Los efectos del ejercicio sobre la capacidad aeróbica y la fatiga en las mujeres con síndrome de sjögren primario
Effects of exercise on aerobic capacity and fatigue in women with
primary Sjo¨ gren’s syndrome
B. E. Stro¨ mbeck, E. Theander and L. T. H. Jacobsson
Objective. To investigate the effect of a moderate to high intensive exercise program on two primary outcomes (aerobic capacity, fatigue),
and three secondary outcomes [anxiety, depression and health-related quality of life (HRQoL)] in women with primary Sjo¨gren’s syndrome
Methods. Twenty-one women with primary SS were ranked according to degree of fatigue and allocated to an exercise group (TG; n ¼ 11) or a
control group (CG; n ¼ 10). The exercise method was Nordic walking for 45min three times a week for 12 weeks. Outcome measures assessed
at baseline and after 12 weeks were aerobic capacity, fatigue, ratings of perceived exertion (RPE), anxiety, depression and HRQoL.
Results. Nine women in the TG and 10 women in the CG completed the study. Analysis showed significant differences between
the groups regarding aerobic capacity (P ¼ 0.03), fatigue (P ¼ 0.03), RPE (P ¼ 0.03), and depression (P ¼ 0.02) with the better values for
the TG. There were no differences in anxiety or HRQoL.
Conclusion. Our findings support the use of appropriate aerobic exercise in the treatment of primary SS.
KEY WORDS: Sjo¨gren’s syndrome, Controlled study, Fatigue, Depression, Physiotherapy.
Fatigue is a common symptom in rheumatic diseases [1, 2] and is
one of the most frequent non-exocrine complaints in primary
Sjo¨ gren’s syndrome (primary SS) . Factors associated with
fatigue in rheumatic diseases are sleep disturbances , disease
activity, pain, anxiety, depression and decreased level of physical
activity . Aerobic capacity has been reported to be reduced in
rheumatic diseases including primary SS [6–8]. It has also been
indicated that fatigue is related to reduced aerobic capacity in
women with primary SS . Reduced fatigue after aerobic exercise
therapy has earlier been described in rheumatic diseases [7, 9, 10]
but not, as far as we know, in primary SS.
The purpose of this controlled clinical trial was to investigate
whether (i) aerobic capacity and fatigue, and (ii) anxiety, depression
and health-related quality of life (HRQoL) would benefit from a
12-week exercise programme in women with primary SS.
Patients and methods
Based on the results of a previous study  of exercise therapy
and systemic lupus erythematosus (SLE), we expected a mean
increase in VO2max of 3.8 ml/kg/min and a S.D. of 2.76 in the
exercise group (TG). No difference was expected in the control
group (CG). Based on this, a sample size of ten in each group
would be required to enable detection of a significant difference
between groups with 80% power.
Inclusion criteria for participation in the study were: (i) female
gender and age 67 yrs; (ii) primary SS diagnosed according to
the American European Consensus Criteria (AECC)  and
(iii) living in a specific area of southern Sweden. The exclusion
criteria were: (i) use of beta-blocker therapy, or (ii) disease
manifestations known to prevent or limit exercise performance.
A total of 94 patients were recruited and 26 agreed to participate.
Sixty women were limited to participate or declined participation,
and eight women did not answer the invitation. The mean age
of the 68 women who did not participate was 52 (24–67) yrs.
Of the 26 women who agreed to participate, 21 women
remained for the intervention after the assessments. None of the
patients had concomitant disease manifestations, and none
were on medication that would limit exercise performance.
The characteristics of the study population (those who completed
the study) are presented in Table 1.
The study was a controlled intervention trial with two exercise
programmes. One group, the TG, did medium to high-intensity
aerobic exercises and the other group, the CG, did low-intensity
home exercises. To balance the patient allocation to any of
the two groups, patients were ranked by fatigue as measured by
the Profile of Fatigue (ProF) ; see below. Patients with odd
numbers were allocated to the TG and patients with even numbers
were allocated to the CG. Thus, the allocation was 11 patients to
TG and 10 patients to CG.
