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World&Nutrition&Journal&|eISSN&2580-7013& &
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Corresponding author:
Ermita I. Ibrahim Ilyas
Department of Medical Physiology Medical Faculty
of Medicine, Universitas Indonesia
Email address : ermitailyas@gmail.com
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Journal&Website:&
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Effects&of&Electrolyte&Beverage&on&Preventing&Dehydration&Among&
Workers&in&Different&Enviromental&Temperature&
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1. Department of Medical Physiology, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia##
2. Department of Nutrition Medical Faculty Universitas Indonesia – Cipto Mangunkusumo General
Hospital
3. Medical Research Unit, Medical Faculty, Universitas Indonesia
Abstract((
Introduction:& .E570( EF2( 717850/1G57( ?E1EF87( 9M( 9>D/05EF5( 5/( >E9F5E9F( 8/TF959:7( EF2( D<GM98E1(
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Methods:& V<9M( 0EF2/>9W72( 2/4?17R?19F272( D1E87?/( 8/F50/1172(509E1( M542G( OEM( D70U/0>72(9F( 5O/(
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57>D70E5407C(9373(</5(EF2(8/F:7F97F51G(8//1(7F:90/F>7F53(V<7( M4?X785M( O707( 0EF2/>1G( E11/8E572(
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U0/>(?1//2(EF2(409F7(ME>D17M(E5(?7U/07(EF2(EU570(5<7(9F570:7F59/F3(
Results:&&5( ?EM719F7C(M4?X785M(/U(5<7(</5( 7F:90/F>7F5(O/0HD1E87(<E2( <9T<70(2E91G(O/0H9FT(</40MC(
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/U( 8/F:7F97F51G(8//1( 7F:90/F>7F5( [D]A3AJ\3( &U570( 5<7( 9F570:7F59/FC( U/0( 5<7( M4?X785M( 9F( </5(
7F:90/F>7F5( E1/F7C( 5<707( O707( M9TF9U98EF51G( 1/O70( :E147( /U( ?1//2( :9M8/M95GC( <7>/T1/?9FC( EF2(
<7>E5/8095C( ?45( M9TF9U98EF51G( <9T<70( :E147( U/0( ?1//2( M/294>C( ^N$( [409F7( MD789U98( T0E:95G\C( DQC(
409FE0G( M/294>C( 409FE0G( D/5EMM94>( EF2( 409FE0G( 8<1/0927( [D]A3AJ\C( E>/FT( M4?X785M( O</( <E2(5<7(
717850/1G57(209FH(8/>DE072(5/(5<7(D1E9F(OE5703((
Conclusion:(V<9M(M542G(8/FU90>72(5<E5(8/FM4>D59/F(/U(717850/1G57(?7:70ET7(2409FT(O/0H9FT(9F(</5(
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Keywords#<G20E59/FC(717850/1G57(?7:70ET7C(</5(7F:90/F>7F5C(O/0H70M(
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Introduction
Dehydration is a condition of body water deficit. In
general, according to the research by The
Indonesian Regional Hydration Study (THIRST)
held on 2009, 46.1% of population in Indonesia had
mild dehydration.1 In a physical work setting,
dehydration may result from the excessive sweat
output compared to the water intake. Hydration in
the work place became a special issue in which it
can affect productivity, safety, and cost.
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Physical work increases heat production in
the body which needs to be dissipated out from the
body to achieve body heat balance.2 In a warm
environment, excess of metabolic heat is dissipated
to the environment by combination of conduction,
convection, radiation, and evaporation of the sweat.
When the environmental temperature approaches
and exceeds the skin temperature, dry heat loss (by
conduction, convection, and radiation) diminishes
and is replaced by the ‘heat gain’. In that condition,
the only available heat loss mechanism is by sweat
evaporation, and the sweat rate increases.3 Severity
of sweat losses during work in a hot environment is
dependent primarily on work intensity and
duration. Sweating draws water from vascular,
interstitial, and extra-cellular fluid compartments
resulting in the secretion of hypotonic sweat.
