【目的】専門家が監督する個別化健康プログラムが実際の企業環境でどの程度効果的か，その実用性は明確ではない．そこで今回は，職場における個別化健康プログラムが体組成および労働生産性に与える影響を検討した．
【方法】平均年齢47.6歳の女性従業員4名を対象に，外部専門家監修による6か月間の個別健康プログラム（前半3か月：対面指導、後半3か月：フォローアップ）を実施した．体組成は毎月測定し，労働生産性を評価した．
【結果】すべての参加者で6か月間を通じて体重と体脂肪量が減少し，特に3〜6か月の間で体脂肪量の一貫した減少が認められた．労働生産性のスコアはわずかな変動を示したものの，一定の傾向はみられなかった．
【結論】本症例シリーズは，外部専門家が監督する個別化健康プログラムが従業員の体組成の変化に寄与する可能性を示唆する．しかし，短期間の身体的の変化が必ずしも労働生産性の向上に直結するとは限らなかった．
Introduction: Maintaining employee health and productivity is vital for corporate sustainability. Sedentary behavior and physical inactivity contribute to obesity, metabolic and musculoskeletal disorders, and reduced productivity. Although many companies have adopted workplace health programs, the practical effects and feasibility of expert-supervised individualized interventions in real corporate settings remain unclear.
Methods: This descriptive case series involved four female employees (mean age: 47.6 years) who participated in a six-month personalized workplace health program supervised by external experts. The program included personal training and nutritional management and was divided into two phases: a three-month face-to-face training phase (Phase A) and a three-month follow-up phase (Phase B). Body composition parameters (body weight, skeletal muscle mass index, and body fat mass [BFM]) were measured monthly, and work productivity was assessed using the World Health Organization Health and Work Performance Questionnaire.
Results: All participants showed reductions in body weight and BFM over six months, with the most consistent decrease observed in BFM between the third and sixth months. Presenteeism scores exhibited slight fluctuations but no consistent trend.
Conclusions: This case series suggests that externally supervised individualized health programs may contribute to improved body composition among employees. However, short-term physical improvements may not directly lead to measurable gains in work productivity. These findings provide preliminary insights into the potential value and implementation considerations of expert-led workplace health interventions.
Maintaining and improving employee health and productivity have become critical factors for supporting corporate competitiveness and sustainability in modern workplaces. Prolonged sedentary behavior and physical inactivity in the workplace are widely known risk factors for obesity, metabolic disorders, and musculoskeletal disorders1－3), which not only reduces employee well-being but also causes decreased productivity and increased absenteeism, which is a significant economic burden for companies4－8). Furthermore, the aging workforce owing to the declining birthrate and aging population has made these issues even more serious, thereby increasing the importance of workplace health management.
Given this background, many companies have introduced workplace health promotion initiatives to improve employee well-being. Systematic reviews indicate that such workplace interventions can produce modest improvements in health behaviors, risk factors, and anthropometric outcomes9). However, systematic reviews and meta-analyses have shown that although workplace health promotion programs can improve job satisfaction and reduce sickness absences, the strength and consistency of these effects vary across studies, partly due to differences in study design and methodological quality10).
Recent studies have indicated that workplace health interventions incorporating exercise and nutrition guidance based on specialized knowledge and skills can contribute to improvements in employee’s physical health and well-being11，12). Moreover, recent cross-sectional evidence has shown that body composition particularly fat mass index (FMI) is associated with absenteeism risk, especially among female employees, suggesting that improving body composition may be a key strategy to mitigate productivity loss due to health-related factors13). Given that achieving such changes in body composition often requires individualized and professionally supervised programs, the involvement of external health professionals those independent of internal corporate health divisions may enhance both the effectiveness and sustainability of workplace health initiatives. Therefore, further investigation is warranted to clarify the potential advantages of externally supervised, individualized workplace health programs, particularly in small- and medium-sized enterprises where internal health resources are limited.
To explore these issues, we conducted a descriptive case series involving four employees who participated in a six-month personalized workplace health program supervised by external experts. The intervention included personal training and nutritional management and was divided into two phases: a three-month face-to-face training phase (Phase A) and a three-month follow-up phase (Phase B). The purpose of this case series was not to perform inferential statistical analysis but to document individual changes in body composition (skeletal muscle mass and body fat mass) and work productivity (absolute and relative presenteeism) over time. By presenting detailed case-based observations, this report aims to provide preliminary insights into the potential benefits and practical considerations of externally supervised workplace health interventions.
