A daily diary investigation of the effects of work stress on exercise intention realisation: Can...
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Daily diary investigation of work stress and exercise
Payne, N., Jones, F. & Harris, P.R. (2010). A daily diary
investigation of the effects of work stress on exercise intention
implementation: Can planning overcome the disruptive effects of work?
Psychology and Health, 25, 1, 111-129. DOI:10.1080/08870440903337622
A Daily Diary Investigation of the Impact of Work Stress on Exercise
Intention Realisation: Can Planning Overcome the Disruptive Influence
of Work?
Nicola Payne
Middlesex University
Fiona Jones
University of Leeds
Peter R. Harris
University of Sheffield
Nicola Payne, School of Health and Social Sciences, Psychology
Department, Middlesex University; Fiona Jones, Institute of
Psychological Sciences, University of Leeds; Peter R. Harris,
Department of Psychology, University of Sheffield.
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Daily diary investigation of work stress and exercise
This project was supported by a grant from the U.K. Economic and
Social Research Council.
Correspondence concerning this article should be addressed to
Nicola Payne, Psychology Department, Middlesex University, Hendon NW4
4BT. E-mail: [email protected]
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Daily diary investigation of work stress and exercise
Abstract
Using the theoretical context of the Theory of Planned Behaviour,
this study examined whether work has a disruptive influence on
people’s ability to carry out their daily intentions to exercise, and
whether daily planning helps overcome this. A daily questionnaire was
completed by 42 employees for 14 days. A brief daily planning
intervention was administered to half of the employees. Multilevel
modelling was used to analyse the data. The moderating effects of
daily perceived behavioural control (PBC), job demands and work-
related anxiety and depression on the relationship between intention
to exercise and subsequent behaviour were investigated, as well as
the impact of the intervention. Intention and PBC predicted exercise.
Job demands appeared to disrupt people’s ability to carry out their
daily exercise intentions. Contrary to expectation, people in the no
intervention group were more likely to exercise. Furthermore, on low-
demand days they were most successful in realising their exercise
intentions (when they intended to exercise for longer), whereas
people in the intervention group, on high-demand days were least
successful in realising their exercise intentions. The intervention
may have operated contrary to expectation by drawing attention to
potential failure.
Key words: physical exercise, theory of planned behaviour,
implementation intentions, planning, job demands, multilevel modeling
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Daily diary investigation of work stress and exercise
A Daily Diary Investigation of the Impact of Work Stress on Exercise
Intention Realisation: Can Planning Overcome the Disruptive Influence
of Work?
Research increasingly highlights the potential role that
individuals have to play in influencing their own health. Research
linking diseases such as coronary heart disease to unhealthy
behaviours, such as lack of physical exercise is abundant (e.g. Blair
et al., 1989). However, many people find it difficult to engage in
healthy behaviours. Social cognition models help explain the
processes involved in initiating and implementing health behaviours.
According to a number of these theories, including Protection
Motivation Theory (Rogers, 1983), the Theory of Reasoned Action
(Fishbein & Ajzen, 1975) and the Theory of Planned Behaviour (TPB;
Ajzen, 1988, 1991), intention is the key determinant of behaviour.
However, reviews and meta-analyses show that intention only explains
moderate proportions of variance in behaviour (e.g. Armitage &
Conner, 2001; Sheeran, 2002; Sutton, 1998), including exercise
behaviour (e.g. Blue, 1995; Hagger, Chatzisarantis, & Biddle, 2002;
Hausenblas, Carron, & Mack, 1997).
Perceived behavioural control (PBC; i.e. how easy or difficult
it is to perform
a behaviour) is proposed as a further determinant of behaviour in the
TPB (Ajzen, 1988,
1991). PBC may directly aid the prediction of behaviour (Ajzen, 1991)
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Daily diary investigation of work stress and exercise
or may act as a moderator of the intention–behaviour relationship.
PBC has sometimes been found to add relatively little to the
prediction of behaviour (e.g. on average, it explained 2% of the
variance in behaviour in a meta-analysis; Armitage & Conner, 2001).
The evidence for an interaction between intentions and PBC is
conflicting (e.g. 9 out of 19 studies in a meta-analysis reported a
significant interaction effect; Armitage & Conner, 2001).
Sheeran (2002) suggested that intenders who do not act (i.e.
people who intend to perform a specific behaviour but subsequently do
not) and non-intenders who do act are responsible for the gap between
intentions and behaviour. However, research on exercise rarely finds
many non-intenders who subsequently exercise (e.g. Godin, Shephard, &
Colantonio, 1986; Rhodes, Courneya, & Jones, 2003). Thus, intenders
who fail to act have become the focus of much research. Rhodes et al.
(2003) found that this group exhibited less positive attitudes and
decreased PBC over exercise compared to intenders who succeeded in
exercising. However, Godin et al. (1986) found few differences
between the cognitive profiles of the two groups. Overall, evidence
suggests that PBC may not be sufficient to account for the gap
between intentions and behaviour.
A limitation of much research into the TPB is that the gap
between measurements of intentions and behaviour is frequently long.
Therefore, intentions may fail because they change over time (i.e.
lack of temporal stability). Sheeran and Abraham (2003) found that
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Daily diary investigation of work stress and exercise
temporal stability moderated the relationship between exercise
intentions and behaviour and mediated the impact of other moderators,
such as past behaviour and anticipated regret. Thus, temporal
stability appears to be a key to translate intentions into behaviour.