Metabolic heat production is balanced by both dry
and evaporative (sweating) heat loss, but very high
metabolic rates coupled with warm weather
demands a larger thermal requirement for
evaporative cooling, leading to greater sweat losses
and subsequently larger water requirement.
It is widely known that water and
electrolyte balance is very important to be
continuously maintained to sustain cognitive and
physical performance. Body water deficit results
from hot weather and/or low water consumption,
even as much as two percent of body weight, may
impair physical and/or work performance. Any
water deficit will affect performance in athlete or
worker and lead to altered physical function and
health. Therefore, an adequate level of hydration is
essential. The possibility of water and electrolyte
losses through sweating should be put into
consideration for people working in hot
environments. Electrolyte beverage usually
contains water, electrolytes such as sodium,
potassium, calcium, and carbohydrate as well. The
addition of electrolytes to ingested water will keep
the plasma electrolyte concentration and osmolality
stable thus the water diuresis can be avoided.
Electrolyte beverage has been reported to be more
effective in retaining water in the body and
preventing hemoconcentration than plain water.
Ingestion of plain water will cause voluntary
dehydration due to decrease of the osmolality that
lead to stimulate the water diuresis. Chang et al.4
in 2010, reported that the recovery from high blood
viscosity induced by dehydration was faster with
electrolyte beverage consumption than with plain
water or tea. A strong correlation between
hematocrit and blood viscosity suggests that fluid
retained in the body reduced the hemoconcentration
and blood viscosity.4 In our preliminary study
showed that workers in two factories, with different
environment which are hot and conveniently cool
environment were prone to dehydration. We found
that hemoglobin concentration, hematocrit, blood
viscosity and blood sodium concentration of
workers in hot environment were significantly
higher than workers in conveniently cool
environment.5
This present study was performed to
evaluate the effect of electrolyte beverage in
preventing dehydration from workers, especially
noted from clinical symptoms and laboratory
measurements (hemoglobin, hematocrit, blood
viscosity, blood and urine minerals, urine specific
gravity and pH) and to compare the effects of
electrolyte beverage and plain water in preventing
dehydration in workers in real work setting. It is
very important to prevent worker from dehydration
and to protect or reduce the risk of having
cardiovascular problem which can be caused by
hemoconcentration and high blood viscosity. This
study hopefully could give information needed in
the occupational field settings with workers who
work in a hot and conveniently cool environment,
who are considered to be at risk of dehydration that
might lower their productivity. Therefore, the
management departments may obtain some insights
from this research to overcome this problem.
Methods:
Study Design
The study was a crossover, randomized, double-
blinded placebo controlled trial involving
apparently healthy male subjects workers age 25–
45 years old, working minimally for 8 hours per-
day in two selected manufactures in Cibitung,
West-Java. They did not have renal disease and
diabetes mellitus, and willing to participate in the
study by signing the informed consent.
We could not find any references on the
difference effect of electrolyte drink versus the
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drinking water on hydration status and electrolytes
concentration. Therefore this study was conducted
as a preliminary study to have 40 subjects for each
environment condition or minimal 80 subjects for
the total sample.
After signing the informed consent, the
selected subjects were classified according to their
environmental temperature, i.e. the hot and
conveniently cool environments, which were
determined by room temperature measurement
(36–38°C versus 20–22 °C, respectively). Subjects
working in hot environment were those working
close to the heat. Subjects working in conveniently
cool environment were those doing the
administration task in the office facilitated with air
conditioner. The subjects of each environment
temperature were randomly allocated into two
different interventions by using crossover
approach, in which each subject acted as his own
control (Figure 1). Then, each subject will get both
interventions for two days period. Subjects were
advised to consume 300 mL of the provided fluid
every 30 minutes for those working in hot
environment and every hour for those working in
the conveniently cool environment. Each subject
had two days of non-electrolyte beverage (plain
water) and, after the crossover, had two days of
electrolyte beverage as well. These drinks were
provided during 8-hours working period in 4 days
of intervention (the subjects can have ad libitum
drink), served personally in similar shape and color
glasses. The total fluid intake was recorded through
measuring the left over drink. During the
intervention, lunch and break time snacks were
provided with calorie contributing to 30-40% of the
total calorie.
