Exploring the happiness and sense of purpose associated with older peoples' activities using ecological momentary analysis: an observational study

Background Older people have more leisure time, but many are physically inactive. Momentary feelings of pleasure or happiness and sense of purpose can be sources of intrinsic motivation. This study’s objective was to investigate how the type (sedentary, active) and context (social and environmental) of older peoples’ activities relate to momentary feelings of happiness and purpose. Details of activities, contexts and feelings of retired or semi-retired adults (n=67, aged 50-78y) were captured over 7 days using ecological momentary assessment (EMA) via a smart phone app. Participants were prompted on their smart phone six times at random per day, resulting in 2,065 valid prompts. They wore an Actigraph accelerometer on the waist for 7 days to measure physical activity. Happiness and sense of purpose outcome variables were regressed on activities, context and potential confounding variables (e.g. age, gender, physical activity). Regression standard errors were clustered on participants to account for the hierarchically structured data. Interactions between activities and contexts were explored.


Background And Rationale
The benefits of physical activity for slowing the ageing process and improving quality and length of life are wellknown (Bangsbo et al., 2019), yet > 25% of adults 55-64y in England report fewer than 30 minutes per week at health-improving moderate-vigorous intensity. The percentage inactive rises to almost 70% for those aged 85+ (Sport England, 2019).
Sense of purpose and pleasure are sources of intrinsic motivation identified in self-determination theory (Ryan and Deci, 2001), which underpins many health-related behaviour change interventions (Patrick and Williams, 2012), and could be leveraged to promote physical activity among older people (Cabrita et al., 2017) who try to balance feelings of pleasure-(i.e. happiness -and purpose) from moment to moment in everyday life (Dolan, 2014). Understanding how older peoples' activities relate to momentary feelings of happiness and/or purpose would help to inform the design of effective interventions and policies to increase physical activity and reduce sedentary behaviour among older people, which is a public health priority (Public Health England, 2014).
Previous studies of older peoples' activities and their relationship to experiential feelings use retrospective evaluations (Oerlemans, Bakker and Veenhoven, 2011;Kavčič and Avsec, 2018;Stone et al., 2018). A recent study of older adults sampled using the American Time-Use Survey (ATUS) found active leisure (e.g. sports, exercise and recreation) was associated with greater 'happiness' and 'meaningfulness' when compared with passive (sedentary) leisure (e.g. screen time) (Yamashita, Bardo and Liu, 2018). However, this study did not consider activities' social and environmental contexts, which are important among older people (Finlay et al., 2015;Boulton, Horne and Todd, 2018). Furthermore, activities were classified as active or passive retrospectively by the researchers, which risked misclassifications. Moreover, memories of feelings experienced yesterday -as collected by the ATUS -are less reliable than immediate recall, particularly for older adults (Galenkamp et al., 2016), who may be experiencing decline in short-term memory (Verhaeghen, 2013).
A more accurate method of capturing behaviour, feelings and contexts simultaneously is via prompted, frequent, real-time self-reports known as ecological momentary assessments (EMA) (Shiffman, Stone and Hufford, 2008). A study using smartphone-delivered EMA over 30 days in a small sample (n = 10) of older adults (65-83y), found that social, outdoor leisure activities were associated with higher experiential pleasure than non-leisure activities performed alone or indoors (Cabrita et al., 2017). Experiential feelings of purpose were not considered in this study.
The objective of this study, therefore, was to investigate how the type (sedentary, active), social (alone or with others) and environmental (indoors or outdoors) contexts of activities relate to momentary feelings of happiness and purpose assessed using EMA methods in a sample of retired or semi-retired, community-living older adults.

Study Design, Participants And Setting
A cross-sectional observational design was adopted. Participants were recruited via responses to messages posted on social media groups (e.g. Facebook sports club groups), forums (e.g. London School of Economics Alumni) and personal contacts. Participants were eligible if ≥ 50 years, fully or semi-retired, owned a smartphone, and able to attend an enrolment meeting in London or Loughborough, East Midlands (UK). Seventy-three adults met the inclusion criteria and consented to take part. Recruitment spanned February to December 2019. During their enrolment meeting, eligible participants provided informed consent, were familiarised with study procedures and equipment, assigned an initialised Actigraph activity monitor, shown how to download and login to the EMA app and asked to complete a survey.

