Maximal aerobic capacity across age in healthy Hispanic and Caucasian women
Brian C. Schiller, Yoli G. Casas, Christopher A. Desouza and Douglas R. Seals Journal of Applied Physiology 91:1048-1054, 2001. You might find this additional information useful... This article cites 30 articles, 17 of which you can access free at: http://jap.physiology.org/cgi/content/full/91/3/1048#BIBL This article has been cited by 2 other HighWire hosted articles: Hypothalamic-Pituitary-Adrenal Axis Response and Recovery from High-Intensity Exercise in Women: Effects of Aging and Fitness T. Traustadottir, P. R. Bosch, T. Cantu and K. S. Matt J. Clin. Endocrinol. Metab., July 1, 2004; 89 (7): 3248-3254. [Abstract] [Full Text] [PDF]
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Adiposity Contributes to Differences in Left Ventricular Structure and Diastolic Function with Age in Healthy Men P. E. Gates, C. L. Gentile, D. R. Seals and D. D. Christou J. Clin. Endocrinol. Metab., October 1, 2003; 88 (10): 4884-4890. [Abstract] [Full Text] [PDF]
J Appl Physiol 91: 1048–1054, 2001.
Maximal aerobic capacity across age in healthy Hispanic and Caucasian women BRIAN C. SCHILLER,1 YOLI G. CASAS,1 CHRISTOPHER A. DESOUZA,1 AND DOUGLAS R. SEALS1,2 1 Department of Kinesiology and Applied Physiology, University of Colorado, Boulder 80309; and 2Divisions of Cardiology and Geriatric Medicine, Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262 Received 27 December 1999; accepted in final form 23 April 2001
dent risk factor for all-cause and cardiovascular disease mortality (4, 5), the prevalence of which increases markedly with age (1, 10). Hispanics are the fastest growing segment of the US population and by the year 2020 will constitute our largest minority group (32). As a consequence, the greatest percent growth in older adults in the future will be in the Hispanic population. Recent evidence suggests that age-related reductions in physical functional capacity and increases in functional disability, as measured by physical performance tasks, may be greater in Hispanics than Caucasians (7, 15, 16, 26, 28), particularly in women (13). It also is noteworthy that after 60 yr of age, Hispanic women are at a greater risk of premature mortality compared with non-Hispanic white women (19). Whether the age-associated declines in maximal aerobic capacity are greater in Hispanic women and, therefore, could contribute to their greater functional disability and premature mortality with age is unknown. Accordingly, the primary experimental objective of the present investigation was to test this working hypothesis. To determine whether any group differences observed in the decline in maximal aerobic capacity with age could be attributed to Hispanic ethnicity per se, subjects of similar socioeconomic status (SES) were studied because SES is independently and positively related to functional capacity and disease risk (28, 36).
aging; maximal oxygen uptake; Mexican-American METHODS MAXIMAL AEROBIC CAPACITY,
as assessed by maximal oxy˙ O2 max), declines with advancing age in gen uptake (V healthy men and women (2, 6, 9, 12, 30). This decline contributes to a reduction in physical functional capacity, resulting in older individuals working closer to maximal effort when performing a particular submaximal task (3). Eventually, reductions in physical functional capacity with age lead to increased disability, loss of independence, and reduced quality of life (18, 34). Moreover, maximal aerobic capacity is an indepen-
Subjects. We studied 146 healthy sedentary women aged 20–75 yr: 53 Hispanic and 93 Caucasian. The Hispanic women studied constituted all of the healthy available subjects of sufficiently high SES in the region who could be recruited. Subjects were recruited from churches, community centers, newspaper advertisements, and posted flyers primarily from the greater Boulder County, Colorado area. Ethnicity was determined by asking subjects to which ethnic group they belonged. Those who stated “Caucasian, white, or non-Hispanic white” were considered Caucasian and those who chose “Mexican/Mexican-American, Central American,
