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Beneficial effects of exercise: shifting the focus from
body weight to other markers of health
N A King,
1
M Hopkins,
2
P Caudwell,
3
R J Stubbs,
4
J E Blundell
3
1
Institute of Health and
Biomedical Innovation, School of
Human Movement Studies,
Queensland University of
Technology, Brisbane, Australia;
2
Department of Health and
Exercise Science, Trinity and All
Saints College, Leeds, UK;
3
Biopsychology Group, Institute
of Psychological Sciences,
University of Leeds, Leeds, UK;
4
Slimming World, Clover Nook
Road, Somercotes, Alfreton, UK
Correspondence to:
Dr N King, Institute of Health
and Biomedical Innovation,
School of Human Movement
Studies, Queensland University
of Technology, Brisbane, 4059,
QLD, Australia; n.king@qut.edu.
au
Parts of these data were pre-
sented at BASES in UK, 2006,
and at the 9th ICO in Australia,
2006.
Accepted 24 August 2009
Published Online First
29 September 2009
ABSTRACT
Background: Exercise is widely promoted as a method
of weight management, while the other health benefits
are often ignored. The purpose of this study was to
examine whether exercise-induced improvements in
health are influenced by changes in body weight.
Methods: Fifty-eight sedentary overweight/obese men
and women (BMI 31.8 (SD 4.5) kg/m
2
) participated in a
12-week supervised aerobic exercise intervention (70%
heart rate max, five times a week, 500 kcal per session).
Body composition, anthropometric parameters, aerobic
capacity, blood pressure and acute psychological
response to exercise were measured at weeks 0 and 12.
Results: The mean reduction in body weight was 23.3
(3.63) kg (p,0.01). However, 26 of the 58 participants
failed to attain the predicted weight loss estimated from
individuals’ exercise-induced energy expenditure. Their
mean weight loss was only 20.9 (1.8) kg (p,0.01).
Despite attaining a lower-than-predicted weight reduc-
tion, these individuals experienced significant increases in
aerobic capacity (6.3 (6.0) ml/kg/min; p,0.01), and a
decreased systolic (26.00 (11.5) mm Hg; p,0.05) and
diastolic blood pressure (23.9 (5.8) mm Hg; p,0.01),
waist circumference (23.7 (2.7) cm; p,0.01) and
resting heart rate (24.8 (8.9) bpm, p,0.001). In
addition, these individuals experienced an acute exercise-
induced increase in positive mood.
Conclusions: These data demonstrate that significant
and meaningful health benefits can be achieved even in
the presence of lower-than-expected exercise-induced
weight loss. A less successful reduction in body weight
does not undermine the beneficial effects of aerobic
exercise. From a public health perspective, exercise
should be encouraged and the emphasis on weight loss
reduced.
It is difficult to ignore the media attention and
public health messages about the current obesity
epidemic and the emphasis to reduce body weight.
Despite some cynicism about the true status and
implications of the obesity epidemic,
1
there is no
doubt that preventing weight gain can contribute
to improving the health of the nation.
2
The efficacy
of exercise as a means of weight reduction is
regularly scrutinised and doubted.
3
Body weight
loss is commonly regarded as the marker of efficacy
by researchers, and more typically the perceived
measure of success by laypeople. Any lack of
weight loss associated with exercise is often
attributed to poor compliance and/or compensa-
tion for the acute exercise-induced increase in
energy expenditure.
4
That is, the net change in
exercise-induced energy expenditure is modest and
insignificant due to compensatory adjustments in
energy intake and a failure to comply fully with
the exercise prescription. Clearly, if people do not
comply with the exercise prescribed (by themselves
or others), the expected weight loss will not occur.
The success of exercise in promoting weight loss
will vary between individuals;
5
however, those
who lose less weight should not be labelled as
failures or be perceived negatively. Evidence sug-
gests that individuals have unrealistic weight loss
expectations,
6
which is indicative of an inappropri-
ate focus on body weight. Blair and Lamonte
suggested that ‘‘a focus on weight loss is often
counterproductive and unsuccessful, and some-
times may even be unnecessary.’’
