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IJOMEH 2004; 17(4) 457
International Journal of Occupational Medicine and Environmental Health, 2004; 17(4): 457 — 464
LEISURE-TIME PHYSICAL ACTIVITY,
CARDIORESPIRATORY FITNESS AND WORK
ABILITY: A STUDY IN RANDOMLY SELECTED
RESIDENTS OF ŁÓDŹ
DOROTA KALETA
1
, TERESA MAKOWIEC-DĄBROWSKA
2
, and ANNA JEGIER
3
1
Department of Preventive Medicine
Medical University of Łódź, Poland
2
Department of Work Physiology and Ergonomics
Nofer Institute of Occupational Medicine Łódź, Poland
3
Department of Sports Medicine
Medical University of Łódź, Poland
Abstract
Objectives: Low physical activity is a serious health problem in developed and developing countries. Much attention is also
given to the role of physical activity in the modification of work ability in adults. The aim of this study was to assess leisure-time
physical activity, cardiorespiratory fitness and their influence on the subjective work ability in a randomly selected group of
professionally active residents of Łódź. Materials and Methods: The study was performed in the randomly selected group of
professionally active persons (n = 198). Physical activity was determined by means of the Seven Day Physical Activity Recall
(SDPAR). To determine cardiorespiratory fitness in the examined persons, the submaximal treadmill test was performed.
Subjective work ability was evaluated using the work ability index (WAI). Results: Correlation coefficient for the WAI and
leisure-time physical activity was high r = 0.3, p < 0.0001. Moreover, WAI, its compounds and cardiorespiratory fitness
were highly correlated r = 0.4, p < 0.0001. Conclusions: Our analysis of leisure-time physical activity, cardiorespiratory
fitness and WAI emphasizes a great, potential feasibility of improving the WAI and its components, e.g., through the
development, promotion, and broad use of training schedules.
Key words:
Physical activity, Cardiorespiratory fitness, Work ability index
Received: September 30. Accepted: October 30, 2004.
Address reprint requests to D. Kaleta MD, Department of Preventive Medicine, Medical University of Łódź, pl. Hallera 1, 90-647 Łódź, Poland.
INTRODUCTION
Low physical activity is a serious health problem in devel-
oped and developing countries [1]. Numerous studies re-
veal that physical activity and cardiorespiratory fitness can
significantly diminish the risk of cardiovascular diseases,
obesity, diabetes and some neoplastic growths. The re-
cently conducted studies have corroborated the influence
of being fit on the prevention of cardiovascular and other
chronic diseases [2,3]. Leisure-time physical activity is ben-
eficial to health. However, it should be emphasized that
only a meticulously planned schedule of physical activities
can assure tangible advantages resulting from physical
fitness. To promote health and prevent chronic diseases
moderate intensity training (60% of max heart rate, HR)
at least 3 times a week for 40 min is recommended. Ex-
ORIGINAL PAPERS
IJOMEH 2004; 17(4)458
penditure of energy on physical exertion should be higher
than 1000 kcal/week and optimally 2000 kcal/week [4].
Much attention is also given to the role of physical ac-
tivity in the modification of work ability in adults [5–9].
Work ability is a compound feature and its level reflects
the interactions between occupational requirements (the
volume of both physical and mental activities and func-
tional capabilities of workers), their health and subjective
assessment of their status in the given organizational and
social conditions.
Work ability can be objectively assessed on the basis of
the functional status of a given employee and his or her
skills and capabilities. Subjective assessment performed by
the examined person can be used for work ability analysis.
This method is quite cheap, relatively not very complicat-
ed, which can be of some importance when conducting re-
search on large populations. One of the tools used for sub-
jective assessment of work ability is the work ability index
(WAI). WAI was developed at the beginning of the 1990s
by a specialist of the Institute of Occupational Health in
Helsinki [10]. WAI was subsequently used to analyze dif-
ferences between work abilities, depending on their type,
volume and workload. WAI was also used in prospective
studies of age-related fluctuations in work ability. The
work ability index has been used and checked many times
all over the world, including Poland [11,12].
The aim of this study was to assess leisure-time physical
activity, cardiorespiratory fitness and their influence on
the subjective work ability in a group of randomly selected
working residents of Łódź.
MATERIALS AND METHODS
The study was performed in the randomly selected group
of professionally active persons. The selection was made
by the Local Data Base in Łódź, which rendered the data
available together with the proportional draw scheme.