Address for reprint requests and other correspondence: D. R. Seals, Dept. of Kinesiology and Applied Physiology, Campus Box 354, Univ. of Colorado Boulder, CO 80309 (E-mail: seals@spot. colorado.edu).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked ‘‘advertisement’’ in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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Schiller, Brian C., Yoli G. Casas, Christopher A. Desouza, and Douglas R. Seals. Maximal aerobic capacity across age in healthy Hispanic and Caucasian women. J Appl Physiol 91: 1048–1054, 2001.—We tested the hypothesis that the age-related decline in maximal aerobic capacity, as mea˙ O2 max), is greater in sured by maximal oxygen uptake (V Hispanic than in Caucasian women. We studied 146 healthy sedentary women aged 20–75 yr: 53 Hispanic (primarily of Mexican descent) and 93 Caucasian (non-Hispanic white). The groups did not differ in mean age, body mass, percent body fat, estimated physical activity-related energy expenditure, or education-based socioeconomic status (SES). During maximal exercise, respiratory exchange ratio, rating of perceived exertion, and percent predicted maximal heart rate were similar across age and ethnicity, suggesting equivalent ˙ O2 max maximum voluntary efforts in all subjects. V (ml 䡠 kg⫺1 䡠 min⫺1) was inversely related to age (P ⬍ 0.01) in Caucasian (r ⫽⫺0.68) and Hispanic (r ⫽ ⫺0.61) women. The ˙ O2 max with age was the same in absolute rate of decline in V the two groups (⫺0.31 ml 䡠 kg⫺1 䡠 min⫺1 䡠 yr⫺1). The relative rate of decline (% from age 25 yr) also was similar in the Caucasian (⫺9.0%) and Hispanic (⫺9.2%) women. When sub˙ O2 max were jects of all ages were pooled, mean levels of V similar in the two groups (⬃28 ml 䡠 kg⫺1 䡠 min⫺1). These results, the first to our knowledge in Hispanics, indicate that ˙ O2 max, as well as the rate of decline in mean levels of V ˙ O2 max with age, are similar in healthy sedentary Hispanic V and Caucasian women of similar SES. Thus it does not appear that Hispanic ethnicity per se modulates maximal aerobic capacity in this population.
V˙ O2 max ACROSS AGE IN HISPANIC AND CAUCASIAN WOMEN
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cation was determined as the highest number of completed school years. Habitual physical activity was determined from estimates of daily energy expenditure using the Stanford Physical Activity Questionnaire (27) as employed previously by our laboratory (21, 33). ˙ O2 max across Data analysis and statistics. The decline in V subject age within a group was expressed in both absolute units (i.e., l/min, normalized for kg of body mass, and normalized for kg of FFM) and as the relative change. The latter ˙ O2 max per was defined as the mean percent change in V decade of age starting with the initial decade of age through the last decade of age in the group, as described previously by our laboratory (12, 30). Multivariate analysis of variance was used to determine differences in the dependent variables among age groups and between ethnic groups. Analysis of ˙ O2 max expressed per unit kilogram of group differences in V body mass or FFM using the ratio method (ANOVA) and using analysis of covariance in which body mass and FFM served as covariates (23, 31) provided similar results; thus only the more traditional ratio-based values are presented below. Simple regression analyses and partial correlation coefficients were used to determine the relations among the dependent variables. Multiple-regression analyses were used to identify independent determinants for the age-related ˙ O2 max. The slopes and intercepts of regression declines in V lines between groups were compared using analysis of covariance. Data are expressed as means ⫾ SE. The level of statistical significance was set at P ⬍ 0.05 for all analyses. RESULTS