Treatment group (TG). The exercise method was Nordic
walking, which is walking with specially constructed ski poles.
The TG met once a week for 12 consecutive weeks for a 45-min
walk, and were instructed to walk for 45 min twice more every
week at home. All participants were provided with walking poles
and a telemetric heart rate monitor. The weekly group sessions
were conducted by a trained walker. During the first 8 weeks
the patients were told to exercise at a heart rate corresponding
to 60–70% of age-predicted maximum heart rate and for the
remaining 4 weeks they were told to exercise at 70–80% of
age-predicted maximum heart rate. Age-predicted maximum heart
rate was estimated to be 220 minus the age of the individual.
Logs of exercise duration, average heart rate and perceived
exertion were kept by the patient.
Department of Rheumatology, Malmo¨ University Hospital, Malmo¨, Sweden.
Submitted 29 June 2006; revised version accepted 3 January 2007.
Correspondence to: B. Stro¨mbeck, Department of Rheumatology, Malmo¨
University Hospital, SE-205 02 Malmo¨, Sweden.
Rheumatology 2007;46:868–871 doi:10.1093/rheumatology/kem004
Advance Access publication 17 February 2007
ß The Author 2007. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: email@example.com
Control group (CG). The 10 patients in the CG were
given written instructions for range of motion exercises to be
performed at home three times a week over 12 weeks. Otherwise,
the patients were told to maintain their current level of activity
during the 12-week programme. The patients kept exercise logs.
Assessment methods. Assessments were done before and
immediately after the exercise period of 12 weeks. The patients
completed a questionnaire regarding back ground data, fatigue,
anxiety, depression and HRQoL. After this, the bicycle test was
Fatigue was measured with the validated Swedish version of the
disease-specific Profile of Fatigue questionnaire (ProF) .
It consists of 16 items evaluating somatic fatigue and mental
fatigue: the somatic domain (12 items) and the mental domain
(four items). The scoring for the items is 0–7, with 0 labelled
‘no problem at all’, and the calculated total score for the 16 items
is 112. The scoring for each domain is transferred into a 0–7 scale.
The scoring of the instrument has been carefully described
Fatigue was also assessed by a 100-mm visual analogue scale
(VAS) where 0 was defined as ‘not fatigued at all’ and 100 as
Aerobic capacity. The method of A˚ strand  was used to
calculate the maximum oxygen uptake (VO2max). A single
observer, blinded as to the allocation, conducted the bicycle
tests. At the end of every minute during the test, general exertion
was rated on the Borg RPE (ratings of perceived exertion)
scale . The RPE score of the last minute of the bicycle test was
registered. The range of the RPE scale is 6–20, where 6 means
no exertion at all and 20 means maximal exertion.
Health-related quality of life was measured with the Swedish
version of the self-administered Short Form 36 (SF-36) .
This is a generic instrument composed of eight subscales assessing
different dimensions of HRQoL including both physical and
mental health. The scaling ranges from 0 to 100 and higher values
indicate better health.
Anxiety and depression. The Hospital Anxiety and
Depression scale (HADS)  has been constructed to assess
anxiety and depression in patients with somatic diseases.
It contains 14 items for self-assessment on a scale from 0 to 3.
Seven items are intended to measure anxiety and seven depression,
independently of each other, and the entire scale ranges from 0 to
21 each for anxiety and depression. A score of 8–10 on a subscale
represents possible psychiatric morbidity and a score of more than
10 represents clinical anxiety or depression .
The descriptive results are presented as median and range.
Mann–Whitney U test and chi-squared test were used in
comparisons between groups. Intention to treat analysis was
performed for evaluation of the results of aerobic capacity
(VO2max l/min, VO2max ml/kg/min). One patient in the CG
did not manage to complete the bicycle test due to exhaustion
after the 12 weeks, and was therefore given the same value as the
worst performed by the study participants of the two groups.
One patient in the CG could not perform the bicycle test at
follow-up due to osteoarthritis of the knee, and was excluded from
the analysis of aerobic capacity. Wilcoxon matched pairs signed
rank sum test was used in comparisons within groups.
