Aging and energy Linda
Vaughan,
Francesco
ABSTRACT
Whether
expenditure1’2 Zurlo,
sedentary
and
energy
Eric
Ravussin
expenditure
mal or lower in elderly people has not yet been clearly Twenty-four-hour energy expenditure (24EE) and components
elderly
were
(17 male,
32 ± 8%
fat)
and
measured 2 1 female; young
male,
± 23. 1 kg; 25 ± 13% fat) subjects.
The
3 1 female; elderly
24 subjects
in well-trained
a group
its different
was
by use of a respiratory chamber in 7 1 ± 6 y, I ± SD; 7 1 .2 ± 13.5 kg; (33
meal
is norestablished.
± 4 y; 84.5 had
lower
mean height (P < 0.001), weight (P < 0.01), and fat-free mass (P < 0.00 1) but higher percent body fat (P < 0.01) than did the young adults. Absolute 24EE, basal metabolic rate (BMR), and sleeping metabolic rate were significantly lower (P < 0.01) in the elderly subjects than in the young subjects. However, after differences in fat-free mass, fat mass, and sex were adjusted for, only BMR was found to be lower in the elderly subjects (P < 0.01). Despite a reduced adjusted BMR in older subjects, sedentary 24EE was decreased only in proportion to their reduced body size, suggesting that the lower energy intake reported in elderly people might be mainly related to lower physical activity in free-living conditions. Am J Clin Nutr 199 1;53:82 1-5.
the
made
resolved.
position,
WORDS
energy
Elderly expenditure
people,
metabolic
rate,
corn-
body
people
age
(10,
there
metabolic
rate
in-
dicated significant age-related declines (1, 2); based on a more recent longitudinal study, Keys et al (3) estimated that the decline in basal metabolism was 1-2% per decade from the second to the seventh decade of life. Subsequent work (4, 5) has supported Keys’ conclusion that the decrease in basal metabolic rate seen in elderly people can be explained largely by decreases in lean body mass. Total body protein was shown to decline with age, with the majority of loss occurring in the muscle mass (6). In addition to age-related changes in metabolic rate, the thermic response to foods may decline with advancing age. Golay et al (7) reported a decreased thermogenic response to an oral glucose load in older adults (iage 53 y) as compared with younger adults ( age 24 y). Schwartz et al (8) recently showed that the blunted thermic effect of food in elderly people was related to an abnormal sympathetic nervous response. Another study reported a significantly higher thermogenic response to a mixed Am J C/in Nuir
l99l;53:82l-5.
Printed
in USA.
© 1991 American
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/821/4715056 by guest on 26 April 2018
Society
is voluntary
physical
reduction
males
response
total
reduction
fat mass
through
steady
fifth
(males)
(9). Thus, not
been
expenditure
which
of
usually
(10)
expenditure,
intake
in energy
but
the
caloric
intake
for reduced
a gradual
with
has
energy
activity,
in total
to compensate
is often
energy
there
with
increasing
is not
sufficient,
expenditure,
increase
in body
or sixth
(females)
and
weight
and
decade
of
life (14). Previous effect
work
from
this
of age on basal
in Pima
Indians
ducted
a wider
range
and
18-57
energy
to determine effect
expenditure
and
and
a conclusive
energy
present
expenditure
study
in Caucasian
y) by use ofa effect
metabolic
of food,
not show
or total
y (15). The
the
resting
did
rate
of ages (18-85
expenditure,
respiratory
of age
rate,
on
total
sleeping
spontaneous
males
y (young)
and were
females recruited
24-h
physical
known
to alter
mal
status,
and
and/or
cardiovascular
potential
subjects
subjects’ subjects in health
were
responsibilities volunteering and fitness;
or physical
energy
rate,
activity.