Subject characteristics: relation to age. Selected subject characteristics are shown in Table 1. In the Caucasian women, no significant relations were observed between age and height, SES, FFM, or physical activity-related energy expenditure; however, body mass and percent body fat increased (P ⬍ 0.01) with advancing age. In the Hispanic women, only percent body fat was positively related to age (P ⬍ 0.05). Maximal exercise responses: relation to age. Mean values per decade of age obtained during maximal exercise are presented in Table 2. In both groups, heart rate as a percentage of age-predicted maximum, peak respiratory exchange ratio, and rating of perceived ˙ O2 max were not different across age, indiexertion at V ˙ O2 max decating similar maximal voluntary efforts. V clined with advancing decades of age in both groups regardless of manner of expression (P ⬍ 0.01). Maximal heart rate also declined with age (P ⬍ 0.01). ˙ O2 max with age. Figure 1 shows Rate of decline in V ˙ O2 max across age in the the individual subject data for V ˙ O2 max (ml 䡠 kg⫺1 䡠 min⫺1) was inversely two groups. V related to age in both the Caucasian (r ⫽ ⫺0.68) and the Hispanic (r ⫽ ⫺0.61) women (P ⬍ 0.001); the mean absolute rates of decline were similar in the two groups (⫺0.31 ml 䡠 kg⫺1 䡠 min⫺1 䡠 yr⫺1) (Fig. 2A). The relative (%) ˙ O2 max from mean levels at age ⬃25 rates of decline in V yr also were similar in the Caucasian (⫺9.0%/decade) and Hispanic (⫺9.2%/decade) women (Fig. 2B). There also were no differences in either the absolute or the relative rates of decline between the two groups when ˙ O2 max was expressed in liters per minute or per unit V FFM (ml 䡠 kg FFM⫺1 䡠 min⫺1) (data not shown). In addi-
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or South American” were considered Hispanic as described by Winkleby et al. (35). Hispanic women also volunteered that they or their parents or grandparents were born in Mexico, Central, or South America. Ninety percent of the Hispanic subjects were of Mexican descent. All subjects were healthy as assessed by medical history. Subjects 50 yr of age and older were further evaluated for clinical evidence of cardiopulmonary disease with a physical examination and electrocardiograms during rest and maximal exercise. Subjects were nonsmokers and were not using any regular medications that could influence maximal aerobic capacity. The nature, purpose, and risks of the study were explained to each subject in English or Spanish, as needed, before written informed consent was obtained. The experimental protocol was approved by the Human Research Committee at the University of Colorado at Boulder. ˙ O2 max was determined during continuous Measurements. V incremental treadmill exercise using on-line computer-assisted, open-circuit spirometry as described in detail previously (11, 29, 30). Expired air volume was measured with a turbine (model VMM-2, Interface Associates, Laguna Niguel, CA) previously calibrated against a 7-liter syringe (Hans Rudolph, Kansas City, MO). Gas fractions were analyzed with a mass spectrometer (model MGA-1100, Perkin-Elmer, Pomona, CA). Before each trial, the mass spectrometer was calibrated with standard gases of known concentrations. After a 6- to 10-min warm-up period, each subject walked at a comfortable speed that corresponded to ⬃70% of age-predicted maximal heart rate. Heart rate was monitored via a five-lead electrocardiogram. Treadmill grade was increased 2.5% every 2 min until volitional exhaustion. At the end of each stage, subjects were asked to rate perceived effort using the Borg scale (6–20). Each treadmill test lasted between 8 and 12 min. Maximal heart rate was defined as the highest value recorded during exercise. To ensure that subjects