Workers' physical activity data contribute to estimating maximal oxygen consumption: a questionnaire study to concurrently assess workers' sedentary behavior and cardiorespiratory fitness

Self-assessment of cardiorespiratory fitness: evaluation of reliability and validity of a step test eliminating a step board

PURPOSE

Conventional assessment of cardiorespiratory fitness (CRF) requires specialized equipment and designated spaces, limiting accessibility. To address this, the modified National Institute of Occupational Safety and Health, Japan step test (mJST) was developed for self-assessment without a step board. This study evaluated the reliability and validity of the mJST.

METHODS

A total of 131 participants (49% female, aged 30-59) were divided into a derivation group (n = 82) to establish an estimated maximal oxygen consumption ( V ˙ O2 max) model using multiple regression, and validation group (n = 49) to test the accuracy of the model. All participants completed the mJST and a  V ˙ O2 max treadmill test. The mJST comprised whole-body exercise for 3min and 40s followed by a 2-min recovery period. Heart rates (HRs) during the mJST were self-recorded using a wrist-worn device and measured via electrocardiograph. Test-retest reliability and validity were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis.

RESULTS

Excellent test-retest reliability was observed with electrocardiograph HRs (ICC = 0.92); however, fair to good reliability was observed with the wrist-worn device (ICC = 0.75). Bland-Altman analysis showed that mJST overestimated  V ˙ O2 max by 1.24 mL·kg-1·min-1, likely owing to discrepancies in HR readings from the wrist-worn device. The correlation between estimated and measured  V ˙ O2 max was moderate (r = 0.68).

CONCLUSIONS

Eliminating the step board in step tests may aid in regular assessments of CRF to support ongoing health management. Despite limitations in device accuracy, the mJST demonstrated sufficient reliability and validity as a practical tool.

Hypoglycemic timeslots after hospital discharge in patients with diabetes on multiple daily insulin injection: Dose of Insulin CHanged According to the Reported Glucose by Libre Pro (DISCHARGe study)

INTRODUCTION

Insulin improves clinical outcomes in hospitalized patients; however, hypoglycemia hinders discharge transition in patients with insulin-treated diabetes. Studies on hypoglycemic timeslots, rates, and risk factors during discharge transition are lacking.

MATERIALS AND METHODS

Fifteen patients with type 2 diabetes (T2D) receiving multiple daily insulin (MDI) injections participated. Glucose variability metrics and hypoglycemia were monitored using a continuous glucose monitoring system starting a day pre-discharge through 13 days of discharge transition. Hypoglycemia was analyzed chronobiologically using Cosinor analysis. Anthropometric measurements, C-peptide, insulin dose, and glucagon were assessed.

RESULTS

The mean patient age was 52.7 ± 12.6 years; 13/15 were male; body mass index was 28.1 ± 5.9 kg/m2, T2D duration was 8.6 ± 8.8 years, HbA1c was 12.4 ± 2.5%, and total daily insulin dose averaged 36.6 ± 15.1 units and hospitalization lasted 13.1 ± 2.3 days. Time in range decreased post-discharge. Time below range increased from 7.0% at discharge to 17.6% by the study end (manova, P < 0.001). Hypoglycemic events peaked post-breakfast, with the highest amplitude (42 points) recorded at 12:00. The highest and lowest numbers of hypoglycemia occurred at 12:00 and 17:30, respectively. However, the highest hypoglycemic timeslot (11:00-12:00) was not significantly associated with clinical and biochemical parameters.

CONCLUSIONS

The chronobiology of hypoglycemia exists during the discharge transition in patients with MDI-treated T2D. Hypoglycemia frequency and severity peaked pre-lunch, reached a nadir at 17:30, and exaggerated post-discharge, emphasizing the need for pre-breakfast insulin dose reductions on the discharge day.

The impact of occupational sitting time and occupation on cardiometabolic health in Japanese workers

PURPOSE

Prolonged sitting time (ST) has been suggested as a risk factor for CVD. Particularly, occupational ST (OST) is determined by occupation-specific activities and can impact the health status of workers. However, there is limited information on the impact of OST across different occupations among Japanese workers. This study aimed to examine how OST and occupation associate to CVD risks.

