Impaired economy of gait and decreased six-minute walk distance in Parkinson's disease

Changes in the biomechanics of gait may alter the energy requirements of walking in Parkinson's Disease (PD). This study investigated economy of gait during submaximal treadmill walking in 79 subjects with mild to moderate PD and the relationship between gait economy and 6-minute walk distance (6 MW). Oxygen consumption (VO(2)) at the self-selected treadmill walking speed averaged 64% of peak oxygen consumption (VO(2) peak). Submaximal VO(2) levels exceeded 70% of VO(2) peak in 30% of the subjects. Overall the mean submaximal VO(2) was 51% higher than VO(2) levels expected for the speed and grade consistent with severe impairment in economy of gait. There was an inverse relationship between economy of gait and 6MW (r = -0.31, P < 0.01) and with the self-selected walking speed (r = -0.35, P < 0.01). Thus, the impairment in economy of gait and decreased physiologic reserve result in routine walking being performed at a high percentage of VO(2) peak.

Association of age and comorbidity with physical function in HIV-infected and uninfected patients: results from the Veterans Aging Cohort Study

HIV clinical care now involves prevention and treatment of age-associated comorbidity. Although physical function is an established correlate to comorbidity in older adults without HIV infection, its role in aging of HIV-infected adults is not well understood. To investigate this question we conducted cross-sectional analyses including linear regression models of physical function in 3227 HIV-infected and 3240 uninfected patients enrolled 2002-2006 in the Veterans Aging Cohort Study-8-site (VACS-8). Baseline self-reported physical function correlated with the Short Form-12 physical subscale (ρ = 0.74, p < 0.001), and predicted survival. Across the age groups decline in physical function per year was greater in HIV-infected patients (β(coef) -0.25, p < 0.001) compared to uninfected patients (β(coef) -0.08, p = 0.03). This difference, although statistically significant (p < 0.01), was small. Function in the average 50-year old HIV-infected subject was equivalent to the average 51.5-year-old uninfected subject. History of cardiovascular disease was a significant predictor of poor function, but the effect was similar across groups. Chronic pulmonary disease had a differential effect on function by HIV status (Δβ(coef) -3.5, p = 0.03). A 50-year-old HIV-infected subject with chronic pulmonary disease had the equivalent level of function as a 68.1-year-old uninfected subject with chronic pulmonary disease. We conclude that age-associated comorbidity affects physical function in HIV-infected patients, and may modify the effect of aging. Longitudinal research with markers of disease severity is needed to investigate loss of physical function with aging, and to develop age-specific HIV care guidelines.

Sex-specific associations of depressive symptoms and cardiovascular risk factors in older adults

OBJECTIVES

To examine sex-specific associations between depressive symptoms and cardiovascular risk factors in older men and women.

METHOD

One hundred and thirty-one healthy, community-dwelling older adults [mean age = 66(6.59), 63% male] completed the Beck depression inventory, and engaged in assessment of systolic and diastolic blood pressure, body mass index (BMI), waist circumference (WC), fasting total, low- and high-density lipoprotein cholesterol (TC, LDL-C, and HDL-C), triglycerides, glucose, insulin, and maximal aerobic capacity (Vo2max). Sex-stratified hierarchical regression analyses examined the association between depressive symptoms and each risk factor adjusting for age, education, and BMI (select models).

RESULTS

Significant associations were found between higher levels of depressive symptoms and greater BMI, WC, insulin, LDL-C, and lower Vo2max in women only (p < 0.05). The insulin association was partially mediated by BMI.

CONCLUSION

In healthy older women, but not men, higher levels of depressive symptoms were associated with greater CVD risk factors. Depressive symptoms may confer biobehavioral risk for cardiovascular and metabolic diseases in older women in part via their association with pertinent biomedical risk factors.