Study overview
This study was done at two automobile spare-parts
factories in Cibitung West Java in January to
February 2012. Before starting the recruitment and
including the subjects into the study, informed
consent was asked and recorded. This study
received ethical approval from the Ethics
Committee of the Faculty of Medicine Universitas
Indonesia (No. 30/PT02/FK/ETIK/2012, January
18, 2012). All subjects signed the informed consent
form to show their willingness to participate in the
study.
Data Collection
Subjects were interviewed regarding their socio-
demographic characteristic, employment duration
and medical history. Interview was needed to
clarify the food record as well. Food record method
was used to assess energy intake and was done in 4
consecutive days during the intervention period.
Anthropometric measurements were done before
the intervention, which included body weight and
height to calculate the body mass index. Vital sign
measurements including blood pressure and heart
rates were collected through physical examination.
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Blood and urine samples were collected before
intervention to obtain baseline data on hemoglobin,
hematocrit, blood viscosity, blood glucose, renal
function (estimated creatinine-clearance test),
blood and urine electrolytes (sodium, potassium
and chloride), urine color, pH, and urine specific
gravity (USG) by using standardized procedures.
The data was collected again after two days after
the working time during the four days study period
to obtain data on the effect of each of the
intervention.
Statistical Analyses
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Data was recorded using a special form and was
edited, coded, and administered into the working
sheet by using statistical program for social
sciences (SPSS) software version 20. All data was
presented accordingly based on its normality
distribution, and analyzed by using unpaired-T test
or Mann-Whitney test, paired-T test or Wilcoxon
test, and Chi-square or McNemar test.
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Results
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The recruitment of the subjects started from 6th
January 2012 and ended on 3rd February 2012.
Figure 2A and Figure 2B show the flow of the
intervention and data collection scheme, and we
analyzed 39 subjects receiving both interventions in
each workplace conditions, i.e. hot and
conveniently cool environment.
Before the intervention, this study found
that there were significant differences in several
hydration and electrolytes biomarkers, in which
hemoglobin, hematocrit, blood viscosity and blood
sodium were higher among those working in hot
environment compared to those working in the
conveniently cool environment workplace
(P<0.05), as shown in Table 1. The general
conditions of the subjects in both temperature
workplaces were not affected by the interventions,
as presented in Table 2.
In the blood measurement, there were
significant lower values of blood viscosity,
hemoglobin, hematocrit, and blood sodium
concentration among subjects after receiving
electrolyte drink compared to subjects receiving
plain water for two days, but only among those
working in hot environment workplace, as shown
in Table 3.
However, Table 4 shows that those having
electrolyte drink had significantly higher USG, pH,
urinary sodium, potassium and chloride compared
to those having plain water in which, again, only
found among those working in hot environment
workplace.