METHODS

Using a cross-sectional design, a total of 1874 workers were included in this study. ST was assessed using the Worker's Living Activity-time Questionnaire during working and non-working days. CVD risks were evaluated using a combination of questionnaires and medical checkup records. We conducted multivariable-adjusted logistic regression analyses to assess the associations between occupations (clerical support, professionals, service, and sales) and OST (categorized as long, middle, or short) with CVD risks. All analyses were adjusted for sex, age, smoking status, alcohol consumption, exercise habits, and either OST or occupation, depending on the primary exposure.

RESULTS

The results indicated that workers in services and sales had significantly lower odds ratios (ORs) for hypertension (OR = 0.52, 95% CI: 0.40-0.69) and CVD risk (OR = 0.61, 95% CI: 0.47-0.78) compared to clerical support, while professionals showed higher ORs for dyslipidemia (OR = 1.49, 95% CI: 1.16-1.91). When analyzed by OST categories, the short OST group showed reduced risks for obesity (OR = 0.77, 95% CI: 0.59-1.00) compared to the long OST group.

CONCLUSION

This study emphasizes the need to consider both occupation and OST when assessing health risks, highlighting the importance of targeted interventions for specific occupational groups.

Aerobic fitness predicted by demographics, anthropometrics, health behaviour, physical activity and muscle fitness in male and female recruits entering military service

INTRODUCTION

The physical and mental training load can be high during military service. Therefore, tailored preconditioning programmes based on assessment of physical fitness could increase readiness for military service, especially among those ones with lower baseline fitness level. The purpose of present study was to investigate how self-assessed health behaviour, physical activity and muscle fitness can predict physical fitness in young male and female military cohorts.

METHODS

Demographics, health behaviour and daily physical activity preceding military service were surveyed by a questionnaire. Thereafter, physical fitness was assessed during the military service by the tests of 12 min running, 1 min push-ups and sit-ups. Explosive power of the lower extremities was studied by maximal standing long jump. Measurements of body anthropometry consisted of body mass, height, and waist circumference.

RESULTS

The two strongest individual predictors of objectively measured running distance in 12 min were self-reported physical activity and physical readiness in both men and women. Self-reported physical activity, readiness for military service, sitting time, education, smoking and body anthropometrics together explained 52% of the variance in the 12 min running test result (R2=0.52, mean absolute percentage error (MAPE) 8.8%, mean absolute error (MAE) 207 m) in men, while for women the predictive values were weaker. Addition of muscle fitness results to the adjusted regression model further improved the model, which explained 59% of the variance in the 12 min running tests result of male conscripts (R2=0.59, MAPE 7.8%, MAE 181 m).

CONCLUSION

In the present study, self-reported physical activity, muscle fitness, physical readiness for military service, sitting time, education, smoking and body anthropometrics predicted inadequately the measured endurance capacity among recruits. The present questionnaire-based variables do not accurately predict physical fitness of recruits and thus, they are not either suitable for practical use for preconditioning programmes or preselection before entering the military service.

Association between physical activity patterns of working-age adults and social jetlag, depressive symptoms, and presenteeism

OBJECTIVES

This study aimed to evaluate the association of physical activity with social jetlag, depressive symptoms, and presenteeism.

METHODS

This cross-sectional study included 8247 working-age adults (females, 44.6%; age, 20-64 years). Social jetlag was defined as the absolute difference between the midpoint of bedtime and wake time on workdays and free days. Depression symptoms were assessed using the Center for Epidemiologic Studies Depression Scale, and presenteeism was evaluated using the Work Functioning Impairment Scale. Exercise habits were classified into 4 groups based on the World Health Organization guidelines: nonactive (NA; n = 4223), insufficiently active (IA; n = 3009: exercise below guideline levels), weekend warriors (WW; n = 220: exercise 1-2 times per week meeting guideline levels), and regularly active (RA; n = 793: exercise at least 3 d/wk meeting guideline levels). Using multiple and Poisson regression analyses, we examined the association between exercise habits and each outcome.

RESULTS

Social jetlag, depression, and presenteeism were more favorable with shorter sedentary times and longer durations of moderate- and vigorous-intensity exercise. Compared with the RA group, the NA group had a significantly higher prevalence of social jetlag (prevalence ratio [PR] = 1.30), depression (PR = 1.31), and presenteeism (PR = 1.35). The IA group had a significantly higher prevalence of depression (PR = 1.33) and presenteeism (PR = 1.38).

