Article Text

Download PDFPDF

Original research
Association of work performance and interoceptive awareness of ‘body trusting’ in an occupational setting: a cross-sectional study
  1. Chisato Tanaka1,2,
  2. Kenta Wakaizumi3,4,
  3. Shizuko Kosugi2,5,
  4. Shintaro Tanaka1,
  5. Ko Matsudaira6,
  6. Hiroshi Morisaki5,
  7. Masaru Mimura1,
  8. Daisuke Fujisawa1,2
  1. 1Neuropsychiatry, Graduate School of Medicine, Keio University School of Medicine, Shinjuku-ku, Japan
  2. 2Interdisciplinary Pain Center, Keio University Hospital, Shinjuku-ku, Japan
  3. 3Shirley Ryan AbilityLab, Chicago, Illinois, USA
  4. 4Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
  5. 5Department of Anesthesiology, Graduate School of Medicine, Keio University School of Medicine, Shinjuku-ku, Japan
  6. 6Department of Medical Research and Management for Musculoskeletal Pain, 22nd Century Medical and Research Center, Faculty of Medicine, The University of Tokyo-Hospital, Tokyo, Japan
  1. Correspondence to Dr Shizuko Kosugi; shizuko.kosugi{at}gmail.com

Abstract

Objectives Work performance has been known to be influenced by both psychological stress (mind) and physical conditions (body). The aim of this study was to investigate the association between work performance and ‘body trusting’, which is a dimension of interoceptive awareness representing mind–body interactions.

Methods A cross-sectional study was conducted among a sample of workers in an industrial manufacturing company in Japan. Participants were assessed with a self-reported questionnaire including evaluations of work performance, body trusting, psychological distress, pain persistence, workplace and home stressors, and workaholism. Participants’ sociodemographic, health and lifestyle characteristics were collected from their annual health check data. The association between work performance and body trusting was examined using multivariable regression analyses in the overall sample and in a subsample of people with pain.

Results A total of 349 workers participated in the study. A significant association between work performance and body trusting was observed, with higher body trusting representing higher work performance. The association was significant after controlling for psychological distress, workplace and home stress, workaholism and participants’ characteristics (p<0.001). Compared with people without pain (n=126, 36.1%), people with pain (n=223, 63.9%) showed less body trusting, which was associated with decreased work performance after controlling for pain-related variables (p<0.001).

Conclusions Workers with higher body trusting showed higher work performance, even after controlling for various influencing factors. Body trusting may be an important target to promote work performance and to prevent loss of performance induced by health problems.

  • pain management
  • mental health
  • preventive medicine
  • public health
  • adult psychiatry

Data availability statement

Data are available upon reasonable request. Analysed data in this study are available under the permission of the Institutional Review Board in Keio University School of Medicine corresponding to each request (https://www.ctr.med.keio.ac.jp/rinri/).

http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

Statistics from Altmetric.com

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Strengths and limitations of this study

  • This is the first study that demonstrated the effect of individuals’ level of ‘body trusting’ on work performance.

  • This effect was significant after controlling for pain, workplace stressors and mental health factors.

  • Our findings imply that interventions to improve body trusting, such as mindfulness, may increase work performance.

  • This is a single-centre, cross-sectional study with limited generalisability and a lack of information on cause–effect relationships.

INTRODUCTION

The promotion of work performance and occupational health is an urgent task in modern industrial society. Especially in developed countries with an ageing population and low birth rate, the negative impacts of decreasing productivity on national gross domestic product are spreading.1 The ratio of the population aged 65 and over to the total population in Japan was 28.1% as of 20192; this ratio is expected to increase further, with a declining total population as well as a declining working age population. Therefore, qualitative strengthening of the labour force is an emerging issue.3 The Japanese Ministry of Economy, Trade and Industry advocates ‘Health and productivity management’, which encourages companies to commit strategically to employees’ health promotion such as by increasing the rate of medical examinations, working towards early detection of mental illness and intervening in lifestyle habits such as smoking and drinking. These investments in employees’ health are intended to enhance the employees’ work performance and the corporation’s value.4

Work performance is influenced by both psychological stress and physical health problems.5 Stress-related mental illnesses, such as depression and anxiety disorders, are important risk factors that impair work performance.6 Second to mental problems, physical disabilities that incur pain such as chronic low back pain have a strong impact on work productivity loss.7 Since pain intensity, frequency and duration are critical factors in determining the impact on physical disability,8 these pain characteristics are related to lowered performance in people with pain.