Fishbein and Ajzen (1975) suggested that measurements of intention
and behaviour should be close together in time and Courneya and
McAulay (1993) found that this led to larger exercise intention–
behaviour correlations. Yet, ignoring the issue of temporal stability
remains a limitation of much TPB research. Therefore, the present
study used daily measurements of intentions and behaviour.
Working Life
Godin et al. (1986) suggested that intenders who do not act may
experience significant social and environmental constraints that
restrict them from engaging in healthier behaviour. Much research
focuses on the constraints produced by working life and has found
that high levels of job demands, work-related hassles and perceived
work stress are linked to reduced exercise (e.g. Cohen, Schwartz,
Bromet, & Parkinson, 1991; Hellerstedt & Jeffery, 1997; Heslop et
al., 2001; Johansson, Johnson, & Hall, 1991; Ng & Jeffery, 2003;
Payne, Jones, & Harris, 2002; Weidner, Boughal, Connor, Pieper, &
Mendell, 1997), although some studies do not support this link (e.g.
Landsbergis, Schnall, Deitz, Warren, & Pickering, 1998; Steptoe,
Lipsey, & Wardle, 1998). Payne et al. (2002) found that the presence
of job demands as well as low-exercise PBC appeared to impede
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Daily diary investigation of work stress and exercise
people’s ability to carry out their intentions to exercise and
differentiated intenders who succeeded in exercising from intenders
who failed. Such demands may not be completely accounted for by PBC
because they may reflect actual control and/or unexpected demands.
The concept of job demands only encompasses a limited aspect of
working life. Work stress has been linked to anxiety, depression and
negative moods, which may spill over into home life and have an
impact on health behaviours (e.g. Jones, O’Connor, Conner, McMillan,
& Ferguson, 2007). These negative affects have been associated with a
lack of exercise in a number of studies (Allgo¨ wer, Wardle, &
Steptoe, 2001; Anton & Miller, 2005; Ezoe & Morimoto, 1994; Farmer et
al., 1988) and positive affect has been linked to increased exercise
(Griffin, Friend, Eitel, & Lobel, 1993). Warr (1990) suggested that
context-specific measures of affect may be useful for occupational
research, and yet research rarely examines the impact of work-related
affect on exercise. In addition, the TPB has been criticised for
excluding affective processes (e.g. Conner & Armitage, 1998).
Attitudes towards behaviour have an affective component and research
has investigated the emotional appraisal of intentions to exercise
(e.g. Mohiyeddini, Pauli, & Bauer, 2009). However, the more general
impact of affect is rarely examined.
In summary, PBC, the variable suggested by the TPB to help
people convert intentions into behaviour, may not be sufficient to
account for why some people intend to exercise but fail to act.
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Various factors such as temporal stability may facilitate intention
realisation but social and environmental constraints, such as the
demands and negative affectivity produced by working life, may be
disruptive. The present study examined this potentially disruptive
influence of daily work factors on daily intention realisation.
In order to successfully carry out intentions to exercise,
individuals may have to overcome constraints produced by working life
and making plans, including contingency plans, may help do this.
Planning
Gollwitzer (1990, 1993, 1999) proposed that forming
implementation intentions, which involve planning where and when to
perform a specific behaviour, may help bridge the gap between
intentions and behaviour, promoting behavioural enactment rather than
intention formation. Implementation intentions form a mental link
between specific behavioural acts and specific situations, so that
when these situational cues are encountered, the behaviour is
elicited automatically. According to a number of meta-analyses (e.g.
Gollwitzer & Sheeran, 2006), participants who form implementation
intentions are significantly more likely to carry out a variety of
behaviours, including exercise (e.g. Milne, Orbell, & Sheeran, 2002;
Prestwich, Lawton, & Conner, 2003).
Schwarzer’s (1992) Health Action Process Approach is one of only
a few theories to take account of planning. Schwarzer proposed that
action planning (i.e. planning when, where and how to exercise,
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Daily diary investigation of work stress and exercise
similar to implementation intentions) and coping planning (i.e.
anticipating barriers to exercise and planning how to overcome them)
are involved in translating intentions into behaviour. Sniehotta,
Scholz, and Schwarzer (2006) found that cardiac patients who made
action and coping plans were significantly more successful in
exercising than patients who made action plans only or a no
intervention control group. Lippke, Ziegelmann, and Schwarzer (2004)
obtained similar findings in orthopaedic patients. In both studies,
the interventions were quite complex (e.g. Sniehotta et al. (2006)
used one-to-one training) making them potentially demanding in terms
of organizational resources such as time and finances. Scholz, Schuz,
Ziegelmann, Lippke, and Schwarzer (2008) also found that coping
planning significantly predicted increased exercise and that both
action and coping planning moderated the relationship between
intention and behaviour, such that intenders who made plans were more
likely to successfully realize their intentions.
Since many complex health behaviours, such as exercise, are
performed each day (or at least more than once a week), it may prove
problematic to ask people to make plans only once and assume that
this will remain constant across all days. In addition, the context
in which a person exists (e.g. the conditions of their job) may
change from day to day. If such contextual factors affect behaviour,
even making plans may not be enough for successful behavioural
enactment (Cox, 1997). Thus, the present study examined whether a
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daily planning intervention focusing on work helps people carry out
their daily intentions to exercise and helps overcome the potentially
disruptive influence of work. In contrast to much previous research,
this intervention was self-administered, brief and relatively
undemanding, thus appropriate for daily use.
