Share this article on:

00005768-199801000-0002400005768_1998_30_170_kallinen_backgrounds_1miscellaneous-article< 118_0_11_5 >Medicine & Science in Sports & Exercise©1998The American College of Sports MedicineVolume 30(1)January 1998pp 170-176Effort tolerance in elderly women with different physical activity backgrounds[Applied Sciences: Physical Fitness and Performance]KALLINEN, MAURI; SUOMINEN, HARRI; VUOLTEENAHO, OLLI; ALEN, MARKKUPeurunka-Medical Rehabilitation and Physical Exercise Centre, Laukaa, FINLAND; Department of Health Sciences, University of Jyväskylä, Jyväskylä, FINLAND; and Department of Physiology, University of Oulu, Oulu, FINLANDSubmitted for publication June 1996.Accepted for publication September 1997.ABSTRACTTo study effort tolerance in elderly women with different physical activity backgrounds, 52 physically active (PA) and 42 sedentary control women (CO) aged 66-85 yr were assigned to perform cycle ergometer exercise to their volitional maximum. Oxygen uptake, respiratory exchange ratio (RER), heart rate, work power, and rate pressure product were measured to evaluate the severity of exercise. Plasma C-ANP (C-terminus of the atrial natriuretic peptide prohormone) and plasma N-ANP (N-terminus of the atrial natriuretic peptide prohormone) were analyzed as indicators of cardiac load. Eighty-one percent (N = 42) of the PA and 52% (N = 22) of CO performed the ergometer exercise. The mean peak oxygen uptake was 22.6 and 15.1 mL·kg-·min-1 among PA and CO, respectively. Twenty-two of the 42 PA and 19 of the 22 CO terminated the ergometer exercise before attaining the objective maximum. The most common reasons for termination were the subject's own wish, abnormal cardiovascular response, or lower limb tiredness. Both C-ANP and N-ANP increased after exercise. The increase in plasma C-ANP correlated significantly with a few physiological variables, whereas comparable associations with N-ANP were not found. It is concluded that inexperience of physical exertion and medical as well as physiological factors limit effort tolerance among elderly women. Differences in the response of C-ANP and N-ANP were found that are suggested to be due to differences in the postsecretory mechanisms between these hormones.Age has been shown to have a high impact on aerobic capacity and effort tolerance among women (6,31). Whether the effort tolerance of elderly people is diminished by incipient or existing disease or by a sedentary lifestyle is an important question for exercise prescription. One of the means to approach this question is physical performance testing. There may, however, be problems in doing this in the case of elderly people(24). Some of these concern disturbances in cardiovascular functioning and signs of underlying coronary heart disease together with low functional capacity of the musculoskeletal system(11,23). Additionally, the number of serious cardiovascular complications seems to be higher among older than younger adults (9).In earlier studies reporting on aerobic capacity and exercise tolerance among elderly women(2,7,10,11,18,19,30,31), a selected group has typically been tested excluding subjects with chronic diseases or health problems. It is thus difficult to say which specific factors generally limit effort tolerance among elderly women. During cycle ergometer exercise, loading of the musculoskeletal and, particularly, the cardiovascular systems has to be considered. The assessment of cardiac load during exercise is important when estimating the risk of cardiovascular complications. Physiological factors such as oxygen uptake, work power, and rate pressure product (RPP, multiple measure comprising systolic blood pressure and heart rate) can be used as indirect and noninvasive measures of cardiac load. More specific markers of cardiac load are, however, needed.A 126-amino acid atrial natriuretic peptide (pro-ANP) is stored in human cardiomyocytes and secreted into the circulation in equimolar amounts as N-ANP(amino acids 1-98) and C-ANP (amino acids 99-126)(25,26). The 28-amino acid carboxyterminal peptide (C-ANP) is biologically active, having natriuretic, diuretic and vasodilatory effects (5). The 99-amino acid aminoterminal peptide (N-ANP) is biologically inactive and more stable, having a 5-10 time longer half-life than C-ANP (25). The stimulus for ANP release is increased atrial tension(4,13,16). The N-ANP plasma concentration at rest could be a marker of symptomless left-ventricular dysfunction. The resting N-ANP concentration above 54 pmol·L-1 has a sensitivity of 90% and a specificity of 92% in detecting of patients with symptomless left-ventricular dysfunction. Furthermore, the concentration of N-ANP at rest increases with the clinical severity of heart failure(14). It has been pointed out that C-ANP and N-ANP increase during physical loading (3). Plasma ANP has been shown to increase proportionally with the severity of exercise, the relative intensity of the exercise evidently being the most important factor in the ANP increase (8).It was our main purpose to elucidate the factors that limit effort tolerance in elderly women. The effect of health status and level of physical activity on effort tolerance and aerobic