- Email: [email protected]
Respiratory muscle function in physically active elderly women
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ELSEVIER
Archives of Gerontology and Geriatrics 22 (1996) 123 130
ARCHIVES OF GERONTOLOGY AND GERIATRICS
Respiratory muscle function in physically active elderly women 1 Ant6nio B. Rendas*, Teresa Gamboa, Teresa Ramilo, Amdlia S. Botelho, Cristina B~.rbara, Miguel Mota-Carmo Departamentos de Fisiologia, Fisiopatologia e de Pneumologia, Faculdade de Ci~ncias Mkdicas, Universidade Nova de Lisboa, Lisboa, Portugal
Received 24 July 1995; revised 27 October 1995; accepted 1 November 1995
Abstract This study was performed in 52 women, aged 60 to 76 years: 27 were engaged in a gymnastics program, 3 h a week, for at least 2 years; 25 were age-matched controls. All were lifelong nonsmokers, free of disease symptoms and lived independently at home; none had previously engaged in exercise programs. Spirometry included volumes, flows and maximal voluntary ventilation (MVV); maximal mouth pressures both inspiratory (MIP) and expiratory (MEP) were also measured. The two groups differed only in the mean value of MEP (cm of water) which was 107.7 +_ 37.3 S.D. in the active group and 87.4 _+ 22.8 S.D. in the controls (P = 0.028). MIP and MVV were also higher in the active group but the differences were not significant. However, a significant correlation between MVV and both MIP and MEP was only found in the active group, suggesting a relation between muscular endurance and strength. This exercise program, although not oriented towards the respiratory system, improved the performance of the respiratory muscles probably by an effect on the abdominal musculature. Keywords: Elderly; Exercise; Lung volumes; Forced expiratory flows; Maximal voluntary ventilation; Maximal mouth respiratory pressures
1Supported by grants 456/87/SAU and PBIC/C/SAU/1580/92 from Junta Nacional de Investiga¢~o Tecnol6gica, Lisboa, Portugal. * Departamento de Fisiopatologia, Faculdade de Ci~ncias M6dicas, Campo de Santana 130, 1200 Lisboa, Portugal. Tel.: 351 1 8853000; Fax: 351 1 851920. 0167-4943/96/$15.00 © 1996 Elsevier Science Ireland Ltd. All rights reserved SSDI 0167-4943(95)00686-9
124
A.B. Rencla~ et a/.
Arch. Geronto/. Geriatr. 22 (1996) 123 130
I. Introduction
The decline in lung function with aging is caused by irreversible changes in pulmonary structure and by an increased stiffness of the chest wall due to irreversible changes in the bones and joints of the thorax (Peterson and Fishman, 1992). The changes occurring in the respiratory muscles of the elderly have been less studied and yet, they are probably the only reversible factor that may reduce the decline in lung function with aging. On the other hand, recent data from the Framingham study (Sorle et al., 1989) have shown an inverse relationship between forced expiratory volume and mortality, particularly in elderly women, suggesting that a taster decline in lung function with age could indicate decrease survival. Elderly athletes have higher lung function indices than sedentary age-matched controls (Hagberg et al., 1988). This finding, although generally accepted, is based upon a limited number of observations, mostly case reports. Even less studies have been performed in individuals who were sedentary most of their lives and only started physical exercise late in life. Nevertheless this number is expected to increase in the future particularly with the diffusion of health promotion programs for elderly people (Fries et al., 1993). The present study was performed in such a group of elderly, to assess the effects on the respiratory muscles and on lung function, of a physical exercise program, not specifically oriented towards the respiratory system.
