Among healthy women, Hispanic (Mexican American) ethnicity may be associated with modestly higher levels of adiposity and slightly lower amounts of FFM overall and in the trunk region in particular.

Hispanic women may undergo greater age-related reductions in physical functional capacity compared with Caucasian women. If so, a greater rate of decline in muscle strength with age could contribute. We tested this hypothesis in 82 healthy sedentary Caucasian (n = 37) and Hispanic (n = 45) adult women aged 21-78 years of similar socioeconomic status. Absolute one-repetition maximum (1-RM) strength of the knee extensors (KE) declined with advancing age in the Caucasian (r = -.55, p < .01) and Hispanic (r = -.45, p < .01) women; the rates of decline were similar in the two groups (-7% to 8% x decade(-1), p = .60). KE strength normalized for thigh fat-free mass (FFM) also declined with age in the Caucasian (r = .52, p < .01) and Hispanic (r = -.41, p < .01) women, the rates of decline being similar (-6% to 7% x decade(-1), p = .66). For all functional performance tasks (10-m walk, stair ascent, stair descent, and chair stand), performance time increased with advancing age (mean of four tasks vs age: Caucasian, r = .64, p < .01; Hispanic, r = .56, p < .01). Absolute and normalized KE 1-RM were inversely related to the mean time for the four performance tasks (r = -.34 to -.58, all p < .01). Normalized KE 1-RM was the best independent predictor of the age-related decline in task performance in both groups. These cross-sectional findings do not support the hypothesis that Hispanic ethnicity per se is associated with a greater decline in KE strength and performance tasks associated with KE strength in healthy women.

We tested the hypothesis that the age-related decline in maximal aerobic capacity, as measured by maximal oxygen uptake (VO(2 max)), is greater in 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 maximum voluntary efforts in all subjects. VO(2 max) (ml x kg(-1) x min(-1)) was inversely related to age (P < 0.01) in Caucasian (r =-0.68) and Hispanic (r = -0.61) women. The absolute rate of decline in VO(2 max) with age was the same in the two groups (-0.31 ml x kg(-1) x min(-1) x 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 subjects of all ages were pooled, mean levels of VO(2 max) were similar in the two groups (approximately 28 ml x kg(-1) x min(-1)). These results, the first to our knowledge in Hispanics, indicate that mean levels of VO(2 max), as well as the rate of decline in VO(2 max) with age, are similar in healthy sedentary Hispanic and Caucasian women of similar SES. Thus it does not appear that Hispanic ethnicity per se modulates maximal aerobic capacity in this population.

We determined the influence of oral contraceptives (OC) on the capacity of the endothelium to release tissue-type plasminogen activator (t-PA). Twenty-three healthy premenopausal women were studied: 12 nonusers and 11 users of OC. Net endothelial release rates of t-PA were calculated as the product of the arteriovenous concentration gradient and forearm plasma flow in response to intra-arterial bradykinin (BK: 12.5-50 ng. 100 ml tissue(-1) x min(-1)) and sodium nitroprusside (SNP: 1.0-4.0 microg x 100 ml tissue(-1) x min(-1)). Net release of t-PA antigen and increment in t-PA activity across the forearm to BK increased (P < 0.01) in a dose-dependent fashion and to similar extents in the nonusers and users of OC. At the highest BK dose, net release of t-PA antigen was 64.5 +/- 8.2 and 66.2 +/- 15.4 ng x 100 ml tissue(-1) x min(-1) in the nonusers and users of OC, whereas the net increment in t-PA activity was 18.6 +/- 3.0 and 16.0 +/- 2.0 IU. 100 ml tissue(-1) x min(-1), respectively. There was no effect of SNP on t-PA release in either group. These results indicate that endothelial t-PA release is not altered in premenopausal women who use oral contraception.