Table 1 General characteristics of the subjects by different workplace environment before interventions
Variables
Hot environment
Cool environment
P-value
Age, y
29 (25–44)^
30 (25–45)^
0.086*
Duration of working, y
8 (1–22)^
8 (1–30)^
0.695*
Working hours/day
12 (8–12) ^
8 (7–12) ^
<0.001*
Body weight, kg
64.81±11.9~
68.97±12.0~
0.129**
Body height, m
1.67 (1.55–1.87) ^
1.66 (1.57–1.83) ^
0.682*
BMI, kg/m2
23.6±4.8~
24.8±4.2~
0.227**
Hemoglobin, g/dL
15.6 (12.3–18.0)^
14.8 (12.6–17.2)^
0.017*
Hematocrit, %
46 (39– 49)^
44 (40–49)^
0.040*
Blood viscosity,
mPa.s
23.0±8.2~
12.0±2.2~
<0.001**
Blood sodium,
mOsm/L
140 (136–145)^
138 (135–141)^
<0.001*
USG
1.0178±0.0076~
1.0187±0.0077~
0.626**
Blood pressure, mmHg:
Systolic
110 (90–160)^
120 (80–150)^
0.243*
Diastolic
80 (60–100)^
80 (60–100)^
0.949*
BMI, body mass index; USG, urine specific ^median (minimum-maximum); ~mean (SD),
*Mann-Whitney test; **unpaired-t test(
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Table 2 General conditions of the subjects by beverage-drink type intake in different workplace environments
General Conditions
Hot-environment
Cool-environment
Plain water
Electrolyte drink
P-value
Plain water
Electrolyte
drink
P-value
Systolic BP (mmHg)
Baseline
120
(100– 140)^
110
(90–160)^
0.907*
110
(80–140)^
120
(90–150)^
0.817*
After two days
120
(100–150)^
120
(100–150)^
0.683*
110
(100–150)^
120
(100–150)^
0.161*
Diastolic BP (mmHg):
Baseline
80
(60–90)^
80
(60–100)^
0.861*
70
(60–100)^
80
(60–100)^
0.238*
After two days
80
(70–100)^
80
(60–90)^
0.397*
80
(60–100)^
80
(60–100)^
0.285*
Heart rate (times/minute):
Baseline
72 (60–88)^
72±6~
0.900*
78±7~
72±7~
0.706**
After two days
78 (60–84)^
78 (66 –84)^
0.408*
73±8~
74±8~
0.498**
Fluid intake (mL):
Baseline
3732.8±745.9~
3640.0±666.4~
0.219**
1785.5±489.0~
1805.3±459.7~
0.781**
After two days
3813.6±6653.4~
4059
(1660–4800)^
0.159*
1749±518.0~
1778±492.9~
0.698**
^median (minimum-maximum); ~mean (SD), *Wilcoxon test; **paired-t test+
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Table 3 Hydration biomarkers of the subjects taken from blood sample by beverage-drink type intake in different workplace environments
Hydration biomarkers
Hot-environment
Cool-environment
Plain water
Electrolyte
drink
P-value
Plain water
Electrolyte
drink
P-value
Viscosity (mPa.s):
Baseline
16.6
(8.3–36.9)^
15.0
(7.4–39.2)^
0.685*
12.1±2.3~
12.1±2.0~
0.939**
After two days
12.6
(7.4–29.0)^
12.2±2.6~
0.013*
11.6±2.0~
12.1±2.5~
0.146**
Changes after – baseline
-2.0
(-16.0–3.1)^
-4.1
(-22.1–1.1)^
0.277*
-0.5±2.4~
0.05±2.3~
0.371**
Hemoglobin (mg/dL):
Baseline
14.9±1.1~
15.0±1.1~
0.455**
14.8
(13.0–16.3)^
14.7±0.9~
0.928*
After two days
14.8±1.1~
14.4±1.0~
0.001**
14.5±0.7~
14.7±0.7~
0.060**
Changes after – baseline
-0.1±0.8~
-0.4
(-2.0–0.8)^
0.088*
-0.2±0.5~
-0.1±0.6~
0.295**
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!