In addition, there is an interaction effect between psychological stress and physical disability. Mind and body relate to each other and together can impact health in synergy. For example, people with pain frequently show psychological distress, and people with heightened psychological distress are more vulnerable to pain and show a lower level of physical activity.9 However, little is known about the interaction effect between psychology and physical conditions on work performance.

A key construct of the mind–body interaction is known as interoceptive awareness, which is the conscious perception of sensations from inside the body that creates a sense of the physiological condition of the body, such as heartbeat, respiration, satiety and the autonomic nervous system related to emotions.10 Interoceptive awareness is composed of multiple dimensions, among which ‘not worrying’ and ‘body trusting’ have been reported to strongly associate with stress and depression.11 Since the ‘not worrying’ dimension is considered not sufficiently robust,12 in the current study, we focused on ‘body trusting’ as an index of interoceptive awareness.

Body trusting is an ‘attitude of body awareness’ in the process of examining the major components of interoceptive awareness. People with higher body trusting show more positive responses to bodily cues.13 Body listening skills to sense the experiences of one’s body actively are helpful to feel safety and trustworthiness in the body.14 Body trusting is associated with physical function in people with mental illness or pain,11 15 as is psychological well-being, which has been shown to clearly enhance work performance.16 We could not find any studies that specifically refer to the association between body trusting and work performance. Therefore, in the current study, we aimed to investigate that association and hypothesised that people with high levels of body trusting show better work performance even after controlling for factors that may influence that performance. Since pain is a common symptom that impairs psychological and physical well-being as well as work performance, this study also examines the association of body trusting and work performance while controlling for the influence of properties of pain.

Methods

Study design

This cross-sectional survey was conducted in a technology development division of an industrial steel manufacturing company. The branch office in which we worked is located in the suburbs of Tokyo, Japan. The main tasks of the workers are documentation and data management concerning the development of new products and sales. Most employees are so-called white-collar workers who work mainly at their desks and are at potential risk for pain and mental health problems caused by visual display terminal work and prolonged sitting posture.17 18

This study was conducted in the form of a fill-in paper questionnaire. A set of questionnaires was distributed to all targets by the company’s healthcare administration team on 19 July 2018. The participants filled the questionnaires out individually and returned the completed questionnaires to our research unit by post. Anonymised data were collected by 10 August 2018. A total of 349 workers participated in the study. A multivariate regression analysis was used in three models in the total sample as well as four models in the pain subsample.

Participants

We included people (1) with full-time employment; (2) who consented to provide his/her annual health check data; (3) who were able to understand and complete the questionnaires in Japanese. All participants were informed about the aim of the study through the company’s intranet and a document attached to the questionnaires. They were informed that responding to the questionnaire was voluntary and that submitting the questionnaire means that they consented to participate in the study.

Patient and public involvement

Patients were not involved in the design, reporting or dissemination plans of our research.

Measurements

Work performance

The participants’ overall work performance was measured by the Japanese version of the WHO Health and Work Performance Questionnaire (HPQ) Short Form. Participants self-rated their work performance on the days they worked during the past 4 weeks using an 11-point Likert scale ranging from 0 (the lowest imaginable performance) to 10 (the highest imaginable performance). The HPQ has been validated in the Japanese population with a Cronbach’s α of 0.73.

Body trusting

The participants’ level of body trusting was measured with a subscale of the Multidimensional Assessment of Interoceptive Awareness (MAIA), a self-report questionnaire assessing interoceptive perception.14 The MAIA consists of eight dimensions: noticing, not ignoring, not worrying, attention regulation, emotional awareness, self-regulation, listening and trusting. The body trusting subscale contains three items: ‘I am at home in my body’, ‘I feel that my body is a safe place’ and ‘I trust my body sensations’. Each item was rated on a 5-point scale ranging from 0 (never) to 4 (always). The average score of the three items was used to estimate the level of body trusting. Higher scores indicate greater confidence and reliability in one’s body experience. The reliability and validity of the body trusting subscale have been confirmed in several populations, including outpatients with current pain (Cronbach’s α=0.77) and people recovered from pain (Cronbach’s α=0.82).11 The reliability and the validity of the Japanese version of MAIA have been also validated, as have the reliability and validity of the body trusting subscale (Cronbach’s α=0.83).19

Psychological distress

The participants’ psychological distress was assessed by the Kessler Psychological Distress Scale (K6). The respondents rated their psychological distress during the past 30 days on six items (eg, nervousness, worthlessness) on a 5-point scale of frequency from 0 (none of the time) to 4 (all of the time). A higher total score represents more severe psychological distress. In a previous survey, participants who scored 13 points or more were categorised as having serious psychological distress.20 We chose to use 13 as a cut-off value for this study as well.