Study participants were drawn retrospectively from employees of LIM Projects Inc. and its affiliated companies who had participated in the company's existing workplace health program. Recruitment had originally occurred via an informational session held by the company. For the present study, four female employees (mean age: 47.6 years) whose program records were available and who had previously consented to the use of anonymized program data for research were included.
2. Ethical ConsiderationsThis retrospective observational study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of Aichi Medical University Hospital (approval number: 2024–215). The analyses used existing program data collected during routine workplace activities; no additional interventions or measurements were performed for research purposes. Participants had provided consent for the use of anonymized program data for research, and all data were handled in anonymized form.
3. Observed Workplace Health Program (Figure 1)This study retrospectively analyzed data from a six-month workplace health maintenance program that was conducted as part of routine corporate health promotion activities, not as a research-specific intervention. The program was implemented from June to November 2024 and aimed primarily to support the maintenance and improvement of employee health and physical fitness.
The program consisted of two observation phases:
・ Phase A (June–August 2024): Participants attended weekly in-person personal training sessions, received monthly body composition assessments, and participated in individualized health consultations and nutritional guidance.
Each personal training session lasted approximately 60 minutes and primarily consisted of bodyweight-based exercises, such as squats, lunges, planks, and core stabilization activities. Exercise intensity was monitored using heart rate and perceived exertion to maintain moderate-to-high effort levels according to each participant’s physical condition. There was no standardized algorithm for exercise selection; rather, training content was determined collaboratively with each participant based on individual health goals, physical ability, and preferences. No unified physical function test other than regular body composition measurement was implemented.
Nutritional guidance was provided by a licensed nutrition professional and aimed to estimate each participant’s daily energy and protein requirements (approximately 1.2–1.5 g/kg/day) and to promote the adoption of balanced dietary habits. Counseling sessions included feedback on dietary records, education on meal composition, and strategies to encourage sustainable behavioral change.
・Phase B (September–November 2024): The in-person training sessions were discontinued, but monthly assessments and health consultations continued to support behavioral maintenance.
In both phases, participants’ work productivity was evaluated using the Japanese version of the World Health Organization Health and Work Performance Questionnaire (WHO-HPQ)14). All sessions were conducted by licensed physical therapists and occupational therapists, each with more than 10 years of professional experience in clinical and workplace health management.
This study retrospectively described a six-month individualized expert-supervised workplace health management program (June–November 2024) that was implemented as part of routine corporate health promotion activities (not initiated for research). The program consisted of two consecutive phases: Phase A (June–August 2024) with weekly in-person personal training sessions (~60 minutes/session, primarily bodyweight exercises such as squats, lunges, planks, and core stabilization; intensity monitored by heart rate and perceived exertion) and monthly individualized health and nutritional consultations, and Phase B (September–November 2024) consisting of monthly follow-up assessments and health consultations (in-person training discontinued). Monthly body composition measurements (InBody 270) and monthly work productivity assessments (WHO-HPQ, Japanese version) were routinely collected throughout both phases; key reporting points used in the manuscript are baseline, 3 months, and 6 months.
Body composition was assessed in all participants using a segmental multifrequency bioelectrical impedance analyzer (InBody 270; InBody Japan, Tokyo, Japan). Certified physical and occupational therapists performed measurements. The participants were asked to remove their socks, heavy clothing, and metallic accessories before standing upright on the device’s contact electrodes. Skeletal muscle mass index (SMI) was determined by dividing the skeletal muscle mass (SMM) by the square of height.
5. Work ProductivityParticipants evaluated their job performance using the WHO-HPQ15，16). This well-established tool, known for its reliability, assesses the health-related costs of absenteeism and decreased productivity (presenteeism) owing to illness. This study used the Japanese version of the abbreviated WHO-HPQ14). The questionnaire included two primary questions to measure presenteeism: “On a scale of 0 to 10, where 0 represents the worst possible job performance in your role, and 10 represents the performance of an outstanding worker, how would you rate the typical performance of most workers in a similar job?” Using the same 0–10 scale, how would you evaluate your overall job performance on the days you worked during the past 4 weeks?”