60 y (elderly)
aged from
medications respiratory,
over
chamber
metabolic
the
Phoenix
activity
basal
people sent
metabolic
with
disease
a detailed
clearly
or with
and
chronic
were
excluded.
ofthe
Many
expressed be atypical
population
prescreened people on
rate
protocol
described.
for participation thus, they may
of the elderly
cancer
and aged
metropolitan
area for a 5-d protocol. Potential volunteers were through a telephone interview. Smokers, amputees, thyroid
was conadults
methods
Caucasian 18-30
laboratory
metabolic
aged
to measure
Subjects
ofbasal
influencing
1 3). This
however,
thermic
studies
or sedentary
thermogenic
factor
is a significant
The process ofaging is one oftransition. Over several decades, many age-related changes occur that can influence energy cxpenditure. Total energy expenditure includes basal metabolic rate, the thermic effect offood, and the energy to support physical cross-sectional
trained
se on
69 y) compared
age 7 1 y); no comparison
but not always (1 1, 12) decreases with age. In addition to age-related changes in energy
Subjects
Early
Another
elderly
Introduction
activity.
per
age
(
subjects
younger
of age
(
males
control
with
effect
(16) KEY
elderly
ofsedentary
abnor-
renal, All
study,
with
of the elderly a strong in body
interest
weight
as a whole.
I From the Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, and the Arizona State University, Department of Family Resources and Human Development, Tempe, AZ. 2 Reprints not available. Receivediune 18, 1990. Accepted for publication August 15, 1990.
for Clinical
Nutrition
821
822
VAUGHAN
TABLE
1
Physical
characteristics
ofthe
ET
AL
subjects*
Young
Elderly
(n=64)t
Age (y) Height (cm) Weight (kg) Ratio of waist to thigh circumference Fat-free mass (kg)
Fat mass(kg) Percent body fat (%) *
I ± SD; range
t Thirty-three j: Seventeen
24.0
±
170.3 84.5
±
1.50
±
61.0 22.5 25.0
±
±
± ±
(n=38)f
3.6 (18-30) 8.6 (149-190) 23.1 (41.3-135.3) 0.13 10.7 16.3 13.0
(1.31-1.87) (34-91.4) (2.8-59.1) (5-45)
protocol
Subjects
were admitted to the metabolic ward of the Clinical and Nutrition Section of the National Institute of Diabetes and Digestive and Kidney Diseases. After detailed description ofthe protocol, written informed consent was obtained. Subjects were given a physical examination, completed a medical history, and were placed on a controlled metabolic diet (20% of calories from protein, 30% from fat, and 50% from carbohydrate) for maintenance ofentry weight. Blood was drawn after an overnight fast for routine laboratory testing. Within 2 d of admission, each subject was hydrostatically weighed to determine percentage of body fat with simultaneous measurement of residual lung volume by the helium-dilution method (17). Percent body fat was calculated from the equation of Keys and Brozek (18). After a minimum of2 200 g carbohydrate/d,
d on the controlled
diet,
which
provided
subjects underwent a 3-h oral glucosetolerance test for classification as diabetic or nondiabetic (19). On a subsequent day, each subject underwent a measurement of 24-h energy expenditure in a respiratory chamber (16). Basal metabolic rate was measured at the end ofthe day in the chamber by use of a ventilated-hood system over a 12-mm period after of adaptation,
as previously
described
(16).
Because
ofthe poor reproducibility ofthe thermic effect offood calculated as previously described (16, 20), the daily thermic effect of food (three meals and one snack) was assessed as the integrated 24h energy expenditure corrected for the effect of activity above the sleeping metabolic rate. Values ofthe thermic effect of food are given as a percentage ofenergy intake and include the energy cost of arousal. The research protocol was approved by the human subjects dian
committees
Health
Statistical
Service,
of the
National
and Arizona
Institutes
State
of Health,
the
In-
University.