2. Methods
The study was performed in 52 women aged between 60 and 76 years who lived independently at home and had not been previously involved in exercise programs. The active group included 27 women engaged in a gymnastics program for at least 2 years, the mean duration of the activity period for the whole group was 5.8 _+ 2.8 years. The exercise program consisted of three sessions per week, lasting 1 h each; each session included stretching, muscular conditioning, aerobics and cooldown periods: the exercises consisted of stretching, calisthenics, walking and slow-jogging. During the aerobic period which lasted around 20 30 min, it was aimed to maintain the heart rate between 30 and 50% of the maximal individual heart rate. The sedentary group included 25 women living in the same geographical area and with a similar life style. None of the women ever complained of cough and sputum production, or pulmonary, chest wall and heart disease as assessed by a standard questionnaire (Medical Research Council. 1986). None was taking medications that could have affected the respiratory measurements, including the musculature. The women who complained of occasional wheezing, not associated with colds, and of dyspnea only when hurrying on level ground or walking uphill, were included in the study. The degree of current and previous activity was assessed by a scale (Grimby, 1986),
A.B. Rendas et al./ Arch. Gerontol. Geriatr. 22 (1996) 123-130
125
which is divided in six grades as follows: (1) hardly no physical activity; (2) mostly sitting, sometimes a walk, easy gardening or similar tasks; (3) light physical exercise around 2-4 h per week, e.g. walks, fishing, dancing, ordinary gardening etc. including walks to and from shops; (4) moderate exercise 1-2 h per week, e.g. jogging, gymnastics, heavier gardening, home-repair or easier physical activities more than 4 h per week; (5) moderate exercise at least 3 h per week, e.g. tennis, swimming, jogging, etc; (6) hard or very hard exercise regularly and several times per week, where physical exertion is great, e.g. jogging, skiing. Spirometric measurements, including functional residual capacity (FRC) by multi-breath helium dilution, were performed using a computerized version of the dry spirometer Volugraph 2000 (Mijhnardt, Bunnik, Holland), this equipment was also used for the measurement of the 12 s maximal voluntary ventilation (MVV). Forced spirometry was measured using a pneumotachograph model Compact (Vitalograph, Buckingham, England). Maximal mouth respiratory pressures, inspiratory (MIP) and expiratory (MEP), were measured using and a three-way valve system with a 1 mm leak connected to an aneroid manometer model Magnehelic (Dwyer Instruments, Michigan City, IN, USA) with a scale in cm of water (cmH20), calibrated using a mercury column. All the procedures were carefully explained to the individuals who gave their consent. Measurements were performed seated using a well-fitted flanged mouth piece (Hans Rudolph, Kansas City, MO, USA) and wearing a nose clip. After careful explanation, each one performed at least three slow vital capacity (VC) maneuvers followed by a single measurement of FRC. The forced spirometry also included at least three maneuvers. Measurements to obtain the spirometric data were performed in curves selected according to standard criteria (American Thoracic Society, 1987). For the MVV the highest of two values was recorded and the measurements were performed according to standardized recommendations (Ferris, 1978). For the inspiratory pressure measurement, a maximal expiration was performed followed by a sustained inspiratory effort, kept for 1 s, against the occluded valve. For the expiratory pressure measurement, a maximal inspiration was performed followed by a sustained expiratory effort, kept for 1 s against the occluded valve; the cheeks were held during the whole maneuver. After a period of training each patient performed at least three maneuvers for each measurement and the highest value, in cm of water, was recorded; if the difference between the best and the second best was higher than 5% more maneuvers were performed up to a maximal of five. All the spirometric results were corrected to BTPS values and represented as mean + standard deviation (S.D.). Besides the abbreviations already mentioned the following ones were used: TLC (total lung capacity), RV (residual volume), FVC (forced vital capacity), FEV~ (forced expiratory volume in the first second), FEF25 75'y,,(maximal midexpiratory flow). Handgrip strength was measured in both arms, in triplicate, using a Lafayette dynamometer, model 78/011 (Lafayette Instrument Company, Lafayette, IN, USA) and reported as the mean value of the six readings.
126
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Arch. Gerontol. Geriatr. 22 (19961 123 130
All the procedures were performed by two physicians with previous experience on lung function testing in the elderly. The selection and the training of the group was done by a physical education specialist also experienced on working with elderly populations. For comparison between groups we employed unpaired two-tailored Student's t-tests. We calculated correlation coefficients, as measures of linear association between the different parameters. We considered P values less than 0.05 as statistically significant. The Statgraphics program was used for the statistical analyses.