Work–home demands

We evaluated occupational stress based on a job demands–resources model.21 We investigated both workplace and home stresses as well as degree of satisfaction from the viewpoint of work–home interference. The work demands are composed of work overload and work emotional demands. We evaluated the participants’ work overload using four items developed by Furda,22 which refer to a demanding workload (eg, job quantity) and high pressure (eg, time pressure). We evaluated the participants’ work emotional demands using six questions developed by van Veldhoven that refer to the frequency of emotionally challenging events in one’s job circumstance (eg, ‘Is your work emotionally stressful?’, ‘Does your work involve people who continuously complain or emotionally appeal to you in another way?’).23 The work overload and emotional work demands were rated on a 5-point scale from 1 (never) to 5 (always). Higher total scores indicate a higher degree of work demands. Likewise, we evaluated the participants’ home demands on a six-item questionnaire with a 5-point scale referring to home overload and home emotional demands (eg, ‘Do you find that you are busy at home?’, ‘How often do emotional issues arise at home?’).24 Higher total scores indicate higher home demands.

Work–home resources

To evaluate the participants’ resources at work and at home, we used the ‘social supports’ and ‘controllability’ subscales of the Brief Job Stress Questionnaire (BJSQ).25 The BJSQ is an instrument developed by the Japanese Ministry of Health, Labour and Welfare and its research group, and it has been widely used in Japan as a regular yearly screening for high psychosocial stress in the workplace, which is a mandatory stress check system for enterprises with 50 or more employees.

Degrees of support from one’s supervisors, coworkers and family were assessed using three items on a 4-point Likert scale ranging from 1 (strongly agree) to 4 (strongly disagree); for example, ‘How often do you feel free to talk to your boss?’, ‘How often do your colleagues listen to your personal problems?’. Likewise, personal controllability at work was assessed by three items on a 4-point Likert scale. Family control was measured by four items such as ‘I determine what happens at home’. Items were scored on a 5-point Likert scale that ranged from 1 (never) to 5 (always). The higher total scores of social supports and controllability represent worse resources at work and home.

Workaholism

Workaholism, an addictive attitude towards work, has also been known as a relevant factor for work performance.26 We used the Dutch Work Addiction Scale (DUWAS)27 to evaluate the participants’ tendency towards workaholism. DUWAS includes two trends of cognitive bias to work: working excessively (eg, I stay busy and keep many irons in the fire) and working compulsively (eg, I feel guilty when I take time off work). Each subscale consists of five items, which were rated on a 4-point Likert scale from 1 (totally disagree) to 4 (totally agree). A higher score indicates a higher tendency of workaholism.

Pain-related measures

We asked the participants whether they had experienced pain within 4 weeks preceding the survey. The participants with pain symptoms in the last 4 weeks were asked to report their pain intensity measured by the numeric rating scale,28 where ‘0’ corresponds to no pain and ‘10’ indicates the worst imaginable pain. We asked the participant whether their pain duration was less than 3 months, corresponding to the definition of ‘chronic pain’ by the International Association of Study for Pain.29 We asked the participants about their frequency of pain at three levels: almost every day, 2 or more days per week, 1 day or less a week.

Demographic and lifestyle-related measures

The participants’ sociodemographic and health-related characteristics were collected from the latest data of their annual health check. The following data were collected: age, sex, body mass index (BMI, kg/m2), smoking status (current smoker or non-smoker), daily alcohol intake (ethanol equivalent: 0, 1–23, 24–45 or ≥46 g), educational background (high school graduate or junior college graduate, bachelor’s degree, master’s degree or doctorate), physical exercise habits (whether a participant exercises more than 30 min, twice per week), sleep duration (<5, 6, 7, 8 or ≥9 hours), blood pressure and serum concentrations of low-density lipoprotein (LDL) cholesterol. In accordance with an extensive cohort study in Japan,30 high alcohol intake was defined as consuming more than 46 g of ethanol equivalent per day. We defined low education as below a bachelor’s degree, short sleep as shorter than 5 hours of sleep duration, hypertension as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg following the definition by the Japanese Society of Hypertension and high LDL cholesterol as serum concentrations of LDL cholesterol ≥140 mg/dL following the definition by Japan Atherosclerosis Society.

Statistical analyses

Full sample analyses

We examined an association between body trusting and work performance using a multivariable regression analysis with adjustments for age and sex (model 1A). In model 2A, we added sociodemographic characteristics, lifestyle and health measures to the variables of model 1A; this included low education, BMI, current smoker, high alcohol intake, exercise habits, short sleep, hypertension, high LDL cholesterol and presence of pain within 4 weeks. In model 3A, we added serious psychological distress (K6 ≥13 points), work/home demands and resources, workaholic tendency and work/home dissatisfaction to the variables of model 2A.