7
Furthermore,
body weight per se might not be the most
important risk factor for obesity comorbidities.
8–10
It is possible that media attention and the
persistent barrage of messages to reduce obesity
are to blame for the obsession with the capacity of
exercise to produce marked and rapid weight loss.
Exercise gives rise to a wide range of health
benefits, not just weight loss.
11
Disappointment and low-self esteem associated
with poor weight loss could lead to low exercise
adherence and a general perception that exercise is
futile and not beneficial. This viewpoint is
potentially damaging—a more transparent and
positive attitude to the health benefits of exercise
is required. Individuals who drop out of exercise
interventions—possibly due to disappointing
weight loss—have a history of previous weight
loss attempts, and exercise adherence is associated
with intrinsic motivation.
12 13
Unfortunately,
focusing on exercise-induced changes in body
weight undermines the arguably more important
health benefits associated with exercise. Although
there is some debate about the direct association
between weight loss per se and health benefits,
there is evidence to suggest that reductions of 5–
10% in body weight improve some health risk
markers.
14
For several years Steve Blair has pro-
moted the idea that fitness is more important than
fatness, since there are data to demonstrate that a
fat but fit person has fewer health risks than a lean
but unfit individual.
15
There is a real need to
promote physical activity and to prevent it being
undervalued by the community and by public
health professionals.
16
In fact, whensedentary people undertake exercise,
the activity provides a massive stimulus with
widespread physiological implications. The effect
cannot be readily anticipated, but studies have noted
considerable diversity in the responses.
17 18
In addi-
tion, the energy expended in exercise is believed, by
some,
19
to stimulate compensation so that energy
balance is preserved. We have examined these issues
under controlled scientific conditions.
Original article
924 Br J Sports Med 2009;43:924–927. doi:10.1136/bjsm.2009.065557
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MATERIALS AND METHODS
Fifty-eight sedentary overweight/obese men (BMI 30.5 (SD
3.3) kg/m
2
) and women (BMI 32.6 (4.8) kg/m
2
) completed a 12-
week supervised aerobic exercise programme (70% heart rate
max) five times a week in the Human Appetite Research Unit at
the University of Leeds. Each exercise session was designed to
expend approximately 500 kcal. Body composition (air plethys-
mography—Bodpod, Concord), anthropometry, aerobic capa-
city (submaximal VO
2
max test), blood pressure, resting heart
rate and the acute affective response (Positive and Negative
Affect Scale (PANAS)
20
) to exercise were measured at weeks 0
and 12. Subjects were instructed not to restrict their energy
intake during the study.
RESULTS
When all 58 subjects’ data were pooled, the mean reduction in
body weight was 23.3 (3.6) kg (p,0.01)—however there was
large interindividual variability (fig 1). Based on empirical
evidence,
21
the mean weight loss matched the predicted weight
loss. Further examination of the weight-change data revealed
that subjects could be categorised into two groups (responders
and non-responders) based solely on their actual initial weight
relative to the calculated weight change. Calculations were
based on the assumed energy costs of 9540 kcal/kg and
1100 kcal/kg of fat mass and fat-free mass respectively.
21
The non-responders (n = 26) lost less weight than predicted
based on their individual total exercise-induced energy expen-
diture. Although statistically significantly lower than baseline
(week 0), their mean weight loss was only 20.9 (1.8) kg
(p,0.01), compared with the remaining participants (respon-
ders) who experienced an average weight loss of 25.2 (3.64) kg
(p,0.01). Indeed, some of the classified non-responders actually
gained weight Therefore, based on body weight alone, exercise
could be regarded as ineffective and futile for the non-
responders (and even counterproductive for the weight gainers).
However, the effectiveness of exercise should not be exclusively
judged on changes in body weight because it undermines the
other health benefits that are commonly associated with
exercise. Despite the lower-than-expected weight loss, the
non-responders did achieve improvements in health markers.