gave a maximal voluntary effort, at least three of the following criteria were met: 1) voluntary exhaustion (unable to continue walking); 2) a respiratory exchange ratio of at least 1.10; 3) achievement of age-predicted maximal heart rate; and 4) rating of perceived exertion ⱖ18 units (20). No subjects had to be retested for failing to meet these criteria. Body mass was measured to the nearest 0.1 kg with a physician’s balance scale (Detecto, Webb City, MO). In all 146 subjects, body fat percent was estimated from the sum of five-site skinfold measurements with a Lange caliper (22). Fat-free mass (FFM; kg) was calculated from percent body fat and body mass using the two-compartment model. In addition, body composition was measured in all of the Hispanic subjects (n ⫽ 53) and a subgroup of Caucasian subjects (n ⫽ 56) using dual-energy X-ray absorptiometry (DXA; DXA-IQ, Lunar Radiation, Madison, WI; software version 4.1), which became available after the initial cohort of Caucasian women ˙ O2 max expressed per kilohad been studied. The values for V gram FFM obtained from skinfold measurements and those from DXA were similar with regard to depicting both agerelated rates of decline and mean ethnic group differences. Given this internal validation of the skinfold-derived values in the present study sample, and the fact that these values allowed us to use a much larger and, therefore, representative Caucasian control population from which to determine any ethnicity-related differences, these values were used rather than the DXA-derived values. Education was used as a measure of SES rather than income, occupation, or a combination of the three because education is more closely associated with risk factors for chronic disease than income or occupation (24, 25, 36). Edu-
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Table 1. Selected age group and pooled mean subject characteristics Age Group, yr Variable
20–29
30–39
n Age, yr Height, cm SES, yr education Body mass, kg Body fat, % FFM, kg EPAEE, kcal 䡠 kg⫺1 䡠 day⫺1
14 25 ⫾ 1 167 ⫾ 2 17 ⫾ 1 61 ⫾ 2 26 ⫾ 2 44 ⫾ 1 35 ⫾ 1
14 33 ⫾ 1 164 ⫾ 1 18 ⫾ 1 64 ⫾ 3 29 ⫾ 2 45 ⫾ 1 36 ⫾ 1
n Age, yr Height, cm SES, yr education Body mass, kg Body fat, % FFM, kg EPAEE, kcal 䡠 kg⫺1 䡠 day⫺1
12 25 ⫾ 1 161 ⫾ 2 18 ⫾ 1 64 ⫾ 4 32 ⫾ 2 43 ⫾ 1 36 ⫾ 1
13 34 ⫾ 1 162 ⫾ 1 18 ⫾ 1 64 ⫾ 4 32 ⫾ 2 43 ⫾ 2 34 ⫾ 1
40–49
50–59
⬎60
r With Age
Pooled Mean Value
18 64 ⫾ 1 161 ⫾ 1 14 ⫾ 1 72 ⫾ 3 36 ⫾ 1 46 ⫾ 1 34 ⫾ 1
NS NS 0.30* 0.40* NS NS
46 ⫾ 2 164 ⫾ 1 16 ⫾ 1 66 ⫾ 1 33 ⫾ 1 44 ⫾ 1 35 ⫾ 1
5 65 ⫾ 2 157 ⫾ 3 13 ⫾ 1 71 ⫾ 4 39 ⫾ 2 43 ⫾ 1 35 ⫾ 1
NS NS NS 0.42* NS NS
42 ⫾ 2 160 ⫾ 1† 16 ⫾ 1 65 ⫾ 2 34 ⫾ 1 42 ⫾ 1‡ 35 ⫾ 1
Caucasian subjects 21 45 ⫾ 1 163 ⫾ 1 16 ⫾ 1 66 ⫾ 2 34 ⫾ 1 42 ⫾ 1 35 ⫾ 1
26 54 ⫾ 1 167 ⫾ 1 16 ⫾ 1 67 ⫾ 2 34 ⫾ 1 43 ⫾ 1 34 ⫾ 1
Hispanic subjects 8 44 ⫾ 1 158 ⫾ 2 17 ⫾ 1 64 ⫾ 4 36 ⫾ 1 41 ⫾ 2 35 ⫾ 1
15 53 ⫾ 1 159 ⫾ 2 16 ⫾ 1 64 ⫾ 3 36 ⫾ 1 40 ⫾ 1 34 ⫾ 1
tion, there were no differences between the groups in either the slope or the intercept for all regression models of the rate of decline in maximal aerobic capacity with age. Rate of decline in maximal heart rate with age. Both groups demonstrated an inverse relation between maximal heart rate and age (Caucasian, r ⫽ ⫺0.66; Hispanic, r ⫽ ⫺0.75; both P ⬍ 0.01; Fig. 3). The slopes of the age-related declines in maximal heart rate were not different (P ⫽ 0.90) in the Caucasian (⫺0.62 beats䡠 min⫺1 䡠yr⫺1) and Hispanic (⫺0.75 beats䡠min⫺1 䡠yr⫺1) women.
Subject characteristics: relation to ethnicity. Mean values for age, SES, body mass, body fat percent, and estimated energy expenditure were not different between groups. The Hispanic women were shorter and had a slightly smaller FFM (P ⬍ 0.05) (Table 1). Maximal exercise responses: relation to ethnicity. Mean values are presented in Table 2. Heart rate as a percentage of age-predicted maximum, peak respiratory exchange ratio, and rating of perceived exertion at ˙ O2 max were not different in the two groups, indicating V similar maximal voluntary efforts (Table 2). Mean val˙ O2 max (Fig. 4) were similar in the pooled ues for V