3. Results The two groups were similar regarding age, height, weight and body mass index (Table 1). According to the scale of Grimby, the exercise group was labelled as grade 5 and the control group as grade 3. No differences were found between the two groups regarding the spirometry and the handgrip strength (Table 1). The higher values found in the active group for MVV (70.7 _+ 18.3 1/min) and MIP (76.6 _+ 25 cmH20) were not significantly different from those found in the control group: 67.4 _+ 18.5 1/min for MVV and 67.4 _+ 20.9 cmHzO for MIP. The MEP values were significantly different between the two groups with a mean value of 107.7 _+ 37.3 cmH20 in the active group and a mean value of 87.4 + 22.8 cmH20 in the control group (P = 0.028). Table 1 Mean values from the two groups Control (;i = 25}
Exercise (n = 27)
Age (years) Height (cm} Weight (kg) BMI (kg/m 2) Handgrip (kg} VC {11 FRC (11 TLC (11 RV (11 FVC {1} FEV I (11 FVC/FEV~ (%) FEF25 75,,,(1s i)
Mean
S.D.
Mean
S.D.
67.4 152.0 60.7 26. I 22.4 2.61 2.03 4.07 1.42 2.50 1.92 76.6 1.99
5.10 5.30 8.20 3.10 4.06 0.48 (/.58 /I.67 0.38 0.48 0.38 5.00 (I.66
67.6 153.0 64.9 27.5 21.6 2.67 2.06 4.10 1.41 2.59 1.96 75.9 1.92
4.50 5.90 7.60 3.20 4.95 0.42 0.45 0.54 0.46 0.40 0.31 6.20 0.64
No statistically signiticant differences were found.
A.B. Rendas et al./ Arch. Gerontol. Geriatr. 22 (1996) 123-130
127
Exercise Group 150-
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Control Group 150-
150-
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Fig. 1. Correlation between M W and M E P and MIP. MVV correlates significantly with M E P and M I P only in exercise group. Each point represents one case.
In the exercise group, a significant correlation was found between the MVV and both respiratory pressures; these relations were not significant in the control group (Fig. 1). Two of the women from the active group (7%) reported occasional wheezing on exposure to smoke; in the control group this symptom was reported by three (12%). Four women from this group (16%) also reported shortness of breath while hurrying on level ground or walking uphill. Ten women from the active group (37%) and seven from the control group (28%) reported to be under treatment for arterial hypertension (diastolic blood pressure (115 mmHg).
4. Discussion This study showed that a gymnastics program of moderate intensity and long duration, started late in life, although not directed to the respiratory system, improved the strength of the expiratory muscles and had no effect on forced expiratory flows and pulmonary volumes and capacities (Table 1). There was also a tendency towards an increase in MIP and MVV suggesting that the program had a general effect on the strength and the endurance of the respiratory musculature. Contrary to what had been described in aging athletes (Hagberg et al., 1988), we have found no significant differences in the spirometric parameters between the
128
A.B. Rendas el al., Arch. Gerontol. Geriatr. 22 (1996) 123 130
exercise and control groups. This is probably due to the fact that, in lifelong athletes, the effects of exercise on the lungs and chest wall take place during a much longer time period, starting early in adult life, thus allowing for the parenchymal changes to occur. The effect of physical training on the pulmonary volumes of nonathletic elderly remains controversial, with one study reporting an increase (Frandin et al., 1991) and other no change (Sidney and Shepard. 1977), whereas a third one only found an improvement when the baseline values where low (Niinimaa and Shepard, 1978). The similar spirometric values found in our two groups could have been due to the moderate increase in work load produced in the exercise group and also by the use of a control group who was active in the performance of their daily activities. Although we have not used a specific scale to evaluate the activities of daily living (ADL), the information gathered from the scale of Grimby allowed us to conclude that all the women performed domestic work at home and walked to do their shopping. In the future it will be important to evaluate the effects of exercise on ADL using appropriate scales. The presence of mild dyspnea, grade 1 of the MRC questionnaire, in a few controls, probably reflected a lesser degree of fitness in that group. Wheezing reported as an isolated finding was similar in both groups and had already been described in other studies (Dow et al., 1991; Sparrow et al., 1993) who suggested that it could be related to an increase in bronchial reactivity or to an altered autonomic function with aging. One recent European study on maximal respiratory pressures in healthy adults between 18 and 70 years (Bruschi et al., 1992) found that age influenced a decrease in MEP only in older women and suggested that this could be due to a greater decline of abdominal muscular strength in comparison