9.8 (148-186) 13.5 (46-96)
±
-
(60-85)
1.66 ± 0.27 48.5 ± 10.4 22.7 ± 7.7 32.0 ± 8
Vaughan,
Francesco
ABSTRACT
Whether
expenditure1’2 Zurlo,
sedentary
and
energy
Eric
Ravussin
expenditure
mal or lower in elderly people has not yet been clearly Twenty-four-hour energy expenditure (24EE) and components
elderly
were
(17 male,
32 ± 8%
fat)
and
measured 2 1 female; young
male,
± 23. 1 kg; 25 ± 13% fat) subjects.
The
3 1 female; elderly
24 subjects
in well-trained
a group
its different
was
by use of a respiratory chamber in 7 1 ± 6 y, I ± SD; 7 1 .2 ± 13.5 kg; (33
meal
is norestablished.
± 4 y; 84.5 had
lower
mean height (P < 0.001), weight (P < 0.01), and fat-free mass (P < 0.00 1) but higher percent body fat (P < 0.01) than did the young adults. Absolute 24EE, basal metabolic rate (BMR), and sleeping metabolic rate were significantly lower (P < 0.01) in the elderly subjects than in the young subjects. However, after differences in fat-free mass, fat mass, and sex were adjusted for, only BMR was found to be lower in the elderly subjects (P < 0.01). Despite a reduced adjusted BMR in older subjects, sedentary 24EE was decreased only in proportion to their reduced body size, suggesting that the lower energy intake reported in elderly people might be mainly related to lower physical activity in free-living conditions. Am J Clin Nutr 199 1;53:82 1-5.
the
made
resolved.
position,
WORDS
energy
Elderly expenditure
people,
metabolic
rate,
corn-
body
people
age
(10,
there
metabolic
rate
in-
dicated significant age-related declines (1, 2); based on a more recent longitudinal study, Keys et al (3) estimated that the decline in basal metabolism was 1-2% per decade from the second to the seventh decade of life. Subsequent work (4, 5) has supported Keys’ conclusion that the decrease in basal metabolic rate seen in elderly people can be explained largely by decreases in lean body mass. Total body protein was shown to decline with age, with the majority of loss occurring in the muscle mass (6). In addition to age-related changes in metabolic rate, the thermic response to foods may decline with advancing age. Golay et al (7) reported a decreased thermogenic response to an oral glucose load in older adults (iage 53 y) as compared with younger adults ( age 24 y). Schwartz et al (8) recently showed that the blunted thermic effect of food in elderly people was related to an abnormal sympathetic nervous response. Another study reported a significantly higher thermogenic response to a mixed Am J C/in Nuir
l99l;53:82l-5.
Printed
in USA.
© 1991 American
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/821/4715056 by guest on 26 April 2018
Society
is voluntary
physical
reduction
males
response
total
reduction
fat mass
through
steady
fifth
(males)
(9). Thus, not
been
expenditure
which
of
usually
(10)
expenditure,
intake
in energy
but
the
caloric
intake
for reduced
a gradual
with
has
energy
activity,
in total
to compensate
is often
energy
there
with
increasing
is not
sufficient,
expenditure,
increase
in body
or sixth
(females)
and
weight
and
decade
of
life (14). Previous effect
work
from
this
of age on basal
in Pima
Indians
ducted
a wider
range
and
18-57
energy
to determine effect
expenditure
and
and
a conclusive
energy
present
expenditure
study
in Caucasian
y) by use ofa effect
metabolic
of food,
not show
or total
y (15). The
the
resting
did
rate
of ages (18-85
expenditure,
respiratory
of age
rate,
on
total
sleeping
spontaneous
males
y (young)
and were
females recruited
24-h
physical
known
to alter
mal
status,
and
and/or
cardiovascular
potential
subjects
subjects’ subjects in health
were
responsibilities volunteering and fitness;
or physical
energy
rate,
activity.