The Present Study
In summary, the aim of the present study was to examine the
disruptive influence of work on people’s ability to carry out daily
intentions to exercise and whether a simple daily planning
intervention could overcome this. Thus, there were two core research
questions:
(1) Are individuals less likely to realise their intentions to
exercise on days when they experience higher levels of job demands
and negative affect (i.e. work-related anxiety and depression)?
(2) Does making daily plans help people to carry out their daily
intentions to exercise and, in particular, does it overcome the
potentially disruptive influence of work?
Planning included a combination of action
planning/implementation intentions (i.e. deciding when, where and how
to exercise each day) and coping planning (i.e. considering potential
barriers and how these might be overcome each day).
The study used the TPB as a basis for investigating the proximal
predictors of behaviour and so the direct and moderating effects of
PBC were included. Thus this study aimed to examine whether the
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direct and moderating effects of work factors and of planning exert
an influence over and above the effects of PBC.
The present study utilised daily diaries. This should eliminate
much of the limitation of temporal stability found in previous
research, since measures of intention and behaviour are close
together in time and thus intention is likely to remain stable.
Measures of behaviour based on retrospective reports over long
periods inherently suffer from problems of recall, which may be
overcome by more proximal daily measures (Bolger, Davis, & Rafaeli,
2003). Daily measures of exercise are found to be as reliable as
direct, objective measures taken using continuous heart rate and
motion monitors (e.g. Taylor et al., 1984). Furthermore, daily
diaries provide rich data, which can more accurately reflect the
complexity of intention–behaviour relationships and dynamic
moderators of this relationship. Although several diary studies have
investigated stress and eating (e.g. Conner, Fitter, & Fletcher,
1999; Jones et al., 2007; Newman, O’Connor, & Conner, 2007; O’Connor,
Jones, Conner, McMillan, & Ferguson, 2008; Stone & Brownell, 1994;
Wolff, Crosby, Roberts, &Wittrock, 2000), daily diaries are rarely
used to examine work stress and exercise or to investigate the impact
of planning on intention realisation.
In addition, data will be analysed using multilevel random
coefficient modeling (MRCM), which is widely regarded as the
appropriate method of analysis for daily diary data (Nezlek, 2001;
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Nezlek & Zyzniewski, 1998; Raudenbush & Bryk, 2002; Snijders &
Bosker, 1999). Much previous diary research in this area (e.g. Conner
et al., 1999; Stone & Brownell, 1994) conducted ordinary-least-
squares multiple regression analysis and it is only relatively
recently that similar research has begun to employ MRCM (e.g. Jones
et al., 2007; Newman et al., 2007; O’Connor, et al., 2008).
Method
Sample
Participants were UK employees of a company involved in the
design, marketing and sales of computer hardware and software to
businesses. Employees involved at each stage from design to sales
participated in the study and jobs ranged from administrative to
management positions. Volunteers were recruited via an internal
global e-mail requesting participants who were currently exercising
but sometimes found it a struggle to maintain. This instruction aimed
to ensure that only those who intended to exercise (and therefore
were appropriate for a planning intervention) were included.
Sixty-one employees enquired about participating and, of these,
19 withdrew when given details of the study and 42 went on to begin
completion of the daily diaries for 14 days. The use of time lags
between intention and behaviour (i.e. exercise intention was recorded
on one day and behaviour was recorded the following day) meant that
for each participant there were 13 days of useable data. Although
there were a possible 546 days of useable data (i.e. 42 participants
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for 13 days), four participants failed to complete one or more days.
One of these participants accounted for more than half of the missing
days and so his/her data was not analysed. This left 41 participants
and 539 days of data in total. Participants worked on 348 (64%) of
these days.
Of the 41 employees, 18 (45%) were female. Twenty-one percent
were aged 16–24 years, 41% were aged 25–34 years, 17% were aged 35–44
years, 19% were aged 45–54 years and 2% were aged 55 years or older.
The Diary
Exercise
Respondents were asked ‘What forms of exercise did you do today
and how long did you devote to each?’ Exercise was defined in the
questionnaire as ‘taking part in purposeful activity which increases
the heart rate and produces at least a light sweat and is often
structured and pursued for health and fitness benefits. Do not
include walking, nightclub dancing, swimming with the kids, etc.,
unless these activities fulfil the above definition’. All forms of
exercise reported were in the moderate-strenuous category (Godin &
Shephard, 1985). Participants responded in hours or minutes. The
amounts of time spent on each form of exercise (all converted to
hours) were summed to form a measure of the total number of hours of
exercise per day.
Work day
Participants were asked if they had worked that day.
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Daily diary investigation of work stress and exercise
Work-related affect
This was measured by six items from Warr (1990). Participants
were asked: ‘For how much of your time today has your job made you
feel depressed, gloomy, miserable, tense, uneasy and worried’.
Responses were on a six-point scale ranging from 1 (never) to 6 (all
the time). Mean scores across the first three items were computed to
give a total measure of depression (between participants alpha 0.87)
and mean scores across the last three items were computed to give a
total measure of anxiety (between participants alpha .0.87). High
scores denote high anxiety and high depression.
Job demands
This was measured by an 11-item scale adapted from Karasek
(1985). The items began with the stem ‘Today my job involved . . .
’. For example, ‘Today my job involved working fast’ and ‘Today my
job involved being asked to do an excessive amount of work’. Items
were accompanied by a five-point response scale ranging from 1
(strongly disagree) to 5 (strongly agree). Mean scores across the 11
items were computed to give a total measure of job demands (between
participants alpha .0.93). A high score denotes high levels of job
demands.