with men. The effect of exercise in the respiratory muscles was reported in one study (Robinson and Kjeldgaard, 1982), performed in younger subjects, male and female, whose training consisted of running for 20 weeks. This study found an isolated and significant increase in MEP and considered that running was not an adequate stimulus for the increase in inspiratory muscle strength but suggested that the general improvement in physical condition could have increased the strength of the abdominal muscles and thus contributed to the significant increase in MEP. Our results seem to be in accordance with these findings. Another study, performed in elderly men and women (Belman and Gaesser, 1988), demonstrated that specific ventilatory training of the respiratory muscles for 8 weeks, improved muscle endurance assessed by a simultaneous increase in maximum sustained ventilation and MVV; unfortunately maximal respiratory pressures were not reported. In our study, although we have not used a standardized measurement of endurance, we considered MVV a reliable index since the flow rates were normal (Arora and Rochester, 1988). Taking this into account we considered that the higher values of MVV found in the active group could have been due to an effect of the exercise program on the endurance of respiratory muscles also confirmed by the significant correlation between endurance (MVV) and strength (MIP and MEP) found only in the exercise group. The purpose of this study was to evaluate respiratory muscle function using non-invasive methods, for
A.B. Rendas et al./ Arch. Gerontol. Geriatr. 22 (1996) 123-130
129
that reason we did not perform specific measurements of diaphragmatic function. Since we found no significant difference in MIP between the two groups, we considered the question of changes in diaphragmatic function less relevant for the present study. The respiratory muscles of the elderly seem to respond favorably to physical exercise, even when it is started only late in life; this improvement may reduce the deterioration of lung function parameters such as forced expiratory volume with aging. Whether this improvement will have an effect on reducing mortality with aging needs to be evaluated by longitudinal studies using a larger sample and with measurements of heart and circulatory parameters. The possible benefits of including specific respiratory muscle training (using voluntary isocapnic hyperpnea, inspiratory resistive loading or threshold loading), in physical exercise programmes for the elderly, must be weighted against the costs of such training and the adherence of the individuals. If such effects can be achieved by total body exercise, as shown in the present study, this approach may be more appropriate in the elderly population.
References American Thoracic Society (1987): Standardization of spirometry - - 1987 update. Am. Rev. Respir. Dis., 136, 1285-1298. Arora, N.S. and Rochester, D.F. (1988): Respiratory muscle strength and maximal voluntary ventilation in undernourished patients. Am. Rev. Respir. Dis., 126, 5 8. Belman, M.J. and Gaesser, G.A. (1988): Ventilatory muscle training in the elderly. J. Appl. Physiol., 64, 899-905. Bruschi, C.,Cerveri, I., Zoia, M., Fanfulla, F.,Fiorentini, M., Casali, L., Grassi, M. and Grassi, C. (1992): Reference values of maximal respiratory mouth pressures: a population-based study. Am. Rev. Respir. Dis., 146, 790 793. Dow, L., Coggon, D., Osmond, C. and Holgate, S.T. (1991): A population survey of respiratory symptoms in the elderly. Eur. Respir. J., 4, 267-272. Ferris, B.G. (1978): Epidemiology standardization project. Am. Rev. Respir. Dis., l l8(Part 2), 1-120. Frandin, K., Grimby, G., Mellstrom, D. and Svanborg, A. (1991): Walking habits and health-related factors in a 70 year-old population. Gerontology, 37, 281 288. Fries, J.F., Bloch, D.A., Harrington, H., Richardson, N. and Beck, R. (1993): Two-year results of a randomized controlled trial of a health promotion program in a retiree population: the Bank of America Study. Am. J. Med., 94, 455-462. Grimby, G. (1986): Physical activity and muscle training in the elderly. Acta Med. Scand. Supplement 711, 233 237. Hagberg, J.M., Yerg, J.E. and Seals, D.R. (1988): Pulmonary function in young and older athletes and untrained men. J. Appl. Physiol., 65, 101-105. Medical Research Council on Environmental and Occupational Health (1986): Questionnaire on Respiratory Symptoms. Medical Research Council, London. Niinimaa, V. and Shepard, R.J. (1978): Training and oxygen conductance in the elderly. I. The respiratory system. J. Gerontol., 33, 354-361. Peterson, D.D. and Fishman, A.P. (1992): Aging of the respiratory system. In: Update: Pulmonary Diseases and Disorders, pp. 1 17. Editor: A.P. Fishman. McGraw-Hill, New York. Robinson, E.P. and Kjeldgaard, J.M. (1982): Improvement in ventilatory muscle function with running. J. Appl. Physiol., 52, 1400-1406.
