Objectives Long-term heavy work impairs employees, and they may retire prematurely by law. We investigated the value of energy expenditure (EE) during work shifts as a means to define heavy workload. Methods The study comprised 79 male [mean age 32.2 (standard deviation [SD] 7.5) years] and 33 female [33.5 (SD 11.2) years] employees in different occupations classified as "heavy work" (EE of 1400 and 2000 kcal for women and men, respectively). Cycle ergometry determined exercise performance. Gas exchange measures were performed during selected phases of work, and heart rate (HR) recordings were obtained for a complete work shift. EE was calculated from gas exchange measures. Results Male and female subjects differed significantly for maximal power output (Pmax) [men=206.3 (SD 47.3) watts; women=149.6 (SD 36.1) watts] and maximal oxygen consumption (VO2max) [men=2.965 (SD 0.63) l/min; women= 1.958 (SD 0.50) l/min] in the cycle ergometer test. Shift HR (HRSh) was found between 102 (SD 14) b/min [57.6 (SD 8.5) percentage of maximal HR (% HRmax)] and 99 (SD 10) b/min [55.5 (SD 5.9) % HRmax] dependent on tasks and groups. Working EE was found between 1864 (SD 732) kcal and 1249 (SD 609) kcal for men and women, respectively, but approximately 60% of subjects were well below the legal limits. Conclusions The legal definition of heavy workload by mean working EE per 8-hour work shift applies to all investigated occupations; however, a substantial proportion of workers may not fulfill the criterion if applied individually. Alternative definitions of heavy workload in terms of absolute oxygen consumption or EE relative to cardiorespiratory fitness lead to similar classification results of the investigated occupations.
Wultsch, G., Rinnerhofer, S., Tschakert Dr., G., & Hofmann, P. (2012). Governmental regulations for early retirement by means of energy expenditure cut offs. Scandinavian Journal of Work, Environment and Health, 38(4), 370–379. https://doi.org/10.5271/sjweh.3195