PBC over exercise the following day
PBC over exercise was measured using three items adapted from
Sparks, Guthrie, and Shepherd (1997): ‘For me to exercise tomorrow
would be. . . .’, 1 (very difficult) to 7 (very easy); ‘I am
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Daily diary investigation of work stress and exercise
confident that I can exercise tomorrow if I wanted to’, 1 (not at all
confident) to 7 (very confident) and ‘How much personal control do
you feel you have over whether you exercise tomorrow?’, 1 (no
control) to 7 (complete control). A mean score across the three items
was computed to give a total measure of PBC (between participants
alpha .0.89). A high score denotes high PBC.
Exercise intention the following day
This was measured using a single item corresponding to the
measure of behaviour: ‘What forms of exercise do you intend to do
tomorrow and how long will you devote to each?’ Participants
responded in hours or minutes. The amounts of time spent on each form
of exercise (all converted to hours) were summed to form a measure of
the total number of hours participants intended to exercise the
following day.
Planning
Random allocation was used to place participants in the
intervention and no intervention conditions. This was achieved by
assigning a number to each participant, writing these numbers on
slips of paper and allocating the first half drawn at random to the
intervention group. Twenty-one participants received a diary with the
addition of items related to planning. These items attempted to help
participants overcome factors during the day that could disrupt their
intentions, and thus these additional items were only relevant on
days on which participants intended to exercise. After the item,
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Daily diary investigation of work stress and exercise
‘What forms of exercise do you intend to do tomorrow and how long
will you devote to each?’, the following paragraph was added to the
daily diary for the intervention group:
Try to think about when you will be able to make time for
exercise tomorrow. For example, if you are working tomorrow,
when can you fit it in around your busy working day, what
facilities would be most convenient and when during the day do
you feel most up to exercising?
This was followed by open-ended questions asking participants:
‘When will you exercise?’, ‘Where will you exercise?’, ‘What
preparations will you need to make?’, ‘What might get in the way?’
and ‘How might you overcome these things?’ An example response to
each of these questions was provided to assist participants in
forming their own plans.
Procedure
Participants who expressed an interest in the research were sent
information about it by email.
As preference for completion mode may affect compliance and response
rates (Green, Rafaeli, Bolger, Shrout, & Reis, 2006), participants
were given the option of completing electronic or paper and pencil
diaries. Twenty-two participants (52%) opted for electronic diaries.
For 14 days they were sent a diary each evening at approximately
18:00 hours and asked to return it once completed. The 20
participants who opted for paper copies were sent a pack of 14
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diaries by post to their home address and asked to return seven by
post at the end of each week using the stamped addressed envelopes
provided. Green et al. (2006) suggested that providing explicit
directions to participants promotes compliance. Thus, the importance
of completing the diaries every evening was emphasised. The research
conforms to the ethical guidelines of the British Psychological
Society and was approved by a University ethics committee.
Data Analyses
The study yielded multilevel data such that daily observations
(level 1) are nested within each person (level 2). Consequently,
there is non-independence of observations, because multiple data
points are collected from the same people and thus ordinary-least-
squares multiple or logistic regression analysis is inappropriate.
MRCM should be conducted instead (Nezlek, 2001; Nezlek & Zyzniewski,
1998; Raudenbush & Bryk, 2002; Snijders & Bosker, 1999). MRCM enables
examination of within person relationships amongst level 1 variables
(e.g. on days when people have higher levels of job demands are they
less likely to carry out their daily exercise intentions than on days
when they have lower levels of job demands?). MRCM can also
incorporate level 2 variables (e.g. Are people more likely to carry
out their daily exercise intentions in the intervention group than in
the no intervention group?). As previous research in this area (e.g.
Hellerstedt & Jeffery, 1997; Heslop et al., 2001; Johansson et al.,
1991; Payne et al., 2002; Weidner, et al., 1997) has investigated
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Daily diary investigation of work stress and exercise
between-person relationships (e.g. are people with higher levels of
job demands less likely to carry out their exercise intentions than
people with lower levels of job demands?), this article focuses on
within-person relationships.
Analyses were conducted using the programme HLM6 (Raudenbush,
Bryk, Cheun, & Congdon, 2004). Unlike OLS analyses, in MRCM different
centring options are available at each level of analysis. In all
analyses, continuous level 1 variables were group – (i.e. person)
mean centered and categorical level 1 and level 2 variables were
zero-centred to aid the interpretation of coefficients (Nezlek, 2001;
Nezlek & Zyzniewski, 1998).
MRCM also separates true and random error. In all analyses, the
reliability of the estimates of random error terms was examined.
Where a random error term of a coefficient could not be reliably
estimated (i.e. p > 0.20; Harris, Daniels, & Briner, 2003), it was
fixed and thus was non-randomly varying (Nezlek, 2001; Nezlek &
Zyzniewski, 1998).
Results
On average, participants succeeded in exercising on 57% of the
days they intended to exercise. Eight participants (19%) succeeded in
exercising on one-third or fewer of intended days, but 18
participants (44%) succeeded in exercising on more than two-thirds of
intended days (with four succeeding on all the intended days).
There were 196 days on which participants did not intend to
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exercise and did not exercise. Thirty-nine participants had at least
1 such day and on average people had 5 such days. There were 22 days
on which participants did not intend to exercise but did exercise.