capacity was studied. Therefore, we also evaluated cardiac load by biochemical (C-ANP and N-ANP) and by various physiological variables during ergometric loading. Physically active elderly women and noninstitutionalized sedentary control women were studied for comparison.METHODSSubjectsSixty physically active women aged 66-85 yr were selected from a sample of 600 members of Finnish sport organizations on the basis of a physical activity questionnaire. Most of them had a life-long training background and were still active in various sports (running, cross-country skiing, track and field, and gymnastics). As a control group, a random sample of 71 sedentary women aged 70-81 yr was taken from the population register of the rural municipality of Jyväskylä. The control women performed light habitual physical activities (housekeeping, shopping, and walking). None of them, however, reported regular endurance type training or other vigorous physical exercise.Fifty-two (87%) of the physically active women and 42 (59%) of the control women took part in the laboratory examinations (22). Those women who failed to attend the laboratory examinations were interviewed by phone about the reasons to their nonparticipation in further examinations. Almost all of the control group explained their nonparticipation by reference to health problems, and the physically active women failed to take part mostly because of travel arrangements. The ethical committee of the Central Hospital of Central Finland approved the study protocol, and all subjects gave their written informed consent.Laboratory ExaminationsBefore the laboratory investigations, questionnaires were sent to the subjects to elicit background data concerning their health, medication, and physical activity. The laboratory examinations consisted of various anthropometric and physiological measurements. A detailed physical examination was done to place the contraindications for the exercise(1). The precise exclusion criteria are listed inAppendix 1. Blood pressure, body height and weight, body fat (by bioelectrical impedance), and 12-lead ECG were taken before the exercise. In addition, erythrocyte sedimentation rate and blood hemoglobin concentration were measured before the exercise. Serum gamma glutamyltransferase, alanine aminotransferase activities, and creatinine concentration were analyzed afterward to exclude hepatic or renal disturbances.Subjects were to perform an exhaustive cycle ergometer exercise to their volitional maximum. The subjects were asked to keep the pedaling frequency within the limits of 50-60 rpm as far as possible and a weight of 200-300 g was added after every 2 min to the cycle's basket connected to a mechanical braking system (Monark 814 E, Sweden). The mean incremental loading after every 2 min was 18 W, depending on pedaling frequency. The subjects were encouraged to continue pedaling the ergometer to their personal maximum unless they experienced any exceptional symptoms (chest pain, dizziness, severe breathlessness, musculoskeletal pain). ECG leads II, V1, V5 and the well-being of the subject were monitored continuously; 12-lead ECG, and brachial arterial cuff pressure were recorded at minimum intervals of 2 min. Oxygen uptake, carbon dioxide production, ventilation, and respiratory exchange ratio (RER) were measured after each 30 s with a gas analyzer(Minjhardt Oxycon-4, Odijk, The Netherlands). The indications for exercise cessation were based on the guidelines of American College of Sports Medicine(1) (Appendix 2.). The point of maximal effort was evaluated by the laboratory personnel on the basis of objective signs of subject's exhaustion, i.e., breathlessness, or if, for example, the pedaling frequency and work power consistently decreased in spite of the subject's effort. On the other hand, if the exercise was terminated for medical criteria (Appendix 2) or if the subject suddenly stopped without having reached exhaustion, the test was considered submaximal. According to their ability to perform the exercise submaximally or maximally, the physically active subjects and controls were divided into submaximally exercised (submax) and maximally exercised subjects (max).To evaluate the cardiac load, a 10-mL blood sample from subject's (sitting) cubital vein was taken by venapuncture in EDTA tubes immediately before and within 1 minute after the ergometer test for the plasma C-ANP and N-ANP analysis (26). The subjects were highly cooperative, and thus good-quality samples were obtained in all cases except in three cases in which we failed to get a blood sample within a minute after the exercise. The blood samples were placed immediately in ice and centrifuged within 60 min at 4°C. Plasma was separated and stored at -80°C for further analysis. Plasma C-ANP and N-ANP radioimmunoassays were carried out by using the methods described previously (27-29). For the C-ANP assay, plasma samples were extracted with Sep-Pak C18 cartridges(Waters, Milford, MA) with a recovery of 82 ± 10%. N-ANP was measured directly from 25-μL plasma samples. The sensitivities of the C-ANP and N-ANP assays were 2 pmol·L-1 plasma and 30 pmol·L-1 plasma, respectively. The intra- and interassay coefficients of variation