Factors Associated with Cardiorespiratory Fitness in a Swiss Working Population.

BACKGROUND: Good cardiorespiratory fitness (high VO2max) has beneficial effects on morbidity and mortality. Therefore, a tool to estimate VO2max in daily clinical practice is of great value for preventing chronic diseases in healthy adults. This study aimed at exploring the cardiometabolic profile in a representative Swiss working population. Based on these insights, a regression model was derived revealing factors associated with VO2max. METHODS: Cross-sectional data of 337 healthy and full-time employed adults recruited in the Basel region, Switzerland, were collected. Anthropometric measurements to compute body mass index (BMI) and waist circumference (WC) were performed. A 20-meter shuttle run test was conducted to determine individual VO2max. Heart rate (HR) was measured at rest, during maximal exertion, and two minutes after exercise. Systolic (SBP) and diastolic blood pressure (DBP) were assessed at rest and after exercise. A multiple linear regression model was built to identify a set of nonexercise predictor variables of VO2max. RESULTS: Complete data of 303 individuals (63% male) aged 18 to 61 years (mean 33 ± 12 years) were considered for analysis. The regression model (adjusted R2 = 0.647, SE = 5.3) identified sex (ß = -0.699, p < 0.001), WC (ß = -0.403, p < 0.001), difference of maximal to resting HR (ß = 0.234, p < 0.001), smoking (ß = -0.171, p < 0.001), and age (ß = -0.131, p < 0.01) as the most important factors associated with VO2max, while BMI, SBP, and DBP did not contribute to the regression model. CONCLUSIONS: This study introduced a simple model to evaluate VO2max based on nonexercise parameters as part of daily clinical routine without needing a time-consuming, cost-intense, and physically demanding direct assessment of VO2max. Knowledge about VO2max may help identifying individuals at increased cardiovascular risk and may provide the basis for health counselling and tailoring preventive measures.

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 (VO2max) with work related physical activity are sparse. Thus, it is not clear whether occupational physical activity (OPA) contributes to an increase of VO2max. This study examined the association of VO2max 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. VO2max 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 VO2max with leisure-time physical activity (LTPA) at vigorous intensity (ß = 0.212) and sufficient moderate-to-vigorous physical activity (ß = 0.100) on workdays. Female gender (ß = -0.622), age (ß = -0.264), BMI (ß = -0.220), the ratio of maximum to resting heart rate (ß = 0.192), occupational group (low vs. high OPA, ß = -0.141), and smoking (ß = -0.133) were also identified as independent predictors of VO2max. CONCLUSIONS: The present results suggest that VO2max 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 VO2max with regard to health benefits.

Physical Workload and Work Capacity across Occupational Groups.

This study aimed to determine physical performance criteria of different occupational groups by investigating physical activity and energy expenditure in healthy Swiss employees in real-life workplaces on workdays and non-working days in relation to their aerobic capacity (VO2max). In this cross-sectional study, 337 healthy and full-time employed adults were recruited. Participants were classified (nine categories) according to the International Standard Classification of Occupations 1988 and merged into three groups with low-, moderate- and high-intensity occupational activity. Daily steps, energy expenditure, metabolic equivalents and activity at different intensities were measured using the SenseWear Mini armband on seven consecutive days (23 hours/day). VO2max was determined by the 20-meter shuttle run test. Data of 303 subjects were considered for analysis (63% male, mean age: 33 yrs, SD 12), 101 from the low-, 102 from the moderate- and 100 from the high-intensity group. At work, the high-intensity group showed higher energy expenditure, metabolic equivalents, steps and activity at all intensities than the other groups (p<0.001). There were no significant differences in physical activity between the occupational groups on non-working days. VO2max did not differ across groups when stratified for gender. The upper workload limit was 21%, 29% and 44% of VO2max in the low-, moderate- and high-intensity group, respectively. Men had a lower limit than women due to their higher VO2max (26% vs. 37%), when all groups were combined. While this study did confirm that the average workload limit is one third of VO2max, it showed that the average is misrepresenting the actual physical work demands of specific occupational groups, and that it does not account for gender-related differences in relative workload. Therefore, clinical practice needs to consider these differences with regard to a safe return to work, particularly for the high-intensity group.