Eighteen participants had at least 1 such day and on average people
had only 1 such day. There were 191 days on which participants
intended to exercise and succeeded. Forty participants had at least 1
such day and on average people had 5 such days. There were 130 days
on which participants intended to exercise and failed. Thirty-seven
participants had at least 1 such day and on average people had 3 such
days.
Means and standard deviations for all continuous measures were
calculated (intention to exercise M = 0.58 h, SD = 0.69; PBC M =
4.46, SD = 1.59; job demands M = 3.05,
SD = 0.79; anxiety M = 0.86, SD = 1.05; depression M = 0.56, SD =
0.85).
Initial analyses were conducted to check that randomisation was
successful. Ordinary least-squares between-participants analyses
showed that there was no difference between the intervention and no
intervention groups in terms of participant age t (39). = 0.81, p =
0.42 or sex Chi 2 (1, N = 41) = 0.35, p = 0.55 and no difference in
exercise behaviour reported on the first day of diary completion
before the first presentation of the intervention t (39) = 0.97, p =
0.34.
There was also no age difference (t (39) = 0.92, p = 0.36) or
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Daily diary investigation of work stress and exercise
sex difference
(Chi 2 (1,N = 41). 2.61, p = .11) between participants completing
pencil and paper diaries and participants completing electronic
diaries. To further ensure that there was no influence of the mode of
diary completion, MRCM was used to examine whether diary mode
influenced exercise behaviour, intention and PBC. Thus three models
were examined, one with each of these three variables as outcomes.
Diary mode was entered as a level 2 predictor. The level 1 (within
person) model in each analysis is described by the following
equation:
yij = 0j + rij
where yij is daily exercise (or exercise intention or PBC) for
person j on day i, 0j is a random coefficient representing the mean of
y for person j across i days, and rij is the error associated with each
daily measure.
In MRCM, the coefficients from one level are passed on to the
next. The level-2 (between person) model is described by the
equation:
0j = 00 + 01 (group) + u0j
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Daily diary investigation of work stress and exercise
where 00 is the grand mean of the person level means from the
day level model (i.e. 0j) and u0j is the error of 0j. Where 01 is
significant, this indicates that diary mode had a significant effect.
There was no significant effect of diary mode on behaviour (00 =
-.41, SE = .14, p = .004; 01 = .03, SE = .09, p = .75), intention (00
= .73, SE = .09, p < .001; 01 = -.10, SE = .06, p = .07) or PBC (00 =
13.18, SE = .67, p < .001; 01 = .11, SE = .42, p = .78).
The next analyses examined the main research questions. The
level 1 analyses addressed question 1, i.e. whether work has a
disruptive influence on people’s ability to carry out their daily
intentions to exercise, over and above the effects of PBC. The level
2 analyses addressed question 2, i.e. whether the intervention helps
people carry out their daily intentions to exercise and whether it
helps overcome the potentially disruptive influence of work on daily
intention realisation.
The distribution of exercise behaviour was negatively skewed,
such that on 60% of the days participants did not exercise, on 29% of
the days they exercised for 60 min or less, on 9% of the days they
exercised for between 61 and 120 min and on 2% of the days they
exercised for more than 120 min. Therefore, exercise was dichotomised
into days when people exercised and days when they did not exercise.
Since the exercise outcome was dichotomous, the level 1 model is a
Bernoulli model. Thus, the probability of exercise was investigated.
Three models were tested, one for each of the work-related
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Daily diary investigation of work stress and exercise
variables. Job demands were included in model 1, work-related anxiety
in model 2 and work-related depression in model 3. Thus, three level
1 models addressed the first research question: Does work have a
disruptive influence on people’s ability to carry out their daily
intentions to exercise? In each of the level 1 models, the work-
related variable was included alongside the proximal predictors of
behaviour proposed by the TPB (1-day lagged, i.e. measured the
previous day, intention, PBC and intention_ PBC). Potential work-
related moderators of the intention-behaviour relationship were of
particular interest in order to confirm whether work has a disruptive
influence on people’s ability to carry out their daily intentions to
exercise. To investigate moderation, interaction terms, which were
created between 1-day lagged intention and each of the moderators,
were included in each model. In addition, controls were introduced
for exercise measured the previous day (i.e. 1-day lagged exercise)
and days of the week (i.e. six dummy variables). Since the dummy
variables were not significant in any analyses, they were excluded.
The level 1 model in each analysis is described by the following
equation:
prob(yij = 1 ij) = φij
ηij = log (φij) / (1- φij)
ηij = 0j + 1j (1-day lagged exercise) + 2j (1-day lagged
intention) + 3j (1-day lagged PBC) + 4j (1-day lagged intention x 1-
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Daily diary investigation of work stress and exercise
day lagged PBC) + 5j (work-related moderator) + 6j (1-day lagged
intention x work-related moderator)
1j is a slope representing the within person relationship
between 1-day lagged exercise and the log odds of exercise, 2j is a
slope representing the within person relationship between intention
to exercise and the log odds of exercise, 3j is a slope representing
the within person relationship between PBC and the log odds of
exercise, 4j is a slope representing the within person relationship
between the intention x PBC interaction term and the log odds of
exercise (i.e. the moderating effect of PBC), 5j is a slope
representing the within person relationship between a work related
predictor (e.g. job demands) and the log odds of exercise, and 6j is
a slope representing the within person relationship between the
intention x work related predictor interaction term and the log odds
of exercise (i.e. the moderating effect of the work related
predictor).
