Discussion
The sample group was composed of 49 rubber tappers,
most of whom, (81.6%), were female, and only 18.4%
were male. They were 50.2 yr old on average, of which
47.0% were more than 50 yr of age and categorized as
aging people. Their average length of work experience
was 28.1 yr, making them highly experienced tappers.
Daily working hours of the subjects were at 6.7 h on
average; meanwhile, average working days a week were
at 5.3 d. Both were considered normal for people at productive
age. Nevertheless, the tappers need to work during
the night approximately from 01:00–10:00 h when the
rubber trees are still in the dark and produce more latex.