Table 3 (continued)
Hydration biomarkers
Hot-environment
Cool-environment
Plain water
Electrolyte
drink
P-value
Plain water
Electrolyte
drink
P-value
Hematocrit (%):
Baseline
44.5±2.8~
45.0
(38–49)^
0.571*
44 (39–48)^
44 (40–49)^
0.958*
After two days
44.3±2.6~
43.7±2.2~
0.029**
43 (41–48)^
44 (39–50)^
0.167*
Changes after – baseline
-0.2±2.3~
-1.0 (-5–3.0)^
0.118*
0 (-4–3.0)^
-0.1±2.0~
0.478*
Sodium (mOsm/L):
Baseline
141.2±1.9~
141.0
(136–145)^
0.663*
139
(137–141)^
138
(135–141)^
0.078*
After two days
141.0
(136–143)^
141.0
(138–146)^
0.024*
139
(136–140)^
139
(137–141)^
0.114*
Changes after – baseline
-1.0
(-4.0–3.0)^
0 (-3.0–6.0)^
90*
0 (-3.0–3.0)^
0 (-3.0–6.0)^
0.051*
Potassium (mOsm/L):
Baseline
4.0 (3.4–5.0)^
4.0 (3.4–5.0)^
0.468*
4.0 (3.6–6.0)^
4.0 (3.5–5.0)^
0.496*
After two days
4.0 (3.2–4.4)^
4.0 (3.4–5.0)^
0.671*
3.8 (3.4–4.4)^
3.9 (3.3–4.5)^
0.423*
Changes after – baseline
0 (-1.6–0.4)^
0 (-1.0–1.0)^
0.396*
-0.3
(-1.9–0.4)^
-0.3
(-1.3–0.5)^
0.209*
+
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Table 3 (continued)
Hydration biomarkers
Hot-environment
Cool-environment
Plain water
Electrolyte
drink
P-value
Plain water
Electrolyte
drink
P-value
Chloride (mOsm/L):
Baseline
101.0
(97–105)^
101.0
(98–104)^
0.937*
102
(100–107)^
102
(99–106)^
0.342*
After two days
100.0
(97–105)^
101.0
(97–105)^
0.185*
102
(100–105)^
102
(100–106)^
0.483*
Changes after – baseline
-0.2±1.8~
0 (-4.0–4.0)^
0.686*
0 (-4.0–3.0)~
0 (-3.0–3.0)~
0.977*
^median (minimum-maximum); ~mean (SD), *Wilcoxon test; **paired-t test#
Table 4 Hydration biomarkers of the subjects taken from urine sample by beverage-drink type intake in different workplace environments
Hydration biomarkers
(from urine-sample)
Hot-environment
Cool-environment
Plain water
Electrolyte
drink
P-value
Plain water
Electrolyte
drink
P-value
USG status:
Baseline
1.009
(1.001–1.033)^
1.014±0.009~
0.451*
1.009
(1.003–1.032)^
1.015±0.007~
0.207*
After two days
1.004
(1.001–1.022)^
1.006
(1.001–1.032)^
<0.001*
1.006
(1.002–1.029)^
1.007
(1.003–1.026)^
0.401*
Changes after – baseline
-0.007
±0.010~
-0.003
±0.010~
0.115**
-0.005
±0.010~
-0.007
±0.008~
0.454**
6 (5–7)^ 6 (5–7)^ 0.123* 6 (5–7)^ 6.5 (5–8)^ 0.664*
After two days 6 (5–7)^ 6 (5–8)^ 0.003* 6 (5–7)^ 6 (5–7)^ 0.293*
Changes after – baseline 0 (-1.0–1.0)^ 0 (-1.0–2.0)^ 0.003* 0 (-2.0–2.0)^ 0.2±0.8~ 0.947*
Normal urine color, n(%):
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Table 4 (continued)
Hydration biomarkers
(from urine-sample)
Hot-environment