CONCLUSIONS

Exercising with a certain frequency and intensity may help prevent symptoms of depression and social jetlag, and consequently prevent presenteeism.

Feasibility of predicting maximal oxygen uptake by using the efficiency factor in healthy men

Conventionally, efficiency is indirectly estimated through a respiratory gas analyser (oxygen, carbon dioxide), which is a complex and rather costly calculation method that is difficult to perform in many situations. Therefore, the present study proposed a modified definition of efficiency, called the efficiency factor (EF) (i.e., the ratio of work to the corresponding exercise intensity), and evaluated the relation between the EF and maximal oxygen uptake ([Formula: see text]), as well as compared the prediction models established based on the EF. The heart rate (maximal heart rate: 186 ± 6 beats min-1), rating of perceived exertion (19 ± 1), and [Formula: see text] (39.0 ± 7.1 mL kg-1 min-1) of 150 healthy men (age: 20 ± 2 years; height: 175.0 ± 6.0 cm; weight: 73.6 ± 10.7 kg; body mass index [BMI]: 24.0 ± 3.0 kg m-2; percent body fat [PBF]: 17.0 ± 5.7%) were measured during the cardiopulmonary exercise test (CPET). Through multiple linear regression analysis, we established the BMI model using age and BMI as parameters. Additionally, we created the PBF modelHRR utilizing weight, PBF, and heart rate reserve (HRR) and developed PBF modelEF6 and PBF modelEF7 by incorporating EF6 from the exercise stage 6 and EF7 from the exercise stage 7 during the CPET, respectively. EF6 (r = 0.32, p = 0.001) and EF7 (r = 0.31, p = 0.002) were significantly related to [Formula: see text]. Among the models, the PBF modelEF6 showed the highest accuracy, which could explain 62.6% of the variance in the [Formula: see text] at with a standard error of estimate (SEE) of 4.39 mL kg-1 min-1 (%SEE = 11.25%, p < 0.001). These results indicated that the EF is a significant predictor of [Formula: see text], and compared to the other models, the PBF modelEF6 is the best model for estimating [Formula: see text].

Association of sitting time and cardiorespiratory fitness with cardiovascular disease risk and healthcare costs among office workers

Evidence of the impact of domain-specific sitting time (ST) and cardiorespiratory fitness (CRF) on cardiovascular disease (CVD) risk is currently limited. This study aimed to examine the associations between CRF and domain-specific STs in relation to CVD risk and annual healthcare costs among office workers. This cross-sectional study included 1,749 workers from an insurance company. The Worker's Living Activity-time Questionnaire was used to measure the domain-specific STs, including occupational ST and non-working day ST. Additionally, estimated maximal oxygen uptake as the CRF data was calculated using a validated equation: 59.96 - 0.23 × age + 7.39 × sex - 0.79 × body mass index + 0.33 × physical activity score. The company provided medical checkup results for CVD risk factors and healthcare costs. Multiple logistic regression analyses were used to calculate the odds ratios (ORs) for CVD risk. Significantly lower ORs for CVD risk were seen only with high CRF levels, and it was also associated with low annual healthcare costs. There were no associations between domain-specific STs and annual healthcare costs. Further explorations of domain-specific STs, physical activity, and health risks are warranted, and guidelines should focus on increasing CRF to prevent CVD risk among office workers.

Maximal oxygen uptake prediction from submaximal bicycle ergometry using a differential model

The maximal oxygen uptake (VO₂max) estimation has been a subject of research for many years. Cardiorespiratory measurements during incremental tests until exhaustion are considered the golden yard stick to assess VO₂max. However, precise VO₂max determination based on submaximal tests is attractive for athlete as well for clinical populations. Here, we propose and verify such a method based on experimental data. Using a recently developed model of heart rate (HR) and VO₂ kinetics in graded exercise tests, we applied a protocol, which is terminated at 80% of the estimated maximal HR during ergometer cycling. In our approach, initially, formula for maximal HR is selected by retrospective study of a reference population (17 males, 23.5 ± 2.0 years, BMI: 23.9 ± 3.2 kg/m²). Next, the subjects for experimental group were invited (nine subjects of both sexes: 25.1 ± 2.1 years, BMI 23.2 ± 2.2 kg/m²). After calculation of maximal HR using cardiorespiratory recordings from the submaximal test, VO₂max is predicted. Finally, we compared the prediction with the values from the maximal exercise test. The differences were quantified by relative errors, which vary from 1.2% up to 13.4%. Some future improvements for the procedure of VO₂max prediction are discussed. The experimental protocol may be useful for application in rehabilitation assessment and in certain training monitoring settings, since physical exertion is not a prerequisite and the approach provides an acceptable VO₂max estimation accuracy.