were < 10% and < 15%, respectively. The two blood samples for C-ANP and N-ANP analysis were also taken at 15-20-min intervals from those subjects (N = 13) excluded from the exercise to determine the normal variability of C-ANP and N-ANP over time. N-ANP was measured in all of the 42 exercising PA and in 19 of the 22 exercising CO. The sample size of N-ANP was reduced because of problems in the venapuncture of three subjects. C-ANP was measured in 30 exercising PA and 16 exercising CO. The marked reduction of 15 in the sample size of C-ANP was due to technical problems (12 because of technical failure in the centrifuge thermostat and 3 because of problems in performing the venapuncture).Statistical AnalysisAll data are expressed as means ± SD. The difference between the groups at the baseline were analyzed with one-way ANOVA. The effects of physical loading on the response of C-ANP and N-ANP were assessed using ANOVA with repeated measures. Pearson's product moment correlation test was done to determine connections between C-ANP and N-ANP with the physiological variables. Linear regression analysis was used to determine connections between aerobic capacity and the other variables. Subjects with beta-blockers were excluded for all statistical analyses concerning heart rate and rate pressure product (RPP) data. An alpha level of 0.05 was set to mark statistical significance. The statistical software package used was SPSS for windows version 6.0 (SPSS Inc., Cary, NC).RESULTSThe exercised physically active women (PA) and control women (CO) were comparable in age. PA were leaner than CO. Aerobic capacity expressed in peak work power and peak oxygen uptake was higher among PA than CO. This difference was more pronounced when the aerobic capacity figures were expressed in relation to body weight. The RER values tended to be lower among CO than PA(Table 1).TABLE 1. Selected characteristics of the exercised physically active women and control women (values are mean ± SD).Eighty-one percent (N = 42) of the PA who came to the laboratory and 52% (N = 22) of CO performed the ergometer test. Musculoskeletal problems (N = 2), heart arrhythmia (N = 2), and cardiac valve disease (N = 2) were the most common contraindications for the ergometer exercise among PA. The main contraindications among CO were musculoskeletal problems (N = 7), severe coronary heart disease(N = 3), heart arrhythmia (N = 3), acute infections(N = 3), and uncontrolled diabetes (N = 3). One control subject refused to perform the ergometer exercise.Submaximally exercised PA were somewhat older than maximally exercised PA. Cardiovascular and musculoskeletal problems were common in the groups studied especially among CO in the submax-group (Table 2). Three of the exercised controls used digitalis medication, and four used beta-blockers. Among the physically active elderly women, four used digitalis and two used beta-blockers, respectively.TABLE 2. Health status of the submaximally or maximally exercised subjects.Twenty-two of the 42 PA terminated the ergometer exercise before objective exhaustion, and of the CO, only 3 of the 22 went to the maximum. The most common reasons for termination among PA were the subject's own wish to stop or abnormal cardiovascular reactions. Among CO, tiredness of the legs was also a common reason for termination (Table 3). In submaximal exercise, PA differed from CO in aerobic performance characteristics only when expressed in relation to body weight. In maximal exercise, the difference in peak heart rate and rate pressure product (peak RPP) reached statistical significance (Table 4).TABLE 4. Selected characteristics in submaximal and maximal exercise among physically active and control women (values are mean ± SD).TABLE 3. Reasons for early exercise termination in physically active and control women.When looking further at the association between age and aerobic capacity, a significant correlation was observed among PA between age and oxygen uptake(mL·kg-1·min-1) (r = -0.69, P < 0.001). In this group (N = 35), the regression equation for oxygen uptake was: y = 101.3 - (1.07) age. A comparable association was not found among CO (r = 0.026, P = 0.467). Among PA, age did not associate significantly with physical activity in kilometers (r = 0.272, P = 0.081) or lean body mass (r = 0.061, P = 0.703).In those subjects not physically loaded, no change in C-ANP and N-ANP was observed (data not shown). The basal plasma concentrations of C-ANP and N-ANP did not differ between PA and CO (data not shown). Both C-ANP and N-ANP increased during physical loading in submaximal and maximal exercise. No significant differences between the groups were found in the effect of exercise on either C-ANP or N-ANP (ANOVA with repeated measures). The basal level of N-ANP among PA before submaximal exercise was, however, significantly higher than before maximal exercise among PA and higher than before submaximal exercise among CO (Fig. 1). On the basis of the former results, we looked more closely at the associations between the C-ANP and N-ANP responses and various physiological variables. Interestingly, the increases in C-ANP and N-ANP among either PA or CO were not significantly associated