Three level 2 models, one for each of the work-related
variables, addressed the second research question: Does planning help
people carry out their daily intentions to exercise and overcome the
potentially disruptive influence of work on daily intention
realisation? To do this, the intervention (i.e. group) was entered as
a level 2 predictor. It was decided to include cross-level
interactions with all the level 1 predictors. This examined whether
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Daily diary investigation of work stress and exercise
within-person relationships between the level 1 predictors and the
log odds of exercise vary as a function of the intervention (i.e.
group).
The level 2 model in each analysis is described by the following
equation:
0j = 00 + 01 (group) + u0j
1j = 10 + 11 (group) + u1j
2j = 20 +21 (group) + u2j
3j = 30 + 31 (group) + u3j
4j = 40 + 41 (group) + u4j
5j = 50 + 51 (group) + u5j
6j = 60 + 61 (group) + u6j
Where 10, 20, 30, 40, 50 or 60 are significant, this indicates a
significant within person relationship between the level-1 predictor
and the log odds of exercise, (e.g. in the case of 60 this would
indicate that the relationship between intention and the log odds of
exercise is moderated by job demands in model 1, work-related anxiety
in model 2 and work-related depression in model 3). Where 11, 21, 31,
41, 51 or 61 are significant, this indicates that the within person
relationship between the level-1 predictor and the log odds of
exercise is moderated by the intervention (e.g. in the case of 21
this would indicate that the relationship between intention and the
24
Daily diary investigation of work stress and exercise
log odds of exercise is moderated by the intervention, i.e. the
intervention is having an impact on people’s ability to implement
their intentions) and where 01 is significant, this indicates that
the intervention has a direct effect on the log odds of exercise.
These analyses, beginning with model 1 which includes job demands,
are presented in Table 1.
In all three models, the log odds of daily exercise were
primarily predicted by intention to engage in an increased amount of
exercise. Increased PBC and increased exercise the previous day (i.e.
1-day lagged exercise) were also significant predictors, but the
intention x PBC interaction was not.
There was a significant main effect of the intervention (i.e.
group) but in the opposite direction to that predicted, i.e. the log
odds of daily exercise were higher for people in the no intervention
group. There were also several significant interactions. Interactions
were interpreted by plotting them using software developed by
Preacher, Curran, and Bauer (2006). Group was found to interact with
1-day lagged exercise such that in the no intervention group an
increased amount of exercise the previous day increased the log odds
of exercise the following day, but in the intervention group an
increased amount of exercise the previous day decreased the log odds
of exercise the following day. Group was also found to interact with
PBC such that higher PBC increased the log odds of daily exercise for
people in the no intervention group only.
25
Daily diary investigation of work stress and exercise
The only significant effect of a work-related variable was for
job demands in model 1. There was no evidence of a main effect but
there was a significant interaction, i.e. job demands acted as a
moderator of the relationship between intention and the log odds of
exercise, such that people were less likely to carry out their
intentions to exercise on days with higher levels of job demands than
on days with lower levels of job demands. In addition, the intention
x job demands x group interaction term was significant. This more
complex interaction is shown in Figure 1. Lines are plotted at high
and low levels of job demands for the intervention and no
intervention groups. The figure shows that people in the no
intervention group on low-demand days were most successful in
carrying out their intentions to exercise (when they intended to
exercise for longer) and people in the intervention group on high-
demand days were least likely to carry out their intentions to
exercise.
Discussion
The purpose of the present study was twofold; first, to examine
whether daily experiences relating to work have a disruptive
influence on people’s ability to carry out their daily intentions to
exercise and second, to examine whether daily planning helps people
carry out their daily intentions to exercise and whether it helps
overcome the potentially disruptive influence of work. Only job
demands (i.e. not work-related affect) had a disruptive influence on
26
Daily diary investigation of work stress and exercise
people’s ability to carry out their daily exercise intentions. Thus,
the context of peoples’ lives, in particular working life, may have
an impact on health behaviour, an effect not accounted for by the
TPB. However, there was no evidence that the planning intervention in
the present study helped people implement their intentions or
overcome the disruptive influence of work. In fact, the intervention
appeared to be counterproductive. The log odds of daily exercise were
lower for people in the intervention group and even having high PBC
was not useful (in terms of increasing the log odds of exercise) for
people in the intervention group. A significant interaction between
intention, job demands and the intervention also showed that people
in the no intervention group on low demand days were most successful
in carrying out their intentions to exercise (when they intended to
exercise for longer), whereas people in the intervention group on
high demand days were least likely to carry out their intentions to
exercise, i.e. the impact of the intervention coupled with high daily
job demands appeared to be detrimental to intention realisation,
since an increase in intention did not lead to an increase in the log
odds of exercise.
Compared to much previous research (e.g. Armitage & Conner,
2001; Sheeran, 2002; Sutton, 1998), intention was particularly highly
predictive of behaviour. This may be a result of improvements in the
methodology of the present study, specifically the close proximity of
the measurements of intention and behaviour (Ajzen & Fishbein, 1980;
27
Daily diary investigation of work stress and exercise
Courneya & McAulay, 1993) and the use of corresponding measures of
intention and behaviour (Ajzen, 1988). However, there was a
significant proportion of days (24%) on which people intended to
exercise but failed and 90% of people had at least 1 such day,
supporting previous research (Godin et al., 1986; Rhodes et al.,
2003). PBC did not appear to help people implement their intentions,
since there was no evidence of a moderating effect, but PBC had a
significant direct effect on behaviour, consistent with the TPB
(Ajzen, 1988, 1991).