Estimation methods to detect changes in cardiorespiratory fitness due to exercise training and subsequent detraining

PURPOSE

To determine whether estimated maximal oxygen consumption ([Formula: see text]) can detect cardiorespiratory fitness (CRF) changes by behavioral modifications. This study compared changes in measured [Formula: see text]O_2max (m[Formula: see text]O_2max) through exercise intervention with e[Formula: see text]O_2max using a multiple regression model (MRM) and linear extrapolation method (LEM).

METHODS

A cross-sectional analysis involving 173 adults was conducted to establish an MRM by including age, sex, body mass index, questionnaire score, heart rate (HR) from step test, and m[Formula: see text]O_2max. Subsequently, 15 men participated in an intervention experiment comprising an 8-week, high-intensity interval training, followed by 8-week detraining, and completed anthropometric measurements, questionnaires, step tests, and m[Formula: see text]O_2max tests. m[Formula: see text]O_2max changes throughout the intervention were compared to e[Formula: see text]O_2max changes calculated using the MRM and LEM. The LEM used the HR during the step test with constant values (predetermined [Formula: see text]O₂), such as the Chester step test.

RESULTS

Inclusion of the step test HR in a questionnaire-based MRM improved the estimation power, although the MRM underestimated higher m[Formula: see text]O_2max values. In the intervention, m[Formula: see text]O_2max increased by 20.0 ± 14.1% (P < 0.01) and subsequently decreased by 9.5 ± 6.6% (P < 0.01) after exercise training and detraining, respectively. Significant method × time interactions were observed between m[Formula: see text]O_2max and e[Formula: see text]O_2max in the MRM but not in the LEM, i.e., an apparent systematic error (underestimation of high values) of the MRM was absent in the LEM, although the correlation between m[Formula: see text]O_2max and e[Formula: see text]O_2max using the LEM was moderate.

CONCLUSION

e[Formula: see text]O_2max, particularly using the MRM with HR as an explanatory factor, is not an appropriate method for detecting CRF changes along with behavioral modifications.

CLINICAL TRIAL REGISTRATION

Registered number, UMIN000041031; Registered date, 2020/07/08; URL, https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046855.

Heart Rate Variability Based Estimation of Maximal Oxygen Uptake in Athletes Using Supervised Regression Models

Wearable Heart Rate monitors are used in sports to provide physiological insights into athletes' well-being and performance. Their unobtrusive nature and ability to provide reliable heart rate measurements facilitate the estimation of cardiorespiratory fitness of athletes, as quantified by maximum consumption of oxygen uptake. Previous studies have employed data-driven models which use heart rate information to estimate the cardiorespiratory fitness of athletes. This signifies the physiological relevance of heart rate and heart rate variability for the estimation of maximal oxygen uptake. In this work, the heart rate variability features that were extracted from both exercise and recovery segments were fed to three different Machine Learning models to estimate maximal oxygen uptake of 856 athletes performing Graded Exercise Testing. A total of 101 features from exercise and 30 features from recovery segments were given as input to three feature selection methods to avoid overfitting of the models and to obtain relevant features. This resulted in the increase of model's accuracy by 5.7% for exercise and 4.3% for recovery. Further, post-modelling analysis was performed to remove the deviant points in two cases, initially in both training and testing and then only in training set, using k-Nearest Neighbour. In the former case, the removal of deviant points led to a reduction of 19.3% and 18.0% in overall estimation error for exercise and recovery, respectively. In the latter case, which mimicked the real-world scenario, the average R value of the models was observed to be 0.72 and 0.70 for exercise and recovery, respectively. From the above experimental approach, the utility of heart rate variability to estimate maximal oxygen uptake of large population of athletes was validated. Additionally, the proposed work contributes to the utility of cardiorespiratory fitness assessment of athletes through wearable heart rate monitors.

