical means to set, monitor and achieve healthy lifestyle goals, the tracker boosted self-confidence [112] . Participants developed resilience to persist with their new healthy behaviours, seeing their progression to significant achievements such as consistently recording 10,000 daily steps. In some individuals, this extended to positive changes in their self-identity as they began to view themselves as people who were active and made healthy lifestyle choices, which is key to creating long term behaviour change after the initial motivation fades [120] .

For people with SMI, health coach support can facilitate behaviour change addressing additional challenges such as low mood, reduced cognitive function and psychosocial difficulties [40] [46] [52] [53] , making it easier to initiate and sustain new health habits. Participants reported direct coaching benefits for the development and maintenance of their new physical activity, sleep and weight management behaviours. Motivational interviewing techniques were used to good effect in the coaching process [112] . This is an important component to lifestyle intervention programmes given the lack of motivation commonly experienced by people with SMI [100] . The health coach boosted confidence through positive affirmation of participants’ progress at follow up sessions and encouraging maintenance of new healthy behaviours by providing accountability.

An effective professional working relationship between a health coach and the individual being coached is important and may be especially relevant for SMI individuals [100] [112] given previous reports of negative attitudes from healthcare staff impeding behaviour change [122] [123] . Participants benefitted from specific knowledge gained from the coach. Advice regarding meal planning and preparation was highlighted as pivotal to achieving nutritional improvements, healthier food choices and weight loss in people with SMI who may struggle to maintain a daily routine [25] [52] . Practical sleep hygiene advice was also instrumental in participants making positive changes that resulted in more consistent bedtime routines and reduced insomnia [35] [112] . Specific guidance to make small incremental changes enabled substantial progression over time.

A negative spiral has been described for SMI individuals whereby obesity and reduced cardiovascular functioning hampers physical activity resulting in greater depressive symptoms and low self-esteem which in turn may reduce motivation for healthy lifestyle behaviours [44] [98] [99] . Well-Track may reverse this negative spiral. Participants who increased their activity levels reported better quality sleep and improvements in their mood. This can increase their motivation for further positives health choices resulting in additional mental health benefits [40] [113] . Well-Track permitted personalised discussions around a range of lifestyle habits which enhanced this positive spiral, recognising synergistic benefits of physical activity, healthy eating, and quality sleep [95] [96] .

Well-Track increased physical mobility independence, reduced isolation and improved mental well-being [66] [87] [112] [124] . This has important implications for people with SMI as reductions in loneliness and increased social support are recognised factors for promotion of mental health recovery [125] [126] . Participants revealed intrinsic and extrinsic barriers to lifestyle change [43] [52] . The strategies described to overcome this included social support from either the health coach or friends and family. Overcoming mobility restrictions due to concurrent physical health problems was another barrier reduced by the coach through provision of personalised advice for safe exercise modifications.

Strengths of this qualitative study is that it revealed personal experiences, and it recruited from a CMHT which is representative of other UK CMHTs. Its generalisability is limited by recruiting in a single UK county. Participants were self-selecting which may have created bias if those putting themselves forward had above average mental and physical health for individuals with SMI and were, therefore, more able to make lifestyle changes. Self-selection might have also resulted in more of those with a positive experience putting themselves forwards for interview.

Further research is required to determine the sustainability of healthy lifestyle changes made during Well-Track. Given benefits of personal coaching reported here, investigation into the effect of additional sessions and at what time intervals these are most impactful would give further guidance to the intervention’s application. Investigation could be undertaken to see how the intervention could be strengthened by exploring strategies to promote long-term adherence. In addition, determination of potential subgroups of individuals with SMI that may respond most favourably to Well-Track would help direct this resource towards those most likely to benefit. For example, does age, health goals, SMI diagnosis, or current medication type influence participant experience and success as suggested recently in other healthy lifestyle interventions [59] [100] [127] .

By combining an activity tracker with individual consultations with a professional health coach, Well-Track offers the potential for an efficient, scalable and impactful approach for supporting healthy lifestyle changes in SMI individuals to improve their physical and mental health, well-being and overall quality of life.