Working Life
On days when people had lower levels of job demands, they were
more likely to carry out their intentions to exercise than on days
when they had higher levels of job demands, supporting Payne et al.
(2002). Thus, people did not appear to anticipate their level of job
demands for the following day and adjust their intentions
accordingly. Therefore, the relationship between job demands and the
realisation of intentions is likely to be due to unexpected job
demands. It may be of value for further research to distinguish
between the impact of expected and unexpected job demands. An
alternative explanation may be that people were overly optimistic
when forming their intentions and were liable to the planning fallacy
(Kahneman & Tversky, 1979). In other words, even though people may
have been aware that their intentions on previous days were disrupted
by job demands and thus were overly optimistic, they believed that
28
Daily diary investigation of work stress and exercise
their current intentions were realistic. Negative affect related to
work had no impact, suggesting that perception and appraisal of
stress may not be important. However, levels of negative affect were
generally very low.
Planning
The intervention in the present study did not help people carry
out their intentions but instead appeared to be counterproductive.
The intervention had a direct negative impact on behaviour and got in
the way of PBC aiding behaviour. It did not have an influence on
translating intentions into behaviour generally, but it had a
negative impact on translating intentions into behaviour on days with
higher levels of job demands. Whilst interventions focused on action
and coping planning have been found to be effective in previous
research (e.g. Lippke et al., 2004; Sniehotta et al., 2006), asking
people to consider things that might get in the way of exercise and
how these might be overcome could have operated contrary to
expectation in the present study by drawing attention to potential
failure. This is likely to be particularly problematic on days with
high job demands, when presumably there are more things that might
get in the way. It is not possible to know the extent to which
participants in the present study were influenced by this focus,
especially when interventions in previous studies included a similar
focus on ‘barriers’ or ‘obstacles’ and yet were successful. However,
Cervone (1989) provided evidence to support this explanation. He
29
Daily diary investigation of work stress and exercise
found that dwelling on factors that could impair performance on a
cognitive task diminished judgments of perceived self-efficacy on the
task and also impaired task persistence. Hallam and Petosa (1998)
similarly suggested that once people are faced with real barriers to
exercise, they may reevaluate their ability to overcome these
barriers. Budden and Sagarin (2007) found that people who formed
implementation intentions exercised significantly less than people
who did not. They suggested that this may be explained by the
influence of an individual difference variable (socially prescribed
perfectionism), which may have been overrepresented in their sample.
Research by Powers, Koestner, and Topciu (2005) suggested that for
socially prescribed perfectionists, implementation intentions may
lead to self-criticism and impede goal progress because they focus on
failed performance rather than on achieving success. This factor may
also have had an influence in the present study. Thus, focusing on
factors that may support performance may be a better method of
intervention. This could be related to ideas raised by Prospect
Theory, i.e., that the way a message is framed influences how people
respond to the message (Tversky & Kahneman, 1981). Indeed, exercise
promotion messages framed in terms of gains (i.e. benefits of
exercising) rather than losses (i.e. risks of not exercising) have
been more successful in promoting exercise (Jones, Sinclair, &
Courneya, 2003; Robberson & Rogers, 1988).
It is also possible that the intervention in the present study
30
Daily diary investigation of work stress and exercise
was too brief to enable individuals to make sufficiently detailed and
comprehensive plans. This brevity was a deliberate attempt to make
the intervention relatively undemanding and appropriate for daily
use. However, in previous research, interventions often involve one-
to-one training or the provision of more complex written
instructions, which is more likely to ensure that participants are
guided to make clear, precise and realistic plans.
In addition to this, it is possible that the no intervention
condition in the present study acted as an intervention in itself. In
other words, responding to the question ‘what forms of exercise do
you intend to do tomorrow and how long will you devote to each?’ may
involve more than responding to a question such as ‘do you intend to
exercise tomorrow?’, perhaps involving at least some rudimentary form
of planning but without the focus on potential barriers as in the
intervention condition.
Limitations
The use of paper and pencil diaries, which are returned at the
end of each week, is common in similar research (e.g. Jones et al.,
2007; O’Connor et al., 2008). However, it is not possible to check
whether participants completing diaries via this mode comply with
instructions, particularly with regard to the timing of diary
completion. Green et al. (2006) found that in general, compliance and
resulting data quality were not affected by mode of completion (i.e.
paper and pencil vs. electronic). We also found no differences
31
Daily diary investigation of work stress and exercise
between participants completing diaries via the different modes.
Green et al. (2006) also found that participants only expressed
negative opinions about completing electronic diaries. Therefore, it
may be important to offer paper and pencil as a mode of completion in
order to promote compliance. We also offered very specific
instructions about completing the diaries in the evening in a further
effort to promote compliance. Of course, evening completion may lead
to exercise impacting on the recall of job demands and work-related
affect. However, if this were the case, one would expect a positive
relationship between exercise intention implementation and job
demands (Taylor, 2000) and not the negative one found in the present
study.
Diary studies often involve small samples and this limits the
generalisability of the findings. In addition, in the present study,
the number of level 1 and level 2 units (i.e. the number of days per
participant and the number of participants) was relatively small.
Since a large number of predictors (including complex interaction
terms) were included in each model, the results should be viewed with
some caution. However, the number of units was adequate for
conducting MRCM (Raudenbush & Bryk, 2002).
