Determining the maximum acceptable work duration for high-intensity work

Abstract

The aim of this study was to determine the maximum acceptable work duration (MAWD) for high-intensity work. Thirty young individuals participated in this study. Their maximum oxygen uptake (VO2max) and maximum work rate (MWR) were assessed first. Each subject then performed two cycling tests (60% and 70% MWR) on two separate days. Oxygen uptake and heart rate data were collected throughout the test. The results indicate that the MAWD in the 60% MWR test (18.8 min) was about threefold greater than the MAWD in the 70% MWR test (6.5 min). The MAWD was inversely correlated with the relative workload indices: relative oxygen uptake (RVO2; r = -0.82, P < 0.001) and relative heart rate (RHR; r = -0.79, P < 0.001). The RVO2 was defined as the elevation in oxygen uptake from the resting level as a percentage of the difference between maximum and resting oxygen uptake. The RHR was defined as the elevation in heart rate from the resting level as a percentage of the difference between maximum and restingheart rate. Furthermore, more than 80% of the variations were explained by the exponential decrease regression model for predicting MAWD using the above two variables. The findings of this study can provide useful information for the design of high-intensity jobs.

Occupational physical activity, energy expenditure and 11-year progression of carotid atherosclerosis

“…VO 2 max has been found to differ markedly by gender, age, health status, and other factors (63). Relative measures correlate better with fatigue, heart rate elevations, and related health consequences of aerobic strain at work than absolute measures as shown by others (99), and, for the first time, for atherosclerosis in this study.…”

Occupational physical activity and 20-year incidence of acute myocardial infarction: results from the Kuopio Ischemic Heart Disease Risk Factor Study

“…Relative measures correlate better than absolute measures with actual cardiovascular workload, fatigue, heart rate elevations, and related health consequences of aerobic strain at work as shown by others (78) and for the first time for progression of atherosclerosis (26) and incidence of myocardial infarction (this paper) in this study population.…”

Load carriage, human performance, and employment standards

“…Compared with the observations of Wu and Wang (2001), bipedal load carriage resulted in halving the acceptable work times at intensities above 60% maximal oxygen consumption (Peoples et al 2016). That outcome highlights the specific nature of different work and ambulatory tasks, both of which must be replicated within screening tests.…”

“…2), then one would predict that the maximal acceptable duration for continuous work (Saha et al 1979;Wu and Wang 2001) would decline as mass was added, or as workers were asked to work harder whilst carrying constant loads. However, previous estimations of maximal acceptable work durations were either theoretically derived (Bink 1962) or estimated from unloaded exercise, with sedentary subjects performing an exercise mode that was unrelated to most occupations (cycling: Wang 2001, 2002).…”