As an operator the personal identification number (PE-
SEL) was used. Of the directly drawn 2000 persons, 1029
completed the questionnaire assessing physical activity.
Subsequently, 825 individuals were systematically drawn
and invited to take the treadmill test. Of this group, 317
persons reported and entered the study (attendance rate,
38%). Finally, 271 subjects (including 198 professionally
active persons) were qualified for the treadmill test after
physical examination performed by physicians. The study
group composed of persons in good health, confirmed by
the physical examination and treadmill test, comprised
103 males (mean age, 42.9 ± 11.2 years) and 95 females
(mean age, 42 ± 11.5 years).
Physical activity was determined by means of the Seven
Day Physical Activity Recall (SDPAR) [13,14]. Informa-
tion was obtained during an interview conducted by ade-
quately trained interviewers. The questionnaire permitted
the collection of data concerning the frequency, intensity
and length of both occupational and leisure-time physi-
cal activity 7 days prior to the examination. SDPAR also
permitted the collection of data on the number of hours of
physical activity with low (1.5 METs – metabolic equiva-
lents), moderate (4 METs), high (6 METs) and very high
(10 METs) intensity. SDPAR also included energy expen-
diture during sleep (1MET). Taking into consideration
all the data, daily or weekly energy expenditure could be
calculated (kcal/day, kcal/week) [15]. To determine car-
diorespiratory fitness in the examined persons the sub-
maximal treadmill test was performed. It was an essential
prerequisite for the determination of peak oxygen uptake
VO
2max
(ml • kg
-1
• min
-1
) calculated indirectly according
to Astrand-Ryhming. The treadmill test was instituted af-
ter an appropriate qualification, including physical exami-
nation and electrocardiogram at rest.
Subjective work ability was evaluated using the work ability
index, a score composed of different items. Each of those
items was determined according to different scales arranged
in order of importance. Current work ability compared with
the lifetime best was assessed from 0 to 10 points; work abil-
ity in relation to the demands of the job from 2 to 10 points;
the number of current diseases diagnosed by a physician
from 1 to 7 points; and estimated work ability impairment
due to diseases from 1 to 6 points. Sick leave during past
12 months, self-estimated prognosis of work ability for two
years on, and mental resources to work were determined
from 1 to 5, 1, 4 or 7 and from 1 to 4 points, respectively.
In each case the highest score was attributed to the most
ORIGINAL PAPERS D. KALETA, ET AL.
IJOMEH 2004; 17(4) 459
favorable conditions, e.g. a lack of disease and sick leave,
the highest capabilities. The work ability index is calculated
by summing the estimated points for each item. The high-
est WAI reflects the best workers perception of his or her
work ability. The range of the index is from 7 to 49 points.
According to the classification worked out by the authors,
four categories of work ability assessment could be distin-
guished: poor (WAI up to 27 points), moderate (WAI from
28 to 36 points), good (WAI from 37 to 43 points), or excel-
lent (WAI from 44 to 49 points).
Statistical analysis
Chi-square test, Student’s test (for normal distributions)
and non-parametric Mann-Whitney test (for other distri-
butions) was used for analyzing the difference between
groups. The relations between work ability and maximal
oxygen consumption and leisure time physical activity
were analyzed using Spearman rank correlation. A level
of statistical significance was established at a value of p =
0.05. The statistical analysis was performed with the use of
STATGRAPHICS 5.0.
RESULTS
In the study group, we did not note any age-related signifi-
cant differences between men and women (42.9 ± 11.2 vs.
42 ± 11.5 years of age). Table 1 summarizes the charac-
teristics of the study population taking into consideration
age, anthropometric indicators, educational level, marital
status, and job characteristic.
In the study group, total weekly energy expenditure on
leisure-time physical activity accounted approximately for
270 ± 520 kcal/week, and time spent on this activity was
1.4 ± 2.3 h/week, including low, moderate and high inten-
sity (0.7 ± 1.4, 0.7 ± 1.6 and 0.02 ± 0.2 h/weekly, respec-
tively). More than half of the population (53.5%) did not
take part in any kind of sports or recreation. In the rest of
the group the following values of energy spent on physical
activity were obtained: 28.3% – 1 to 499 kcal/week; 8.1%
– 500 to 999 kcal/week; 8.1% – 1000 to 1999 kcal/week;
and 2% – 2000 kcal/week or more (Fig. 1).
