Emergency Service teams operate in some of the most challenging workplaces and experience higher rates of mental ill health than the general population. Effective interventions are required to enhance wellbeing, but as a first step it is crucial to understand the context through which to develop these initiatives. This preliminary study will test the feasibility of implementing a larger study to map the relationship between physical responses associated with levels of stress (heart rate variability) and personal, social and organisational factors that mediate these responses. In doing so, it is hoped to provide an insight into factors that shape emergency staff members' response to stress to help develop and personalise wellbeing initiatives.

The study team is proposing a large study in the Essex Emergency Services to map the relationship between physiological indicators of stress and subjective mediators and, in doing, provide insight into factors that shape a staff members' response to stress, which could help to develop and personalise wellbeing initiatives.

However, before undertaking a large study it is proposed to establish operational feasibility. This feasibility study will enrol ten shift-working staff from each of three emergency services (Essex Police, Essex County Fire and Rescue Service and East of England Ambulance Service Trust). Over a 3-day period, we will evaluate participants' physiological response to stressors by measuring HRV (using Firstbeat Bodyguard 2 beat-to-beat heart rate monitor). During the same period, participants will keep a personal online journal of events during the day. As part of the lifestyle assessment, data from the heart rate monitor and journal will be analysed and participants will receive a Summary Report including information on their body's reaction to stress and how this may be managed. Following the lifestyle assessment, the research team will facilitate semi-structured interviews; they will use participants' lifestyle assessment Summary Reports to inform appropriate questions. The team will discuss subjective experiences with participants as well as their overall experience with the data collection process.

The objectives of the feasibility study are to:

1. Evaluate feasibility of undertaking a larger definitive study in terms of:

   • Willingness and eligibility of emergency services' staff to take part in the study
   • Recruitment timeframe
   • Participant adherence to lifestyle assessment protocols (including wearing a heart rate monitor and completing an online journal over a 3-day period)
   • Proportion of participants in whom an interview is arranged and completed
   • Feasibility of other operational aspects not included above.

2. Undertake an initial evaluation of physiological indicators and subjective mediators of stress and identify any i) associations between them and ii) patterns that emerge between individual participants.

Inclusion Criteria:

• are aged 18 or older
• full-time employees
• work shift patterns and will be on-duty during the study period
• are able to take part in and contribute to the study (see exclusion criteria below).

Exclusion Criteria:

• off-duty or on leave during the study period
• part-time (or on-call) employees
• not working shift patterns
• currently taking part in research that may impact on results, design or scientific value of this study (or other studies)
• not able to read or understand the English Language as it will not be possible to provide translation services for the study

In addition, the results from the heart rate monitor may be unreliable with certain medical conditions and, as such, staff will not be able to take part if they have had a heart transplant or if they have a pacemaker, heart disease, atrial fibrillation, atrial flutter or uncontrolled thyroid disorder.

A purposive, non-probability sample will be selected and recruited comprising ten operational shift working staff from each of three emergency services (Essex Police, Essex County Fire and Rescue Service and East of England Ambulance Trust).