with each other (r = 0.086-0.113, P = 0.552-0.753). Among PA significant correlations were found only between the percentage increase in plasma C-ANP and between peak W per body weight (peak W·kg-1) (r= 0.448, P = 0.013) and peak oxygen uptake(mL·kg-1·min-1) (r = 0.533, P = 0.003). The corresponding significant correlations among CO were between percentage increase in plasma C-ANP and heart rate increase (r = 0.752, P = 0.002) and peak W per kilogram body weight (Peak W·kg-1) (r = 0.541, P = 0.030). Peak RPP (rate pressure product), however, was not associated with the increase in C-ANP and N-ANP among either PA or CO (r =-0.191 to 0.236, P = 0.143-0.998). There was also no association between age and the increase in C-ANP and N-ANP among either PA or CO (r =-0.270 to 0.244, P = 0.150-0.957). The data of both the submaximally and maximally exercised women were included in these analyses. The subjects with beta-blockers were excluded from the data on heart rate, systolic and diastolic blood pressure increase, and rate pressure product.Figure 1-The plasma concentrations of C-ANP and N-ANP at rest and after submaximal and maximal exercise (exercise) among two groups of elderly women. Values in the columns are means ± SD. * Significant difference compared with the resting values of PA-max and CO-submax.(P < 0.05).DISCUSSIONIt has been suggested that changes in body composition and cardiorespiratory and musculoskeletal system together with diminished physical activity lead to a decrease in aerobic capacity and effort tolerance(21). By appropriate physical exercise, it is possible to resist the deleterious effects of aging (21). In our study, the physically active women had superior aerobic performance and effort tolerance compared with the less active control women. Age was negatively correlated with aerobic capacity only in the physically active women, whereas no association between age and lean body mass was found in this group. In physically active women, no significant association between the age and physical activity (in kilometers) was seen. Among control women, age was not significantly associated with aerobic capacity and effort tolerance. The effect of aging and cause-and-effect relationships must be, however, looked with caution in a study with cross-sectional design and limited number of selected subjects and low age range.The physically active women had less than half the number of diseases compared with the control women. In addition to the number of cardiovascular diseases, the number of musculoskeletal complaints was higher in the control women. It is thus worthy of consideration that musculoskeletal problems also may hamper effort tolerance in cycle ergometer tests among elderly women. Another point of view is that medications such as beta-blockers may also hamper loading of the musculoskeletal system. However, when the subjects using beta-blockers were excluded, no differences were found in the results in respect of the aerobic power. This may be due the fact that there were also beta-blocker users among the physically active women. Although our elderly subjects had chronic diseases, no complications emerged in relation to exercise. Our subjects had difficulties in reaching the true maximum, which may, together with properly adjusted contraindications for exercise, protect them from complications.Fifty-three percent of the physically active elderly terminated the exercise before showing objective signs of exhaustion. The mean respiratory exchange ratio (RER) did not reach values over 1.00 even in cases of maximal exercise. It would appear difficult to push elderly people to peak effort where they have no current experience of such effort. This may especially be true during more difficult conditions, such as when measuring maximal oxygen uptake directly. It was also evident that the control women in particular had difficulties in reaching their peak aerobic capacity. In some earlier studies,“maximal” exercise has not been exactly defined, and RER values were usually missing. Furthermore, the subject's health and physical activity levels have been variously described in these studies(6,11,19,31). In some of other studies, RER values ≥ 1.1 have been properly reported in carefully screened healthy subjects (10,12,17,20). It is thus difficult to compare these studies with each other because of different study populations and methodology. It is obvious that subjects in this study were not totally healthy but were selected only against contraindications for exercise. Thus our results reflect the health, exercise capacity, and effort tolerance of an elderly female population with different physical activity levels.In the present study, some technical difficulties were encountered in measuring the oxygen uptake directly in all of the subjects. The mouthpiece felt uncomfortable for some of the subjects, and we had to use an air-cushioned mask, which had to be positioned very carefully to avoid leakage of air from the mask. Despite of these precautions, we were unable to measure the direct oxygen uptake in seven subjects of the physically active women and nine of the control women.Our second purpose in this study was to evaluate the cardiac load