Physiological and labour-productive effects of fluid consumption during forestry work

The physiological and labour productive effects of two fluid consumption levels were studied on forest workers to compare the effects of a mildly dehydrated physical condition with a fully hydrated condition. Four forest workers each produced manually 2.4 m3 of pulpwood/day on 8 consecutive working days in climatic conditions varying between 8 and 28 C WBGT. They consumed water (0.17 l or 0.6 l) at half hourly intervals with one fluid level assigned to each day. The forest work required a significantly lower percentage of the heart rate reserve at the high fluid consumption level compared with the low level (36.5% versus 39.9%, p = 0.0024). The time taken to perform the work was significantly lower with the consumption of 0.6 l each half hour compared to the consumption of 0.17 l (209.0 versus 234.1 min, p = 0.0003). Moreover, it was found that the fluid consumption level of the previous day had a significant influence on the time taken