Table 2. Age group and pooled mean responses to maximal exercise across age Age Group, yr Variable
20–29
30–39
˙ O2 max, l/min V ˙ O2 max, ml 䡠 kg⫺1 䡠 min⫺1 V ˙ O2 max, ml 䡠 FFM⫺1 䡠 min⫺1 V HRmax, bpm %HRmax RERmax RPEmax ˙ Emax, l/min V
2.1 ⫾ 0.1 34.2 ⫾ 1.4 46.1 ⫾ 1.3 192 ⫾ 3 101 ⫾ 2 1.14 ⫾ 0.02 19.4 ⫾ 0.1 63.5 ⫾ 3.2
2.1 ⫾ 0.1 33.4 ⫾ 1.5 47.5 ⫾ 1.6 186 ⫾ 2 101 ⫾ 1 1.17 ⫾ 0.02 19.3 ⫾ 0.1 66.4 ⫾ 2.6
˙ O2 max, l/min V ˙ O2 max, ml 䡠 kg⫺1 䡠 min⫺1 V ˙ O2 max, ml 䡠 FFM⫺1 䡠 min⫺1 V HRmax, bpm %HRmax RERmax RPEmax ˙ Emax, l/min V
2.1 ⫾ 0.1 34.0 ⫾ 2.2 49.9 ⫾ 2.5 196 ⫾ 2 103 ⫾ 1 1.19 ⫾ 0.01 19.0 ⫾ 0.3 63.2 ⫾ 3.8
1.9 ⫾ 0.1 30.3 ⫾ 1.6 43.1 ⫾ 2.3 185 ⫾ 2 100 ⫾ 1 1.20 ⫾ 0.02 19.4 ⫾ 0.2 67.3 ⫾ 3.0
50–59
⬎60
r With Age
Pooled Mean Value
1.8 ⫾ 0.1 26.2 ⫾ 1.0 40.5 ⫾ 1.1 174 ⫾ 2 103 ⫾ 1 1.18 ⫾ 0.01 19.3 ⫾ 0.1 66.0 ⫾ 3.6
1.5 ⫾ 0.1 21.5 ⫾ 1.1 33.8 ⫾ 1.3 167 ⫾ 2 103 ⫾ 2 1.16 ⫾ 0.02 18.8 ⫾ 0.2 52.9 ⫾ 5.3
⫺0.61* ⫺0.70* ⫺0.58* ⫺0.70* NS NS NS NS
179 ⫾ 1 102 ⫾ 1 1.17 ⫾ 0.01 19.2 ⫾ 0.1 63.2 ⫾ 1.7
1.5 ⫾ 0.1 20.7 ⫾ 1.3 34.3 ⫾ 1.9 165 ⫾ 6 101 ⫾ 3 1.18 ⫾ 0.02 19.6 ⫾ 0.2 54.0 ⫾ 7.0
⫺0.60* ⫺0.61* ⫺0.53* ⫺0.75* NS NS NS NS
181 ⫾ 2 102 ⫾ 1 1.19 ⫾ 0.01 19.2 ⫾ 0.1 60.5 ⫾ 1.8
40–49
Caucasian subjects 1.8 ⫾ 0.1 28.0 ⫾ 1.0 43.6 ⫾ 1.8 180 ⫾ 2 102 ⫾ 1 1.20 ⫾ 0.01 19.3 ⫾ 0.1 64.2 ⫾ 2.8
Hispanic subjects 1.7 ⫾ 0.1 26.8 ⫾ 0.8 42.1 ⫾ 1.4 181 ⫾ 2 102 ⫾ 1 1.18 ⫾ 0.02 19.0 ⫾ 0.3 56.1 ⫾ 5.6
1.6 ⫾ 0.1 25.5 ⫾ 1.5 40.3 ⫾ 1.8 173 ⫾ 3 101 ⫾ 2 1.19 ⫾ 0.02 19.0 ⫾ 0.4 57.0 ⫾ 3.2
˙ O2 max, maximal oxygen uptake; HRmax, maximal heart rate; RERmax, maximal respiratory exchange ratio; Values are means ⫾ SE. V ˙ Emax, maximal ventilation in STPD units; FFM, fat-free mass; bpm, beats per minute. * P ⬍ RPEmax, maximal rating of perceived exertion; V 0.01. J Appl Physiol • VOL
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Values are means ⫾ SE; n, no. of subjects. SES, socioeconomic status; FFM, fat-free mass; EPAEE, estimated physical activity-related energy expenditure. NS, nonsignificant. * P ⬍ 0.01, † P ⬍ 0.01, ‡ P ⬍ 0.05 vs. Caucasian group.
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˙ O2 max) in Fig. 1. Age-related declines in maximal oxygen uptake (V the Caucasian and Hispanic women.
DISCUSSION
There are at least three new and, we believe, significant findings from the present investigation. First, among healthy sedentary women aged 20–75 yr of similar SES, Hispanic (primarily of Mexican descent) ethnicity per se is not obviously associated with greater age-related declines in maximal aerobic capacity when compared with Caucasians. Second, mean levels of maximal aerobic capacity are not lower in healthy sedentary Hispanic compared with Caucasian women. Third, the age-related declines in maximal heart rate are not different in Hispanic and Caucasian women. To our knowledge, the present results represent the first data on maximal aerobic capacity and its associated physiological correlates in Hispanics. Our working hypothesis of augmented declines in maximal aerobic capacity with age in Hispanic women was based on three previous sets of, albeit indirect, observations. The first was that Hispanic adults in general, and Hispanic women in particular, have been reported to experience greater reductions in physical functional capacity with age than their Caucasian peers (7, 13, 15, 16, 26, 28). Because maximal aerobic J Appl Physiol • VOL
˙ O2 max Fig. 2. Absolute (A) and relative (B) mean rates of decline of V from age 25 yr.
capacity is known to be an important determinant of physical functional capacity (3), it follows that His˙ O2 max panic adults may undergo greater reductions in V with age than Caucasians. The second observation is
Fig. 3. Age-related declines in maximal heart rate in the Caucasian and Hispanic women. bpm, Beats/min.