by biochemical and physiological variables during cycle ergometer loading. Our results are well in line with earlier observations of C-ANP and N-ANP responses (3,8,15). There was an increase in C-ANP and N-ANP concentrations with submaximal and maximal exercise among both physically active and control women. It is also noticeable in our data that basal levels of N-ANP were highest in those active elderly women whose exercise was submaximally terminated (Fig. 1). When looking at the individual values of N-ANP and the reason for termination, we found out that in some subjects whose blood pressure was elevated at rest and rose considerably high during exercise there was also a high basal N-ANP concentration. There were, however, no significant differences in the systolic or diastolic blood pressure or its responses to exercise between the submaximal or maximal exercise. Also, there were other reasons (subject's own wish to stop, heart arrhythmia; Table 3) why the exercise was terminated (submaximal exercise) in the physically active group having high N-ANP concentration. The results remained the same when excluding the subjects with beta-blockers and heart failure, which are also common causes to the elevated basal N-ANP concentration. It seems thus that elevated basal N-ANP concentration predicts interruption of the exercise, which was seen in our study only in the physically active women. To clarify the reason for this needs further studies with precise evaluation cardiac function (atrial pressure measurements, echocardiography).No significant association between increases in C-ANP and N-ANP was found in this study despite the fact that these forms of ANP are secreted in equimolar amount into circulation. Furthermore, there were no associations between the N-ANP increase and physiological variables, whereas connections between C-ANP and with only a few physiological variables were found. This may be due to the fact that the concentration of C-ANP and N-ANP is stimulated by atrial tension and other physiological variables such as rate pressure product, blood pressure, heart rate, and oxygen consumption are not directly related to atrial tension. Plasma C-ANP may, however, be more sensitive to acute response than N-ANP (25). On the other hand, N-ANP is more stable having a longer half-life than C-ANP(25). Furthermore, the efficient receptor binding and enzymatic degradation of C-ANP causes large and rapid fluctuations in plasma C-ANP levels (29). It is possible, therefore, that the changes in plasma C-ANP observed in the present study are caused by postsecretory mechanisms. The increase in heart rate in the control women was strongly associated with that in C-ANP. In the physically active women, a comparable association was not found. These results remained the same when excluding the subjects with beta-blockers and heart failure. Heart rate has been not been considered the major stimulus for ANP release in the earlier studies (8). It may be that the strong connection between heart rate and C-ANP increase may be due to the steeper increase in heart rate and C-ANP concentration among the control women without any closer causal relationship between heart rate and C-ANP release.In conclusion, both cardiovascular and musculoskeletal problems make the measurement of maximal aerobic capacity difficult among elderly women. It is also apparent that elderly women's effort tolerance is diminished not only for medical and physiological reasons but also an account of mental adaptation to a more inactive lifestyle. Technical difficulties also exist while measuring oxygen uptake among elderly women. The development of more comfortable and specific methods would improve the possibilities of evaluating true maximal aerobic capacity among elderly women. Some differences in the response of C-ANP and N-ANP were found that could be due to differences in the postsecretory mechanisms between these hormones.This study was supported by the Ministry of Education, Finland and Peurunka-Medical Rehabilitation and Physical Exercise Centre, Laukaa, Finland. Our special thanks go to Professor Juhani Leppäluoto for his valuable comments on the manuscript.Address correspondence to: Dr. Mauri Kallinen, Peurunka-Medical Rehabilitation and Physical Exercise Centre, FIN-41350 Laukaa as, Finland. E-mail: mauri.kallinen@peurunka.fi.REFERENCES1. American College of Sports Medicine. Guidelines for Exercise Testing and Prescription, 5th Ed. Philadelphia: Williams & Wilkins, 1995, pp. 29-109. [Context Link]2. Badenhop, D. T., P. A. Cleary, S. F. Schaal, E. L. Fox, and R. L. Bartels. Physiological adjustments to higher or low-intensity exercise in elders. Med. Sci. Sports Exerc. 15:496-502, 1983. [CrossRef] [Full Text] [Medline Link] [Context Link]3. Baker, B. L., W. C. Wu, C. J. Winter, et al. Exercise increase the circulating concentration of the N-terminus of the atrial natriuretic factor prohormone in normal individuals. Am. Heart J. 12:1395-1402, 1991. [CrossRef] [Medline Link] [Context Link]4. Cody, R. J., S. H. Kubo, J. H. Laragh, S. A. Atlas, A. Shaknovitch, and K. Ryman. Exercise induced secretion of atrial natriuretic factor and its relation to hemodynamic and sympathetic stimulation in untreated essential hypertension. Am. J. Cardiol. 