Improved VO2max Estimation by Combining a Multiple Regression Model and Linear Extrapolation Method

Maximal oxygen consumption (VO_2max) is an important health indicator that is often estimated using a multiple regression model (MRM) or linear extrapolation method (LEM) with the heart rate (HR) during a step test. Nonetheless, both methods have inherent problems. This study investigated a VO_2max estimation method that mitigates the weaknesses of these two methods. A total of 128 adults completed anthropometric measurements, a physical activity questionnaire, a step test with HR measurements, and a VO_2max treadmill test. The MRM included step-test HR, age, sex, body mass index, and questionnaire scores, whereas the LEM included step-test HR, predetermined constant VO₂ values, and age-predicted maximal HR. Systematic differences between estimated and measured VO_2max values were detected using Bland-Altman plots. The standard errors of the estimates of the MRM and LEM were 4.15 and 5.08 mL·kg^-1·min^-1, respectively. The range of 95% limits of agreement for the LEM was wider than that for the MRM. Fixed biases were not significant for both methods, and a significant proportional bias was observed only in the MRM. MRM bias was eliminated using the LEM application when the MRM-estimated VO_2max was ≥45 mL·kg^-1·min^-1. In conclusion, substantial proportional bias in the MRM may be mitigated using the LEM within a limited range.

Calibrating a Comprehensive Immune Age Metric to Analyze the Cross Sectional Age-Related Decline in Cardiorespiratory Fitness

Cardiorespiratory fitness (CRF) is essential for sustained work ability in good health, but declines with aging, as does the functionality of the immune system, the latter process commonly referred to as immunosenescence. This study aimed to compare the capacity of immunosenescence biomarkers with chronological age for predicting low CRF in a cross-sectional sample recruited from the regional working population. CRF was determined by submaximal bicycle ergometer testing in a cross-sectional sample of 597 volunteers aged 20-70 years from the 'Dortmund Vital Study' (DVS, ClinicalTrials.gov Identifier: NCT05155397). Low CRF was scored if the ergometer test was not completed due to medical reasons or if the power output projected to a heart rate of 130 bpm divided by body mass was below sex-specific reference values of 1.25 W/kg for females and 1.5 W/kg for males, respectively. In addition to established biomarkers of immunosenescence, we calibrated a comprehensive metric of immune age to our data and compared its predictive capacity for low CRF to chronological age, while adjusting our analysis for the influence of sex, obesity, and the level of regular physical activity, by applying univariate and multiple logistic regression. While obesity, low physical activity, chronological and immune age were all associated with increased probability for low CRF in univariate analyses, multiple logistic regression revealed that obesity and physical activity together with immune age, but not chronological age, were statistically significant predictors of low CRF outcome. Sex was non-significant due to the applied sex-specific reference values. These results demonstrate that biological age assessed by our immunological metric can outperform chronological age as a predictor for CRF and indicate a potential role for immunosenescence in explaining the inter-individual variability of the age-related decline in cardiorespiratory fitness.

An Arabic Sedentary Behaviors Questionnaire (ASBQ): Development, Content Validation, and Pre-Testing Findings

Background: Sedentary behaviors (SB) are very prevalent nowadays. Prolonged sitting associates with chronic disease risks and increased mortality even while controlling for physical activity. Objective measurement of SB is costly, requires technical expertise, and is challenging in terms of time and management. Currently, there is no validated self-reported instrument in the Arabic language that assesses SB among individuals and relates sedentary time to social, environmental, and health outcomes. The aim of this research was to develop a multi-item Arabic SB questionnaire (ASBQ). Methods: The ASBQ was developed through an extensive literature review and discussion by the research team (n = 5), then went through content validation (n = 10 experts) and pre-testing using cognitive interviewing procedures (n = 51 respondents, mean (SD) age was 38.3 (18.2) years, and with 49% females). Results: The ASBQ included 13 questions comprising a wide range of sedentary activities. The Arabic SB instrument showed excellent content validity for assessing sedentary time in adolescents and adults with a very high item-level and scale-level content validity index. A kappa statistic, a measure of interrater reliability, was 0.95. The pre-testing showed that the instrument was highly rated by a diverse sample of Saudi adolescents and adults. Conclusion: The ASBQ received excellent acceptance by a panel of experts with promising pre-test results. Further testing of psychometric properties, including test-retest reliability and criterion validity is required.