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groups of Hispanic and Caucasian women regardless of manner of expression. Absolute levels of maximal heart rate also were similar in the two groups. ˙ O2 max. Table Correlates of the age-related decline in V 3 shows the significant independent predictor vari˙ O2 max normalables of the age-related reductions in V ized for body mass in the two groups as determined by multiple-regression analysis. Variables of physiological interest entered into the multiple regression model included age, body mass, FFM, estimated physical activity, and maximal heart rate. Age and FFM were the significant independent predictors in the Caucasian group (both P ⬍ 0.01). FFM was the only significant independent predictor in the Hispanic group (P ⫽ 0.01).
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that, within Mexican-American women, leisure-time physical activity levels decline with advancing age and that older Mexican-American women have the lowest levels of leisure-time physical activity among any majority or minority group (8). Jackson et al. (23) have shown that declines in leisure-time physical activity levels are strongly associated with age-related reductions in maximal aerobic capacity among healthy women. Third, Hispanic women demonstrate a greater prevalence of overweight and obesity compared with Caucasian women (14, 17, 35). Because greater increases in body mass and fatness with age are linked to ˙ O2 max among healthy greater age-related declines in V women (23, 31), the high prevalence of obesity reported J Appl Physiol • VOL
Table 3. Multiple-regression predictor variables ˙ O2 max (l/min) for V Group
Predictor 1
Predictor 2
Caucasian Hispanic
Age* Fat-free mass*
Fat-free mass*
* P ⱕ 0.01.
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˙ O2 max in the Caucasian Fig. 4. Mean pooled group values (⫾ SE) for V ˙ O2); A], and Hispanic women expressed as l/min [oxygen uptake (V normalized per kg of body mass (B), and normalized per kg fat-free mass (FFM; C).
previously in Hispanic women would, in itself, act to lower maximal aerobic capacity. In contrast to our hypothesis, the results of the present cross-sectional study indicate that both the absolute and relative rates of decline in maximal aerobic capacity were similar in our healthy Hispanic and Caucasian women. These findings were independent of ˙ O2 max used for comparison. Both the the expression of V absolute (⫺0.31 ml 䡠 kg⫺1 䡠 min⫺1 䡠 yr⫺1) and relative (⬃9% decrease per decade from mean levels at age 25 yr) rates of decline were similar to the values reported by our laboratory in earlier meta-analysis and labora˙ O2 max and age in healthy tory-based investigations of V women (12, 30), and to the results of others (6). In ˙ O2 max in the pooled ethnic addition, mean levels of V groups were almost identical. Thus, taken together, these results fail to indicate any obvious association between Hispanic ethnicity per se and maximal aerobic capacity among healthy adult women. This lack of association likely is due, at least in part, to the absence of differences in the physiological and behavioral factors described above that are known to ˙ O2 max in healthy women. For example, esinfluence V timated habitual physical activity did not decline with age in either group, nor were mean levels different in the Hispanic compared with the Caucasian women. The absence of any significant differences in estimated physical activity levels with age or ethnicity in the present study most likely was due to the fact that the women were all of similarly high SES. SES is directly related to leisure-time activity levels (25). There are several experimental considerations that should be mentioned. First, we used a cross-sectional, rather than a longitudinal, study design. It has been suggested that these two approaches may provide different results when used to determine age-related de˙ O2 max (6). However, as our laboratory has clines in V found previously (12, 30), investigations in which both study designs were employed in the same study sample(s) have demonstrated similar mean rates of decline with age using these different approaches. Second, our subject samples consisted only of healthy women. If women with clinically documented disease (e.g., severe obesity, the prevalence of which is higher in Hispanic women) had been included, our results may have been different. Third, although our overall subject number (n) of ⬃150 women represents a relatively large study sample for a laboratory-based physiological investigation, it nevertheless is a small subject sample from an epidemiological perspective, particularly considering the limited number of Hispanic subjects in general (n ⫽ 53) and in certain age intervals. In this regard, it
V˙ O2 max ACROSS AGE IN HISPANIC AND CAUCASIAN WOMEN
This study was supported by National Institute on Aging (NIA) Awards R03 AG-16387, RO1 AG-06537, and AG-13038 and by Division of Research Resources Research Grant 5 01 RR-00051. Y. G. Casas was supported by NIA Research Supplement for Underrepresented Minority Graduate Research Assistants AG-13038. C. A. DeSouza was supported initially by Research Supplements to Minority Individuals in Postdoctoral Training HL-39966 and AG-13038 and later by Mentored Research Scientist Award HL-03840. REFERENCES
4.
5.
6. 7. 8.
9.
10. 11.
12.
13.
14. 15.
16. 17. 18. 19. 20. 21.
22.