The measure of intention used in the present study was a
frequency measure rather than a measure of intention strength, such
as ‘I intend to exercise next week’, 1 (strongly disagree) to 5
(strongly agree). The choice of measure was based on the
32
Daily diary investigation of work stress and exercise
recommendation of Courneya (1994) who found that the use of
continuous-open or continuous-closed scales for both intention and
behaviour was the most satisfactory solution to obtain corresponding
measures of intention and behaviour. However, this led to a lack of
correspondence with the measure of PBC strength.
Conclusion
In the present study, only job demands were found to disrupt
daily intention realisation. Since this study is only focused on the
context of work, it would be useful for further research to examine
and compare the various contexts of peoples’ lives in more detail in
order to tease apart the various influences on exercise. Further
research could also investigate other work stressors, as well as
examining both negative and positive affect in more detail in order
to obtain a more complete picture of working life. Since we spend
much of our waking lives at work, it might be expected that work
would influence exercise. However, the workplace provides a
convenient forum for health behaviour change interventions. It may
prove beneficial for employers to introduce physical exercise as
advocated stress management training (Long, 1993), which may reduce
levels of stress and anxiety at work and in life outside work (e.g.
Taylor, 2000). However, since the planning intervention in the
present study did not help people overcome this and may be
counterproductive, it may be beneficial for future interventions to
focus on helping people make positive plans to actively support
33
Daily diary investigation of work stress and exercise
exercise within the work context, rather than make more negatively
focused plans concerning potential barriers caused by work. It will
also be important to ensure that such interventions strike a balance
between ensuring that they are sufficient to help people plan
adequately, while being cost effective.
34
Daily diary investigation of work stress and exercise
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Table 1
Summary of Three Multilevel Random Coefficient Models Predicting the
Log Odds of Exercise (within person N = 539, between person N = 41)
Predictor Coeff SE OR CI
Model 1
Intercept 00 -.08 .15 .93 .69, 1.25
Group 01 -.24* .10 .79 .65, .95
Lagged
exercise
10 .59* .26 1.81 1.08,
3.04
Lagged ex. x
group
11 -.60**
*
.18 .55 .39, .79
Intention 20 1.50**
*
.37 4.46 2.17,
9.16
Int. x group 21 .06 .24 1.07 .67, 1.70
PBC 30 .18*** .04 1.20 1.10,
1.311
PBC x group 31 -.12** .03 .92 .86, .97
Intention x
PBC
40 .05 .05 1.06 .95, 1.17
Int. x PBC x
group
41 -.07 .04 .91 .84, .99
Demands 50 -.01 .01 .99 .97, 1.02
45
Daily diary investigation of work stress and exercise
Demands x
group
51 -.01 .01 .99 .98, 1.01
Int. x
demands
60 -.10** .01 1.04 1.01,
1.06
Int. x dem. x
group
61 .09** .01 .99 .95, .99
table continues
46
Daily diary investigation of work stress and exercise
Predictor Coeff SE OR CI
Model 2
Intercept 00 -.04 .15 .96 .72, 1.29
Group 01 -.28** .10 .75 .63, .91
Lagged
exercise
10 .49* .26 1.64 .99, 2.72
Lagged ex. x
group
11 -.51** .18 .60 .43, .85
Intention 20 1.18**
*
.34 3.26 1.67,
6.35
Int. x group 21 .27 .22 1.30 .84, 2.02
PBC 30 .17*** .04 1.18 1.90,
1.30
PBC x group 31 -.07* .03 .93 .88, .99
Intention x
PBC
40 .005 .05 1.005 .92, 1.10
Int. PBC x
group
41 -.04 .04 .96 .90, 1.03
Anxiety 50 -.11 .19 .89 .62, 1.29
Anxiety x
group
51 .14 .12 1.15 .91, 1.45
Int. x
anxiety
60 -.12 .21 1.13 .75, 1.70
47
Daily diary investigation of work stress and exercise
Int. x anx. x
group
61 -.03 .18 .97 .69, 1.38
table continues
48
Daily diary investigation of work stress and exercise
Predictor Coeff SE OR CI
Model 3
Intercept 00 -.01 .15 .99 .74, 1.33
Group 01 -.30** .10 .74 .61, .90
Lagged
exercise
10 .50* .26 1.65 .99, 2.74
Lagged ex. x
group
11 -.51** .17 .60 .43, .85
Intention 20 1.08** .34 2.94 1.51,
5.71
Int. x group 21 .37 .22 1.45 .94, 2.25
PBC 30 .17*** .04 1.18 1.09,
1.29
PBC x group 31 -.07* .03 .93 .88, .99
Intention x
PBC
40 -.02 .05 .98 .89, 1.08
Int. x PBC x
group
41 -.03 .04 .97 .91, 1.04
Depression 50 -.29 .25 1.34 .83, 2.16
Depression x
group
51 -.02 .15 .98 .74, 1.31
Int. x
depression
60 -.53 .28 1.70 .97, 2.97
49
Daily diary investigation of work stress and exercise
Int. x dep. x
group
61 -.37 .22 .69 .45, 1.06
Note. OR = odds ratio, CI = confidence interval.
*p < .05. **p < .01. ***p < .001.
50
Daily diary investigation of work stress and exercise
Figure caption
Figure 1. The interaction between intention to exercise, job demands
and the intervention predicting the log odds of exercise
51