Ecological Momentary Assessment
Details of activities, contexts and feelings were captured using EMA (Shiffman, Stone and Hufford, 2008). Several studies have demonstrated the feasibility, acceptability, reliability and validity of smartphone-based EMA to measure behaviours and feelings in a variety of older populations (Maher, Rebar and Dunton, 2018;Paolillo et al., 2018;Liu and Lou, 2018). Ethica software (www.ethicadata.com) was selected because it had both Android and IOS versions, making it compatible with most mobile phones. The EMA protocol was piloted in six smartphone users aged 50 + and modifications made.
At the initial meeting participants completed a survey through the Ethica app which asked about age, gender, ethnicity, religion, self-assessed health, highest educational level achieved, whether living alone, whether working part-time or not, number of adults in household, and overall life satisfaction and worthwhileness of life, all of which have been previously identified as confounding factors in analyses of subjective wellbeing (Dolan, Kudrna and Stone, 2017), or associated with choice of leisure-time activities (Galenkamp et al., 2016). Principal sources for question wordings included the Office for National Statistics harmonised wordings for the 2011 Census and the Taking Part Survey questions (Ipsos MORI, 2018) Over the seven days of monitoring, participants received six prompts at random within 150-minute windows between 06:30 and 21:30 to complete 6 questions about their main activity in the last hour and their feelings of happiness and sense of purpose during that activity. They were instructed to answer prompts immediately but only when safe and convenient. Participants were asked: What was your main activity in the last hour? (21 activities, grouped into six higher-level categories (physical, mental, social, recreational, travel and resting), similar to those used in previous studies of older peoples' activities (Chang, Wray and Lin, 2014); Galenkamp et al., 2016; Yamashita, Bardo and Liu, 2018)). They were then asked to rate their happiness and sense of purpose on a visual analogue scale by moving a slider from the default setting of 5 to a number between 0 (not at all) and 10 (totally/wholly) (

Accelerometry
Participants were asked to wear an Actigraph accelerometer, either GT3x or wGT3X-BT (Actigraph, 2013) over the right hip using an elasticated waist band during waking hours for seven consecutive days. These devices have been identified as having acceptable validity and reliability in older adults (Copeland and Esliger, 2009). Data were collected at a sampling rate of 100 Hz and downloaded in epochs of 60 seconds for analysis using Actilife software. Raw Actigraph data files were reprocessed to derive outcome variables, using custom data reduction software (KineSoft, V.3.3.67, Loughborough, UK). Non-wear time was defined as ≥ 60 minutes of consecutive zero counts, allowing for 2 minutes of non-zero interruptions (Tay, Chan and Diener, 2014). Participants' accelerometer data was considered valid if they had ≥ 5 days with ≥ 10 hours of valid accelerometer wear (Pruitt et al., 2008). Vertical axis intensity cut-points derived for use in older participants were adopted (Copeland and Esliger, 2009).

Statistical Methods
The unit of analysis is a single response to an EMA prompt. Happiness and purpose outcome measures were regressed on activities undertaken, controlling for confounding influences from the social and environmental context (e.g. where they took place), accelerometer assessed physical activity/time spent sedentary, and participant characteristics. Given the use of multiple regression methods, a key consideration governing sample size was degrees of freedom. Using a two-tailed test and 95% confidence level, assuming 20 independent variables, a sample size of 1,302 responses was sufficient to detect a very small effect size of 0.01 (Faul, F., Erdfelder, E., Lang, A.-G. & Buchner, 2007). To account for the hierarchically-structured the data, the errors of the regressions were clustered on individuals. Given the number of independent variables that could potentially be included in the regressions, multicollinearity was likely. To preserve degrees of freedom, a pragmatic approach was adopted. Accordingly, backwards elimination was used to derive parsimonious estimates, and further independent variables were removed where variance inflation factors exceeded 10, which eliminated most of the confounding variables except for accelerometer assessed sedentary time. All analyses were conducted using Stata version 14.2 (StataCorp, 2018) and statistical significance was set at p < 0.05.