1. American Heart Association. Heart and Stroke Facts: 1996 Statistical Supplement. Dallas, TX: American Heart Association, 1996. 2. Astrand I. Aerobic work capacity in men and women with special reference to age. Acta Physiol Scand 49: 1–92, 1960. 3. Binder EF, Birge SJ, Spina R, Ehsani AA, Brown M, Sinacore DR, and Kohrt WM. Peak aerobic power is an important J Appl Physiol • VOL
23. 24.
component of physical performance in older women. J Gerontol A Biol Sci Med Sci 54: M353–M356, 1999. Blair SN, Kohl HW, Barlow CE, Paffenbarger RS Jr, Gibbons LW, and Macera CA. Changes in physical fitness and all-cause mortality. A prospective study of healthy and unhealthy men. JAMA 273: 1093–1098, 1995. Blair SN, Kohl HW, Paffenbarger RS Jr, Clark DG, Cooper KH, and Gibbons LW. Physical fitness and all-cause mortality. A prospective study of healthy men and women. JAMA 262: 2395–2401, 1989. Buskirk ER and Hodgson JL. Age and aerobic power: the rate of change in men and women. Fed Proc 46: 1824–1829, 1987. Chiodo LK, Kanten DN, Gerety MB, Mulrow CD, and Cornell JE. Functional status of Mexican American nursing home residents. J Am Geriatr Soc 42: 293–296, 1994. Crespo CJ, Keteyian SJ, Heath GW, and Sempos CT. Leisure-time physical activity among US adults. Results from the Third National Health and Nutrition Examination Survey. Arch Intern Med 156: 93–98, 1996. Dempsey JA and Seals DR. Aging, exercise, and cardiopulmonary function. In: Perspectives in Exercise Science and Sports Medicine. Exercise in Older Adults, edited by Lamb DR, Gisolfi CV, and Nadel E. Carmel, IN: Cooper Publishing Group, 1995, vol. 8, p. 237–304. Eaker ED, Chesebro JH, Sacks FM, Wenger NK, Whisnant JP, and Winston M. Cardiovascular disease in women. Circulation 88: 1999–2009, 1993. Evans SL, Davy KP, Stevenson ET, and Seals DR. Physiological determinants of 10-km performance in highly trained female runners of different ages. J Appl Physiol 78: 1931–1941, 1995. Fitzgerald MD, Tanaka H, Tran ZV, and Seals DR. Agerelated declines in maximal aerobic capacity in regularly exercising vs. sedentary women: a meta-analysis. J Appl Physiol 83: 160–165, 1997. Haan MN and Weldon M. The influence of diabetes, hypertension, and stroke on ethnic differences in physical and cognitive functioning in an ethnically diverse older population. Ann Epidemiol 6: 392–398, 1996. Haffner SM, Stern MP, Mitchell BD, and Hazuda HP. Predictors of obesity in Mexican Americans. Am J Clin Nutr 53: 1571S–1576S, 1991. Hamman RF, Mulgrew CL, Baxter J, Shetterly SM, Swenson C, and Morgenstern NE. Methods and prevalence of ADL limitations in Hispanic and non-Hispanic white subjects in rural Colorado: the San Luis Valley Health and Aging Study. Ann Epidemiol 9: 225–235, 1999. Hazuda HP. Inclusion of ethnic minorities in sarcopenia research: challenges and strategies. Muscle Nerve Suppl 5: S27– S31, 1997. Hazuda HP, Mitchell BD, Haffner SM, and Stern MP. Obesity in Mexican American subgroups: findings from the San Antonio Heart Study. Am J Clin Nutr 53: 1529S–1534S, 1991. Holloszy JO and Kohrt WM. Exercise. In: Handbook of Physiology. Aging. Bethesda, MD: Am. Physiol. Soc., 1995, sect. 11, chapt. 24, p. 633–666. Hopper SV. The influence of ethnicity on the health of older women. Clin Geriatr Med 9: 231–259, 1993. Howley ET, Bassett DR Jr, and Welch HG. Criteria for maximal oxygen uptake: review and commentary. Med Sci Sports Exerc 27: 1292–1301, 1995. Hunt BE, Davy KP, Jones PP, DeSouza CA, Van Pelt RE, Tanaka H, and Seals DR. Systemic hemodynamic determinants of blood pressure in women: age, physical activity, and hormone replacement. Am J Physiol Heart Circ Physiol 273: H777–H785, 1997. Jackson AS, Pollock ML, and Ward A. Generalized equations for predicting body density of women. Med Sci Sports Exerc 12: 175–181, 1980. Jackson AS, Wier LT, Ayers GW, Beard EF, Stuteville JE, and Blair SN. Changes in aerobic power of women, ages 20–64 yr. Med Sci Sports Exerc 28: 884–891, 1996. Liberatos P, Link BG, and Kelsey JL. The measurement of social class in epidemiology. Epidemiol Rev 10: 87–121, 1988.