Participation in leisure-time physical activity to some extent
depended on the type of work and its load. In male white-
collar employees 67% (n = 32), in blue-collar workers 29%
Table 1. Characteristics of study population
Characteristics
Men
(n = 103)
Women
(n = 95)
P
Men vs. women
Mean SD Mean SD
Age (years) 42.9 11.2 42.1 11.5 p > 0.05
Hight (cm) 176.4 6.3 161.4 5.2 p < 0.001
Weight (kg) 81.9 10.8 62.1 10.6 p < 0.001
Body mass index – BMI (kg/m
2
) 26.3 3.4 23.8 3.7 p < 0.001
n%n%
Education level
Primary 17 16.5 14 14.7 p > 0.05
Secondary 44 42.7 52 54.7 p > 0.05
University 42 40.8 29 30.5 p > 0.05
Marital status
Married 69 67 58 61.1 p > 0.05
Not married 34 33.0 37 35.9 p > 0.05
Job characteristic
Mental work 48 46.6 57 60 p > 0.05
Physical work 28 27.2 21 22.1 p > 0.05
Mixed physical and mental work 27 26.2 17 17.9 p > 0.05
p < 0.01 men vs. women
LEISURE-TIME PHYSICAL ACTIVITY, CARDIORESPIRATORY FITNESS AND WORK ABILITY ORIGINAL PAPERS
IJOMEH 2004; 17(4)460
(n = 8) and in the group with mixed activity 30% (n =
8) declared participation in leisure-time physical activity.
In male white-collar employees, weekly energy expendi-
ture was the highest 952 ± 853 kcal/week, in blue-collar
workers the lowest – 142 ± 186 kcal/week and in man with
mixed professional activity – 833 ± 508 kcal/week. In fe-
male white-collar workers – 32 (56%), in blue-collar work-
ers – only 4 (19%) and in the group with mixed activity 8
(47%) persons participated in leisure time physical activity.
In women, type of the work did not influence the level of
leisure-time physical activity. In female white-collar work-
ers this expenditure accounted for 484 ± 538 kcal/week, in
blue-collar workers – 245 ± 183 kcal/week and in the group
with mixed activity was 295 ± 171 kcal/week.
Energy expenditure on leisure-time physical activity dimin-
ished gradually with increasing workload. It was described
as a percentage of VO
2max
after calculation of energy expen-
diture at work and oxygen uptake, taking account of resting
metabolism (1 MET). In the study group the workload was
not very high because only 15 men and 8 women exceeded
30% of VO
2max
, which means that they worked hard. In the
male group with the workload up to 15% of VO
2max
(n =
32), 15–30% of VO
2max
(n = 13), and > 30% of VO
2max
(n
= 3) weekly energy expenditure on leisure-time physical
activity amounted to 1017 ± 831 kcal, 420 ± 458 kcal and
90 ± 38 kcal, respectively. In the female group these values
were at the levels of 489 ± 535 kcal (n = 31), 260 ± 251
(n = 22) and 321 kcal (n = 1), respectively.
Mean values of maximum oxygen uptake, VO
2max
(l
• min
-1
)
were 2.8 ± 0.6 in men (n = 103) and 2.1 ± 0.6 in women
(n = 95; p < 0.001). Mean relative values of VO
2max
(ml •
kg
-1
• min
-1
) amounted to 35.2 ± 7.8 in men and 35 ± 11.1
in women (p > 0.005).
In the whole study group, WAI was 41.4 ± 5.9 and did
not significantly differ between men and women. To-
Fig. 1. Weekly energy expenditure (kcal/week) on leisure time physical
activity among men and women.
Fig. 2. Relationship between the work ability categories and participa-
tion in leisure-time physical activity.
Table 2. The work ablity index (WAI) and its item values in men and
women
Items of work ability index
Men
(n = 103)
Women
(n = 95)
P
Men vs.
Women
Mean SD Mean SD
Work ability compared with
the lifetime best
8.3 1.5 7.9 1.1 p > 0.05
Work ability in relation
to take up physical activity
4.3 0.8 4.2 0.0 p > 0.05
Work ability to mental effort 4.6 0.6 4.4 1.9 p < 0.05
Work ability to adjust
to professional requirements
8.8 1.3 8.5 1.0 p > 0.05
The number of current diseases
diagnosed by a physician
5.5 0.8 5.2 1.9 p = 0.05
Sick leave during the past year 4.0 1.0 4.0 0.1 p > 0.05
Estimated work impairment
due to disease
6.5 1.0 6.3 0.8 p < 0.05
Self-estimated prognosis
of work ability for two years on
6.3 0.9 5.8 2.0 p < 0.05
Mental resources 3.0 0.8 2.5 3.8 p < 0.0001
Work ability index 42.5 4.7 40.3 1.9 p > 0.05
ORIGINAL PAPERS D. KALETA, ET AL.
