The aim of this cross-sectional observational study was to determine the prevalence and severity of dehydration in rural forestry workers in both winter (minimum and maximum daily temperatures 3–22 °C) and autumn (minimum and maximum daily temperatures 14–27 °C). . A small group of forestry workers may be susceptible to dilutional hyponatremia due to overhydration.
SUMMARY 142
THE PREVALENCE AND SEVERITY OF DEHYDRATION IN SOUTH AFRICAN FORESTRY WORKERS
The assistant research supervisor uses her hand to shade the Uricon prism from light while she records the urine's specific gravity. Percent overhydrated, percent hydrated, percent dehydrated and percent severely dehydrated before shift, before break and end of shift.
INTRODUCTION, THE PROBLEM AND ITS SETTING
- IMPORTANCE OF THE STUDY
- PURPOSE OF THE STUDY
- TYPE OF STUDY
- STUDY OBJECTIVES
- STUDY PARAMETERS
- STUDY LIMITATIONS
- STUDY ASSUMPTIONS
- DEFINITION OF TERMS
- ABBREVIATIONS
- SUMMARY
The aim of the study was to determine the prevalence and degree of dehydration of rural forestry workers who used car manual methods5. End of shift: was defined as the time the forestry workers completed their harvesting task for the day.
LITERATURE REVIEW
INTRODUCTION
THE FORESTRY INDUSTRY IN SOUTH AFRICA
This includes the very poor living in more rural areas, as most of the planting, harvesting and transport operations have been outsourced to independent companies (Edwards 2006). As harvesting is one of the most dangerous occupations in the world, contractors are expected to follow the safety regulations set out in the Occupational Safety and Health Act (Blombäck 2001, Director General 1995).
HEAT ILLNESS
The biggest risk for body temperature is physical activity in a hot environment - the risk of heat illness increases with the duration of the activity, with the increase in the ambient air temperature21. 23 These are not performed by all contractors - a half-hour break is scheduled once a day early to mid-morning.
THERMOREGULATION
Dehydration in turn increases the worker's susceptibility to heat illness (Casa et al 2005 Consensus Document). This in turn reduces peripheral blood flow to the skin, which reduces heat loss through sweat evaporation and conduction, causing an increase in core temperature (Coyle 2004, Ryan, Lambert, Shi, Chang, Summers & Gisolfi 1998) .
PREVALENCE OF DEHYDRATION IN FORESTRY WORKERS
26 The average % of body weight loss at the end of the shift is lower because these workers ate and drank during the shift, in contrast to workers in other studies. Parker et al (2002) attributed the similar prevalence of dehydration between seasons to the fact that woodcutters drank less in winter (1130 ml/shift) than in summer (1640 ml), considering dehydration to be a threat only in hot weather. .
CONSEQUENCES OF DEHYDRATION AND/OR HYPERTHERMIA
The combination of dehydration and hyperthermia approximately doubled the effect on stroke volume and heart rate, causing a significant decrease in cardiac output and blood pressure (Table 2). The level of dehydration reported by Scott et al (2004) in forestry workers in South Africa is reported to have resulted in a significant decrease in concentration, attention, alertness, visual motor tracking ability and an increase in cognitive processing time.
POTENTIAL CAUSES OF DEHYDRATION FOR SOUTH AFRICAN FORESTRY WORKERS
Even if sufficient fluid is transported to the site, it must be placed in locations accessible to the forestry workers during their shifts as they are spread across the site and harvest in different areas. The fluid should be placed close to the workers and not in a central location (Kamhoot 2005).
FLUID RECOMMENDATIONS
The net result was that the forestry workers felt unwell and experienced gastrointestinal complaints (Ashby & Parker 2003). However, since there is no SA study that examines the fluid needs of local forestry workers and since the US military has clearly shown that ingesting too much fluid can be life-threatening, a study that measures the fluid needs of forestry workers is critical to make it possible to develop safe recommendations.
FLUID COMPOSITION
Because forest workers would not be able to measure their weight loss each day, they should be encouraged to drink 2 to 4 cups of fluid after work (Wildman & Miller 2004, p. 248). Adding small amounts of sodium to a fluid is not the only factor to consider when deciding on fluid composition.
METHODS FOR THE MEASUREMENT OF DEHYDRATION
The use in this study appeared impractical as the forestry workers would have a high skin temperature if they were exercising in the sun. It is cost-effective, fast, simple, moderately accurate, portable (Armstrong 2005) and acceptable to the forestry workers as urine samples are required as part of their mandatory medical examinations.
CONCLUSION
The fragile relationship between the industry and the workforce, as well as workers' distrust of the industry's motives, militate against the use of more accurate hematological indices to identify dehydration. To protect both the health of the workforce and the continued health of the industry, a study such as this to determine the prevalence, severity and causes of dehydration among forestry workers in South Africa is urgently needed.
INTRODUCTION
RESEARCH DESIGN
As each contractor harvested a large area of the forest, study sites were again selected on the basis of convenience. Although the sample size should have been 100, some workers were upset to be left out of the study and were included to avoid unrest.
DATA COLLECTION INSTRUMENTS AND TECHNIQUES
Pre-break body weights were recorded just before the start of the break before the worker had eaten and after urination. Pre-shift and post-shift urine samples were collected for most study participants in both areas.