The significance level was set at P 0.05.
The medical ethics committee of Lund University approved the
design of the study (approval no. LU-51-03).
Drop-outs. Nine patients in the TG and ten patients in the CG
completed the study. One patient in the TG was wrongly included
due to misdiagnosis of her condition (protocol violation) and
one patient in the TG dropped out during the training period due
to family matters.
Compliance. The median number of exercise sessions in the
TG during the 12 weeks was 35 (24–47). The median number of
supervised sessions attended by the participants in the TG was
8 (7–12). The median number of home exercise sessions in the CG
was 38 (30–80).
The results of the between-group analyses are given in Table 1.
TABLE 1. Demographic and clinical characteristics, at baseline, and between group
comparison of the median differences of the effect variables after 12 weeks
exercise of the 9 women in the treatment group (TG) and the 10 women in the
control group (CG) who completed the study
Treatment group (TG) Control group (CG)
(n ¼ 9) (n ¼ 10)
Median (range) Median (range) P
Age (years) 60 (41–65) 56.5 (42–63) 0.02
Years since clinical diagnosis 5 (2–14) 8 (3–23) 0.21
BMI 28 (23–32) 25.5 (21–36) 0.56
No. married or cohabiting 6 9 0.21
Years of education 12 (8–15) 13.5 (6–19) 0.66
No. working/not workinga
2/7 5/5 0.21
No. of smokers 0 0
Fatigue (ProF) 54 (23–108) 62.5 (16–99) 0.72
Fatigue (VAS) 58 (19–80) 66.5 (36–83) 0.24
1.6 (1.3–2.2) 1.75 (1.3–2.4) 0.44
24 (17–33) 25 (17–34) 0.72
No. physically active 7 7
Musculoskeletal pain (VAS) 43.5 (16–72)n¼8 68 (15–75)n¼7 0.52
Haemoglobulin 136 (120–159) 136 (123–152) 0.78
CRP 3 (2–9) 2 (2–24) 0.96
CK 1.5 (1–3.3) 1.45 (0.8–2.2) 0.45
Between group comparison of the median changes after intervention
Fatigue (VAS), mm À17 (À41–39) 1.5 (À15–23) 0.03
Fatigue (ProF), total scale À6 (À31–9) À6 (À20–16) 0.51
Somatic fatigue (ProF) À0.67 (À2–0.38) À0.28 (À1.17–0.75) 0.31
Mental fatigue (ProF) À0.5 (À3–1.25) À0.25 (À2.25–1.25) 0.62
0.2 (À0.1–0.6) 0 (À0.3–0.3)b
3 (À1–8) 0 (À6–5)b
RPE À1 (À3–1) 1 (À2–2) 0.03
Anxiety (HADS) À1 (À5–1) À1 (À5–2) 0.87
Depression (HADS) À2 (À4–1) 0.5 (À2–4) 0.02
Physical functioning 15 (0–45) 0 (À15–25) 0.14
Role, physical 0 (À25–50)c
0 (À50–50) 0.61
Bodily pain 0 (À22–21) 0 (À22–59) 0.97
General health 5 (À15–25) À5 (À17–17) 0.25
Vitality 10 (À25–25) 7.5 (À10–30) 0.93
Social functioning 0 (À25–25) 0 (À50–25) 0.58
Role, emotional 0 (À33–100)c
0 (À100–100) 0.74
Mental health À4 (À24–4) À4 (À16–24) 0.30
Working: working part-time or full-time; not working: retired, on sick leave, or unemployed.
n ¼ 9, c
n ¼ 8.
P-values determined by Mann–Whitney U-test and 2
BMI, body mass index; VAS, Visual Analogue Scale (0–100, with 0 ¼ no fatigue/no pain at all);
ProF, Profile of Fatigue (0–112, somatic fatigue 0–7, mental fatigue 0–7, with 0 ¼ no problem
at all); VO2max, maximal oxygen consumption; RPE, ratings of perceived exertion (6–20
with 6 ¼ lightest exertion); HADS, Hospital Anxiety and Depression Scale (anxiety 0–21,
depression 0–21, with 0 ¼ no anxiety/depression); SF-36: Medical Outcome Study Short-Form
36 (0–100 with 0 ¼ lowest level of health).