68:918-924, 1991. [CrossRef] [Medline Link] [Context Link]5. De Bold, A. J., H. B. Borenstein, A. T. Veress, and H. Sonnenberg. A rapid and potent natriuretic response to intravenous injection of atrial myocardial extracts in rats. Life Sci. 28:89-94, 1981. [CrossRef] [Medline Link] [Context Link]6. Fleg, J. L. and E. G. Lakatta. Role of muscle loss in the age-associated reduction in ˙VO2max. J. Appl. Physiol. 65:1147-1151, 1988. [Medline Link] [Context Link]7. Fleg, J. L., F. O'Connor, G. Gerstenblith, et al. Impact of age on the cardiovascular response to dynamic upright exercise in healthy men and women. J. Appl. Physiol. 78:890-900, 1995. [Medline Link] [Context Link]8. Freund, B. J., C. E. Wade, and J. R. Claybaugh. Effects of exercise on atrial natriuretic factor: release mechanisms and implications for fluid homeostasis. Sports Med. 6:364-376, 1988. [CrossRef] [Full Text] [Medline Link] [Context Link]9. Gibbons, L., S. N. Blair, H. W. Kohl, and K. Cooper. The safety of maximal exercise testing. Circulation 80:846-852, 1989. [CrossRef] [Full Text] [Medline Link] [Context Link]10. Hagberg, J. M., J. E. Graves, M. Limacher, et al. Cardiovascular responses of 70- to 79-yr-old men and women to exercise training. J. Appl. Physiol. 66:2589-2594, 1989. [Context Link]11. Kavanagh, T., D. J. Mertens, V. Matosevic, R. J. Shephard, and B. Evans. Health and aging of masters athletes. Clin. Sports. Med. 1:72-78, 1989. [Context Link]12. Kohrt, W. M., M. T. Malley, A. R. Coggan, et al. Effects of gender, age, and fitness level on response of ˙VO2max to training in 60-71 yr olds. J. Appl. Physiol. 71:2004-2011, 1991. [Medline Link] [Context Link]13. Lang, R. E., H. Tolken, D. Ganten, F. C. Luft, H. Ruskoaho, and T. Unger. Atrial natriuretic factor: a circulating hormone stimulated by volume loading. Nature 314:264-266, 1983. [Context Link]14. Lerman, A., R. J. Gibbons, R. J. Rodeheffer, et al. Circulating N-terminal atrial natriuretic peptide as a marker of symptomless left ventricular dysfunction. Lancet 341:1105-1108, 1993. [CrossRef] [Full Text] [Medline Link] [Context Link]15. Mandroukas K., K. Zakas, N. Aggelopoulou, K. Christoulas, G. Abatzides, and M. Karamouzis. Atrial natriuretic factor responses to submaximal and maximal exercise. Br. J. Sports Med. 29:248-251, 1995. [CrossRef] [Medline Link] [Context Link]16. Mannix, E. T., M. O. Farber, G. R. Aronoff, et al. Regulation of atrial natriuretic peptide release in normal humans. J. Appl. Physiol. 71:1340-1345, 1991. [Context Link]17. Panton, L. B., J. E. Graves, M. L. Pollock, et al. Relative heart rate, heart rate reserve and ˙VO2 during submaximal exercise in the elderly. J. Gerontol. 51A:M165-M171, 1996. [Context Link]18. Posner, J. D., K. M. Gorman, H. S. Klein, and A. Woldow. Exercise capacity in the elderly. Am. J. Cardiol. 57:52C-58C, 1986. [Medline Link] [Context Link]19. Posner, J. D., K. M. Gorman, H. S. Klein, and C. J. Cline. Ventilatory threshold: measurement and variation with age. J. Appl. Physiol. 63:1519-1525, 1987. [Medline Link] [Context Link]20. Poulin, M. J., D. Paterson, D. Govindasamy, and D. Cunningham. Endurance training of older men: responses to submaximal exercise.J. Appl. Physiol. 73:452-457, 1992. [Context Link]21. Shephard, R. J. Impact of aging on major physiological systems at rest and during submaximal and maximal exercise. In: Aging, Physical Activity, and Health, R. J. Shephard (Ed.). Champaign, IL: Human Kinetics, 1997, pp. 57-138. [Context Link]22. Sipilä, S. and H. Suominen. Muscle ultrasonography and computed tomography in elderly trained and untrained women. Muscle Nerve 16:294-300, 1993. [CrossRef] [Medline Link] [Context Link]23. Skinner, S. Importance of aging for exercise testing and exercise prescription. In: Exercise Testing and Prescription for Special Cases: Theoretical Basis and Clinical Application, J. S. Skinner(Ed.). Philadelphia: Lea & Febiger, 1993, pp. 75-86. [Context Link]24. Spirduso, W. W. Physical Dimensions of Aging. Champaign, IL: Human Kinetics, 1995, pp. 329-365. [Context Link]25. Thibault, G., K. K. Murthy, J. Gutkowska, et al. NH2-terminal fragment of proatrial natriuretic factor in the circulation: identification, radioimmunoassay and half-life.Peptides 9:47-53, 1988. [CrossRef] [Medline Link] [Context Link]26. Thibault, G., R. Garcia, J. Kutkowska, et al. The propeptide Asn 1-Tyr 126 is the storage form of rat atrial natriuretic factor.Biochem. J. 241:265-272, 1987. [Medline Link] [Context Link]27. Vuolteenaho, O. Radioimmunoassay for beta-endorphin(1-18), a novel pituitary peptide derived from proopiomelanocortin.Biophys. Res. Commun. 130:1226-1232, 1985. [Context Link]28. Vuolteenaho, O., O. Arjamaa, and N. Ling. Atrial natriuretic peptides (ANP): rat atria store high molecular weight precursor but secrete processed peptides of 25-35 amino acids. Biophys. Res. Commun. 129:82-88, 1985. [Context Link]29. Vuolteenaho, O., P. Koistinen, V. Martikkala, T. Takala, and J. Leppäluoto. Effect of physical exercise in hypobaric conditions on atrial natriuretic peptide secretion. Am. J. Physiol. 