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should be noted that we were limited by the availability of Hispanic women of sufficiently high SES to compare with the regional Caucasian population of women (controls). Thus the reader should be aware of the possibility of type II errors, particularly in the context of age-related changes in our Hispanic women. Fourth, the Hispanic women studied here were primarily (⬃90%) of Mexican-American descent. As such, our findings cannot be generalized to Hispanic women of other descent. Fifth, as mentioned previously, SES is directly related to measures of functional capacity and disability (28). Therefore, although the exact relation between SES and maximal aerobic capacity has not been determined, it is possible (even likely) that our results would have been different had we not studied Hispanic and Caucasian women of similar SES. The present findings have important implications for gerontology and geriatric medicine. Age-associated reductions in physical functional capacity result in increased disability, dependence on family and others for care, and costs of health services, as well as reduced quality of life. Current projections indicate marked increases in the number of US adults ⬎65 yr of age in the near future, greatly exacerbating these present problems. Physical functional capacity has been reported to be reduced and functional disability increased in older Hispanic adults, particularly women (13). Because Hispanics are our fastest growing minority population (32), it is important to determine the physiological factors contributing to age-related disability in this group. The present findings indicate that Hispanic ethnicity per se (i.e., cultural and/or genetic predisposition) is not obviously associated with greater declines in maximal aerobic capacity with age or with mean levels. Thus this factor does not appear to contribute directly to ethnicity-related differences in physical functional capacity. In conclusion, these results, the first to our knowledge in Hispanics, do not support the hypothesis that the rate of decline in maximal aerobic capacity with age is greater in healthy sedentary Hispanic women than in Caucasian women of similar SES. Thus it does not appear that Hispanic ethnicity per se modulates maximal aerobic capacity, an important determinant of physical functional capacity, in this population.
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25. Luepker RV, Rosamond WD, Murphy R, Sprafka JM, Folsom AR, McGovern PG, and Blackburn H. Socioeconomic status and coronary heart disease risk factor trends. The Minnesota Heart Survey. Circulation 88: 2172–2179, 1993. 26. National Center for Health Statistics. Health indicators for Hispanics, blacks, and white Americans. In: Vital Health Statistics. Hyattsville, MD: Public Health Service, 1984, p. 1– 88. 27. Sallis JF, Haskell WL, Wood PD, Fortmann SP, Rogers T, Blair SN, and Paffenbarger RS Jr. Physical activity assessment methodology in the Five-City Project. Am J Epidemiol 121: 91–106, 1985. 28. Shetterly SM, Baxter J, Morgenstern NE, Grigsby J, and Hamman RF. Higher instrumental activities of daily living disability in Hispanics compared with non-Hispanic whites in rural Colorado. The San Luis Valley Health and Aging Study. Am J Epidemiol 147: 1019–1027, 1998. 29. Stevenson ET, Davy KP, and Seals DR. Maximal aerobic capacity and total blood volume in highly trained middle-aged and older female endurance athletes. J Appl Physiol 77: 1691– 1696, 1994. 30. Tanaka H, DeSouza CA, Jones PP, Stevenson ET, Davy KP, and Seals DR. Greater rate of decline in maximal aerobic
31.
32. 33.
34. 35. 36.
capacity with age in physically active vs. sedentary healthy women. J Appl Physiol 83: 1947–1953, 1997. Toth MJ, Gardner AW, Ades PA, and Poehlman ET. Contribution of body composition and physical activity to age-related ˙ O2 in men and women. J Appl Physiol 77: decline in peak V 647–652, 1994. US Bureau of the Census. The Nation’s Hispanic Population1994. Washington, DC: US Department of Commerce, 1995. Van Pelt RE, Davy KP, Stevenson ET, Wilson TM, Jones PP, Desouza CA, and Seals DR. Smaller differences in total and regional adiposity with age in women who regularly perform endurance exercise. Am J Physiol Endocrinol Metab 275: E626– E634, 1998. WHO. Aging and working capacity. In: World Health Org Tech Rep Ser 835: 1– 49, 1993. Winkleby MA, Gardner CD, and Taylor CB. The influence of gender and socioeconomic factors on Hispanic/white differences in body mass index. Prev Med 25: 203–211, 1996. Winkleby MA, Jatulis DE, Frank E, and Fortmann SP. Socioeconomic status and health: how education, income, and occupation contribute to risk factors for cardiovascular disease. Am J Public Health 82: 816–820, 1992.
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