Population and Age-Based Cardiorespiratory Fitness Level Investigation and Automatic Prediction

Maximal oxygen consumption (VO₂max) reflects aerobic capacity and is crucial for assessing cardiorespiratory fitness and physical activity level. The purpose of this study was to classify and predict the population-based cardiorespiratory fitness based on anthropometric parameters, workload, and steady-state heart rate (HR) of the submaximal exercise test. Five hundred and seventeen participants were recruited into this study. This study initially classified aerobic capacity followed by VO₂max predicted using an ordinary least squares regression model with measured VO₂max from a submaximal cycle test as ground truth. Furthermore, we predicted VO₂max in the age ranges 21–40 and above 40. For the support vector classification model, the test accuracy was 75%. The ordinary least squares regression model showed the coefficient of determination (R²) between measured and predicted VO₂max was 0.83, mean absolute error (MAE) and root mean square error (RMSE) were 3.12 and 4.24 ml/kg/min, respectively. R² in the age 21–40 and above 40 groups were 0.85 and 0.75, respectively. In conclusion, this study provides a practical protocol for estimating cardiorespiratory fitness of an individual in large populations. An applicable submaximal test for population-based cohorts could evaluate physical activity levels and provide exercise recommendations.

The Determination of Step Frequency in 3-min Incremental Step-in-Place Tests for Predicting Maximal Oxygen Uptake from Heart Rate Response in Taiwanese Adults

The maximal oxygen uptake (VO_2max) prediction models established by step tests are often used for evaluating cardiorespiratory fitness (CRF). However, it is unclear which type of stepping frequency sequence is more suitable for the public to assess the CRF. Therefore, the main purpose of this study was to test the effectiveness of two 3-min incremental step-in-place (3MISP) tests (i.e., 3MISP_30s and 3MISP_60s) with the same total number of steps but different step-frequency sequences in predicting VO_2max. In this cross-sectional study, a total of 200 healthy adults in Taiwan completed 3MISP_30s and 3MISP_60s tests, as well as cardiopulmonary exercise testing. The 3MISP_30s and 3MISP_60s models were established through multiple stepwise regression analysis by gender, age, percent body fat, and 3MISP-heart rate. The statistical analysis included Pearson's correlations, the standard errors of estimate, the predicted residual error sum of squares, and the Bland-Altman plot to compare the measured VO_2max values and those estimated. The results of the study showed that the exercise intensity of the 3MISP_30s test was higher than that of the 3MISP_60s test (% heart rate reserve (HRR) during 3MISP_30s vs. %HRR during 3MISP_60s = 81.00% vs. 76.81%, p < 0.001). Both the 3MISP_30s model and the 3MISP_60s model explained 64.4% of VO_2max, and the standard errors of the estimates were 4.2043 and 4.2090 mL·kg^-1·min^-1, respectively. The cross-validation results also indicated that the measured VO_2max values and those predicted by the 3MISP_30s and 3MISP_60s models were highly correlated (3MISP_30s model: r = 0.804, 3MISP_60s model: r = 0.807, both p < 0.001). There was no significant difference between the measured VO_2max values and those predicted by the 3MISP_30s and 3MISP_60s models in the testing group (p > 0.05). The results of the study showed that when the 3MISP_60s test was used, the exercise intensity was significantly reduced, but the predictive effectiveness of VO_2max did not change. We concluded that the 3MISP_60s test was physiologically less stressful than the 3MISP_30s test, and it could be a better choice for CRF evaluation.