They experienced a significant increase in aerobic capacity (6.3
(6.0) ml/kg/min; p,0.01), reduction in waist circumference
(23.08 (2.66) cm; p,0.01), and decreases in systolic (26.0
(11.5) mm Hg; p,0.05), diastolic blood pressure (23.9
(5.8) mm Hg; p,0.01) and resting heart rate (24.8 (8.9) bpm;
p,0.001). The reduction in both systolic and diastolic blood
pressure was more marked when examining the changes in
those individuals who were classed as hypertensive (140/90 mm
Hg) at baseline. They experienced a significant reduction in
systolic (215 (10.4) mm Hg p,0.0001) and diastolic (210 (4.6),
p,0.0001) blood pressure.
In addition to the reduction in health risk markers, the non-
responders experienced an acute improvement in psychological
state reflected in the exercise-induced increase in positive mood,
which was maintained during the 12 weeks. Interestingly,
although the difference in weight loss between the groups
was statistically significant, there were no statistically signifi-
cant differences in the health benefits. Furthermore, when all
subjects’ data were pooled, there was no association between
weight loss and improvements in health markers. Therefore, the
exercise itself, independent of weight loss, made a significant
contribution to the health benefits. There were no significant
differences between men and women, and the proportion of
men in each group was similar (responders = men:women, 9:23,
28% and non-responders = men:women, 10:16, 38%).
Moreover, these results show that, if people fail to lose weight
following a recommendation to perform physical activity, it is
not necessarily a result of poor compliance. In some individuals,
who are resistant to weight loss, it will be due to strong
physiological compensatory processes.
DISCUSSION
These data demonstrate that significant and meaningful health
benefits can be achieved even in the presence of lower-than-
expected exercise-induced weight loss. A novel feature of this
study is that the exercise intervention was supervised, and each
session was monitored and measured directly. Therefore, unlike
most of the other exercise intervention trials, we can guarantee
that the lower-than-expected weight loss was not due to poor
compliance. Indeed, the degree of adherence and total exercise
energy expenditures did not differ between the two groups.
Importantly, based on each individual’s predicted weight loss,
those who lost less weight than predicted still experienced
improvements in other markers of health. It is important to
note that these health markers are not overtly accessible to most
individuals, whereas other markers such as body weight,
perceptions of fitting of clothes and perceived body image are
more accessible and transparent. Therefore, most individuals are
‘‘blind’’ to the exercise-induced health improvements. Indeed,
these data demonstrate that subjects who lost less than the
predicted weight still experienced a mean reduction of
approximately 3.7 cm in waist circumference. Waist circumfer-
ence is promoted as being more important than BMI at
predicting risk of obesity-related disease,
22 23
and a better marker
of success than BMI in response to exercise.
24
The reductions in
diastolic and systolic blood pressure in the non-responders were
similar to other studies.
25
There is a need to increase knowledge and understanding of
the health benefits of exercise, and reduce the emphasis on
weight loss.
11
This agrees with the evidence that cardiorespira-
tory fitness is a more powerful predictor of risk than body
weight.
16
In addition, evidence from the Finnish Diabetes
Preventions study showed that individuals who did not lose
weight but who did increase their physical activity maintained a
reduction in the risk of diabetes.
26
Exercise should be promoted
as an optimistic method of improving weight management and
overall health by highlighting the importance of using other
Figure 2 Mean reduction in resting heart rate during the 12-week
exercise intervention in R and NR. There was a significant main effect of
week but no statistically significant main effect of group or group6time
interaction.
Original article
Br J Sports Med 2009;43:924–927. doi:10.1136/bjsm.2009.065557 925
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markers of success. Weight loss is not the only benefit of
exercise; nor is it the most useful and appropriate marker of
health.
27
A recent intervention in postmenopausal obese women
using low-intensity, low-volume exercise showed improve-
ments in cardiorespiratory fitness with no effect on body
weight.
