The Analysis And Prediction Model For Recovery Time After Exhaustion In High-intensity Work

While technological advances and automation have reduced the need for labor in favor of machines, many strenuous activities such as load carrying and manual lifting are routinely performed by people. Some of this work is defined as high-intensity work, which can be specified as any physical activity that mobilizes the contraction of large muscle groups and requires oxygen uptake(VO2) of at least 50% of the maximum oxygen uptake(VO2max). In reality, a large number of occupations such as firefighting, rescuing, tracking, disaster salvaging, and competitive sports can be classified as high-intensity work. Workers engaging in high-intensity work usually work in a harsh environment. High-intensity work is associated with higher perceived fatigue, which only prevents workers from accurately completing their work, but also results in declining cognitive performance, even facing with potential dangers. Ergonomics should be incorporated into work-rest schedule planning to improve efficiency and safety.In this article, 47 participants perform the reaction task aimed at measuring cognitive performance at four time points, including before high-intensity work, after high-intensity work, after Ts, and after complete recovery time. Later,some date were used to establish Ts and CRT prediction model. For the participants, six of them were chosen randomly as the cross-validation group. The remaining formed the estimation group. The estimation data were used to derive the Ts and CRT estimate, while the cross-validation data were used for validation. Before participating in the laboratory test, each participant provided demographic information and filled out the perceived functional ability(PFA) and physical activity rating(PA-R) questionnaires. During the test, all participates were required to perform one cycling test(at 70% maximum working capacity). Participants continued cycling until exhaustion and then sat and recovered until they no longer felt tired or their heart rates(HR) returned to baseline values. The times were recored as Ts and CRT. With the help of SPSS, we found that with sex, RBMI, HR, PFA score, and PA-R score data, Ts can be easily estimated. We also found that CRT was significantly correlated with relative body mass index, the PFA score, PA-R score, and maximum heart rate(HRmax). Accordingly, a prediction model for CRT was proposed. Furthermore, by replacing HRmax with age-predicted maximal HR, we obtained a more convenient prediction model that was independent of any physiological indexes that can only be obtained by subject testing.In conclusion, cognitive performance declined after high-intensity work and reached an even higher level than that before high-intensity work after Ts. The duration from subjective recovery to heart rate recovery to baseline status allows for performing mental activities. With Ts and CRT estimation, physical and mental work shift schedules that improve work efficiency and safety could be designed.