Absolute presenteeism was defined as the participant’s self-rated job performance score (0–10 scale) during the past 4 weeks.
Relative presenteeism was calculated as the ratio of the participant’s self-rated performance to the perceived typical performance of others in similar roles, using the following formula:
Relative presenteeism = (Self-rated performance) / (Perceived typical performance)
This ratio ranges from 0.25 to 2.0, where lower values indicate reduced productivity relative to peers.
6. OutcomesThe primary outcomes of this study were as follows: Body composition parameters included body weight, SMM-to-fat-free mass ratio (SMM/FFM), SMI, and body fat mass (BFM). Work productivity indicators: WHO-HPQ scores, including absolute and relative presenteeism.
As this report is a descriptive case series, analyses are primarily descriptive. Individual time-series for each case are presented (means and monthly values). No inferential statistics (e.g., group P-values) are used to support generalizable claims; observed changes are described qualitatively and quantitatively per case.
For each participant (A, B, C, and D), changes in body composition parameters (body weight, SMM/FFM ratio, SMI, and BFM) were descriptively tracked monthly for six months. Baseline characteristics of the four participants are summarized in Table 1. All participants were female employees engaged in sales or clerical work, with a mean age of 47.6 years. None had known chronic diseases, and no information on medication use was available.
| Participant |
Age (years) |
Sex |
Height (cm) |
Weight (kg) |
Occupation | Chronic disease | Medication use |
|---|---|---|---|---|---|---|---|
| A | 53 | Female | 152.0 | 76.7 | Sales/clerical | None | No data |
| B | 49 | Female | 152.0 | 65.3 | Sales/clerical | None | No data |
| C | 45 | Female | 152.6 | 65.0 | Sales/clerical | None | No data |
| D | 53 | Female | 161.0 | 68.2 | Sales/clerical | None | No data |
| None: no known chronic diseases; No data: no available information on medication use. | |||||||
Changes in body weight and body composition over the six-month period are summarized in Table 2 and Figure 2. Participant A showed a mild and gradual decrease in body weight, from 76.7 kg at baseline to 75.5 kg at six months, accompanied by a modest reduction in BFM. Participant B experienced a more pronounced weight decrease (65.3 kg → 60.3 kg) and a notable reduction in BFM (27.3 kg → 22.8 kg). Participant C weight changed from 65.0 kg at baseline to 64.0 kg at six months. Participant C showed a gradual decrease in body weight, changing from 65.0 kg at baseline to 64.0 kg at six months, and her body fat mass decreased from 26.9 kg to 24.8 kg over the same period. Participant D demonstrated a steady reduction in body weight (68.2 kg → 66.0 kg) and a mild decrease in BFM.
| Phase A | Phase B | |||||||
|---|---|---|---|---|---|---|---|---|
| Baseline | 1 month | 2 months | 3 months | 4 months | 5 months | 6 months | ||