Cool-environment
Plain water
Electrolyte
drink
P-value
Plain water
Electrolyte
drink
P-value
pH:
Baseline
6 (5–7)^
6 (5–7)^
0.123*
6 (5–7)^
6.5 (5–8)^
0.664*
After two days
6 (5–7)^
6 (5–8)^
0.003*
6 (5–7)^
6 (5–7)^
0.293*
Changes after – baseline
0 (-1.0–1.0)^
0 (-1.0–2.0)^
0.003*
0 (-2.0–2.0)^
0.2±0.8~
0.947*
Normal urine color, n(%):
Baseline
32 (82.1)
35 (89.7)
0.549***
35 (89.7)
33 (84.6)
0.727***
After two days
39 (100)
36 (92.3)
-
39 (100)
39 (100)
-
Sodium (mOsm/L):
Baseline
64
(14–232)^
95
(10 - 256)^
0.553*
70.8
(0–299.0)^
94.0
(30.0–266.3)^
0.379*
After two days
29.8
(13.0–143.8)^
62 (13–301)^
<0.001*
41.0
(13.1–180.6)^
50.4
(15.3–194.1)^
0.426*
Changes after – baseline
-41.0
(-192.0–104.7)^
3.2±94.4~
0.054*
-13.7
(-281.5–103.6)^
-36.4
(-244.5–97.4)^
0.577*
+
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Table 4 (continued)
#
Hydration biomarkers
(from urine-sample)
Hot-environment
Cool-environment
Plain water
Electrolyte
drink
P-value
Plain water
Electrolyte
drink
P-value
Potassium (mOsm/L):
Baseline
16.0
(1.0–97.2)^
20.0
(2.0–93.0)^
0.942*
15.0
(0–110.5)^
23.7
(4.4–109.0)^
0.302*
After two days
6.0
(1.0 – 51.2)^
11.0
(1.0–94.5)^
<0.001*
8.5
(2.5–46.0)^
9.4
(3.2–73.3)^
0.384*
Changes after – baseline
-7.0
(-71.0–18.0)^
-1.0
(-92.0–74.5)^
0.246*
-2.8
(-79.4–20.0)^
-13.2
(-86.4–11.8)^
0.468*
Chloride (mOsm/L):
Baseline
65.0
(7.1–356.0)^
116.4±84.8~
0.577*
27.6
(0–199.1)^
122.3±75.4~
<0.001*
After two days
23.0
(7.0–146.7)^
100.0
(10.0–274.3)^
<0.001*
35.2
(8.5–167.3)^
45.4
(10.5–177.7)^
0.276*
Changes after – baseline
-31.0
(-283.0–118.5)^
-25.7±114.5~
0.161*
5.4
(-78.4–128.5)^
-41.7
(-247.2–94.6)^
<0.001*
^median (minimum-maximum); ~mean (SD),
*Wilcoxon test; **paired-t test; ***McNemar-test
!
World.Nutr.J+|+49+
Discussion
This study aimed to evaluate the effect of
electrolyte beverage in preventing dehydration for
workers, especially noted from clinical symptoms
and laboratory measurements (hemoglobin,
hematocrit, blood viscosity, blood and urine
minerals, urine specific gravity and pH). This
study’s objective was also to compare the effect of
electrolyte beverage and plain water (non-
electrolyte drink) in promoting hydration and
electrolytes balance among the workers in hot and
conveniently cool environment. We tried to keep
the subjects as stated in the protocol of the study,
however, two subjects from the hot environment
and one subject from the cool environment had to
leave due to urgent reasonable reasons (Figure 2A
and Figure 2B).
