Exaggerated exercise blood pressure is related to impaired endothelial vasodilator function.

BACKGROUND: Persons with high normal blood pressure (BP) or mild hypertension who also have an exaggerated BP response to exercise are at risk for worsening hypertension. The mechanisms that explain this relationship are unknown. We examined the relationships of endothelial vasodilator function and of aortic stiffness with exercise BP. METHODS: Subjects were 38 men and 44 women, aged 55 to 75 years, with untreated high normal BP or mild hypertension but otherwise healthy. Exercise was performed on a treadmill. Endothelial vasodilator function was assessed as brachial artery flow-mediated vasodilation (FMD) during reactive hyperemia. Aortic stiffness was measured as pulse wave velocity (PWV). RESULTS: Among men, resting systolic BP explained 34% of the variance (P < .01) in maximal exercise systolic BP and FMD explained an additional 11% (P < .01); resting systolic BP explained 23% of the variance in maximal pulse pressure (PP) (P < .01), and FMD explained an additional 10% (P < .01). Among women, resting systolic BP was the only independent correlate of maximal systolic BP (R2 = 0.12, P < .03) and FMD correlated negatively with maximal PP (R2 = 0.12, P < .03). Among men, FMD was the only independent correlate of the difference between resting and maximal systolic BP (R2 = 0.20, P < .02). The FMD was the only independent correlate of the difference between resting and maximal PP among men (R2 = 0.17, P < .03) and among women (R2 = 0.12, P < .03). The PWV did not correlate with exercise BP responses. CONCLUSIONS: These results suggest that impaired endothelial vasodilator function may be a mechanism contributing to exercise hypertension and may also be one link between exaggerated exercise BP and worsening hypertension.

Relationships of insulin sensitivity with fatness and fitness and in older men and women.

PURPOSE: Increased body fatness, especially abdominal obesity, and low levels of fitness are associated with decreased insulin sensitivity. Men and women differ in obesity, body fat distribution, and fitness levels. This cross-sectional study evaluated sex differences in the relationships of insulin sensitivity with fatness and fitness and obesity. METHODS: Subjects were nonsmoking, nondiabetic, sedentary men (n = 50) and women (n = 61) aged 55-75 years with mild hypertension. Study measures were insulin sensitivity (QUICKI: 1/[log(fasting insulin) + log(fasting glucose)]), lipids and lipoproteins, total body fatness using dual energy x-ray absorptiometry (DXA), anthropometrics, abdominal obesity using magnetic resonance imaging (MRI), and aerobic fitness assessed as Vo(2) peak during treadmill testing. RESULTS: Women had a higher percentage of body fat and more abdominal subcutaneous and less visceral fat than men. Among women, QUICKI correlated negatively with body mass index (BMI), percent body fat, abdominal total fat, subcutaneous fat, and visceral fat but not with lipids. Among men, QUICKI correlated negatively with total and abdominal fatness and triglycerides. QUICKI correlated with fitness in men only. Using stepwise regression, among women, decreased total abdominal fat accounted for 33%, and postmenopausal hormone therapy accounted for an additional 5% of the variance in QUICKI. Among men, only a higher level of fitness independently correlated with insulin sensitivity, accounting for 21% of the variance (p < 0.01). CONCLUSIONS: Abdominal obesity among women and fitness among men were the strongest determinants of insulin sensitivity in this older cohort. This raises the question whether there are sex differences in the lifestyle changes that would be most effective in improving insulin sensitivity.

Are fitness, activity, and fatness associated with health-related quality of life and mood in older persons?

PURPOSE: This study sought to determine whether levels of fitness, habitual physical activity, and fatness are associated health-related quality of life and mood in older persons. METHODS: The subjects were men (n = 38) and women (n = 44), ages 55 to 75 years, who had milder forms of hypertension, but who were otherwise healthy and not engaged in a regular exercise or diet program. Aerobic fitness was assessed by maximal oxygen uptake during treadmill testing, muscle strength by a one-repetition maximum, habitual activity by questionnaire, fatness by dual-energy x-ray absorptiometry, and body mass index. Health-related quality of life was assessed by the Medical Outcomes Study SF-36, and mood by the Profile of Mood States (POMS). Correlations were determined by bivariate and multivariate regression. RESULTS: Higher aerobic fitness was associated with more desirable outcomes, as indicated by the POMS anger and total mood disturbance scores and by the SF-36 bodily pain, physical functioning, vitality, and physical component scores. Increased fatness was associated with less desirable outcomes, as indicated by the POMS anger, depression, and total mood disturbance scores and by the SF-36 bodily pain, physical functioning, role-emotional, role-physical, social functioning, vitality, and physical component scores. Higher physical activity was associated with an increased POMS score for vigor and a decreased SF-36 score for bodily pain. Strength was not related to health-related quality of life or mood. Aerobic fitness was the strongest predictor of the SF-36 score for vitality and the POMS score for total mood disturbance, whereas fatness was the strongest predictor of the POMS anger score and the SF-36 bodily pain, physical functioning, and physical component scores. CONCLUSIONS: Even in the absence of regular exercise and a weight-loss diet, relatively small amounts of routine physical activity within a normal lifestyle, slight increases in fitness, and less body fatness are associated with a better health-related quality of life and mood.

Usefulness of anthropometrics and dual-energy x-ray absorptiometry for estimating abdominal obesity measured by magnetic resonance imaging in older men and women.

PURPOSE: Increasing evidence suggests that abdominal obesity may be a better predictor of disease risk than total fatness. This study sought to determine how obesity and fat distribution measured by readily available anthropometric and dual-energy x-ray absorptiometry (DXA) methods is related to abdominal obesity assessed by magnetic resonance imaging (MRI). METHODS: Men (n = 43) and women (n = 47), ages 55 to 75 years, were assessed for body mass index, waist-to-hip ratio, waist circumference, and skin folds by anthropometric methods; for percentage of body fat by DXA; and for abdominal total, subcutaneous, and visceral fat by MRI. RESULTS: In stepwise regression models, the waist-to-hip ratio explained 50% of the variance in abdominal visceral fat among men (P <.01), and body mass index explained an additional 6% of the variance (P <.01). Among women, waist circumference was the only independent correlate of abdominal visceral fat, accounting for 52% of the variance (P <.01). Among men, the percentage of body fat was the only independent correlate of abdominal subcutaneous fat, explaining 65% of the variance (P <.01). Among women, the percentage of body fat explained 77% of the variance in abdominal subcutaneous fat and body mass index explained an additional 3% (P <.01). CONCLUSIONS: Obesity and body composition obtained by readily available anthropometric methods and DXA provide informative estimates of abdominal obesity assessed by MRI imaging.