60 y (elderly)
aged from
medications respiratory,
over
chamber
metabolic
the
Phoenix
activity
basal
people sent
metabolic
with
disease
a detailed
clearly
or with
and
chronic
were
excluded.
ofthe
Many
expressed be atypical
population
prescreened people on
rate
protocol
described.
for participation thus, they may
of the elderly
cancer
and aged
metropolitan
area for a 5-d protocol. Potential volunteers were through a telephone interview. Smokers, amputees, thyroid
was conadults
methods
Caucasian 18-30
laboratory
metabolic
aged
to measure
Subjects
ofbasal
influencing
1 3). This
however,
thermic
studies
or sedentary
thermogenic
factor
is a significant
The process ofaging is one oftransition. Over several decades, many age-related changes occur that can influence energy cxpenditure. Total energy expenditure includes basal metabolic rate, the thermic effect offood, and the energy to support physical cross-sectional
trained
se on
69 y) compared
age 7 1 y); no comparison
but not always (1 1, 12) decreases with age. In addition to age-related changes in energy
Subjects
Early
Another
elderly
Introduction
activity.
per
age
(
subjects
younger
of age
(
males
control
with
effect
(16) KEY
elderly
ofsedentary
abnor-
renal, All
study,
with
of the elderly a strong in body
interest
weight
as a whole.
I From the Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, and the Arizona State University, Department of Family Resources and Human Development, Tempe, AZ. 2 Reprints not available. Receivediune 18, 1990. Accepted for publication August 15, 1990.
for Clinical
Nutrition
821
822
VAUGHAN
TABLE
1
Physical
characteristics
ofthe
ET
AL
subjects*
Young
Elderly
(n=64)t
Age (y) Height (cm) Weight (kg) Ratio of waist to thigh circumference Fat-free mass (kg)
Fat mass(kg) Percent body fat (%) *
I ± SD; range
t Thirty-three j: Seventeen
24.0
±
170.3 84.5
±
1.50
±
61.0 22.5 25.0
±
±
± ±
(n=38)f
3.6 (18-30) 8.6 (149-190) 23.1 (41.3-135.3) 0.13 10.7 16.3 13.0
(1.31-1.87) (34-91.4) (2.8-59.1) (5-45)
protocol
Subjects
were admitted to the metabolic ward of the Clinical and Nutrition Section of the National Institute of Diabetes and Digestive and Kidney Diseases. After detailed description ofthe protocol, written informed consent was obtained. Subjects were given a physical examination, completed a medical history, and were placed on a controlled metabolic diet (20% of calories from protein, 30% from fat, and 50% from carbohydrate) for maintenance ofentry weight. Blood was drawn after an overnight fast for routine laboratory testing. Within 2 d of admission, each subject was hydrostatically weighed to determine percentage of body fat with simultaneous measurement of residual lung volume by the helium-dilution method (17). Percent body fat was calculated from the equation of Keys and Brozek (18). After a minimum of2 200 g carbohydrate/d,
d on the controlled
diet,
which
provided
subjects underwent a 3-h oral glucosetolerance test for classification as diabetic or nondiabetic (19). On a subsequent day, each subject underwent a measurement of 24-h energy expenditure in a respiratory chamber (16). Basal metabolic rate was measured at the end ofthe day in the chamber by use of a ventilated-hood system over a 12-mm period after of adaptation,
as previously
described
(16).
Because
ofthe poor reproducibility ofthe thermic effect offood calculated as previously described (16, 20), the daily thermic effect of food (three meals and one snack) was assessed as the integrated 24h energy expenditure corrected for the effect of activity above the sleeping metabolic rate. Values ofthe thermic effect of food are given as a percentage ofenergy intake and include the energy cost of arousal. The research protocol was approved by the human subjects dian
committees
Health
Statistical
Service,
of the
National
and Arizona
Institutes
State
of Health,
the
In-
University.
9.8 (148-186) 13.5 (46-96)
±
-
(60-85)
1.66 ± 0.27 48.5 ± 10.4 22.7 ± 7.7 32.0 ± 8