263:R647-R652, 1992. [Medline Link] [Context Link]30. Warren, B. J., D. C. Niemann, R. G. Dotson, et al. Cardiorespiratory responses to exercise training in septuagenarian women.Int. J. Sports Med. 14:60-65, 1993. [CrossRef] [Medline Link] [Context Link]31. Wells, C. L., M. A. Boorman, and D. M. Riggs. Effect of age and postmenopausal status on cardiorespiratory fitness in masters women runners. Med. Sci. Sports. Exerc. 24:1147-1154, 1992. [CrossRef] [Full Text] [Medline Link] [Context Link]APPENDIX 1: PREDETERMINED CONTRAINDICATIONS FOR EXERCISE TESTING IN ELDERLY WOMENRecent (under 3 months) or suspected myocardial infarction; Unstable coronary heart disease, angina pectoris at rest or during light activities(dressing, eating, washing);Premature ventricular beats (over 30%);Uncontrolled atrial arrhythmia influencing cardiac functioning (atrial fibrillation, sustained supraventricular tachycardia);Third degree atrioventricular block, left bundle branch block (LBBB);Pacemaker (fixed rhythm);Recent systemic or pulmonary embolia (under 6 months);Ventricular aneurysm;Cardiomyopathy;Severe stenosis of aortic valve;Deep vein thrombosis in the extremities or thrombosis in the heart;Suspected or diagnosed aortic aneurysm;Suspected or active myocarditis or pericarditis;Acute infection;Severe psychological distribution (psychosis, dementia);Systolic blood pressure at rest over 200 mm Hg, diastolic over 120 mm Hg;Uncontrolled metabolic disease (diabetes, thyrotoxicosis, myxedema, etc.);Anemia (hemoglobin under 100 g·L-1);Disorders of neuromuscular system (hemiplegia, osteoarthritis), which make cycling difficult;The subject refuses to exercise. [Context Link]APPENDIX 2: PREDETERMINED INDICATIONS FOR TERMINATING THE EXERCISESystolic blood pressure rise over 250 mm Hg, diastolic over 120 mm Hg;Decrease in systolic blood pressure by more than 10 mm Hg or unchanged in spite of loading;Angina pectoris;2-mm horizontal decrease or down-sloping ST segment in the exercise ECG;Rise in number of the ventricular premature beats (over 30% of the QRS complexes);R on T premature ventricular beats;Sudden fall in heart rate in spite of loading;Sustained supraventricular tachycardia;Second or third degree atrioventricular block;Subject confused, poor cooperation, or movement coordination;Subject's pallor, bluish skin, nausea;Severe pain in musculoskeletal system;Subject refuses to continue the exercise. [Context Link] PHYSICAL PERFORMANCE; AGING; EXERCISEovid.com:/bib/ovftdb/00005768-199801000-0002400005768_1983_15_496_badenhop_physiological_|00005768-199801000-00024#xpointer(id(R2-24))|11065213||ovftdb|00005768-198315060-00010SL0000576819831549611065213P47[CrossRef]10.1249%2F00005768-198315060-00010ovid.com:/bib/ovftdb/00005768-199801000-0002400005768_1983_15_496_badenhop_physiological_|00005768-199801000-00024#xpointer(id(R2-24))|11065404||ovftdb|00005768-198315060-00010SL0000576819831549611065404P47[Full Text]00005768-198315060-00010ovid.com:/bib/ovftdb/00005768-199801000-0002400005768_1983_15_496_badenhop_physiological_|00005768-199801000-00024#xpointer(id(R2-24))|11065405||ovftdb|00005768-198315060-00010SL0000576819831549611065405P47[Medline Link]6656559ovid.com:/bib/ovftdb/00005768-199801000-0002400000406_1991_12_1395_baker_concentration_|00005768-199801000-00024#xpointer(id(R3-24))|11065213||ovftdb|SL00000406199112139511065213P48[CrossRef]10.1016%2F0002-8703%2891%2990583-4ovid.com:/bib/ovftdb/00005768-199801000-0002400000406_1991_12_1395_baker_concentration_|00005768-199801000-00024#xpointer(id(R3-24))|11065405||ovftdb|SL00000406199112139511065405P48[Medline Link]1835277ovid.com:/bib/ovftdb/00005768-199801000-0002400000416_1991_68_918_cody_hypertension_|00005768-199801000-00024#xpointer(id(R4-24))|11065213||ovftdb|SL0000041619916891811065213P49[CrossRef]10.1016%2F0002-9149%2891%2990409-Eovid.com:/bib/ovftdb/00005768-199801000-0002400000416_1991_68_918_cody_hypertension_|00005768-199801000-00024#xpointer(id(R4-24))|11065405||ovftdb|SL0000041619916891811065405P49[Medline Link]1656723ovid.com:/bib/ovftdb/00005768-199801000-0002400005557_1981_28_89_bold_natriuretic_|00005768-199801000-00024#xpointer(id(R5-24))|11065213||ovftdb|SL000055571981288911065213P50[CrossRef]10.1016%2F0024-3205%2881%2990370-2ovid.com:/bib/ovftdb/00005768-199801000-0002400005557_1981_28_89_bold_natriuretic_|00005768-199801000-00024#xpointer(id(R5-24))|11065405||ovftdb|SL000055571981288911065405P50[Medline Link]7219045ovid.com:/bib/ovftdb/00005768-199801000-0002400004560_1988_65_1147_fleg_associated_|00005768-199801000-00024#xpointer(id(R6-24))|11065405||ovftdb|SL00004560198865114711065405P51[Medline Link]3182484ovid.com:/bib/ovftdb/00005768-199801000-0002400004560_1995_78_890_fleg_cardiovascular_|00005768-199801000-00024#xpointer(id(R7-24))|11065405||ovftdb|SL0000456019957889011065405P52[Medline Link]7775334ovid.com:/bib/ovftdb/00005768-199801000-0002400007256_1988_6_364_freund_implications_|00005768-199801000-00024#xpointer(id(R8-24))|11065213||ovftdb|00007256-198806060-00003SL000072561988636411065213P53[CrossRef]10.2165%2F00007256-198806060-00003ovid.com:/bib/ovftdb/00005768-199801000-0002400007256_1988_6_364_freund_implications_|00005768-199801000-00024#xpointer(id(R8-24))|11065404||ovftdb|00007256-198806060-00003SL000072561988636411065404P53[Full