Workers should be personally monitored, such as checking
the heart rate, or body water loss
9)
. Although standard is
difficult to be set, the worker should be take a break, if the
heart rate exceeds the standard. As shown in Fig. 4, the
heart rate decreased quickly after the subject began to take
a rest. Body water loss can be measured by weighing the
worker on a scale at the beginning and end of each work
day. Occupational Safety & Health Administration of U.S.
Department of Labor recommends to shorten the next work
cycle by one third if the heart rate exceeds 110 beats per
minute, and to increase fluid intake if a weight loss exceeding
1.5% of total body weight is observed in a work day
9)