28
Furthermore, partly due to the culture of focusing on
obesity and weight loss, individuals will actively seek opportu-
nities which are specifically targeted to promote weight loss—
and exercise is one of those. From a public health perspective,
exercise should therefore be encouraged; and even though body
weight may not change markedly, or match expectations, lean
tissue will be increased (or preserved), and body shape will
change (waist circumference). There will also be a lowering of
risk factors for comorbidity problems and diabetes. In the
present study, the reduction in waist circumference—even in
the non-responders—is important, since this variable is a proxy
measure of visceral fat which is highly associated with
cardiometabolic risk factors.
11
It may therefore be important
to encourage the replacement of BMI and body weight with
waist circumference as a measure of the effectiveness of
exercise.
Within this framework, there is a key role for physicians and
health professionals. These professionals—including dieti-
tians—not only can promote physical activity as a contribution
to health but also can be instrumental in improving weight
management in non-responders (table 1). We have demon-
strated that non-responders fail to lose the expected weight
because of an increase in appetite reflected in an increased
Table 1 Mean absolute and percentage changes in anthropometry, body composition and health markers
after 12 weeks of monitored exercise in responders (n = 32) and non-responders (n = 26)
Variable Group Absolute change Change (%)
Body mass (kg) Responders 25.2 25.7
Non-responders 20.9 21.0
BMI (kg/m
2
) Responders 21.8 25.7
Non-responders 20.3 21.0
Fat mass (kg) Responders 24.9 215.3
Non-responders 21.2 24.7
Body fat (%) Responders 23.5 210.5
Non-responders 21.1 23.7
Lean mass (kg) Responders 20.3 20.6
Non-responders +0.3 +0.4
Waist circumference (cm) Responders 26.0 25.8
Non-responders 23.7 23.7
VO
2
max (ml/kg/min) Responders +9.1 +32.5
Non-responders +6.3 +23.0
Diastolic blood pressure (mm Hg) Responders 23.4 23.7
Non-responders 23.9 24.6
Systolic blood pressure (mm Hg) Responders 22.9 21.9
Non-responders 26.0 24.3
For both groups, exercise induced statistically significant changes in all variables; however, none of the differences between the
groups were statistically significant.
Figure 1 Variability in individual
changes in body weight (kg) after
12 weeks of monitored exercise.
Original article
926 Br J Sports Med 2009;43:924–927. doi:10.1136/bjsm.2009.065557
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selection of high-fat foods and a decrease in fruit and vegetable
consumption
29
and because of an increased orexigenic (hunger)
response.
30
Therefore, using dietary behaviour strategies, dieti-
tians and health professionals could help to counter appetite
stimulation in the non-responders and therefore help weight
management while preserving all of the health benefits of
exercise.
In conclusion, these data provide support for the belief that
poor weight loss associated with exercise should not undermine
its capacity to improve health. Health professionals, it can be
argued, have a responsibility to promote exercise, publicise the
health benefits independent of body weight and, more
importantly, shift the focus from changes in body weight to
changes in overall physical and psychological well-being. Our
intervention study has clearly demonstrated that when exercise
is carried out, people experience beneficial physiological and
psychological effects independent of any effect on body weight.
However, the implication of these results for weight manage-
ment and the obesity epidemic should be interpreted carefully.
The results do not mean the exercise is fruitless or ineffective in
the battle against obesity. Overall, exercise can help to check
weight gain, and in some people it is very effective. Others need
additional help to deal with any compensatory response.
Funding: This study forms part of a larger project funded by the Biotechnology and
Biological Sciences Research Council (BBS/B/05079).
Competing interests: None.
Ethics approval: Ethics approval was provided by University of Leeds Ethics
Committtee.
Patient consent: Obtained.
Provenance and peer review: Not commissioned; not externally peer reviewed.
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Original article
Br J Sports Med 2009;43:924–927. doi:10.1136/bjsm.2009.065557 927
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doi: 10.1136/bjsm.2009.065557
September 29, 2009
2009 43: 924-927 originally published onlineBr J Sports Med
N A King, M Hopkins, P Caudwell, et al.
health
focus from body weight to other markers of
Beneficial effects of exercise: shifting the
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