Text]00007256-198806060-00003ovid.com:/bib/ovftdb/00005768-199801000-0002400007256_1988_6_364_freund_implications_|00005768-199801000-00024#xpointer(id(R8-24))|11065405||ovftdb|00007256-198806060-00003SL000072561988636411065405P53[Medline Link]2976519ovid.com:/bib/ovftdb/00005768-199801000-0002400003017_1989_80_846_gibbons_exercise_|00005768-199801000-00024#xpointer(id(R9-24))|11065213||ovftdb|00003017-198910000-00011SL0000301719898084611065213P54[CrossRef]10.1161%2F01.CIR.80.4.846ovid.com:/bib/ovftdb/00005768-199801000-0002400003017_1989_80_846_gibbons_exercise_|00005768-199801000-00024#xpointer(id(R9-24))|11065404||ovftdb|00003017-198910000-00011SL0000301719898084611065404P54[Full Text]00003017-198910000-00011ovid.com:/bib/ovftdb/00005768-199801000-0002400003017_1989_80_846_gibbons_exercise_|00005768-199801000-00024#xpointer(id(R9-24))|11065405||ovftdb|00003017-198910000-00011SL0000301719898084611065405P54[Medline Link]2791248ovid.com:/bib/ovftdb/00005768-199801000-0002400004560_1991_71_2004_kohrt_response_|00005768-199801000-00024#xpointer(id(R12-24))|11065405||ovftdb|SL00004560199171200411065405P57[Medline Link]1761503ovid.com:/bib/ovftdb/00005768-199801000-0002400005531_1993_341_1105_lerman_circulating_|00005768-199801000-00024#xpointer(id(R14-24))|11065213||ovftdb|00005531-199305010-00001SL000055311993341110511065213P59[CrossRef]10.1016%2F0140-6736%2893%2993125-Kovid.com:/bib/ovftdb/00005768-199801000-0002400005531_1993_341_1105_lerman_circulating_|00005768-199801000-00024#xpointer(id(R14-24))|11065404||ovftdb|00005531-199305010-00001SL000055311993341110511065404P59[Full Text]00005531-199305010-00001ovid.com:/bib/ovftdb/00005768-199801000-0002400005531_1993_341_1105_lerman_circulating_|00005768-199801000-00024#xpointer(id(R14-24))|11065405||ovftdb|00005531-199305010-00001SL000055311993341110511065405P59[Medline Link]8097801ovid.com:/bib/ovftdb/00005768-199801000-0002400002412_1995_29_248_mandroukas_natriuretic_|00005768-199801000-00024#xpointer(id(R15-24))|11065213||ovftdb|SL0000241219952924811065213P60[CrossRef]10.1136%2Fbjsm.29.4.248ovid.com:/bib/ovftdb/00005768-199801000-0002400002412_1995_29_248_mandroukas_natriuretic_|00005768-199801000-00024#xpointer(id(R15-24))|11065405||ovftdb|SL0000241219952924811065405P60[Medline Link]8808538ovid.com:/bib/ovftdb/00005768-199801000-0002400000416_1986_57_52c_posner_exercise_|00005768-199801000-00024#xpointer(id(R18-24))|11065405||ovftdb|SL0000041619865752c11065405P63[Medline Link]3511665ovid.com:/bib/ovftdb/00005768-199801000-0002400004560_1987_63_1519_posner_ventilatory_|00005768-199801000-00024#xpointer(id(R19-24))|11065405||ovftdb|SL00004560198763151911065405P64[Medline Link]3693190ovid.com:/bib/ovftdb/00005768-199801000-0002400006014_1993_16_294_sipila_ultrasonography_|00005768-199801000-00024#xpointer(id(R22-24))|11065213||ovftdb|SL0000601419931629411065213P67[CrossRef]10.1002%2Fmus.880160309ovid.com:/bib/ovftdb/00005768-199801000-0002400006014_1993_16_294_sipila_ultrasonography_|00005768-199801000-00024#xpointer(id(R22-24))|11065405||ovftdb|SL0000601419931629411065405P67[Medline Link]8446128ovid.com:/bib/ovftdb/00005768-199801000-0002400006543_1988_9_47_thibault_radioimmunoassay_|00005768-199801000-00024#xpointer(id(R25-24))|11065213||ovftdb|SL00006543198894711065213P70[CrossRef]10.1016%2F0196-9781%2888%2990008-3ovid.com:/bib/ovftdb/00005768-199801000-0002400006543_1988_9_47_thibault_radioimmunoassay_|00005768-199801000-00024#xpointer(id(R25-24))|11065405||ovftdb|SL00006543198894711065405P70[Medline Link]2966345ovid.com:/bib/ovftdb/00005768-199801000-0002400001005_1987_241_265_thibault_natriuretic_|00005768-199801000-00024#xpointer(id(R26-24))|11065405||ovftdb|SL00001005198724126511065405P71[Medline Link]2952112ovid.com:/bib/ovftdb/00005768-199801000-0002400000461_1992_263_r647_vuolteenaho_natriuretic_|00005768-199801000-00024#xpointer(id(R29-24))|11065405||ovftdb|SL000004611992263r64711065405P74[Medline Link]1415653ovid.com:/bib/ovftdb/00005768-199801000-0002400004355_1993_14_60_warren_cardiorespiratory_|00005768-199801000-00024#xpointer(id(R30-24))|11065213||ovftdb|SL000043551993146011065213P75[CrossRef]10.1055%2Fs-2007-1021147ovid.com:/bib/ovftdb/00005768-199801000-0002400004355_1993_14_60_warren_cardiorespiratory_|00005768-199801000-00024#xpointer(id(R30-24))|11065405||ovftdb|SL000043551993146011065405P75[Medline Link]8463026ovid.com:/bib/ovftdb/00005768-199801000-0002400005768_1992_24_1147_wells_cardiorespiratory_|00005768-199801000-00024#xpointer(id(R31-24))|11065213||ovftdb|00005768-199210000-00013SL00005768199224114711065213P76[CrossRef]10.1249%2F00005768-199210000-00013ovid.com:/bib/ovftdb/00005768-199801000-0002400005768_1992_24_1147_wells_cardiorespiratory_|00005768-199801000-00024#xpointer(id(R31-24))|11065404||ovftdb|00005768-199210000-00013SL00005768199224114711065404P76[Full Text]00005768-199210000-00013ovid.com:/bib/ovftdb/00005768-199801000-0002400005768_1992_24_1147_wells_cardiorespiratory_|00005768-199801000-00024#xpointer(id(R31-24))|11065405||ovftdb|00005768-199210000-00013SL00005768199224114711065405P76[Medline Link]1435163Effort tolerance in elderly women with different physical activity backgroundsKALLINEN, MAURI; SUOMINEN, HARRI; VUOLTEENAHO, OLLI; ALEN, MARKKUApplied Sciences: Physical Fitness and Performance130