Update for Chapter 3 of the Exposure Factors Handbook
Chapter 3—Ingestion of Water and Other Select Liquids
February 2019
Page 3-29
levels. Intake was for plain water (i.e., including tap
water, water from a cooler or drinking fountain, spring
water, and noncarbonated bottled water), water in
beverages and food, and total water (i.e., the sum of
plain water and moisture in beverages and food).
Beverages included “all types of liquid milk, shakes,
fruit or vegetable juices, juice drinks, carbonated and
noncarbonated sweetened or unsweetened drinks,
coffee, tea, hot chocolate, all alcoholic drinks, and
carbonated water.” Multiple linear regression was
used to compute adjusted mean water intake based on
covariates such as sex, age, race/ethnicity, body mass
index, income, education, smoking status, chronic
illness, survey wave, survey day, and leisure-time
physical activity. Leisure-time physical activity was
categorized as having any leisure-time activity lasting
≥10 minutes over the previous month, and according
to the average activity level on a given day (i.e., mostly
sitting, mostly standing, carry light loads or climb
hills, or heavy work or carry heavy loads). Table 3-90
provides a summary of water intake for adults
according to these activity categories. Higher intake
rates of plain and total water were associated with
participation in any leisure-time activity. Higher
intake of moisture from beverages and total water
were associated with higher average activity levels on
a usual day (see Table 3-90).
Kant and Graubard (2010) used a similar approach
with data from NHANES 2005−2006 to estimate
water intake for children ages 2−19 years of age
(N = 3,978). However, the activity level definitions
differed from those used for adults in Kant and
Graubard (2009). Kant and Graubard (2010) classified
activity levels for 2- to 11-year-old children based on
the number of times per week the child was reported
to have played or exercised hard enough to induce
sweat. The categories were: 0 times = none, 1−2 = a
little, 3−4 = some, and ≥5 = a lot. For children
12−19 years of age, activity levels were based on three
questions about whether participants had any
leisure-time activity lasting ≥10 minutes. The three
questions pertained to vigorous, moderate, or muscle
strengthening activities. The categories were no to all
three questions = none, yes to 1 question = a little, yes
to 2 questions = some, and yes to all three
questions = a lot. Table 3-90 provides water intake
estimates based on these activity levels. Kant and
Graubard noted that the physical activity level was
only weakly associated with plain water intake, but not
with the moisture content of beverages or foods, or
with total water.
These studies provide information on water intake
based on physical activity. However, the water
categories are somewhat different from those used
elsewhere in this chapter. For example, plain water
category appears to include both tap water and bottled
water. Likewise, beverage moisture may include both
water that is intrinsic to purchased drinks (i.e., widely
distributed beverages such as carbonated soft drinks)
as well as beverages that may be prepared with
community tap water (e.g., coffee).
3.
6.1.5. Yang and Chun (2014)―Consumptions of
Plain Water, Moisture in Foods and
Beverages, and Total Water in Relation to
Dietary Micronutrient Intakes and Serum
Nutrient Profiles among U.S. Adults
Yang and Chun (2014) conducted a study similar
to Kant et al. (2009). They estimated water intake
among adults, ages 20 years of age and older, based on
activity levels. NHANES 2005−2006 data were used
to estimate intake of plain water, water from beverages
and food, and total water. The definitions of these
water categories were the same as those in Kant et al.
(2009), but the levels of physical activity were defined
differently. Yang and Chun (2014) based the activity
levels on “the metabolic equivalent (MET) score
calculated by combining the intensity level of the
leisure-time activities reported, mean duration and
frequency.” Water intake was evaluated for four
activity levels: no activity (0) and three tertiles of the
MET score (T1, T2, and T3). The mean daily total
water intake for adults was 3,066 g (see Table 3-90).
Yang and Chun (2014) reported that the contributions
to total water were 46% from beverages, 32% from
plain water, and 22% from food, and higher activity
was associated with higher total water intake.
Like the Kant et al. (2009) study, this study
provides information on total water intake based on
activity levels. However, the water categories differ
from those used elsewhere in this chapter.
3.
6.1.6. Montain and Ely (2010)―Water
Requirements and Soldier Hydration
Montain and Ely (2010) provided an overview of
factors that affect soldiers’ hydration and water
balance, including environment, physical activity and
load, and body size and gender. For example,
increasing temperature and relative humidity increase
sweating and the need for water replacement. The type
of clothing worn and the load being carried can also
affect the rate of perspiration and need for water
replacement. Factors affecting water needs in cold
climates include: cold-induced diuresis (increased
urine loss), respiratory water loss from breathing cold
dry air, clothing insulation that induces sweating, and
the metabolic cost of movement in cold terrain. High
altitude hypoxia can also contribute to water loss.
Because sweat losses are dependent on exercise