Subsample analyses

First, we compared the characteristics of people with pain within 4 weeks (pain group) to those of people without pain (no-pain group). Χ2 tests were used for categorical variables and Student’s t-tests were used for continuous variables. We calculated Cohen’s d as an effect size between the two groups.

Then, in the sample of participants with pain, we conducted multiple linear regression analyses to examine the association of body trusting with work performance. Four multivariable regression models were used with the following variables: age and sex (model 1B); pain intensity, pain duration (≥3 months), pain frequency (more than 2 days/week) and the variables included in model 1 (model 2B); low education, BMI, current smoker, high alcohol intake, exercise habits, short sleep, hypertension, high LDL cholesterol and the variables included in model 2B (model 3B); serious psychological distress, work/home demands and resources, workaholic tendency, work/home dissatisfactions and the variables included in model 3B (model 4B).

All statistical analyses were performed by Statistical Package for Social Sciences (SPSS) V.25.0 software package (IBM). Statistical significance was identified by two-tailed p values <0.05.

Results

All 545 employees in the office were invited to participate in the study. Of those, 354 people responded to the questionnaire (65% response rate). Five people with incomplete data were excluded, and 349 participants were included in the analyses.

The participants’ mean age was 40.9, ranging from 18 to 68 years. The participants were predominantly male (84%). One-third of the participants reported that they had an exercise habit, and one-fourth reported short sleep. Serious psychological distress was identified in 33 participants (9%), and 223 participants (64%) reported pain in the last 4 weeks. The mean work performance score was 6.47, and the mean body trusting score was 2.82 points (table 1).

Table 1

Demographic characteristics and measures of all participants (n=349)

In the full sample analyses, body trusting was positively associated with work performance, meaning that people with higher levels of body trusting were more likely to have better work performance. This association remained significant even after adjusting for age and sex (model 1A; p<0.001); sociodemographic characteristics, lifestyle and health measures (model 2A; p<0.001); and psychological distress, various stress-related factors and workaholism (model 3A; p<0.001) (table 2).

Table 2

Association of body trusting with work performance of all participants (n=349)

There were 223 people with pain (63.9%), with a mean pain intensity of 2.6. Among them, 155 (69.5%) people’s responses corresponded to chronic pain. The work performance of people with pain did not differ from those without pain. However, people with pain showed significantly lower levels of body trusting (p=0.001), higher BMI (p=0.03), a higher frequency of short sleep (p=0.02), worse home demands (p=0.001) and greater compulsive workaholism (p=0.02) (table 3).

Table 3

Demographic characteristics and measures of participants with and without pain

Body trusting was significantly associated with work performance in this pain group as well. The association remained significant after adjustments for age and sex (model 1B; p<0.001); pain intensity, pain duration and pain frequency (model 2B; p<0.001); sociodemographic characteristics, lifestyle and health measures (model 3B; p<0.001); and psychosocial factors (model 4B; p<0.001) (table 4).

Table 4

Association between body trusting and work performance in participants with pain (n=223)

Discussion

Implications of the study

This study demonstrated that workers with more body trusting showed higher levels of work performance. This association was significant after controlling for variables that have been known to affect work performance including sociodemographic and lifestyle factors, physical and psychological measures and various stress-related issues. The positive association between the level of body trusting and work performance was consistent in a subsample of people with pain. These findings suggest that body trusting is an independent mediator for increasing work performance.

There are a few possible mechanisms to explain why body trusting has a positive association with work performance. First, people with high body trusting are more likely to have positive body images (such as feeling safe and trustworthy) about themselves.31 This positive body image serves as a foundation for their psychological well-being (ie, self-esteem, optimism and proactive coping), which contributes to better cognitive performance. Many studies have demonstrated that better psychological well-being promotes work performance through flexible, creative, integrated, information-open-minded and effective thinking, resulting in improved accuracy and speed of information processing and flexible optimisation of cognitive function.32

Second, body trusting may contribute to better work performance through a buffering effect of negative emotions. People with negative body image are more prone to show heightened anxiety and depression than those without negative body image.33 For example, sedentary behaviour, which is known to decrease work performance, can be attributed to both mental and physical problems.