IJOMEH 2004; 17(4) 461
tally, 42.4% of the examined persons obtained excellent
and 38.9% – good assessment of the work ability index,
whereas moderate and poor assessments were achieved by
16.2% and 4.6% of the participants, respectively. It should
be emphasized that among persons who obtained poor
assessment of the WAI there were only women. Table 2
presents the WAI values in men and women.
To answer the question whether leisure-time physical ac-
tivity is associated with the level of work ability, the cor-
relations between the general WAI, its items and leisure-
time physical activity were calculated. Spearman rank cor-
relation coefficient was used. This analysis indicated that
correlations were positive and frequently high (Table 3).
Correlation coefficient for the WAI and leisure-time phys-
ical activity was r = 0.3, p < 0.0001. The level of leisure-
time physical activity had a significant impact on current
work ability compared with the lifetime best, work ability
to adjust to professional requirements, the number of cur-
rent diseases diagnosed by a physician, sick leaves during
the past year, and mental resources to work. Among per-
sons who declared participation in leisure-time physical
activity, the percentage of individuals with excellent work
ability was significantly higher as compared with persons
who did not take up any physical exercises (in the female
group it was 54.5% vs. 29.4 p = 0.04, in the male group
62.5% vs. 27.3%; p = 0.0007; Fig. 2).
The correlation between WAI, its items and cardiorespi-
ratory fitness was analyzed. It was noted that in the ex-
amined group these features were highly correlated. Cor-
relation coefficient of WAI and maximal oxygen uptake
(ml • kg
-1
• min
-1
) was r = 0.4, p < 0.0001 (Table 3).
The level of WAI in persons who took and did not take lei-
sure-time physical activity was analyzed in relation to the
type of workload (e.g., physical, mixed and mental). The
obtained results indicated that blue-collar workers mostly
benefited from participation in leisure-time physical activ-
ity (Fig. 3). The analyses of the level of WAI, depending
on the workload presented as the percentage of VO
2max
,
also confirmed the above-mentioned hypothesis (Fig. 4).
Similarly, in the previous analysis, individuals who worked
hard mostly benefited from leisure-time physical activity,
however, the differences were not statistically significant
due to the small number of participants. Moreover, among
women whose work was physically demanding, only one
Table 3. Statistically significant correlations between work ablity
index (WAI), its items and the level of leisure-time physical activity
(kcal/week) and maximal oxygen uptake VO
2max
(ml • kg
-1
• min
-1
)
Items of work ability
index
WAI and the leisure-
time physical activity
WAI and maximal
oxygen uptake
Men
(n = 103)
Women
(n = 95)
Men
(n = 103)
Women
(n = 95)
r
Spearman
r
Spearman
r
Spearman
r
Spearman
Work ability compared
with the lifetime best
0.199 0.291 0.318 0.482
Work ability in relation
to take up physical
activity
0.218 0.301 0.430
Work ability to mental
effort
0.214 0.157 0.248 0.300
Work ability to
adjust to professional
requirements
0.300 0.220 0.357 0.392
The number of current
diseases diagnosed by a
physician
0.254 0.228 0.237 0.317
Sick leave during the
past year
0.256 0.308 0.269
Estimated work
impairment due to
disease
0.222
Self-estimated
prognosis of work
ability for two years on
0.252 0.246 0.357
Mental resources
0.250 0.241 0.205 0.266
Work ability index
0.310 0.302 0.368 0.465
Fig. 3. WAI in persons who take and do not take up leisure-time
physical activity in relation to the type of workload: physical, mixed
(physical and mental), and mental.
LEISURE-TIME PHYSICAL ACTIVITY, CARDIORESPIRATORY FITNESS AND WORK ABILITY ORIGINAL PAPERS
IJOMEH 2004; 17(4)462
of them admitted having practiced leisure-time physical
activity.
Participation in leisure-time physical activity also de-
pended on the education level in the study participants
(Fig. 5).
A correlation between the general work ability index,
age, and body mass index was also analyzed. A negative
correlation between the age (r = -0.6, p < 0.0001), BMI
(r = -0.3, p < 0.0001), and the general WAI was con-
firmed.
