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Physical work capacity (VO2 max) and work ability (WAI) of active employees (men and women) in Poland
International Congress Series 1280 (2005) 156 – 160
www.ics-elsevier.com
Physical work capacity (VO2 max) and work ability (WAI) of active employees (men and women) in Poland J. Bugajskaa,T, T. Makowiec-Da˛browskab, A. Jegierc, A. Marszaleka a
Central Institute for Labour Protection-National Research Institute, Warsaw, Poland b Nofer Institute of Occupational Medicine, Lo´dz´, Poland c Medical University, Lodz´, Poland
Abstract. The aim of the study was to assess the level of physical work capacity and the value of work ability in occupationally active persons and to evaluate the impact of physical work capacity on work ability. The level of physical work capacity, whose indicator is VO2 max, determines the capacity to perform hard or prolonged work, good tolerance and the possibility to eliminate changes due to fatigue. So, the value of VO2 max, which determines the potential capacity for hard physical effort, can be a significant element in the subjectively perceived work ability. VO2 max was estimated with a linear regression equation, which was individually calculated between the measured heart rate and VO2 during submaximal exercise. The Work Ability Index (WAI) served as a tool for assessing work ability. The results show the importance of knowledge about the real level of physical work capacity in selecting appropriate intensity of work. VO2 max positively correlates with WAI, especially in a person doing hard physical work. D 2005 Elsevier B.V. All rights reserved. Keywords: Physical work capacity; Work ability index
1. Introduction The level of physical work capacity, whose indicator is VO2 max, determines the capacity to perform hard or prolonged work, good tolerance and the possibility to eliminate changes due to fatigue. General health status and non-occupational physical
T Corresponding author. Tel.: +48 22 6233277; fax: +48 22 6233282. E-mail address: [email protected] (J. Bugajska). 0531-5131/ D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2005.03.001
J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
157
activity have a positive influence on the level of physical work capacity, whereas age and excessive load in occupational work have a negative effect. Knowledge about the level of real capacity is indispensable to create safe employment conditions, especially from the point of view of physical workload. This problem is most important for elderly persons, whose level of VO2 max decreases independently of the kind of performed work [1]. The decrease in VO2 max with age has a significant influence on the ability to perform physical work [2]. VO2 max, which determines the potential capacity for hard physical effort, can be a significant element in the subjectively perceived work ability. 2. Aims The study was aimed at establishing the level of physical capacity and work ability in men and women in employment age. Its secondary aim was to evaluate the impact of physical work capacity on work ability. 3. Methods To estimate VO2 max the subjects performed 2–4 submaximal exercise tests on a bicycle ergometer. On the basis of VO2 and heart rate during these tests, linear regression was estimated and extrapolated to maximal heart rate assessed according to age. Work ability was assessed with the Work Ability Index, determining work ability in the range of 7–49 points [3]. Experts established what kind of work the participants did, and what its load was. The tests were conducted in a group of 524 occupationally active women and 664 occupationally active men. 24.7% of the subjects performed mental work (women— 31.6%, men—19.2%), 38%—light physical work (women—35.5%, men—40%), 26.6%—physical work of moderate intensity (women—27.6%, men—25.7%) and 10.7%—hard physical work (women—5.4%, men—15.1%). The mean age of the women was 43.7 years (S.D. 10.1, min. 19, max. 70), of men— 42.7 years (S.D. 10.4, min. 18, max. 68). Physical work capacity and the Work Ability Index were analyzed for the following age groups: 18–24 years old—2.9% of the subjects (2.9% of women and 3.0% of men), 25–30 years old—11.4% of the subjects (10.7% women, 11.9% men), 31–40 years old—23.8% of the subjects (19.3% women, 27.4% men), 41–50 years—35.9% of the subjects (38.7% women, 33.7% men),41–50 51–60 years old—23.0% of the subjects (26.5% women, 20.2% men) and over 61–2.9% of the subjects (1.9% women, 3.8% men).
Table 1 Mean level of VO2 Men Women
max
of men and women in different age groups (in ml/kg/min)
Age
18–24
25–30
31–40
41–50
51–60
Over 61
Mean S.D. Mean S.D.
