Physiological workload evaluation by means of heart rate monitoring during motor-manual clearcutting operations

ABSTRACT Forest workers encounter many health-related problems due to their harsh working conditions. This study focused on the evaluation of the physical workload of tree fellers during clearcut operations in a pine plantation forest in northern Iran by means of heart rate measurements. Anthropometric and personal data of the subjects such as age, body mass index (BMI), work experience, and health problems were also collected. The subjects were also asked to assess their perceived level of fatigue by means of the Swedish Occupational Fatigue Inventory. Activity sampling was used to record the physical workload of 13 subjects during a working day of 8 h for each one of them by means of a Polar Electro H10 heart rate sensor. The collected data were used for the calculation of heart rate indices that determine the strain of the subjects. The results showed that the mean level of physical workload was 43.54% of the relative heart rate (HRR) which corresponds to heavy work. The workers assigned most of the effective work time to tree processing (39.78%), back cut (18.6%), and undercut (12.07%). The highest mean heart rates (HRwork) were measured during the work elements of tree processing (117.7 bpm), back cut (115.6 bpm), and undercut (114.8 bpm). The study results also showed that the number of harvested trees and the average tree diameter at breast height exerted a significant impact on HRR and the BMI class on HRwork. Furthermore, age class was negatively correlated to net productivity.