Review and special articleMeta-Analysis of Workplace Physical Activity Interventions
Introduction
Although strong evidence shows that exercisers are healthier than non-exercisers, most adults do not perform enough physical activity to achieve health and well-being benefits.1 Workplaces may implement physical programs in hopes of keeping workers healthy and reducing healthcare costs.2 Because employed adults spend about half of their workday waking hours at workplaces, offering physical activity programs at work may be an efficient strategy to increase physical actvity.3, 4, 5 Convenience, group support, existing patterns of formal and informal communication among employees in a worksite, and possible corporate behavior norms are potential advantages of worksite programs over other approaches.6, 7, 8 Workplace programs may be especially important because the imbalance between physical activity and energy intake at work may contribute to the obesity epidemic.4 This meta-analysis addresses the need to quantitatively synthesize the rapidly growing literature reporting workplace physical activity programs.
Despite the potential health and economic benefits of worksite health promotion,2 no previous comprehensive meta-analysis has summarized health and physical activity behavior outcomes from these programs. Several previous narrative reviews were limited in scope and unable to address either the magnitude of outcomes or potential workplace moderators of outcomes.4, 5, 9, 10 The broadest narrative review was conducted using studies published before 1995.11 Two previous meta-analyses addressed physical activity behavior outcomes across some studies included in this project. One 1998 meta-analysis of 26 studies reported an effect size consistent with a standardized mean difference of 0.22, which was not significantly different from zero. The authors noted that their attempted moderator analyses suffered from inadequate statistical power.3 A 1996 meta-analysis synthesized data for diverse adults and reported a workplace effect size consistent with a standardized mean difference of 0.35.12
This meta-analysis moves beyond the previous reported quantitative syntheses by greatly expanding the search strategies to ensure a more comprehensive synthesis, addressing both physical activity behavior and health outcomes, examining work-related outcomes, and conducting exploratory moderator analyses. The research questions were as follows: (1) What are the overall effects of interventions to increase physical activity on physical activity behavior; health (fitness, lipids, anthropometric measures, diabetes risk); well-being (quality of life, mood); and work-related outcomes (work attendance, healthcare utilization, job stress, and job satisfaction)? (2) Do interventions' effects on outcomes vary depending on workplace characteristics? (3) What are the effects of interventions on outcomes among studies comparing treatment subjects before versus after interventions?
Section snippets
Methods
Standard strategies for quantitative systematic reviews were used to locate and secure potential primary studies, determine eligibility, extract data from research reports, meta-analyze primary study results, and interpret findings.
Results
Approximately 38,231 subjects participated in the studies included in the meta-analysis (k=206 comparisons, s=138 reports).17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108,
Discussion
These findings document that some interventions improve physical activity in some subjects, and these changes may in turn improve selected health outcomes, work culture, and job stress. However, significant heterogeneity requires cautious interpretation of findings.
The physical activity mean effect size of 0.21 is similar to that reported in 26 worksite studies (r=0.11, d=0.22)3 and smaller than the effect size reported of 33 workplace studies (r=0.17, d=0.35).12 This might reflect more
Conclusion
Well-designed studies evaluating worksite physical activity promotion programs are needed. Direct comparisons between programs that allow employees to participate on paid work time versus those that do not should be investigated. Also necessary are direct comparisons of programs with and without worksite fitness facilities to determine whether the cost of providing onsite facilities is justified by improvements in employee health and productivity. Investigations targeting at-risk subjects would
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