42.8 F 9.8 44.1 F 10.6
44.1 F 10.4 42.3 F 7.7
43.5 F10.9 36.0 F7.6
38.5 F 10.9 32.9 F9.4
33.4 F 10.6 28.9 F 8.8
29.9 F9.5 26.0 F7.1
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J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
Table 2 Physical work capacity of women and men according to 2strand classification in percent Age (years)
Sex
(%) Excellent
Large
Medium
Low
Very low
20–29
Women Men Women Men Women Men Women Men
23.4 23.5 16.7 44.1 22.9 32.1 19.2 25.6
18.8 7.4 18.8 9.6 10.1 13.3 11.6 15.6
48.4 30.8 43.7 26.5 33.0 29.4 44.2 35.0
9.4 17.3 11.4 13.0 20.7 12.4 16.9 12.8
0 21 9.4 6.8 13.3 12.8 8.1 10.0
30–39 40–49 50–59
In the statistical analysis of the data, correlations were calculated using Pearson’s correlation test. The results were considered statistically significant if p b 0.01. 4. Results The mean value of VO2 max in the group of women was 33.6 ml/kg/min (S.D. 9.8) and in the group of men—39.3 ml/kg/min (S.D. 11.5). The level of VO2 max of men and women in different age groups is presented in Table 1. On the basis the relationship between VO2 max and age, we found that maximal aerobic capacity was strongly inversely correlated with age. This correlation was statistically significant ( p b 0.001). VO2 max decreases in men by 0.40 ml/kg/min a year, and by 0.44 ml/kg/min a year in women. There is a large variability of the distribution of the level of physical capacity (according to 2strandTs classification) in individual age groups of women and men [4]. In the youngest group of men, there is a large share of those with low or very low physical capacity, whereas in the group of the youngest women the number of them with low and very low physical capacity is the smallest in comparison with other age groups (see Table 2). The mean values of Work Ability Index in the group of women were 40.2 (S.D. 6.1) and in the group of men—41.5 (S.D. 5.3). Both in women and in men, this index was highest in persons in the younger groups in comparison with the older groups (Table 3). The Work Ability Index correlated positively with the level of physical work capacity of the subjects: women (r = 0.14) and men (r = 0.07), and negatively with age: women (r = 0.35) and men (r = 0.36), (see Fig. 1). Considering the kind of work done, Fig. 2, WAI correlates positively with work capacity in women performing all the kinds of work under study: mental work (r = 0.26), Table 3 Mean WAI (Work Ability Index) for men and women in different age groups Men Women
Age
18–24
25–30
31–40
41–50
51–60
Over 61
Mean S.D. Mean S.D.
44.8 F3.6 42.9 F4.0
43.9 F4.0 43.5 F4.5
43.0 F 4.4 42.1 F 4.9
40.9 F5.6 40.0 F5.9
39.4 F5.5 37.5 F6.7
37.5 F5.7 37.6 F8.2
J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
159
Fig. 1. Correlation of the Work Ability Index with age and physical work capacity (VO2 max ml/kg/min) ( p b 0.01, Pearson’s correlation test).
light physical work (r = 0.16), medium physical work (r = 0.08) and hard physical work (r = 0.02). In men we observe the same tendency in groups performing mental work (r = 0.03), medium physical work (r = 0.08). This influence is particularly clear in the group of men doing hard physical work (r = 0.39). In the group of men doing light physical work, we observe negative correlation (r = 0.05), (see Fig. 2). 5. Discussion The obtained results indicate that VO2 max of occupationally active women and men in Poland does not significantly differ from that in other European countries [5,6]. However, there is a disturbingly large number of young men with a low or very low level of physical
Fig. 2. Correlation of the Work Ability Index with physical capacity (VO2 kinds of work (*p b 0.01, Pearson’s correlation test).