TRAINING OF RESEARCH TEAMS
After each technique was shown, the translators practiced with the help of the research dietitians. The principal research leader used the same manual three days before the start of the Nelspruit study to train the CHWs in the same techniques.
PILOT STUDY
Qualification was accepted by the principal research supervisor when the same levels of standardization as used previously were achieved. The Principal Research Supervisor checked that this was being done in accordance with the training instructions.
COLLECTION OF DATA
The workers then removed all their clothing and changed into research clothes in the tent (work station four) where they were then weighed. Before the workers were allowed to eat and/or drink, the principal research supervisor verified that all measurements were taken and correctly recorded in their data booklets.
DATA CAPTURING, EDITING AND CLEANING OF DATA : Data collected at the end of shift
87 were correctly recorded, the data collection booklets collected and each person thanked for participating in the study. The statistician checked the SPSS database and felt that no cleaning of the data was necessary.
REDUCTION OF BIAS
The validity of a test or instrument refers to its ability to measure the phenomenon it purports to measure” (Monsen 1992). To ensure that the data is valid, the scales were calibrated by a reputable company before the study.
DATA ANALYSIS
A loss of >2% has been referred to as "the critical water deficit for most people" and decreases both aerobic performance and mental and cognitive function, and increases perception of exertion and lowers heat. In Nelspruit, the contractor delivered cold liquid directly to workers in the forest at random times across the shift – workers "grabbed" the liquid and shared it among themselves, drinking directly from the containers.
COLLATION OF DATA
The study aimed to investigate the prevalence and degree of dehydration experienced by forestry workers harvesting trees during autumn and winter in SA. The workers signed the informed consent if they were willing to participate after the study was explained to them in their own language.
INTRODUCTION
RESEARCH SITE CHARACTERISTICS
65 Rough starters did a combination of stripping and stacking - stripping the bark was the same task as in Nelspruit, but stacking in Richmond involved arranging the logs in rows while the stackers in Nelspruit piled them into large piles. In Nelspruit most forestry workers (63%) were from Mpumalanga (local) or Limpopo Province (32%) with a few from Lesotho (1%) and the Western Cape (4%).
HYDRATION STATUS AS DETERMINED BY URINE SPECIFIC GRAVITY
At the start of the break, 48% in Nelspruit and 53% in Richmond were dehydrated (Table 21, Appendix N). Although not associated with job category in Nelspruit (p=0.641), assistant chainsaw operators in Richmond were significantly more dehydrated than the other groups (p≤0.001).
HYDRATION STATUS AS DETERMINED BY PERCENT LOSS OF BODY WEIGHT
As for USG, percentage change in body weight was calculated only for females in Nelspruit. 139 Since the percentage change in body weight was not adjusted for fluid and food consumed, the percentage of weight loss was probably underestimated and the percentage of body weight gain was overestimated.72.
SYMPTOMS OF DEHYDRATION END SHIFT
FLUID REQUIREMENTS
Dehydration gradually worsened throughout the day and by the end of the shift, more than 60% were dehydrated. By the end of the shift, at least 20% of workers at each study site were at least >2% dehydrated.
INTRODUCTION
THE PREVALENCE AND SEVERITY OF DEHYDRATION IN SOUTH AFRICAN FORESTRY WORKERS
145 levels in NZ forestry workers actually improved intermittently before regressing again at the end of the shift. These results were comparable to those of Parker et al (2001), who found that in weather conditions similar to Richmond, 63% of NZ forestry workers were dehydrated at the end of their shift.
THE PREVALENCE OF OVERHYDRATION
The high heart rates of the forestry workers in their study were attributed to poor nutrition rather than poor hydration. By the end of the shift, without correcting fluid or food intake, over 5% of the workers in Nelspruit had gained over 2% of their body weight.
TYPE OF FLUID CONSUMED
Fluid requirements could only be determined on a subset of the male workers in this study. These results were similar to those of the only other study examining the fluid requirements of forest workers (Paterson 1997).
SYMPTOMS OF DEHYDRATION
This enabled a more accurate determination of the state of hydration and the comparison of this study's results with those of all the other forestry studies as well as those in sports medicine. All the other studies weighed the forestry workers fully clothed before and after which would have led to an underestimation of the degree of dehydration.
LIMITATIONS OF THE STUDY
The study was conducted in collaboration with contractors who had a reputation for being fair and reputable. The forest industry felt that those contractors who did not meet the minimum wage and safety requirements would either not agree to the study or interfere with the conduct of the study by being totally uncooperative.
IMPLICATIONS FOR FURTHER RESEARCH
It was felt that this investigation would be difficult enough to carry out without further opposition. The conclusions of this study were therefore based on the best possible scenarios in SA.
SUMMARY
Most of the workers drank mainly water, which was the only liquid supplied by the contractors. Although both amahewu and a cold drink were adequate choices to meet the increased CHO requirements of prolonged physical activity, neither was supplied in sufficient quantities by the workers.
INTRODUCTION
CONCLUSIONS
Dehydration in soldiers during walking/running exercise in the heat and the effects of fluid intake during and after exercise. This is because of the performance-based or "task system" that women work for.
Preshift
Data Collection Form
Urine Sample
Body
Weight (kg)
Height (m)
Total fluid weighed in morning before starting the shift
Questionnaire
Zulu 1 Sotho 2 Xhosa 3 Other 4