A correlation between leisure-time physical activity and
cardiorespiratory fitness was also analyzed. Statistically sig-
nificant correlation between leisure-time physical activity
and cardiorespiratory fitness in men (r = 0.5, p < 0.0001)
and women (r = 0.4, p < 0.0001) was confirmed.
DISCUSSION
The SDPAR questionnaire and subsequent calculations of
energy expenditure in the study group were conducted in
accordance with the formula [13]. The calculated amount
of energy expenditure on leisure-time physical activity in
the study group of the residents of Łódź did not signifi-
cantly differ from the values expected in the properly de-
signed study. The level of leisure-time physical activity in
the examined group was significantly lower as compared
with the study conducted by Makowiec-Dabrowska et al.
[12]. In the presented study, 53.5% of participants did not
take part in any leisure-time physical activity compared
with 4% of individuals revealed in the aforesaid study [12].
In our study, 2% of persons expended 2000 kcal/week on
leisure-time physical activity versus 20.6% of individuals
examined by Makowiec-Dabrowska et al. [12]. The dif-
ference between characteristic features of the examined
groups, various tools and measurement methods used by
different authors could bring about a wide range of dis-
crepancies in the results obtained. In the described study
the level of physical activity was also lower than that re-
ported by Kaleta et al. [16]. It applied particularly to par-
ticipants with energy expenditure of 2000 kcal/week or
more. In the study conducted by Kaleta et al. [16], 15.4%
of participants (26.7% of males and 4% of females) ex-
pended 2000 kcal or more weekly on leisure-time physical
activity. However, it should be emphasized that in both
studies the groups were small and despite their random
selection none appeared to be a representative sample for
Łódź.
The mean WAI in the whole group was 41.4 ± 5.9 and
the percentage of participants with excellent work ability
amounted to 42.4%, which represented comparable val-
ues with those achieved by Ilmarinen [17] in workers from
western countries.
Apparently the level of leisure-time physical activity
shaped subjective work ability. The results of the present
study, like those of other studies revealed that subjective
assessment of work ability was highly correlated with the
level of physical activity of the examined individuals. More-
over, the results of the previous studies indicated that the
introduction of an adequately selected training schedule
improved both physical endurance and WAI [8,9].
Our research confirmed that among blue-collar workers,
especially those working hard, a certain reluctance to lei-
Fig. 4. WAI in persons who take and do not take up leisure-time
physical activity in relation to difficulty of work presented as the per-
centage of VO
2max
.
Fig. 5. Weekly energy expenditure (kcal/week) on leisure time physical
activity in men and women with different levels of education.
ORIGINAL PAPERS D. KALETA, ET AL.
IJOMEH 2004; 17(4) 463
sure-time physical activity was common. In 2004, Kaleta
et al. [18] revealed that 11.5% of the residents of Łódź
reported physical work as a major reason for not taking up
leisure-time physical activity. Our research confirmed that
the blue-collar workers mostly benefited from leisure-time
physical activity as compared with white-collar employees.
In fact, a statistically significant difference could be ob-
served only in men. There was also a significant differ-
ence between two groups (“yes” and “no”) of white-collar
employees, but the value was lower than that in blue-col-
lar workers (Fig. 4). These data emphasize the need for
focusing training schedules on blue-collar workers. It is
crucial, in view of numerous unquestionable advantages
of leisure-time physical activity among blue-collar workers
reported in the medical literature, manifested not only by
the increased subjective work ability but also by the de-
clined risk for cardiovascular diseases [19].
CONCLUSIONS
1. The results of the present study reveal that in approxi-
mately 78% of the study subjects, physical activity was
too low and did not reach the level recommended for the
prevention of chronic diseases, especially cardiovascular
diseases.
2. Despite the fact that the presented study comprises a
small population (n = 198), the analysis of leisure-time
physical activity and the work ability index emphasize the
potential feasibility of improving the WAI and its items
e.g., through the development, promotion, and broad use
of training schedules. In the light of the previous studies,
much attention should be given to the rationally selected
type, volume and intensity of physical activity because
this schedule can greatly contribute to the improvement
of work ability through the increase in cardiorespiratory
fitness.
3. Preventive schedules focused on the improvement of
work ability through the increase in leisure-time physical
activity should be addressed to employees at large, and to
blue-collar workers, in particular.
4. In Poland and also in other member states of the Euro-
pean Union, workplace should play a significant role in the
promotion of leisure-time physical activity. It is manda-
tory to diminish social and economic consequences of low
physical activity in our country.
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