Aerobic capacity and fatigue in primary SS 869
Fatigue was significantly reduced in the TG, as measured
with VAS (P ¼ 0.03). No reduction of fatigue was seen according
to the ProF.
Aerobic capacity. In the TG, significant improvement was
seen in VO2max l/min (P ¼ 0.03) and the improvement in VO2max
ml/kg/min almost reached statistical significance (P ¼ 0.06).
There was no correlation between changes in VAS fatigue and
in aerobic capacity.
There was a significant improvement in the TG in the
RPE-scale (P ¼ 0.03). The individual changes in fatigue and
aerobic capacity are seen in Fig. 1.
Health-related quality of life. No differences were seen in
any of the eight dimensions of SF-36 in comparisons between
the TG and the CG.
Anxiety and depression
The depression score was significantly lower in the TG (P ¼ 0.02),
whereas no difference between the groups was seen in anxiety.
The TG improved significantly in VO2maxl/min (P ¼ 0.03); VO2max
ml/kg/min (P ¼ 0.02), RPE (P ¼ 0.05), depression (P ¼ 0.02), and
the physical function subscale of SF-36 (P ¼ 0.01). A deterioration
was seen in the mental health subscale of SF-36 (P ¼ 0.03).
There were no differences in any of the outcome measures within
The main purpose of the present study was to investigate the effect
on aerobic capacity and fatigue of an exercise programme in
women with primary SS. To the authors’ knowledge, this is the
first study on this subject dealing with primary SS. The key
findings in our study are that regular episodes with Nordic
walking over 12 weeks improved aerobic capacity and reduced
fatigue in these patients. Many studies have been conducted in
rheumatic diseases to evaluate the effect of exercise on aerobic
capacity . Some studies have also described the effects of
exercise on fatigue, and the results of these support the findings
of our study [7, 9, 10].
Although the depression score at baseline did not represent
psychiatric morbidity, the difference in the depression score
was significant in the TG compared with the CG after the
exercise period. The effect of exercise programmes in reducing
symptoms of depression have been reported for other rheumatic
Fatigue was assessed with two different instruments, the VAS
and the ProF. Only one of these, the VAS, detected a difference
between the groups. The SF-36 vitality scale, which assesses the
opposite of fatigue and may be regarded as a measure of fatigue,
did not change either. The reason for this may be lack of statistical
power of the ProF and the SF-36 vitality scale to detect a change
due to too few participants. All three instruments are valid for
the measurement of fatigue. However, the VAS may be the most
sensitive. It may also capture additional dimensions. Better
sensitivity to change of the VAS than multidimensional scales
in the assessment of fatigue in RA has been reported .
The lacking correlation between change in fatigue and in
aerobic capacity in the TG was unexpected. Chronic fatigue may
have a central origin, i.e. dysregulation of the hypothalamic-
pituitary-adrenal (HPA) axis . The underlying mechanism
by which fatigue benefits from exercise is, as fatigue itself, poorly
understood. Influence on the HPA-axis may be one explanation.
A limiting factor in our study is the small sample size, with just
9 and 10 participants who completed the study in each group.
Of those who answered the invitation and fulfilled the inclusion
criteria (n ¼ 63), 59% (n ¼ 37) declined participation. The majority
of those who volunteered were relatively old and were mainly
unemployed. This suggests a selection bias and limits the
generalizability of the study. Another limitation is the lack of a
long-term follow-up of the exercise effects.
In summary, despite the small sample size, we found significant
improvements in primary outcomes, aerobic capacity and fatigue
(as measured with VAS) after a 12-week aerobic exercise
programme. We also found a reduced depression score. This
suggests that an aerobic exercise programme should be part of the
management of primary SS.
The authors have declared no conflicts of interest.
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