Physical work load affects the maximum oxygen uptake

The Relation between Domain-Specific Physical Behaviour and Cardiorespiratory Fitness: A Cross-Sectional Compositional Data Analysis on the Physical Activity Health Paradox Using Accelerometer-Assessed Data

In contrast to leisure time physical activity (LTPA), occupational physical activity (OPA) does not have similar beneficial health effects. These differential health effects might be explained by dissimilar effects of LTPA and OPA on cardiorespiratory fitness (CRF). This study investigated cross-sectional associations between different physical behaviours during both work and leisure time and CRF by using a Compositional Data Analysis approach. Physical behaviours were assessed by two accelerometers among 309 workers with various manual jobs. During work time, more sedentary behaviour (SB) was associated with higher CRF when compared relatively to time spent on other work behaviours, while more SB during leisure time was associated with lower CRF when compared to other leisure time behaviours. Reallocating more time to moderate-to-vigorous physical activity (MVPA) from the other behaviours within leisure time was positively associated with CRF, which was not the case for MVPA during work. The results of our study are in line with the physical activity health paradox and we call for further study on the interaction between LTPA and OPA by implementing device-worn measures in a longitudinal design. Our results highlight the need for recommendations to take into account the different effects of OPA and LTPA on CRF.

Association of Occupational and Leisure-Time Physical Activity with Aerobic Capacity in a Working Population

Introduction

Objective data on the association of maximal aerobic capacity (VO_2max) with work related physical activity are sparse. Thus, it is not clear whether occupational physical activity (OPA) contributes to an increase of VO_2max. This study examined the association of VO_2max with work and non-work related physical activity in a Swiss working population.

Methods

In this cross-sectional study, a total of 337 healthy and full-time employed adults were recruited. Demographic data, height, weight and BMI were recorded in all subjects. Participants were classified into nine occupational categories (ISCO-88) and merged into three groups with low, moderate, and high OPA. Physical activity was objectively measured by the SenseWear Mini Armband on seven consecutive days (23 hours per day). Participants were regarded as sufficiently active when accumulating ≥30 min of moderate-to-vigorous physical activity per day. VO_2max was evaluated using the multistage 20-meter shuttle run test.

Results

Data of 303 participants were considered for analysis (63% male, age 33 yrs, SD 12). Multiple linear regression analysis (adjusted R² = 0.69) revealed significant positive associations of VO_2max with leisure-time physical activity (LTPA) at vigorous intensity (β = 0.212) and sufficient moderate-to-vigorous physical activity (β = 0.100) on workdays. Female gender (β = -0.622), age (β = -0.264), BMI (β = -0.220), the ratio of maximum to resting heart rate (β = 0.192), occupational group (low vs. high OPA, β = -0.141), and smoking (β = -0.133) were also identified as independent predictors of VO_2max.

Conclusions

The present results suggest that VO_2max is positively associated with LTPA, but not with OPA on workdays. This finding emphasizes the need for employees to engage in sufficient high-intensity physical activity in recreation for maintaining or improving VO_2max with regard to health benefits.

Validity of Cooper's 12-minute run test for estimation of maximum oxygen uptake in male university students

The present study was conducted to validate the applicability of Cooper's 12-minute run test (CRT) for predicting VO₂max in male university students of Kolkata, India, to bypass the exhaustive and complicated protocol of direct estimation of VO₂max. Eighty-eight sedentary male university students recruited by simple random sampling from the University of Calcutta, Kolkata, were randomly assigned to the study group (N = 58) and the confirmatory group (N = 30). VO₂max of each participant was determined by the direct procedure and the indirect CRT method. The mean value of predicted VO₂max (PVO₂max) (42.8±4.0 ml · kg⁻¹ · min⁻¹ with a range of 33.7–50.9) showed a significant difference with VO₂max (39.8±4.0 ml · kg⁻¹ · min⁻¹ with a range of 33.5–47.7) in the study group. Limits of agreement between PVO₂max and VO₂max were large enough (0.10 to 5.94 ml · kg⁻¹ · min⁻¹) with poor confidence intervals indicating inapplicability of the current protocol of CRT in the studied population. The prediction norm [Y = 21.01X – 11.04 (SEE = 0.193 ml · kg⁻¹ · min⁻¹)] was computed from the significant correlation (r = 0.93, P < 0.001) between distance covered in CRT and VO₂max. Application of this norm in the confirmatory group revealed an insignificant difference between PVO₂max and VO₂max. The modified equation is recommended for application of CRT as a valid method to evaluate the cardiorespiratory fitness in terms of VO₂max in sedentary male Indian youth.