130
A.B. Rendas et al. / Arch. Gerontol. Geriatr. 22 (1996) 123 130
Sidney, K.H. and Shepard, R.J. (1977): Maximum and submaximum exercises tests in men and women in the seventh, eight and ninth decades of life. J. Appl. Physiol. 43, 280 287. Sorte, P.D., Kannel, W.B. and O'Connor, G. (1989): Mortality associated with respiratory function and symptoms in advanced age. The Framingham study. Am. Rev. Respir. Dis., 140, 379-384. Sparrow, D., O'Connor, G.T., Basher, R.C., Rosner, B and Weiss, S.T. (1993): Predictors of the new onset of wheezing among middle-aged and older men. Am. Rev. Respir. Dis., 147~ 367-371.
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. .}q
ELSEVIER
Archives of Gerontology and Geriatrics 22 (1996) 123 130
ARCHIVES OF GERONTOLOGY AND GERIATRICS
Respiratory muscle function in physically active elderly women 1 Ant6nio B. Rendas*, Teresa Gamboa, Teresa Ramilo, Amdlia S. Botelho, Cristina B~.rbara, Miguel Mota-Carmo Departamentos de Fisiologia, Fisiopatologia e de Pneumologia, Faculdade de Ci~ncias Mkdicas, Universidade Nova de Lisboa, Lisboa, Portugal
Received 24 July 1995; revised 27 October 1995; accepted 1 November 1995
Abstract This study was performed in 52 women, aged 60 to 76 years: 27 were engaged in a gymnastics program, 3 h a week, for at least 2 years; 25 were age-matched controls. All were lifelong nonsmokers, free of disease symptoms and lived independently at home; none had previously engaged in exercise programs. Spirometry included volumes, flows and maximal voluntary ventilation (MVV); maximal mouth pressures both inspiratory (MIP) and expiratory (MEP) were also measured. The two groups differed only in the mean value of MEP (cm of water) which was 107.7 +_ 37.3 S.D. in the active group and 87.4 _+ 22.8 S.D. in the controls (P = 0.028). MIP and MVV were also higher in the active group but the differences were not significant. However, a significant correlation between MVV and both MIP and MEP was only found in the active group, suggesting a relation between muscular endurance and strength. This exercise program, although not oriented towards the respiratory system, improved the performance of the respiratory muscles probably by an effect on the abdominal musculature. Keywords: Elderly; Exercise; Lung volumes; Forced expiratory flows; Maximal voluntary ventilation; Maximal mouth respiratory pressures
1Supported by grants 456/87/SAU and PBIC/C/SAU/1580/92 from Junta Nacional de Investiga¢~o Tecnol6gica, Lisboa, Portugal. * Departamento de Fisiopatologia, Faculdade de Ci~ncias M6dicas, Campo de Santana 130, 1200 Lisboa, Portugal. Tel.: 351 1 8853000; Fax: 351 1 851920. 0167-4943/96/$15.00 © 1996 Elsevier Science Ireland Ltd. All rights reserved SSDI 0167-4943(95)00686-9
124
A.B. Rencla~ et a/.
