High Intensity Interval Training in Inpatients with Severe Mental Illnesses

Student thesis: Doctoral ThesisDoctor of Philosophy


People experiencing a severe mental illness (SMI) experience physical health disadvantage and premature mortality. The rates of cardiovascular disease, coronary heart disease, diabetes mellitus and metabolic syndrome are at least two-fold higher in people with SMI compared to healthy controls and the premature mortality gap amounts to 13-30 years. Moreover, people with SMI typically experience pronounced socio-occupational difficulties, cognitive impairment and reduced quality of life which may worsen over time.

Physical activity, sedentary behaviour and dietary intake are lifestyle risk factors that can reverse cardiometabolic ill health and improve mental health. The purpose of this PhD was to describe the physical activity, sedentary behaviour, and dietary intake patterns of a sample of patients with SMI and develop and pilot a novel exercise intervention to address physical and mental health amongst a sample of inpatients with SMI who are most unwell. Additionally, a sub-study was conducted to explore attitudes towards the provision of exercise facilities for mental health staff.

Part One of this thesis explores the physical activity, sedentary behaviour, and dietary intake of people with SMI and provides an evidence synthesis of the high intensity interval training (HIIT) literature. Firstly, I summarise lifestyle patterns from a large sample of 406 individuals with established psychosis (Paper One) using self-report data. I report that a majority of patients with psychosis do not meet recommended physical activity guidelines, engage in high levels of sedentary behaviour, and have poor dietary quality, low in fruit and vegetables and high in discretionary foods. Papers 2-4 used systematic review and meta-analyses to summarise the efficacy, safety, and adherence of HIIT interventions in both the general population and people with mental illnesses. The results of these papers indicated that HIIT can safely be delivered in clinical and non-clinical samples, is associated with good adherence, and has potential benefits to physical and mental health, although more work is needed in people with mental illnesses to identify the full range of benefits associated with HIIT. Additionally, I present a further systematic review (Paper 5) that summarises the therapeutic benefits, safety and adherence of exercise interventions delivered specifically in inpatient mental health settings. Paper 5 concludes that whilst exercise may have physical and mental benefits in inpatient mental health settings and appears to be safe and enjoyable, more research is needed to determine optimal exercise parameters and establish the full range of therapeutic benefits.
In Part Two of this thesis, I outline a pilot study of HIIT for inpatients with SMI. Firstly, I outline findings from a series of focus groups investigating, in inpatients with SMI, carer and staff groups, perspectives on implementing HIIT interventions for patient groups in inpatient settings, including perceived barriers and enablers. This qualitative study revealed positive attitudes towards HIIT with beliefs that it would help patients feel more relaxed, build their fitness, and provide a break from the monotony of ward environments. Implementation concerns were also noted that should be addressed to ensure successful implementation of HIIT interventions. Secondly, I outline results from the HIIT pilot study. The pilot study followed a two-part design adapted due to Covid-19 with a project design change: a) A non-blinded randomized controlled trial (RCT) of 12 weeks of bicycle- based HIIT compared to treatment as usual (TAU). b) A naturalistic study of inpatient HIIT; eligible participants were invited to two sessions of HIIT per week. The aim of the pilot study was to determine whether HIIT is acceptable and feasible amongst inpatients with a broad range of severe mental illnesses. High feasibility and acceptability were observed; uptake was high, no adverse evets were experienced, and participants reported satisfaction with HIIT. 

Part Three of this thesis qualitatively explores attitudes towards the provision of exercise facilities in the workplace for mental health staff use via a series of focus groups with staff. Focus groups observed positive views of exercise for mental health staff with beliefs it could benefit staff wellbeing and staff-patient relations. Practical barriers were also noted that should be addressed in future work. A feasibility study was subsequently conducted whereby mental health staff were invited to use a stationary exercise bike in the workplace environment. Uptake was measured and satisfaction explored. 

Part Four of this thesis extends the discussion from Parts 1-3. I outline the research, clinical and policy implications of the body of work presented, and directions for future work. I additionally present a summary of the biological mechanisms by which exercise may exert its effects on mental and physical health. 
Date of Award1 Apr 2022
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorFiona Gaughran (Supervisor), Brendon Stubbs (Supervisor) & Juliana Onwumere (Supervisor)

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