Miriam Y. Cortez-Cooper

Brachial-ankle pulse wave velocity: an index of central arterial stiffness?

Brachial–ankle pulse wave velocity (baPWV) is a promising technique to assess arterial stiffness conveniently. However, it is not known whether baPWV is associated with well-established indices of central arterial stiffness. We determined the relation of baPWV with aortic (carotid-femoral) PWV, leg (femoral-ankle) PWV, and carotid augmentation index (AI) by using both cross-sectional and interventional approaches. First, we studied 409 healthy adults aged 18–76 years. baPWV correlated significantly with aortic PWV (r=0.76), leg PWV (r=0.76), and carotid AI (r=0.52). A stepwise regression analysis revealed that aortic PWV was the primary independent correlate of baPWV, explaining 58% of the total variance in baPWV. Additional 23% of the variance was explained by leg PWV. Second, 13 sedentary healthy men were studied before and after a 16-week moderate aerobic exercise intervention (brisk walking to jogging; 30–45 min/day; 4–5 days/week). Reductions in aortic PWV observed with the exercise intervention were significantly and positively associated with the corresponding changes in baPWV (r=0.74). A stepwise regression analysis revealed that changes in aortic PWV were the only independent correlate of changes in baPWV (β=0.74), explaining 55% of the total variance. These results suggest that baPWV may provide qualitatively similar information to those derived from central arterial stiffness although some portions of baPWV may be determined by peripheral arterial stiffness.

Follicle-stimulating hormone, interleukin-1, and bone density in adult women

Recent studies have indicated that follicle-stimulating hormone (FSH) promotes bone loss. The present study tested the hypothesis that FSH enhances the activity of bone-resorbing cytokines [interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, and IL-6], either by inducing their secretion or by altering their receptor expression. Thirty-six women between the ages of 20 and 50 were assessed for bone mineral density (BMD), reproductive hormone, cytokine ligand and soluble receptor concentrations, and surface expression of cytokine receptors on monocytes. In addition, isolated mononuclear cells were incubated in vitro with exogenous FSH. Univariate regression analyses indicated that BMD was inversely related to serum FSH (r = -0.29 to -0.51, P = 0.03-0.001, depending upon the skeletal site). Physical activity and body composition were also identified as significant factors by multiple regressions. Exogenous FSH induced isolated cells to secrete IL-1beta, TNF-alpha, and IL-6 in proportion to the surface expression of FSH receptors on the monocytes. Endogenous (serum) FSH concentrations correlated with the circulating concentrations of these cytokines. None of these individual cytokines was related to BMD, but the IL-1beta to IL-1 receptor antagonist (IL-1Ra) ratio was inversely related to BMD (r = -0.53, P = 0.002) in all but the most physically active women, who had significantly lower expression of IL-1 type I receptors relative to type II (decoy receptors, P = 0.01). Physical activity also correlated positively with secretion of inhibitory soluble IL-1 receptors (r = 0.53, P = 0.003). Moreover, IL-1Ra correlated strongly with percent body fat (r = 0.66, P < 0.0001). These results indicate that BMD is related to FSH concentration, physical activity, and body composition. Although each of these factors likely has direct effects on bone, the present study suggests that each may also influence BMD by modulating the activity of the osteoresorptive cytokine IL-1beta.

Post-exercise palpation of pulse rates: its applicability to habitual exercisers.

Despite the increased popularity of heart rate (HR) monitors, endurance‐trained adults as well as habitual exercisers often use pulse rate palpation to periodically monitor exercise intensity. However, due to the rapid recovery of HR following exercise bouts, post‐exercise palpation of pulse rates may underestimate exercise HR. To test this hypothesis, we studied 20 young physically active adults performing two sets of exercise for 5 min at 70% and 85% of maximal HR on the treadmill; one with carotid and another with radial pulse count. Post‐exercise palpation of pulse rate was lower (P<0.01) than the actual HR during exercise, underestimating exercise HR by 20–27 bpm (beats per min). Even when ECG tracings of HR were analyzed immediately after exercise (0–15 s), a significant underestimation of exercise HR (7–9 bpm) still persisted (P<0.05). Following exercise, pulse rate obtained by carotid palpation at both intensities and radial palpation at the lower intensity was no different from the corresponding HR measured with ECG. In the radial artery trial at the higher exercise intensity, pulse rate following exercise was lower (10 bpm; P<0.05) than ECG‐derived HR. Arterial stiffness, which is closely associated with arterial baroreflex sensitivity, was not significantly related to the changes in HR with carotid palpation. We concluded that post‐exercise pulse palpations may not be appropriate as an indicator of exercise intensity in habitual exercisers.

Can α-lipoic acid mitigate progression of aging-related decline caused by oxidative stress?

Abstract Aging is progressively deteriorating physiological function that leads to increasing risks of illness and death. Increases in life expectancy and the aging of a large segment of the population have made age-related disability and morbidity increasingly important issues. Supplements such as &agr;-lipoic acid may have antiaging effects by positively affecting oxidative stress, cognitive function, and cardiovascular function.

Arterial Compliance of Rowers: Implications for Combined Aerobic and Strength Training on Arterial Elasticity

Regular endurance exercise increases central arterial compliance, whereas resistance training decreases it. It is not known how the vasculature adapts to a combination of endurance and resistance training. Rowing is unique, because its training encompasses endurance- and strength-training components. We used a cross-sectional study design to determine arterial compliance of 15 healthy, habitual rowers [50 +/- 9 (SD) yr, 11 men and 4 women] and 15 sedentary controls (52 +/- 8 yr, 10 men and 5 women). Rowers had been training 5.4 +/- 1.2 days/wk for 5.7 +/- 4.0 yr. The two groups were matched for age, body composition, blood pressure, and metabolic risk factors. Central arterial compliance (simultaneous ultrasound and applanation tonometry on the common carotid artery) was higher (P < 0.001) and carotid beta-stiffness index was lower (P < 0.001) in rowers than in sedentary controls. There were no group differences for measures of peripheral (femoral) arterial stiffness. The higher central arterial compliance in rowers was associated with a greater cardiovagal baroreflex sensitivity, as estimated during a Valsalva maneuver (r = 0.54, P < 0.005). In conclusion, regular rowing exercise in middle-aged and older adults is associated with a favorable effect on the elastic properties of the central arteries. Our results suggest that simultaneously performed endurance training may negate the stiffening effects of strength training.