Based on work environment difference, the
subjects had similar age, however they had
different working hours (Table 1). It was shown
that subjects working in the hot environment had
significantly longer working hours compared to
those working in the cool environment. By working
in a hot environment for a longer period, the risk to
become dehydrated is higher unless the workers are
used to drinking sufficiently. If we could
extrapolate by using an example of very active fire
fighters, then they should have daily water
requirements of about 7 L/day.6
Based on the blood analyses, Table 1 shows
several indices of hydration status. There were
significantly higher hemoglobin concentration,
hematocrit, blood viscosity and blood sodium
among subjects working in hot environment
compared to the subject working in the cool
environment. Particularly, 79.5% of subjects
working in hot environment had high blood
viscosity compared to subjects in the cool
environment (25.6%). These showed that workers
who work in the hot environment are at higher risk
of falling into a dehydration state compared to
those working in the conveniently cool
environment. The sweating process involves the
fluid loss from the extracellular compartment
including fluid from the vascular. Hematocrit can
be described as relationship between the cellular
volume compared to total blood volume. Its level
increases when the total RBC amount increases or
when a person losses fluid which leads to a
decrease of plasma volume, which happens in
sweating process. Working in a hot environment
increases sweat rates which results in decrease of
plasma volume. The blood viscosity increases
along with the increasing hematocrit.7
The most widely investigated are body mass
changes, blood indices, urine indices and
bioelectrical impedance analysis.8 Measurement of
haemoglobin concentration and hematocrit has the
potential to be used as a marker or change in
hydration status. However, Armstrong et al9
(1994) stated that hematologic measurements are
not as sensitive to mild hypohydration as the
certain urinary indices. This perhaps suggests that
plasma volume is defended in an attempt to
maintain cardiovascular stability, and so plasma
variables will not be affected by hypohydration or
dehydration until a certain degree of body water
loss has occurred.
The subjects working in hot environment
had higher sodium level than those working in cool
environment. This higher levels of sodium is
probably caused by two things: first, the water loss
from the skin from sweating process made
extracellular fluid depletion more excessive in the
subjects working in hot environment. Second, the
lower water intake of the subjects in hot
environment might be the cause of this higher
sodium level, which is shown at Tabel 2. As a
primary cation in extracellular fluid (ECF), any loss
of water will increase sodium concentration in ECF
compartment, which in turn will increase plasma
osmolality. Plasma osmolality also provides as a
marker of dehydration level because it is closely
controlled by homeostatic system, thus serving as a
primary physiological signal to regulate water
balance, i.e. changes in urine output and fluid
intake.10-11
Plasma or serum sodium concentration and
osmolality will increase when the water loss
inducing dehydration is hypotonic with respect to
plasma. An increase in these concentrations would
be expected, as in many cases of hypohydration,
including water loss by sweat secretion, urine
production or diarrhea. Similar finding was
reported by Armstrong et al9 (1994), which perhaps
suggests that plasma volume is defended in an
attempt to maintain cardiovascular stability. Thus,
!
50#|#World.Nutr.J#
plasma variables will not be affected by
dehydration until a certain degree of body water
loss has occurred.
Baseline fluid intake (plain water and
electrolyte beverage) in both groups, as seen in
Table 2, are not significantly different. However,
subjects working in hot environment had higher
daily fluid requirements compared to subjects in
cool environment, because the skin water loss is
higher as well and this condition will increase the
feeling of thirst. The lower water intake of subjects
in hot environment is probably related to water
provision. The water supply for workers in hot
environment was only provided in a rest area which
probably cannot be easily accessed by workers
because they could not leave their work at any time
and they were not provided with a water container
at their work place. On the days of intervention, the
median of water intake reached up to 3607–4142
mL. During the interventions, the fluid intake was
increase because the researchers provided the water
in tumblers which were held in a carrying bag
which then easily accessed and drank by the
workers. As expected, the amounts of fluid
consumptions during the intervention period were
significantly higher among workers in the hot
environment compared to those working in the cool
environment. By providing the fluid at the
workplace and giving easy access to the fluid
supply, the workers in the hot environment
voluntarily increased their fluid consumption which
then significantly increased their total fluid intake.
By providing different types of fluid drink,
i.e. plain water and isotonic drink, this study
showed perceptual factor in relation to voluntary
drinking. As widely known, voluntary drinking of a
beverage is affected by its palatability, which is
determined by its color, flavor, odor, and
temperature.12-17 The sweet flavour of a drink is a
major factor in its palatability. However, in reality,
people’s prefer flavor differ, which depends on
various factors, including ethnicity and cultural
backgrounds. In this study, it was revealed that
there was no difference in the volume of fluid
intake between the two different types of provided
drink (p>0.05) both in the hot and cool
environment workers (Table 2).