| A | Weight (kg) | 76.7 | 76.5 | 75.3 | 75.0 | 74.6 | 74.8 | 75.5 |
| SMM: FMM (kg) | 22.4:35.6 | 16.9:35.8 | 22.0:34.9 | 21.5:35.3 | 21.3:35.1 | 21.7:34.9 | 22.0:34.9 | |
| SMM/ FFM (ratio) | 0.545 | 0.543 | 0.543 | 0.542 | 0.541 | 0.543 | 0.541 | |
| SMI (kg/m2) | 7.3 | 7.3 | 7.2 | 7.1 | 7.0 | 7.1 | 7.2 | |
| FMI (kg/m2) | 15.4 | 15.5 | 15.1 | 15.3 | 15.2 | 15.1 | 15.1 | |
| BFM (kg) | 35.6 | 35.8 | 34.8 | 35.3 | 35.2 | 34.8 | 34.8 | |
| BFMI (kg/m2) | 15.4 | 15.5 | 15.1 | 15.3 | 15.2 | 15.1 | 15.1 | |
| B | Weight (kg) | 65.3 | 64.1 | 62.5 | 61.5 | 59.3 | 59.6 | 60.3 |
| SMM: FMM (kg) | 20.5:27.3 | 15.2:26.8 | 20.1:25.4 | 20.2:24.3 | 19.7:22.9 | 20.0:22.4 | 20.3:22.9 | |
| SMM/ FFM (ratio) | 0.539 | 0.541 | 0.540 | 0.542 | 0.540 | 0.539 | 0.541 | |
| SMI (kg/m2) | 6.7 | 6.6 | 6.5 | 6.6 | 6.3 | 6.4 | 6.4 | |
| FMI (kg/m2) | 11.8 | 11.6 | 11.0 | 10.5 | 9.9 | 9.7 | 9.9 | |
| BFM (kg) | 27.3 | 26.8 | 25.3 | 24.2 | 22.8 | 22.5 | 22.8 | |
| BFMI (kg/m2) | 11.8 | 11.6 | 11.0 | 10.5 | 9.9 | 9.7 | 9.9 | |
| C | Weight (kg) | 65.0 | 64.2 | 63.7 | 63.2 | 63.3 | 63.2 | 64.0 |
| SMM: FMM (kg) | 20.7:27.0 | 15.8:24.9 | 21.0:24.9 | 20.6:25.4 | 20.7:25.1 | 20.8:24.9 | 21.8:24.7 | |
| SMM/ FFM (ratio) | 0.543 | 0.544 | 0.543 | 0.544 | 0.542 | 0.543 | 0.543 | |
| SMI (kg/m2) | 6.7 | 6.8 | 6.7 | 6.7 | 6.6 | 6.7 | 6.7 | |
| FMI (kg/m2) | 11.6 | 10.7 | 10.7 | 10.9 | 10.8 | 10.7 | 10.6 | |
| BFM (kg) | 26.9 | 25.0 | 25.0 | 25.3 | 25.1 | 24.9 | 24.8 | |
| BFMI (kg/m2) | 11.6 | 10.7 | 10.7 | 10.9 | 10.8 | 10.7 | 10.6 | |
| D | Weight (kg) | 68.2 | 68.3 | 67.9 | 67.3 | 66.7 | 66.3 | 66.0 |
| SMM: FMM (kg) | 23.8:24.4 | 17.9:23.8 | 24.1:23.6 | 23.8:23.3 | 23.9:22.6 | 24.0:22.0 | 23.6:22.8 | |
| SMM/ FFM (ratio) | 0.543 | 0.542 | 0.543 | 0.542 | 0.542 | 0.542 | 0.545 | |
| SMI (kg/m2) | 6.8 | 6.9 | 6.9 | 6.8 | 6.8 | 6.8 | 6.8 | |
| FMI (kg/m2) | 9.4 | 9.2 | 9.1 | 9.0 | 8.7 | 8.5 | 8.8 | |
| BFM (kg) | 24.4 | 23.9 | 23.5 | 23.4 | 22.6 | 22.0 | 22.7 | |
| BFMI (kg/m2) | 9.4 | 9.2 | 9.1 | 9.0 | 8.7 | 8.5 | 8.8 | |
| SMM, skeletal muscle mass; FFM, fat free mass; SMI, skeletal muscle mass index; FMI, fat free mass index; BFM, body fat mass; BFMI, body fat mass index | ||||||||
Changes in body fat mass and skeletal muscle mass index are presented for four participants (A–D) across the 6-month observation period (Baseline to Month 6). Each line represents an individual participant. Body fat mass tended to decrease over time, while skeletal muscle mass index remained relatively stable throughout the program.
A comparison of body composition and WHO-HPQ scores during the intervention period is shown in Table 3 and Figure 3. Across cases, the pattern of fat reduction was most evident during the latter half of the intervention (months 3–6). Changes in work productivity, assessed by the WHO-HPQ, varied among participants. Two participants showed modest improvement in absolute presenteeism scores, while the other two exhibited minimal change or slight decline. No consistent trend was observed across the four cases.