Arch. Geronto/. Geriatr. 22 (1996) 123 130
I. Introduction
The decline in lung function with aging is caused by irreversible changes in pulmonary structure and by an increased stiffness of the chest wall due to irreversible changes in the bones and joints of the thorax (Peterson and Fishman, 1992). The changes occurring in the respiratory muscles of the elderly have been less studied and yet, they are probably the only reversible factor that may reduce the decline in lung function with aging. On the other hand, recent data from the Framingham study (Sorle et al., 1989) have shown an inverse relationship between forced expiratory volume and mortality, particularly in elderly women, suggesting that a taster decline in lung function with age could indicate decrease survival. Elderly athletes have higher lung function indices than sedentary age-matched controls (Hagberg et al., 1988). This finding, although generally accepted, is based upon a limited number of observations, mostly case reports. Even less studies have been performed in individuals who were sedentary most of their lives and only started physical exercise late in life. Nevertheless this number is expected to increase in the future particularly with the diffusion of health promotion programs for elderly people (Fries et al., 1993). The present study was performed in such a group of elderly, to assess the effects on the respiratory muscles and on lung function, of a physical exercise program, not specifically oriented towards the respiratory system.
2. Methods
The study was performed in 52 women aged between 60 and 76 years who lived independently at home and had not been previously involved in exercise programs. The active group included 27 women engaged in a gymnastics program for at least 2 years, the mean duration of the activity period for the whole group was 5.8 _+ 2.8 years. The exercise program consisted of three sessions per week, lasting 1 h each; each session included stretching, muscular conditioning, aerobics and cooldown periods: the exercises consisted of stretching, calisthenics, walking and slow-jogging. During the aerobic period which lasted around 20 30 min, it was aimed to maintain the heart rate between 30 and 50% of the maximal individual heart rate. The sedentary group included 25 women living in the same geographical area and with a similar life style. None of the women ever complained of cough and sputum production, or pulmonary, chest wall and heart disease as assessed by a standard questionnaire (Medical Research Council. 1986). None was taking medications that could have affected the respiratory measurements, including the musculature. The women who complained of occasional wheezing, not associated with colds, and of dyspnea only when hurrying on level ground or walking uphill, were included in the study. The degree of current and previous activity was assessed by a scale (Grimby, 1986),
A.B. Rendas et al./ Arch. Gerontol. Geriatr. 22 (1996) 123-130
125
which is divided in six grades as follows: (1) hardly no physical activity; (2) mostly sitting, sometimes a walk, easy gardening or similar tasks; (3) light physical exercise around 2-4 h per week, e.g. walks, fishing, dancing, ordinary gardening etc. including walks to and from shops; (4) moderate exercise 1-2 h per week, e.g. jogging, gymnastics, heavier gardening, home-repair or easier physical activities more than 4 h per week; (5) moderate exercise at least 3 h per week, e.g. tennis, swimming, jogging, etc; (6) hard or very hard exercise regularly and several times per week, where physical exertion is great, e.g. jogging, skiing. Spirometric measurements, including functional residual capacity (FRC) by multi-breath helium dilution, were performed using a computerized version of the dry spirometer Volugraph 2000 (Mijhnardt, Bunnik, Holland), this equipment was also used for the measurement of the 12 s maximal voluntary ventilation (MVV). Forced spirometry was measured using a pneumotachograph model Compact (Vitalograph, Buckingham, England). Maximal mouth respiratory pressures, inspiratory (MIP) and expiratory (MEP), were measured using and a three-way valve system with a 1 mm leak connected to an aneroid manometer model Magnehelic (Dwyer Instruments, Michigan City, IN, USA) with a scale in cm of water (cmH20), calibrated using a mercury column. All the procedures were carefully explained to the individuals who gave their consent. Measurements were performed seated using a well-fitted flanged mouth piece (Hans Rudolph, Kansas City, MO, USA) and wearing a nose clip. After careful explanation, each one performed at least three slow vital capacity (VC) maneuvers followed by a single measurement of FRC. The forced spirometry also included at least three maneuvers. Measurements to obtain the spirometric data were performed in curves selected according to standard criteria (American Thoracic Society, 1987). For the MVV the highest of two values was recorded and the measurements were performed according to standardized recommendations (Ferris, 1978). For the inspiratory pressure measurement, a maximal expiration was performed followed by a sustained inspiratory effort, kept for 1 s, against the occluded valve. For the expiratory pressure measurement, a maximal inspiration was performed followed by a sustained expiratory effort, kept for 1 s against the occluded valve; the cheeks were held during the whole maneuver. After a period of training each patient performed at least three maneuvers for each measurement and the highest value, in cm of water, was recorded; if the difference between the best and the second best was higher than 5% more maneuvers were performed up to a maximal of five. All the spirometric results were corrected to BTPS values and represented as mean + standard deviation (S.D.). Besides the abbreviations already mentioned the following ones were used: TLC (total lung capacity), RV (residual volume), FVC (forced vital capacity), FEV~ (forced expiratory volume in the first second), FEF25 75'y,,(maximal midexpiratory flow). Handgrip strength was measured in both arms, in triplicate, using a Lafayette dynamometer, model 78/011 (Lafayette Instrument Company, Lafayette, IN, USA) and reported as the mean value of the six readings.