Results
Six participants were removed as they did not meet the criteria for valid accelerometer data. Data on 67 (92%) participants were retained for analysis. The maximum number of responses per participant was 42 (i.e. 6 per day). Owing to missing data, 560 EMA responses were removed, leaving 2,065 from 67 participants -an average of 4.4 per participant per day: a response rate of 73.3%. Sample characteristics are presented in Table 1. Participants ranged from 50-78 years of age, were predominantly white British, had at least degree-level education, mainly resident in London, in good or better self-assessed health, and all except one met the current physical activity guidelines (≥ 150 minutes of MVPA weekly (Public Health England, 2014). Mean values for feelings of momentary happiness and sense of purpose were in line with those found for measures of wellbeing in other surveys using the same scale, e.g. Office for National Statistics, (2020).  Table 2 shows the categorisations and frequencies of participation in different activities. The most reported activity was physical with moderate intensity sport/exercise being the most common (22%). Mental activities were the next most common, with screen time being the most frequent (9.5%). For the regression analyses, the 22 individual activities were reduced to 13 by combining similar activities (e.g. moderate and vigorous sport/exercise both count towards meeting the current physical activity guidelines) and merging low-frequency activities into larger categories. Light sport/exercise was retained as a separate category because it does not count towards the recommended 150 minutes a week of physical activity. Sport or exercise at moderate-vigorous intensity was not significantly associated with either happiness or sense of purpose when compared with mentally passive activities, such as screen time (Table 3). Sport or exercise at light intensity had a positive association with sense of purpose but volunteering or caring for someone had the largest association with sense of purpose of any of the 13 activities. Activities that had the strongest association with momentary happiness were social (e.g. visiting or entertaining friends or family, and going out to a pub, club or restaurant), or recreational (e.g. attending a theatre or other cultural attraction).  Table 3 here] Given the significance of context variables for happiness and purpose (Table 3) Table 4). The regression shows that for many activities, context is important: social activities for example were positively associated with both outcomes compared to solo activities -with the exception of volunteering. In general, sedentary activities were negatively associated with both outcomes, unless they were social sedentary activities (e.g. visiting friends and family). Of the active recreational activities, those that were social and outdoors had the largest positive association with both outcomes. Less sedentary participants were more likely to experience higher feelings of happiness and sense of purpose during any recreational activity. [ Table 4 here]

Discussion
The objective of this study was to investigate how the type (sedentary, active) and context (social and environmental) of older peoples' activities relate to momentary feelings of happiness or purpose to inform the design of interventions and policies. The finding that social (i.e. with other people) light sport/exercise was positively related to happiness, but that moderate-vigorous sport/exercise was not associated with either outcome, points to the potential challenges of promoting higher intensity activities in this age group (Downward and Dawson, 2016). For both outcomes, outdoor activities were associated with higher levels of happiness and sense of purpose. The association between outdoor activities and happiness has been noted previously (Finlay et al., 2015;Cabrita et al., 2017). However, the finding that outdoor activities were associated with greater momentary sense of purpose is new. This study also demonstrates that, although closely related, older people distinguish between the concepts of happiness and sense of purpose. The small overlap in the pattern of significant coefficients between the two outcomes illustrated this. Visiting friends and family, and going to a pub, club or restaurant were strongly associated with feelings of happiness but not purpose for example. Differences such as these suggest there is additional insight provided by investigating momentary sense of purpose (Dolan, 2014). The current analyses also show that less sedentary older adults on average experienced greater feelings of happiness compared with their more sedentary counterparts, which is in line with previous research (Lathia et al., 2017). However, a new finding is that less sedentary older adults also experienced even greater feelings of purpose during their activities. Overall the results suggest that policies and practices that encourage older adults to be less sedentary and spend more time in outdoor and social activities are likely to increase happiness and sense of purpose and could be leveraged to increase physical activity. For example, volunteering, even if solo, will enhance happiness and sense of purpose and if active, will also contribute to increased physical activity levels.
The study has two main limitations: first, the sample was not representative. For example, participants were more physically active (Sport England, 2019) and more highly-educated than UK adults of this age-group (OECD, 2020), likely due to the recruitment strategies and the need to exclude older people without smartphones. Second, the study was not designed to establish causal relationships; however momentary wellbeing was reported immediately after the activity had taken place, so causality is unlikely to be reversed.
In conclusion, this research suggests that the context of leisure-time activities is important for older adults' feelings of both happiness and purpose, with social and outdoor activities being more likely to have the widest appeal. This should be considered when designing physical activity-increasing interventions and policy. There is value in future research measuring momentary sense of purpose as well as happiness in a larger and more representative sample of older people.

Competing interests
The authors declare that they have no competing interests

Availability of data and materials
The datasets generated during the study are obtainable from the corresponding author on reasonable request

Ethics approval and consent to participate
The study received ethical approval from the Loughborough University Ethics (Human Participants) subcommittee on 24 Jan 2019

Consent for publication
Not applicable

Funding
No external funding

Authors' contributions
Karen Hancock: devised the surveys, conducted fieldwork, analysed data and drafted the manuscript as part of her PhD studies.
Prof. Paul Downward: provided technical advice on analysis and commented extensively on the manuscript.
Dr. Lauren Sherar: advised on data collection methods, processed raw accelerometer files and commented extensively on the manuscript.
All authors: conceived the idea for the study.