Japan faces a serious national issue of declining worker numbers due to low birth-rate and longevity. There is an increased need to maintain workers’ health and extend the working years prior to workforce retirement. Hence, research in workers’ physical fitness will play a significant role in occupational health issues. Cardiorespiratory fitness (CRF) assessed by maximal oxygen consumption (VO2max) plays an important role in workers’ health. However, measuring VO2max can be burdensome for subjects and requires skilled examiners. This is a practical disadvantage for including VO2max in workplace health check-ups. In this study, we developed a new CRF measurement procedure in lieu of measuring VO2max.Methods
Our study participants included 101 Japanese workers (55 men and 46 women, aged 30 to 59 years). We measured subjects’ VO2max by the Bruce protocol using treadmill exercise and an indirect calorimeter. Subjects also completed two newly devised assessments: (1) a step-test consisting of a 3 min stepping exercise followed by a 2 min rest and (2) a questionnaire measuring workers’ physical activity level during working time and during non-working time on workdays and non-workdays. We conducted multiple regression analyses with VO2max as a dependent variable and parameters obtained from the procedure as independent variables.Results
We chose the combined heart rates during the step-test’s exercise and recovery periods and the questionnaire’s total score as significant (p<0.05) independent variables. In a multiple regression model, age (years), sex (1, 0), heart rates during the step-test (beats) and total score on the questionnaire (points) accounted for 58.6% of the VO2max variance.Conclusion
The procedure we developed can be performed without a heavy exercise burden on the subject or special skills of the examiner. This study suggests that the procedure can potentially be used to assess CRF in the worker’s health check-ups where VO2max measurements are not available.