126
A.B. Rendas et al.
Arch. Gerontol. Geriatr. 22 (19961 123 130
All the procedures were performed by two physicians with previous experience on lung function testing in the elderly. The selection and the training of the group was done by a physical education specialist also experienced on working with elderly populations. For comparison between groups we employed unpaired two-tailored Student's t-tests. We calculated correlation coefficients, as measures of linear association between the different parameters. We considered P values less than 0.05 as statistically significant. The Statgraphics program was used for the statistical analyses.
3. Results The two groups were similar regarding age, height, weight and body mass index (Table 1). According to the scale of Grimby, the exercise group was labelled as grade 5 and the control group as grade 3. No differences were found between the two groups regarding the spirometry and the handgrip strength (Table 1). The higher values found in the active group for MVV (70.7 _+ 18.3 1/min) and MIP (76.6 _+ 25 cmH20) were not significantly different from those found in the control group: 67.4 _+ 18.5 1/min for MVV and 67.4 _+ 20.9 cmHzO for MIP. The MEP values were significantly different between the two groups with a mean value of 107.7 _+ 37.3 cmH20 in the active group and a mean value of 87.4 + 22.8 cmH20 in the control group (P = 0.028). Table 1 Mean values from the two groups Control (;i = 25}
Exercise (n = 27)
Age (years) Height (cm} Weight (kg) BMI (kg/m 2) Handgrip (kg} VC {11 FRC (11 TLC (11 RV (11 FVC {1} FEV I (11 FVC/FEV~ (%) FEF25 75,,,(1s i)
Mean
S.D.
Mean
S.D.
67.4 152.0 60.7 26. I 22.4 2.61 2.03 4.07 1.42 2.50 1.92 76.6 1.99
5.10 5.30 8.20 3.10 4.06 0.48 (/.58 /I.67 0.38 0.48 0.38 5.00 (I.66
67.6 153.0 64.9 27.5 21.6 2.67 2.06 4.10 1.41 2.59 1.96 75.9 1.92
4.50 5.90 7.60 3.20 4.95 0.42 0.45 0.54 0.46 0.40 0.31 6.20 0.64
No statistically signiticant differences were found.
A.B. Rendas et al./ Arch. Gerontol. Geriatr. 22 (1996) 123-130
127
Exercise Group 150-
150 -
100-
00
50-
~0r = 0.62 p =0.0009
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100 150 200 250
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r=0.5~ p =0.002
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Control Group 150-
150-
100,
100-
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Fig. 1. Correlation between M W and M E P and MIP. MVV correlates significantly with M E P and M I P only in exercise group. Each point represents one case.
In the exercise group, a significant correlation was found between the MVV and both respiratory pressures; these relations were not significant in the control group (Fig. 1). Two of the women from the active group (7%) reported occasional wheezing on exposure to smoke; in the control group this symptom was reported by three (12%). Four women from this group (16%) also reported shortness of breath while hurrying on level ground or walking uphill. Ten women from the active group (37%) and seven from the control group (28%) reported to be under treatment for arterial hypertension (diastolic blood pressure (115 mmHg).