Estimation of maximal oxygen uptake without exercise testing in Korean healthy adult workers

Maximal oxygen uptake is generally accepted as the most valid and reliable index of cardiorespiratory fitness and functional aerobic capacity. The exercise test for measuring maximal oxygen uptake is unsuitable for screening tests in public heath examinations, because of the potential risks of exercise exertion and time demands. We designed this study to determine whether work-related physical activity is a potential predictor of maximal oxygen uptake, and to develop a maximal oxygen uptake equation using a non-exercise regression model for the cardiorespiratory fitness test in Korean adult workers. Study subjects were adult workers of small-sized companies in Korea. Subjects with history of disease such as hypertension, diabetes, asthma and angina were excluded. In total, 217 adult subjects (113 men of 21-55 years old and 104 women of 20-64 years old) were included. Self-report questionnaire survey was conducted on study subjects, and maximal oxygen uptake of each subject was measured with the exercise test. The statistical analysis was carried out to develop an equation for estimating maximal oxygen uptake. The predictors for estimating maximal oxygen uptake included age, gender, body mass index, smoking, leisure-time physical activity and the factors representing work-related physical activity. The work-related physical activity was identified to be a predictor of maximal oxygen uptake. Moreover, the equation showed high validity according to the statistical analysis. The equation for estimating maximal oxygen uptake developed in the present study could be used as a screening test for assessing cardiorespiratory fitness in Korean adult workers.

Work form affects maximum oxygen uptake for one year in workers

Our previous study suggested that the work form is related to the maximum oxygen uptake (VO(2)max). Therefore, we test the hypothesis by a longitudinal study that, besides these lifestyle-related factors, the work form increases VO(2)max among workers. Seven hundred and ninety nine males aged 37.1 ± 10.6 and 395 females aged 37.7 ± 10.5 (range: 20 to 59 yr old), who participated in The Total Health Promotion Plan (THP) at their respective workplaces twice in one year from 1997 to 1998, were selected. Data on VO(2)max were analyzed for age, systolic blood pressure (SBP), body mass index (BMI), work form (sedentary, standing, and ambulatory), exercise, and smoking. Age and the baseline variables for BMI and for VO(2)max showed significant negative relationships with a change in VO(2)max in males and females. Further, a change in the BMI showed a significant negative relationship with a change of VO(2)max in males. However, exercise habit and an ambulatory work form showed significant positive relationships with a change of VO(2)max in males. It was suggested that after adjusting for other factors in males, an ambulatory work form may be associated with an increase in VO(2)max in one year.

Distribution and determinants of maximal physical work capacity of Korean male metal workers

The distribution of maximal physical work capacity (MPWC) can be used to establish an upper limit for energy expenditure during work (EEwork). If physically demanding work has wearing effects, there will be a negative relationship between MPWC and workload. This study was conducted to investigate the distribution of MPWC among Korean metal workers and to examine the relationship between workload and MPWC. MPWC was estimated with a bicycle ergometer using a submaximal test. Energy expenditure was estimated by measuring heart rates during work. The study subjects were 507 male employees from several metal industries in Korea. They had a lower absolute VO2max than the Caucasian populations described in previous studies. The older workers had a lower physical capacity and a greater overload at work. A negative relationship was found between MPWC and workload across all age groups. Upper limits for EEwork for all age groups and for older age groups are recommended based on the 5th percentile value of MPWC.