The Impact of Hourly Prompts on Reducing Prolonged Sitting at Work

The health benefits of physical activity are widely recognised and there is increasing evidence to show the detrimental effects of sedentary behaviour on health. Both total sedentary time and the temporal pattern of accumulation of sedentary behaviour have a significant effect on health, with prolonged, unbroken periods of sitting being most harmful. Working adults spend a considerable proportion of time in the work domain and there is a high level of prolonged sedentary behaviour in many workplaces .

There is limited evidence from small-scale studies that workplace interventions can reduce prolonged sedentary behaviour of office workers. Providing advice to stand at regular intervals during the working day and using passive computer-based prompts, significantly reduced prolonged sitting by 40 minutes per day and increased self-reported energy expenditure . This indicates that there is potential for resource-light interventions to change behaviour in the workplace, however, evidence for effectiveness, feasibility and acceptability is currently limited.

This proposal is part of an ongoing collaboration with NHS Greater Glasgow \& Clyde Healthy Working lives. Representatives from 10 organisations involved with the Healthy Working Lives initiative were previously consulted to find an intervention acceptable to employers and identify companies interested in participating in a pilot study. The consultations generated considerable interest in the project and use of the outlook calendar (available to many staff) to provide prompts to stand-up as an intervention was considered acceptable to many employers. This pilot intervention will therefore build on the group's existing research.

30 desk-based employees will be recruited as participants via an email invitation and the use of posters displayed in the office. Volunteers will be screened regarding inclusion/exclusion criteria given a participant information sheet and asked to provide signed consent.

The study will be a 2-arm RCT of 30 participants split equally between a control and intervention group, where both groups receive education on why and how to reduce prolonged sitting, but the intervention group also receives hourly prompts to stand for a period of 10 weeks. Participants will be randomly assigned to a group either on an individual basis or in clusters by physical location within the office (to minimise the influence of neighbouring colleagues should they be in a different group). The method of randomisation will be decided upon once individuals have volunteered and been screened. Activity monitoring will be made at baseline (before the education session) at week 10 of the intervention and 3 months post-intervention (week 22). All participants will be asked to complete a questionnaire to ascertain basic demographic data, knowledge of and attitudes towards sedentary behaviour and previous engagement with health promotion initiatives. They will then be asked to wear a water-proofed ActivPal monitor on the front of their thigh for a period of 7 days (24 hours a day) in order to measure patterns of sedentary behaviour at baseline. To accompany this measurement they will also keep a diary recording waking and working hours for the same 7 day period.

Following baseline measurements all participants will attend an education session which will cover: what sedentary behaviour is (and how it is different to physical activity), the health problems associated with prolonged sedentary behaviour, how much sitting is recommended and advice on how to reduce and break up prolonged sitting.

Participants will then be randomly assigned (using sealed envelopes prepared by a researcher not involved in recruitment or intervention implementation) to either a control or intervention group so that each group contains 15 participants and, where possible, are physically separated within the office. The control group will return to work as normal following the education session, whereas the intervention group will have a series of prompts uploaded onto their Microsoft Office calendar, via an excel file, reminding them to stand for a period of one minute, every hour during their working day. These prompts will run for a period of 10 weeks. Participants will be able to dismiss prompts as soon as they appear and can choose whether to stand or remain seated. They will also be able to dismiss groups of prompts accumulated during periods away from the computer. The impact on their work is therefore thought to be minimal. The content of the prompts will be brief, varied and contain a positively framed message. During the last week of the 10 week period, both the control group and intervention group will be asked to once again wear an ActivPal monitor and keep a diary for a period of 7 days.

12 weeks after the end of the intervention period, the 7 day ActivPal and diary measurement will be repeated and semi-structured focus groups will be run with participants and organisational representatives with the aim of exploring the feasibility, acceptability, meaningfulness and effectiveness of the intervention. Focus groups will be recorded using a digital voice recorder, topic guides regarding their content are outlined in annex 6 and annex 7.

The validated ActivPal monitors use the acceleration signal from the thigh to categorise data into sitting/lying, standing and walking, but the primary outcome measures will be total time spent sitting at work, and time spent in prolonged sitting events while at work. Electronic copies of this data will be kept for 10 years, alongside electronic and paper copies of the baseline questionnaire and diaries and audio and transcribed accounts of the focus groups, in line with Glasgow Caledonian University's data protection policies. Physical activity data and basic demographic data will also be kept on a password protected database on a secure server. The data held on the database will not be identifiable. The information collected may be used for further analysis by staff and students in the School of Health and Life Sciences at Glasgow Caledonian University at a later date. Access to the database will be controlled by Dr Ben Stansfield, Reader in the School of Health and Life Sciences.

At the end of the study participants will receive an individual report detailing their patterns of sedentary behaviour before, during and after the intervention. They will also have access to the amalgamated report which will be given to the employer summarising the overall findings including the key outcomes of the focus groups.