As seen in Table 2, there was no significant
change neither in systolic nor diastolic blood
pressure during the intervention in both
environment. Intervention with plain water and
isotonic fluid both could maintain the blood
presssure in a stable condition. Dehydration will
typically lower blood pressure slightly due to lower
blood volume but this happens only in extreme
cases. Extreme overhydration (faster than can be
processed and expelled from the body) can lead to
a raised blood pressure. The body regulates
hormones to keep the blood pressure basically
stable except in extreme cases.18
Heart rate is a vital sign to provide clues to
the presence of many medical conditions. Reflex
changes in heart rate are one of the body’s most
basic mechanisms for maintaining proper perfusion
to the brain and other tissues.19 Perfusion is the
flow of blood through an organ. Low blood volume
caused by bleeding or dehydration results in the
heart beating faster as it attempts to maintain
adequate blood pressure. Excitement, stress, and
anxiety activate the nervous system, which may
also speed the heart rate and raise blood pressure.
Total body water by weight was found to be related
to diastolic blood pressure, r= -0.56, p=0.01.18
Table 3 shows that blood viscosity after
intervention is significantly decreased for subjects
in hot environment because they were potentially
dehydrated induced by the high sweat rates. The
isotonic drink had a lower effect on blood viscosity
than the plain water as the isotonic drink contains
electrolytes which pertains the plasma volume and
avoids water diuresis. Hemoglobin and hematocrit
were different after the intervention on both groups.
However, there was no significant difference
between the workers that drink plain water and
electrolyte beverage. The lower hematocrit level
during intervention suggested more liquid entering
the intravascular space which then lowered the
hematocrit level, in accordance to the relationship
between the cellular volume to the total blood
volume.7 These findings remarked that fluid
replacement, either with isotonic drink or plain
water, could avoid the potential hemoconcentration
during work. While the average blood sodium level
of subjects in hot environment during intervention
period was significantly different between plain
water and electrolyte beverage in hot environment
workers, it is not the same in cool convenient
environment.
!
World.Nutr.J+|+51+
Both interventions lowered the urine specific
gravity in hot environment setting as the fluids
diluted the urine (Table 4). The administration of
isotonic drink first will produce lower urine
specific gravity because it retained more fluid in
the body. While in the cool environment setting,
both interventions lowered the urine specific
gravity but there was no difference between the
plain water and electrolyte beverage as there were
no fluid losses in this setting. The administration of
both fluids in subjects of hot environment setting
would lower the renal sodium excretion on the first
phase, then the isotonic drink on the second phase
would made an adequate level in the blood thus
excreting more sodium in the urine. In the
conveniently cool setting both intervention lowered
the renal sodium excretion but no difference
between the both fluid. In that setting the isotonic
drink gave no benefit physiologically. Plain water
and isotonic beverage both could maintain the body
water of the subjects in hot environment, as both
could replace the increasing water loss from
sweating process. In the cool environment, the
baseline body water, which was lower than the
counterpart, increased after the administration of
both fluids, but their peak were more prominent
after the administration of isotonic fluid.
In conclusion consuming electrolyte
beverage would prevent male workers aged 25–45
years, especially those working in a hot
environment from dehydration as compared to non-
electrolyte beverage.
Conflict of Interest
!
Saptawati Bardosono is a one of editors but was not
involved in the review or decision process for this
article.
!
Open Access
!
This article is distributed under the terms of the
Creative Commons Attribution 4.0 International
License (http://creativecommons.org/licenses/by/4.0/),
which permits unrestricted use, distribution, and
reproduction in any medium, provided you give
appropriate credit to the original author(s) and the
source, provide a link to the Creative Commons
license, and indicate if changes were made.
Acknowledgement
This study was supported by PT Amerta Indah
Otsuka Indonesia.
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