max
ml/kg/min) according to different
160
J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
work capacity. This may result from the way the subjects were recruited (voluntary participation): among the young men, most were involved in mental work. The results of this study show that VO2 max decreases with age in men at a similar rate as in other countries. In women, this decrease is slightly faster than in other countries. According to studies made in other countries, it decreases in men by 0.25–0.8 ml/kg/min a year, and in women by 0.25–0.4 ml/kg/min a year [7]. The results of our study also show the importance of physical work capacity for the ability to work. This is proved by the positive correlation between VO2 max and WAI, especially in this group of male subjects who performed heavy physical work. The correlation coefficient was similar to that of other studies [8]. Poor correlation between VO2 max and WAI for other kinds of work and in the whole group can be caused by the fact that the level of subjectively perceived work ability also depends on many other factors not related to a capacity for physical effort. On the basis of the test results, it may be also concluded that these data show the importance of knowledge about the real level of physical work capacity for selecting appropriate intensity of work. Acknowledgements This research was funded by the State Committee for Scientific Research of Poland within the frame of Programme 21-21 commissioned by the Minister of Economy, Labour and Social Policy. References [1] J. Ilmarinen, et al., Changes in maximal cardiorespiratory capacity among ageing municipal employees, Scand. J. Work, Environ & Health 17 (Suppl. 1) (1991) 99 – 109. [2] J. Ilmarinen, Ageing Workers in the European Union—Status and Promotion of Work Ability Employability and Employment, FIOH, 1999. [3] K. Tuomi, et al., Work Ability Index, Finnish Institute of Occupational Health, Helsink, 1998. ˚ strand, K. Rodahl, Textbook of Physiology, McGraw-Hill Book Company, New York, 1986. [4] P.-O. A [5] G.R. Farazdaghi, B. Wohlfart, Reference values for the physical work capacity on a bicycle ergometer for women between 20 and 80 years of age, Clin. Physiol. 21 (6) (2001) 682 – 687. [6] E. Shvartz, R.C. Reinbold, Aerobic fitness norm for males and females aged 6 to 75 years, a review, Aviat. Space Environ. Med. 61 (1990) 3 – 11. [7] B.C.H. De Zwart, M.H.W. Frings-Dresen, F.J.H. Van Dijk, Physical workload and the ageing workers: a review of the literature, Int. Arch. Occup. Environ. Health 68 (1995) 1 – 12. [8] H. Soininen, Effects of physical exercise on health, physical capacity and work ability of ageing police officers, in: J. Ilmarinen, V. Louhevaara (Eds.), Finn Age—Respect for the Aging, People and Work. Research Reports, vol. 26, FIOH, 1999, pp. 128 – 137.
www.ics-elsevier.com
Physical work capacity (VO2 max) and work ability (WAI) of active employees (men and women) in Poland J. Bugajskaa,T, T. Makowiec-Da˛browskab, A. Jegierc, A. Marszaleka a
Central Institute for Labour Protection-National Research Institute, Warsaw, Poland b Nofer Institute of Occupational Medicine, Lo´dz´, Poland c Medical University, Lodz´, Poland
Abstract. The aim of the study was to assess the level of physical work capacity and the value of work ability in occupationally active persons and to evaluate the impact of physical work capacity on work ability. The level of physical work capacity, whose indicator is VO2 max, determines the capacity to perform hard or prolonged work, good tolerance and the possibility to eliminate changes due to fatigue. So, the value of VO2 max, which determines the potential capacity for hard physical effort, can be a significant element in the subjectively perceived work ability. VO2 max was estimated with a linear regression equation, which was individually calculated between the measured heart rate and VO2 during submaximal exercise. The Work Ability Index (WAI) served as a tool for assessing work ability. The results show the importance of knowledge about the real level of physical work capacity in selecting appropriate intensity of work. VO2 max positively correlates with WAI, especially in a person doing hard physical work. D 2005 Elsevier B.V. All rights reserved. Keywords: Physical work capacity; Work ability index
1. Introduction The level of physical work capacity, whose indicator is VO2 max, determines the capacity to perform hard or prolonged work, good tolerance and the possibility to eliminate changes due to fatigue. General health status and non-occupational physical
T Corresponding author. Tel.: +48 22 6233277; fax: +48 22 6233282. E-mail address: [email protected] (J. Bugajska). 0531-5131/ D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2005.03.001
J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
157
