Purpose
Step test protocols are typically based on the heart rate (HR) measured either during exercise or during recovery. This study developed a new step test protocol to estimate maximal oxygen ...consumption (
V
˙
O
2max
) based on HRs measured during and after exercise, assessed the criterion validity of the model, and evaluated the protocol’s test–retest reliability.
Methods
The protocol estimates
V
˙
O
2max
from HR measurements made once a minute during 3 min of step exercise and 2 min of recovery. The model was derived using a group of 118 working adults and cross-validated using a second group of 74 working adults. Furthermore,
V
˙
O
2max
was measured using a conventional treadmill test. While multiple regression analyses were used to develop prediction equations for
V
˙
O
2max
, intraclass correlation coefficients (
ICCs
) were used to examine test–retest reliability.
Results
HRs during and after exercise significantly correlated with the measured
V
˙
O
2max
. The highest correlation (
r
= − 0.61) was for an HR index that combined values of HRs during and after exercise. A model including age, sex, body mass index, and the HR index accounted for 60% of the variance in measured
V
˙
O
2max
(standard error of the estimate, 4.05 mL kg
−1
min
−1
or 10.5%). Cross-validation analyses demonstrated good stability of the
V
˙
O
2max
prediction models. The ICC for the HR index was 0.65 (0.53–0.74), indicating fair to good reliability.
Conclusion
The HR index, based on a combination of HR measurements during and after stepping exercise, offers a validated
V
˙
O
2max
estimation procedure suitable for use in the workplace.
Studies of the effectiveness of high-intensity interval training (HIIT) combined with calorie restriction (CR) are very limited, and the most effective order of intervention is unclear. Therefore, we ...investigated the impact of time-efficient HIIT with CR intervention on metabolic syndrome (MetS) and the impact of the intervention order on changes in MetS risk factors.
Thirty-two participants with MetS underwent an 11-wk intervention program comprising 8 wk of HIIT and 3 wk of CR. Participants were randomly assigned to either the HIIT-then-CR or CR-then-HIIT groups. Thereafter, the CR-then-HIIT group performed a further 8 wk of training once per week after the initial intervention period. Risk factors for MetS and peak oxygen uptake (VO2peak) were assessed during the entire study period.
During the 11-wk intervention period, body composition, MetS risk factors, and VO2peak significantly improved in both groups. No significant differences in these improvements were attributable to the intervention order; nonetheless, there was a tendency toward larger effect sizes in the CR-then-HIIT group. During the postintervention period (8 wk), a single weekly HIIT session prevented VO2peak reduction in the CR-then-HIIT group (–2.0 ± 7.2%; P = 0.31).
The time-efficient intervention program with HIIT and CR had a beneficial effect on MetS; however, the intervention order had no influence on the changes in risk factors.
•High-intensity interval training (HIIT) and calorie restriction (CR) improved cardiorespiratory fitness and metabolic syndrome risk factors.•Intervention order with HIIT and CR has no influence on risk factor improvement.•A single weekly HIIT can potentially help maintain an increase in cardiorespiratory fitness.
Rest-activity rhythms are directly related to health risks, but there are limited objective methods to assess them. This study aimed to investigate the relationship between rest-activity rhythms and ...cardiorespiratory fitness (CRF) in middle-aged workers.
Peak oxygen uptake was measured on a treadmill to assess CRF in 254 middle-aged workers who were divided into low, medium, and high-CRF groups based on tertiles. Participants were asked to wear an accelerometer (activPAL) on their thighs for 1 week, and the logarithmically transformed acceleration data were used for the analysis of a 24-hour rest-activity rhythm. Sex, age, body mass index, occupation, smoking status, and alcohol consumption were used as covariates in Model 1, with Model 2 also including walking count on non-workdays. Repeated measures analysis of variance was used to compare time course of rest-activity rhythms changes on workdays between groups, and post-hoc tests were conducted using Bonferroni's correlation.
Higher CRF correlated with increased physical activity. In model 1, higher CRF showed improved interdaily stability, but the significant difference disappeared in model 2 after adjusting for non-workday walking counts. A time-course group comparison showed that the high group had significantly higher activity levels than those of the low group from 6:00 to 8:59 and 17:00 to 17:59 and the medium group from 6:00 to 7:59 and 19:00 to 19:59.
Workers who have better rest-activity rhythms and engage in higher levels of physical activity on workdays tend to have higher CRF levels. Regular daily routines, influenced by physical activity during holidays, can positively impact cardiopulmonary endurance.
Objectives
This survey aims to investigate consciousness regarding habitual exercise among workers in urban areas and to analyze the associations of workers’ socioeconomic status with their habitual ...exercise and cardiorespiratory fitness (CRF).