| Baseline | 3 months | 6 months | |
|---|---|---|---|
| Body composition | |||
| Weight (kg) | 68.8 (5.5) | 66.8 (6.0) | 66.5 (6.5) |
| SMM/FFM (ratio) | 0.543 (0.0) | 0.543 (0.0) | 0.543 (0.0) |
| SMI (kg/m2) | 6.9 (0.3) | 6.8 (0.2) | 6.8 (0.3) |
| BFM (kg) | 28.6 (4.9) | 27.1 (5.6) | 26.3 (5.8) |
| WHO-HPQ (score) | |||
| Absolute presenteeism | 62.5 (15.0) | 70.0 (8.2) | 67.5 (23.6) |
| Relative presenteeism | 0.84 (0.2) | 0.95 (0.2) | 0.79 (0.3) |
|
Values shown as means (SD). Because this report describes only four cases, no statistical analyses were conducted. WHO-HPQ, World Health Organization Heath and Work Performance Questionnaire; SMM, skeletal muscle mass; FFM, fat free mass; SMI, skeletal muscle mass index; BFM, body fat mass |
|||
This figure shows the changes in absolute presenteeism (bar graph, left axis) and relative presenteeism (dot markers, right axis) at baseline (Start), 3 months, and 6 months for participants A–D. Absolute presenteeism decreased from baseline to 6 months in participants A, B, and D, whereas it increased in participant C. Relative presenteeism increased from baseline to 3 months in all participants but decreased at 6 months in participants A, B, and D.
This case series aimed to describe the effects of a six-month individualized health promotion program including personal training and nutritional management on body composition and work productivity among company employees. Although the small sample size (n=4) precludes statistical analysis, observable trends were identified. In particular, all participants demonstrated reductions in BFM during the six-month period, while changes in presenteeism scores were inconsistent among individuals.
A consistent reduction in body fat mass was observed across participants, particularly between 3 and 6 months. These individual patterns align with previous reports suggesting that structured workplace programs combining exercise and nutritional support can contribute to favorable body composition changes17，18). Even after the more intensive early phase, participants maintained or continued slight improvements, implying that behavioral adaptation and self-management may play key roles in sustaining health outcomes, even in small-scale interventions.
No uniform improvement in presenteeism was observed among the four participants. While previous studies have suggested that workplace health interventions can enhance productivity12), these interventions vary substantially in their components, target populations, and evaluated outcomes. A systematic review has shown that workplace nutrition and physical activity programs differ widely in structure and intensity, and although some studies have reported improvements in absenteeism or work performance, consistent gains in productivity have been observed only in a subset of interventions12). Such methodological heterogeneity including differences in intervention focus, occupational settings, and outcome measures may partly account for discrepancies between previous findings and the present case series. In our cases, although improvements in body composition were observed, the program did not address broader determinants of presenteeism, such as work environment, job demands, or psychosocial factors19－21). These contextual factors, along with the relatively short intervention duration, may explain why changes in productivity were not evident.
This case series has several limitations. The small number of participants (n=4) limits the generalizability of the findings and precludes inferential statistical analysis. However, the descriptive observations provide valuable insights into individual variability in response to workplace health programs. Additionally, the six-month duration may not have been sufficient to capture long-term effects on productivity. Although the WHO-HPQ is widely used to assess work performance, no universally established minimal clinically important difference exists for its presenteeism scales, making interpretation of small changes challenging. In addition, the six-month duration may not have been sufficient to detect meaningful changes in presenteeism. Although some workplace intervention studies have reported modest improvements in WHO-HPQ scores within relatively short periods such as 3 to 6 months22), other evidence suggests that more extended intervention or follow-up periods may be required for consistent or measurable changes in work performance to emerge. Future studies should include a larger number of participants and extended follow-up periods to verify the relationship between physical health improvements and work performance. Finally, as this intervention primarily focused on physical aspects, future workplace health strategies should incorporate psychosocial support to address the multifactorial nature of presenteeism.
This case series documents the feasibility and potential benefits of individualized, expert-supervised workplace health interventions for improving body composition. All four cases showed reductions in body fat mass, although productivity outcomes varied. These findings are preliminary and exploratory, intended to inform the development of larger, controlled studies rather than to establish efficacy.
Some authors are employees of LIM Projects Inc., which had a service contract to provide the workplace health program analyzed in this study. The authors did not receive individual financial incentives related to this work. No other conflicts of interest are declared.
We would like to acknowledge all participants who agreed to participate in this study.