Contribution of Body Mass Index Stratification for the Prediction of Maximal Oxygen Uptake

The purpose of this study was to investigate whether modeling within separate body mass index (BMI) stratifications improves the accuracy of maximal oxygen uptake (VO_2max) prediction compared to a model developed regardless of adults' BMIs. A total of 250 Taiwanese adults (total group, TOG) aged 22-64 years participated in this study, and were stratified into a normal group (NOG: 135), an overweight group (OVG: 69), and an obesity group (OBG: 46), according to the BMI classification recommended by the Taiwan Ministry of Health and Welfare. VO_2max was directly measured on an electromagnetic bicycle ergometer. Using the participant's heart rate in the 3-min incremental step-in-place test and demographic parameters, VO_2max prediction models established for four groups were TOG model, NOG model, OVG model, and OBG model, respectively. Compared with the TOG model, the OVG and OBG models had higher coefficients of determination and lower standard error of estimates (SEEs), or %SEEs. The validities of the NOG (r = 0.780), OVG (r = 0.776), and OBG (r = 0.791) models for BMI subgroups increased by 1.79%, 4.64%, and 8.22% respectively, and the reliabilities (NOG model: ICC = 0.755; OVG model: ICC = 0.765; OBG model: ICC = 0.779) increased by 3.18%, 3.27%, and 9.63%, respectively. These results suggested using separate models established in BMI stratifications can effectively improve the prediction of VO_2max.

Psychometric Properties of the Turkish Adaptation of the Yale Physical Activity Survey

This study aimed to examine the convergent validity and test–retest reliability of the Turkish version of the Yale Physical Activity Survey (YPAS-TR). Eighty-one volunteer older adults were included in the study. Test–retest reliability was evaluated using the intraclass correlation coefficient. Correlation coefficients between YPAS-TR and Physical Activity Scale for the Elderly (PASE), Short Form-36, and Short Physical Performance Battery were examined for convergent validity. Acceptable intraclass correlation coefficient values were reached for YPAS-TR energy expenditure, total physical activity time and summary, vigorous, leisurely walking, moving, standing, and sitting indices (intraclass correlation coefficient = .96–.99). There was a moderate correlation between energy expenditure and total physical activity time with PASE (leisure time activities), PASE (household activities), and PASE (total) (r = .478, r = .468, r = .570, r = .406, r = .490, r = .550, respectively, p < .001). Also, a weak correlation was found between summary and leisurely walking index with PASE (household activities), standing index with PASE (leisure time activities), and PASE (total) (r = .285, p = .010; r = .257, p = .021; r = .238, p = .033; r = .283, p = .010; respectively). The results of the study suggest that the YPAS-TR is a valid and reliable measurement tool that can be used to assess the physical activity patterns of Turkish older adults.

Accuracy of Non-Exercise Estimated Cardiorespiratory Fitness in Japanese Adults

Cardiorespiratory fitness (CRF) is an independent predictor of morbidity and mortality. In Japan, annual physical exams are mandatory in workplace settings, and most healthcare settings have electronic medical records (EMRs). However, in both settings, CRF is not usually determined, thereby limiting the potential for epidemiological investigations using EMR data. PURPOSE: To estimate CRF (mL/kg/min) using variables commonly recorded in EMRs. METHODS: Participants were 5293 Japanese adults (11.7% women) who completed an annual physical exam at a large gas company in Tokyo, Japan, in 2004. The mean age was 48.3 ± 8.0 years. Estimated CRF (eCRF) was based on age, measured body mass index, resting heart rate, systolic and diastolic blood pressure, and smoking. Measured CRF was determined by a submaximal cycle ergometer graded exercise test. RESULTS: Regression models were used for males and females to calculate Pearson’s correlation and regression coefficients. Cross-classification of measured CRF and eCRF was conducted using the lowest quintile, quartile, and tertile as the unfit categories. R’s for eCRF were 0.61 (MD 4.41) for men and 0.64 (MD 4.22) for women. The overall accuracy level was reasonable and consistent across models, yet the unfit lower tertile model provided the best overall model when considering the positive predictive value and sensitivity. CONCLUSION: eCRF may provide a useful method for conducting investigations using data derived from EMRs or datasets devoid of CRF or physical activity measures.

Short-term effects of a social media-based intervention on the physical and mental health of remotely working young software professionals: A randomised controlled trial

The present study aimed to explore the short term effects of a social media-based intervention on the physical and mental health of the software professionals working remotely during the pandemic. Sixty software professionals with poor physical and mental health were randomised to Facebook-based intervention (FIIT) and a control (CONT) group for 2 months. Forty-six remote workers (26.25 ± 3.49 years) completed the study (FIIT = 22; CONT = 26). All the respondents had the median sitting time (7.07 ± 2.30 h/day) during office hours on workdays. We found a significant difference in the sitting time during office hours in workday within the subjects (F_1,46  = 4.66; p < .004; η_p ²  = .048) and between the subjects (F_1,46  = 3.81; p < .004; η_p ²  = .040). Post hoc analysis revealed participants in the FIIT group reduced their sitting time by 58 min during office hours during a typical workday compared with the control group. Nevertheless, we found a significant difference in the scores of stress, anxiety and depression within and between the groups. Short-term social media-based physical and mental health intervention may improve physical and mental health scores in the desk-based office workers working remotely.