Methods
Ten thousand participants, who worked in the Tokyo area of Japan, were recruited for the questionnaire‐based survey. The questionnaire elicited participant's characteristics, socioeconomic status (eg, employment status and annual income), habitual exercise status, and consciousness regarding exercising. After the data‐cleaning procedure, 9406 participants were selected for analyses. CRF was estimated by a validated equation model.
Results
Some (32.9%) participants had an exercise habit, and 93% recognized that exercise is good for health. Of the nonexercise habit group (n = 6308), 73% wanted to develop an exercise habit, and “spare time (40%)” and “financial capability (16%)” were the two most necessary conditions for habituating exercise. As socioeconomic statuses increased, the odds ratios (ORs) for engaging in habitual exercise increased among full‐time (1.22) versus part‐time (reference) employees and those having high (1.76) versus low (reference) incomes, whereas the ORs for low CRF risk decreased among full‐time (0.78) versus part‐time (reference) employees and those having high (0.53) versus low (reference) incomes.
Conclusions
Although most workers recognized the benefits of exercise, many were unable to develop exercise habits and believed that they could develop exercise habits if they had the time and financial capabilities. The survey suggests that workers with a higher socioeconomic status more likely to obtain favorable physical fitness, indicating a health disparity among workers in urban areas.
Sedentary behavior (SB) and cardiorespiratory fitness (CRF) are important issues in occupational health. Developing a questionnaire to concurrently assess workers' SB and CRF could fundamentally ...improve epidemiological research. The Worker's Living Activity-time Questionnaire (WLAQ) was developed previously to assess workers' sitting time. WLAQ can be modified to evaluate workers' CRF if additional physical activity (PA) data such as PA frequency, duration, and intensity are collected.
A total of 198 working adults (93 women and 105 men; age, 30-60 years) completed anthropometric measurements, a treadmill exercise test for measuring maximal oxygen consumption (VO
), and modified WLAQ (m-WLAQ, which included questions about PA data additional to the original questions). Multiple regression analyses were performed to develop prediction equations for VO
. The generated models were cross-validated using the predicted residual error sum of squares method. Among the participants, the data of 97 participants who completed m-WLAQ twice after a 1-week interval were used to calculate intraclass correlation coefficient (ICC) for the test-retest reliability analyses.
Age (r = - 0.29), sex (r = 0.48), body mass index (BMI, r = - 0.20), total sitting time (r = - 0.15), and PA score (total points for PA data, r = 0.47) were significantly correlated with VO
. The models that included age, sex, and BMI accounted for 43% of the variance in measured VO
standard error of the estimate (SEE) = 5.04 ml·kg
·min
. These percentages increased to 59% when the PA score was included in the models (SEE = 4.29 ml·kg
·min
). Cross-validation analyses demonstrated good stability of the VO
prediction models, while systematic underestimation and overestimation of VO
were observed in individuals with high and low fitness, respectively. The ICC of the PA score was 0.87 (0.82-0.91), indicating excellent reliability.
The PA score obtained using m-WLAQ, rather than sitting time, correlated well with measured VO
. The equation model that included the PA score as well as age, sex, and BMI had a favorable validity for estimating VO
. Thus, m-WLAQ can be a useful questionnaire to concurrently assess workers' SB and CRF, which makes it a reasonable resource for future epidemiological surveys on occupational health.
The effects of domain-specific (i.e., occupational, leisure-time on workday, and holiday) sitting time (ST), and exercise on metabolic syndrome (MetS) development are insufficiently studied. The ...present study aimed to examine the single and combined effects of each domain-specific ST and exercise habits on MetS. The total and domain-specific STs of 5530 participants were collected using a validated questionnaire. The multiple logistic regression analyses determined the effects of each domain-specific ST and exercise habit on MetS. Of all participants, 7.8% had MetS. Odds ratios (ORs) for MetS were significant only in the group with the longest leisure-time ST on holidays (OR, 1.43; 95% confidence interval CI, 1.12–1.83); we found no significant associations with any other domain-specific ST after statistical adjustment for confounders. The no-habitual-exercise group clearly had a higher risk for MetS (OR, 1.44; 95% CI, 1.15–1.80). The significantly higher ORs for MetS was shown in only the combined longer total ST (OR, 1.64; 95% CI, 1.12–2.39) and holiday ST (OR, 1.83; 95% CI, 1.30–2.59) with no habitual exercise. These findings suggested that accumulated daily total ST, particularly leisure-time ST on holidays with no-habitual exercise, can increase the risk of MetS and it could possibly be mitigated by habitual exercise.