activity have a positive influence on the level of physical work capacity, whereas age and excessive load in occupational work have a negative effect. Knowledge about the level of real capacity is indispensable to create safe employment conditions, especially from the point of view of physical workload. This problem is most important for elderly persons, whose level of VO2 max decreases independently of the kind of performed work [1]. The decrease in VO2 max with age has a significant influence on the ability to perform physical work [2]. VO2 max, which determines the potential capacity for hard physical effort, can be a significant element in the subjectively perceived work ability. 2. Aims The study was aimed at establishing the level of physical capacity and work ability in men and women in employment age. Its secondary aim was to evaluate the impact of physical work capacity on work ability. 3. Methods To estimate VO2 max the subjects performed 2–4 submaximal exercise tests on a bicycle ergometer. On the basis of VO2 and heart rate during these tests, linear regression was estimated and extrapolated to maximal heart rate assessed according to age. Work ability was assessed with the Work Ability Index, determining work ability in the range of 7–49 points [3]. Experts established what kind of work the participants did, and what its load was. The tests were conducted in a group of 524 occupationally active women and 664 occupationally active men. 24.7% of the subjects performed mental work (women— 31.6%, men—19.2%), 38%—light physical work (women—35.5%, men—40%), 26.6%—physical work of moderate intensity (women—27.6%, men—25.7%) and 10.7%—hard physical work (women—5.4%, men—15.1%). The mean age of the women was 43.7 years (S.D. 10.1, min. 19, max. 70), of men— 42.7 years (S.D. 10.4, min. 18, max. 68). Physical work capacity and the Work Ability Index were analyzed for the following age groups: 18–24 years old—2.9% of the subjects (2.9% of women and 3.0% of men), 25–30 years old—11.4% of the subjects (10.7% women, 11.9% men), 31–40 years old—23.8% of the subjects (19.3% women, 27.4% men), 41–50 years—35.9% of the subjects (38.7% women, 33.7% men),41–50 51–60 years old—23.0% of the subjects (26.5% women, 20.2% men) and over 61–2.9% of the subjects (1.9% women, 3.8% men).
Table 1 Mean level of VO2 Men Women
max
of men and women in different age groups (in ml/kg/min)
Age
18–24
25–30
31–40
41–50
51–60
Over 61
Mean S.D. Mean S.D.
42.8 F 9.8 44.1 F 10.6
44.1 F 10.4 42.3 F 7.7
43.5 F10.9 36.0 F7.6
38.5 F 10.9 32.9 F9.4
33.4 F 10.6 28.9 F 8.8
29.9 F9.5 26.0 F7.1
158
J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
Table 2 Physical work capacity of women and men according to 2strand classification in percent Age (years)
Sex
(%) Excellent
Large
Medium
Low
Very low
20–29
Women Men Women Men Women Men Women Men
23.4 23.5 16.7 44.1 22.9 32.1 19.2 25.6
18.8 7.4 18.8 9.6 10.1 13.3 11.6 15.6
48.4 30.8 43.7 26.5 33.0 29.4 44.2 35.0
9.4 17.3 11.4 13.0 20.7 12.4 16.9 12.8
0 21 9.4 6.8 13.3 12.8 8.1 10.0
30–39 40–49 50–59
In the statistical analysis of the data, correlations were calculated using Pearson’s correlation test. The results were considered statistically significant if p b 0.01. 4. Results The mean value of VO2 max in the group of women was 33.6 ml/kg/min (S.D. 9.8) and in the group of men—39.3 ml/kg/min (S.D. 11.5). The level of VO2 max of men and women in different age groups is presented in Table 1. On the basis the relationship between VO2 max and age, we found that maximal aerobic capacity was strongly inversely correlated with age. This correlation was statistically significant ( p b 0.001). VO2 max decreases in men by 0.40 ml/kg/min a year, and by 0.44 ml/kg/min a year in women. There is a large variability of the distribution of the level of physical capacity (according to 2strandTs classification) in individual age groups of women and men [4]. In the youngest group of men, there is a large share of those with low or very low physical capacity, whereas in the group of the youngest women the number of them with low and very low physical capacity is the smallest in comparison with other age groups (see Table 2). The mean values of Work Ability Index in the group of women were 40.2 (S.D. 6.1) and in the group of men—41.5 (S.D. 5.3). Both in women and in men, this index was highest in persons in the younger groups in comparison with the older groups (Table 3). The Work Ability Index correlated positively with the level of physical work capacity of the subjects: women (r = 0.14) and men (r = 0.07), and negatively with age: women (r = 0.35) and men (r = 0.36), (see Fig. 1). Considering the kind of work done, Fig. 2, WAI correlates positively with work capacity in women performing all the kinds of work under study: mental work (r = 0.26), Table 3 Mean WAI (Work Ability Index) for men and women in different age groups Men Women
Age
18–24
25–30
31–40
41–50
51–60
Over 61
Mean S.D. Mean S.D.