These negative emotions divert attentional resources to the self and away from the task at hand, which impairs work performance.10 34 At the same time, a high level of interoceptive awareness has been known to alleviate negative emotions.11 People with higher levels of body trusting have been shown to exhibit lower levels of trait anxiety.14 A sense of psychological safety helps people overcome their anxiety and make good use of new inputs, promotes work engagement and facilitates creativity.35 People with higher levels of body trusting, who feel greater levels of psychological safety in their body with a healthy body image, are expected to be more resilient and able to cope with stress and adversity, resulting in sustained performance.36

Third, body trusting can promote work performance in the context of interpersonal relationships. Psychological safety and well-being promote friendly behaviour and facilitate improved communication in a community.37 The friendly atmosphere and flexible cognitive functions associated with positive emotions at an individual level facilitate more efficient problem-solving strategies and promote social adaptation with improved compassion and coping abilities, resulting in improved conflict resolution at a team level as well.38

In addition to the psychological effect on the work performance mentioned above, physical difficulty at work (eg, pain) has a negative impact on work performance.39 People with lower levels of body trusting are more vulnerable to bodily dissociation, which is a sense of separation from sensory and emotional experience.40 Body trusting may provide a synergistic effect between psychological health and physical performance because bidirectional promotive effects have been observed between them. Experience of a good physical performance is received as a reward, by which people will strengthen confidence in their own body and physical activities.41 Body trusting is assumed to mediate this virtuous circle of mind–body interaction, contributing to better performance. Future studies are needed to clarify the underlying mechanisms of body trusting in mind–body interactions.

Possible clinical implications of our findings include using body trusting as a focus of intervention to promote work performance. Recently, mindfulness-based training has been garnering attention as a strategy to promote mental health and work performance.42 Mindfulness training improves interoceptive awareness, including body trusting,15 through a comprehensive programme of cultivating non-judgemental acceptance, a sense of self-grounded experience in the present moment and a sense of embodiment of physical sensations.43 By focusing on body trusting, a more efficient programme to promote work performance may be developed.

Limitations of the study

There are a few limitations to this study. First, the study was conducted in a single institution with predominantly male workers, thus the generalisability of the findings is limited. Second, most of the measurements used in this study, including work performance, were based on the participants’ self-reports. Although there is evidence that subjective work performance is significantly correlated with objective work performance,44 more robust methods of measurement exist and should be used in future research. Third, because of the cross-sectional study design, the causal relationship of body trusting and work performance is not clear. Moreover, since employees on leave at the time of the survey were not included in this study, further longitudinal studies will be required to examine the relationship between burn-out and body trusting. Lastly, the current study focused on work performance only at an individual level. Future studies should also examine the impact on work performance at the organisational level, including management. Increasing body trusting may contribute to both increased performance and well-being, meaning that it benefits both employees as individuals and the company as a whole.

Conclusions

This study demonstrated that a higher level of body trusting was significantly associated with increased work performance. This finding was robust after controlling for multiple covariates (including psychological distress and stress-related factors) that may influence work performance, and the finding was consistent in a subsample of people with pain. Considering the high prevalence of mental issues and pain in working populations, the concept of body trusting may play a key role in maintaining work performance and occupational health.

Further studies using more objective measures, especially on work performance and interoceptive awareness (body trusting) in a longitudinal design, and the development of a programme to cultivate a sense of body trusting are warranted.

Data availability statement

Data are available upon reasonable request. Analysed data in this study are available under the permission of the Institutional Review Board in Keio University School of Medicine corresponding to each request (https://www.ctr.med.keio.ac.jp/rinri/).

Ethics statements

Ethics approval

All procedures were approved by the Keio University School of Medicine Ethics Committee (approval number 20170069) and the company’s safety and health committee.

Acknowledgments

The authors thank the staff members and the field coordinators in the survey. They also appreciate Dr Akito Shimazu, professor in the Keio University Faculty of Policy Management, for providing instruments to assess psychosocial factors at home. The authors express their sincere appreciation to Dr Masayuki Hasegawa and other staff from the Research and Engineering Centre of Nippon Steel for their generous support in conducting this survey. The authors thank Editage (www.editage.jp) for English language editing.

References

Footnotes

  • Contributors CT contributed to the study conception, acquisition of data, analysis, interpretation of data and drafting of the manuscript. KW designed the study, analysed the data and edited the first draft. CT, ST and SK participated in data collection. KM, HM and MM revised the manuscript critically for important intellectual content. DF contributed to designing the study, supervised the data analysis and gave critical input on the draft. All authors reviewed and approved the final manuscript.

  • Funding This research was partially supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (grant number JP18K07476), the Health Labour Sciences Research Grant (grant number 19FG1001), and The Mental Health Okamoto Memorial Foundation Research Activity Grant.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.