Objective
Cardiorespiratory fitness (CRF) is an important factor for evaluating cardiovascular disease (CVD) risk. We recently developed a novel method (National Institute of Occupational Safety and ...Health, Japan step test JST) for evaluating CRF in workers; its criterion validity has been investigated. However, its association with health risk must be confirmed before its application in the workplace. Therefore, we aimed to determine the association of JST‐evaluated CRF with the prevalence of CVD risk among Japanese workers.
Methods
For CRF evaluation, working adults completed the JST, which comprised a 3‐minute stepping exercise and a 2‐minute recovery period. Data on CVD risk factors and clinical history were collected through medical certification within 1 year from the date of the JST measurements. Participants were divided into three groups for multiple logistic regression analyses based on the JST values (low, moderate, and high). Odds ratios (ORs) for the prevalence of CVD risk were calculated.
Results
We recruited 885 working adults (46.4% women). The prevalence of CVD risk in the total population was 18.6%. When compared to the reference group (low CRF), the ORs for CVD risk prevalence after adjustments for lifestyle factors (smoking status, alcohol consumption status, and exercise habits) were 0.42 (95% confidence interval CI, 0.28–0.63) and 0.29 (95% CI, 0.18–0.45) for the moderate and high groups, respectively.
Conclusion
An inverse association was noted between the JST‐evaluated CRF and CVD risk prevalence. JST may be helpful for identifying workers at risk for CVD development.
To continue to work healthily, health practices are necessary. This study assessed the impact of health literacy (HL) on health practices in the working life of young Japanese nurses and care ...workers, occupations with heavy physical and psychological burdens. A web-based survey was conducted with 500 women (330 nurses and 170 care workers) under the age of 30 in 2019. Data regarding their demographic characteristics, HL and health practices in their working life were collected. A significant association was found between high HL and better health practices, such as being likely to rest when tired, working at their own pace maintaining a good work-life balance and regularly performing self-check-ups, which were common to nurses and care workers. In addition, sub-analysis among the high-HL group revealed that the attendance of lectures regarding working life and health for new employees was effective for taking rest when needed, working when not overtired and a good work-life balance. The results of this study suggest that high HL relates to healthy practices in the working life of young Japanese nurses and care workers. Increasing HL or fundamentally enhancing attitudes towards their own health or both may, therefore, have some benefits for healthy working practices.
Does asking for the percentage of time spent sitting during work (P-method) instead of asking for the absolute length of time spent sitting (T-method) improve properties of the workers' sitting- and ...walking-time questionnaire (WSWQ)? The purpose of this study was to investigate whether questioning technique influences test-retest reliability and criterion validity of the WSWQ.
Sixty-five Japanese workers completed each version of the WSWQ in random order. Both questionnaires assessed quantities of time spent sitting or walking (including standing) during work time, non-working time on a workday, and anytime on a non-workday. Participants wore the thigh-worn inclinometer (activPAL) as criterion measure. Intraclass correlation coefficients (ICC) and Spearman's ρ were used for the analyses.
For all three domains, values of reliability and validity with the P-method tended to be higher than with the T-method: ICC values ranged from 0.48-0.85 for the T-method and from 0.71-0.85 for the P-method; Spearman's ρ values ranged from 0.25-0.58 for the T-method and from 0.42-0.65 for the P-method. The validities with both methods on a workday (0.51-0.58 for the T-method and 0.56-0.65 for the P-method) were higher than validities on a non-workday (0.25-0.45 for the T-method and 0.42-0.60 for the P-method). In post-survey interviews, 48 participants (77%) chose the P-method as their preferred questioning style.
The study revealed that the P-method WSWQ had better reliability, validity, and ease of answering than the T-method, suggesting that the P-method can improve properties of the WSWQ and consequently advance the quality of epidemiological surveys in this field.
How work burden affects physical and mental health has already been studied extensively; however, many issues have remained unexamined. In 2017, we commenced a prospective cohort study of workers at ...companies in Japan, with a follow-up period of 5–10 years, in order to investigate the current situation of overwork-related health outcomes. From 2017 to 2020, a target population of 150,000 workers across 8 companies was identified. Of these, almost 40,000 workers agreed to participate in the baseline survey. Data on working hours, medical check-up measurements, occupational stress levels, and lifestyle habits were collected. The average age of the participants at baseline was 39.2 ± 11.7 years; 73.1% were men, and 87.7% were regular employees. The most common working hours by self-reported was 41–50 hours per week during normal season, and it increased to more than 50 hours during busy season. Furthermore, more than half of the participants reportedly experienced a form of sleep problem, and the percentage of those who experienced nonrestorative sleep was particularly high.
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