Association between physical and mental health variables among software professionals working at home: a secondary analysis

TRIAL REGISTRATION

Clinical Trials Registry India identifier CTRI/2021/03/032146.

Development and Validation of 3 Min Incremental Step-In-Place Test for Predicting Maximal Oxygen Uptake in Home Settings: A Submaximal Exercise Study to Assess Cardiorespiratory Fitness

The purpose of this research was to develop the 3 min incremental step-in-place (3MISP) test for predicting maximal oxygen uptake (V.O_2max). A total of 205 adults (20–64 years) completed the 3MISP and V.O_2max tests. Using age, gender, body composition (BC) including percent body fat (PBF) or body mass index (BMI), and with or without heart rate (HR) at the beginning of exercise (HR0) or difference between HR at the third minute during the exercise and the first minute post exercise (ΔHR3 − HR4) in the 3MISP test, six V.O_2max prediction models were derived from multiple linear regression. Age (r = −0.239), gender (r = 0.430), BMI (r = −0.191), PBF (r = −0.706), HR0 (r = −0.516), and ΔHR3 − HR4 (r = 0.563) were significantly correlated to V.O_2max. Among the six V.O_2max prediction models, the PBF model^{∆HR3 − HR4} has the highest accuracy. The simplest models with age, gender, and PBF/BMI explained 54.5% of the V.O_2max in the PBF model^BC and 39.8% of that in the BMI model^BC. The addition of HR0 and ∆HR3 − HR4 increases the variance of V.O_2max explained by the PBF and BMI models^{∆HR3 − HR4} by 17.98% and 45.23%, respectively, while standard errors of estimate decrease by 10.73% and 15.61%. These data demonstrate that the models established using 3MISP-HR data can enhance the accuracy of V.O_2max prediction.

Empirical study of the 30-s chair-stand test as an indicator for musculoskeletal disorder risk of sedentary behaviour in Japanese office workers: a cross-sectional empirical study

Objectives

Sedentary behaviour among office workers and the risk of adverse health outcomes are public health problems. However, risk indicators for these outcomes require invasive biochemical examination. A proactive screening tool using a non-invasive, easy-to-use method is required to assess the risk focused on musculoskeletal health for primary prevention. However, middle-aged adults have insufficient awareness of musculoskeletal disorders. This study examined to determine whether the 30-s chair-stand test (CS-30) can be used as a proactive screening index for musculoskeletal disorder risk of sedentary behaviour in office workers.

Design

Cross-sectional study using self-administered questionnaires and physical measurements.

Setting

Four workplaces located in a metropolitan area of Japan.

Participants

431 Japanese office workers aged 20–64 years. 406 valid sets of results remained (valid response rate: 94.2%).

Primary and secondary outcome measures

Musculoskeletal function was measured using the CS-30, quadriceps muscle strength. Receiver operating characteristic curve analysis was used to determine the sensitivity, specificity and optimal cut-off value for the CS-30. The risk of future incidence of musculoskeletal disorders was calculated using current quadriceps muscle strength.

Results

In total participants, 47.0% were male and the mean sitting time in work duration was 455.6 min/day (SD=111.2 min). The mean lower limb quadriceps muscle strength was 444.8 N (SD=131.3 N). For the optimum cut-off value of 23 on the CS-30 for all participants, sensitivity was 0.809 and specificity was 0.231. For men, the optimum cut-off was 25, with a sensitivity of 0.855 and a specificity 0.172. For women, the optimum cut-off was 21, with a sensitivity of 0.854 and a specificity 0.275.

Conclusions

Sensitivity was high, but specificity was insufficient. The CS-30 may be a potential proactive screening index for musculoskeletal disorder risk of sedentary behaviour, in combination with other indicators.

Socioeconomic status relates to exercise habits and cardiorespiratory fitness among workers in the Tokyo area

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.