4. Discussion This study showed that a gymnastics program of moderate intensity and long duration, started late in life, although not directed to the respiratory system, improved the strength of the expiratory muscles and had no effect on forced expiratory flows and pulmonary volumes and capacities (Table 1). There was also a tendency towards an increase in MIP and MVV suggesting that the program had a general effect on the strength and the endurance of the respiratory musculature. Contrary to what had been described in aging athletes (Hagberg et al., 1988), we have found no significant differences in the spirometric parameters between the
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exercise and control groups. This is probably due to the fact that, in lifelong athletes, the effects of exercise on the lungs and chest wall take place during a much longer time period, starting early in adult life, thus allowing for the parenchymal changes to occur. The effect of physical training on the pulmonary volumes of nonathletic elderly remains controversial, with one study reporting an increase (Frandin et al., 1991) and other no change (Sidney and Shepard. 1977), whereas a third one only found an improvement when the baseline values where low (Niinimaa and Shepard, 1978). The similar spirometric values found in our two groups could have been due to the moderate increase in work load produced in the exercise group and also by the use of a control group who was active in the performance of their daily activities. Although we have not used a specific scale to evaluate the activities of daily living (ADL), the information gathered from the scale of Grimby allowed us to conclude that all the women performed domestic work at home and walked to do their shopping. In the future it will be important to evaluate the effects of exercise on ADL using appropriate scales. The presence of mild dyspnea, grade 1 of the MRC questionnaire, in a few controls, probably reflected a lesser degree of fitness in that group. Wheezing reported as an isolated finding was similar in both groups and had already been described in other studies (Dow et al., 1991; Sparrow et al., 1993) who suggested that it could be related to an increase in bronchial reactivity or to an altered autonomic function with aging. One recent European study on maximal respiratory pressures in healthy adults between 18 and 70 years (Bruschi et al., 1992) found that age influenced a decrease in MEP only in older women and suggested that this could be due to a greater decline of abdominal muscular strength in comparison with men. The effect of exercise in the respiratory muscles was reported in one study (Robinson and Kjeldgaard, 1982), performed in younger subjects, male and female, whose training consisted of running for 20 weeks. This study found an isolated and significant increase in MEP and considered that running was not an adequate stimulus for the increase in inspiratory muscle strength but suggested that the general improvement in physical condition could have increased the strength of the abdominal muscles and thus contributed to the significant increase in MEP. Our results seem to be in accordance with these findings. Another study, performed in elderly men and women (Belman and Gaesser, 1988), demonstrated that specific ventilatory training of the respiratory muscles for 8 weeks, improved muscle endurance assessed by a simultaneous increase in maximum sustained ventilation and MVV; unfortunately maximal respiratory pressures were not reported. In our study, although we have not used a standardized measurement of endurance, we considered MVV a reliable index since the flow rates were normal (Arora and Rochester, 1988). Taking this into account we considered that the higher values of MVV found in the active group could have been due to an effect of the exercise program on the endurance of respiratory muscles also confirmed by the significant correlation between endurance (MVV) and strength (MIP and MEP) found only in the exercise group. The purpose of this study was to evaluate respiratory muscle function using non-invasive methods, for
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that reason we did not perform specific measurements of diaphragmatic function. Since we found no significant difference in MIP between the two groups, we considered the question of changes in diaphragmatic function less relevant for the present study. The respiratory muscles of the elderly seem to respond favorably to physical exercise, even when it is started only late in life; this improvement may reduce the deterioration of lung function parameters such as forced expiratory volume with aging. Whether this improvement will have an effect on reducing mortality with aging needs to be evaluated by longitudinal studies using a larger sample and with measurements of heart and circulatory parameters. The possible benefits of including specific respiratory muscle training (using voluntary isocapnic hyperpnea, inspiratory resistive loading or threshold loading), in physical exercise programmes for the elderly, must be weighted against the costs of such training and the adherence of the individuals. If such effects can be achieved by total body exercise, as shown in the present study, this approach may be more appropriate in the elderly population.
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