44.8 F3.6 42.9 F4.0
43.9 F4.0 43.5 F4.5
43.0 F 4.4 42.1 F 4.9
40.9 F5.6 40.0 F5.9
39.4 F5.5 37.5 F6.7
37.5 F5.7 37.6 F8.2
J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
159
Fig. 1. Correlation of the Work Ability Index with age and physical work capacity (VO2 max ml/kg/min) ( p b 0.01, Pearson’s correlation test).
light physical work (r = 0.16), medium physical work (r = 0.08) and hard physical work (r = 0.02). In men we observe the same tendency in groups performing mental work (r = 0.03), medium physical work (r = 0.08). This influence is particularly clear in the group of men doing hard physical work (r = 0.39). In the group of men doing light physical work, we observe negative correlation (r = 0.05), (see Fig. 2). 5. Discussion The obtained results indicate that VO2 max of occupationally active women and men in Poland does not significantly differ from that in other European countries [5,6]. However, there is a disturbingly large number of young men with a low or very low level of physical
Fig. 2. Correlation of the Work Ability Index with physical capacity (VO2 kinds of work (*p b 0.01, Pearson’s correlation test).
max
ml/kg/min) according to different
160
J. Bugajska et al. / International Congress Series 1280 (2005) 156–160
work capacity. This may result from the way the subjects were recruited (voluntary participation): among the young men, most were involved in mental work. The results of this study show that VO2 max decreases with age in men at a similar rate as in other countries. In women, this decrease is slightly faster than in other countries. According to studies made in other countries, it decreases in men by 0.25–0.8 ml/kg/min a year, and in women by 0.25–0.4 ml/kg/min a year [7]. The results of our study also show the importance of physical work capacity for the ability to work. This is proved by the positive correlation between VO2 max and WAI, especially in this group of male subjects who performed heavy physical work. The correlation coefficient was similar to that of other studies [8]. Poor correlation between VO2 max and WAI for other kinds of work and in the whole group can be caused by the fact that the level of subjectively perceived work ability also depends on many other factors not related to a capacity for physical effort. On the basis of the test results, it may be also concluded that these data show the importance of knowledge about the real level of physical work capacity for selecting appropriate intensity of work. Acknowledgements This research was funded by the State Committee for Scientific Research of Poland within the frame of Programme 21-21 commissioned by the Minister of Economy, Labour and Social Policy. References [1] J. Ilmarinen, et al., Changes in maximal cardiorespiratory capacity among ageing municipal employees, Scand. J. Work, Environ & Health 17 (Suppl. 1) (1991) 99 – 109. [2] J. Ilmarinen, Ageing Workers in the European Union—Status and Promotion of Work Ability Employability and Employment, FIOH, 1999. [3] K. Tuomi, et al., Work Ability Index, Finnish Institute of Occupational Health, Helsink, 1998. ˚ strand, K. Rodahl, Textbook of Physiology, McGraw-Hill Book Company, New York, 1986. [4] P.-O. A [5] G.R. Farazdaghi, B. Wohlfart, Reference values for the physical work capacity on a bicycle ergometer for women between 20 and 80 years of age, Clin. Physiol. 21 (6) (2001) 682 – 687. [6] E. Shvartz, R.C. Reinbold, Aerobic fitness norm for males and females aged 6 to 75 years, a review, Aviat. Space Environ. Med. 61 (1990) 3 – 11. [7] B.C.H. De Zwart, M.H.W. Frings-Dresen, F.J.H. Van Dijk, Physical workload and the ageing workers: a review of the literature, Int. Arch. Occup. Environ. Health 68 (1995) 1 – 12. [8] H. Soininen, Effects of physical exercise on health, physical capacity and work ability of ageing police officers, in: J. Ilmarinen, V. Louhevaara (Eds.), Finn Age—Respect for the Aging, People and Work. Research Reports, vol. 26, FIOH, 1999, pp. 128 – 137.