Prediction of cardiorespiratory fitness in older men infected with the human immunodeficiency virus: clinical factors and value of the six-minute walk distance

OBJECTIVES

To investigate factors related to cardiorespiratory fitness in older human immunodeficiency virus (HIV)-infected patients and to explore the utility of 6-minute walk distance (6-MWD) in measuring fitness.

DESIGN

Cross-sectional study in clinic-based cohort.

SETTING

Veterans Affairs Medical Center, Baltimore, Maryland.

PARTICIPANTS

Forty-three HIV-infected men, median age 57 (range 50-82), without recent acquired immunodeficiency syndrome-related illness and receiving antiretroviral (ARV) therapy.

MEASUREMENTS

Peak oxygen utilization (VO(2)peak) according to treadmill graded exercise testing, 6-MWD, grip strength, quadriceps maximum voluntary isometric contraction, cross-sectional area, muscle quality, and muscle adiposity.

RESULTS

There was a moderate correlation between VO(2)peak (mean +/- SD; 18.4 +/- 5.6 mL/kg per minute) and 6-MWD (514 +/- 91 m) (r=0.60, P<.001). VO(2)peak was lower in subjects with hypertension (16%, P<.01) and moderate anemia (hemoglobin 10-13 gm/dL; 15%, P=.09) than in subjects without these conditions. CD4 cell count (median 356 cells/mL, range 20-1,401) and HIV-1 viral load (84% nondetectable) were not related to VO(2)peak. Among muscle parameters, only grip strength was an independent predictor of VO(2)peak. Estimation of VO(2)peak using linear regression, including age, 6-MWD, grip strength, and hypertension as independent variables, explained 61% of the variance in VO(2)peak.

CONCLUSION

Non-AIDS-related comorbidity predicts cardiorespiratory fitness in older HIV-infected men receiving ARV therapy. The 6-MWD is a valuable measure of fitness in this patient population, but a larger study with diverse subjects is needed.

Renal function and cardiovascular response to mental stress

BACKGROUND/AIMS

Cardiovascular reactivity (CVR), defined as an exaggerated hemodynamic response to mental stress, is a putative vascular risk factor and may reflect sympathetic hyperactivity. Chronic kidney disease (CKD) is also associated with sympathetic hyperactivity and vascular risk, but its relationship with CVR is unknown.

METHODS

CVR was assessed in 107 individuals without overt cardiovascular disease or diabetes. Blood pressure and heart rate responses were elicited by three experimental tasks designed to evoke mental stress. Glomerular filtration rate (eGFR) was estimated using the MDRD formula. General linear models estimated the association between renal function and CVR, adjusting for potential confounders.

RESULTS

Mean age was 66 years and 11% had eGFR of <60 ml/min/1.73 m2. After multivariate adjustment, a low eGFR was associated with a greater stress response of systolic blood pressure, heart rate, and pulse pressure. Associations were only partially attenuated after adjustment for lipids and glucose tolerance. When considered as a continuous variable, lower eGFR was associated with a greater blood pressure response after adjustment for glycemia.

CONCLUSION

Although there were relatively few participants with CKD, these results suggest a relationship between CKD and greater CVR. Further investigation is warranted into factors that mediate this relationship and potential clinical consequences of this exaggerated response to stress in CKD.

Central activation, muscle performance, and physical function in men infected with human immunodeficiency virus

Loss of muscle mass and limitations in activity have been reported in persons infected with human immunodeficiency virus (HIV), even those who are otherwise asymptomatic. The extent to which factors other than muscle atrophy impair muscle performance has not been addressed in depth. The purpose of this study was to determine the extent of neuromuscular activation of the knee extensors and ankle dorsiflexors of 27 men infected with HIV receiving antiretroviral therapy and its relationship to muscle performance. The central activation ratio (CAR) was determined using superimposed electrical stimulation during maximum voluntary contractions. In addition to force and power measurements, muscle cross-sectional area and composition was evaluated using computed tomography. Aerobic capacity was determined from treadmill exercise testing. Eleven of the subjects had an impaired ability to activate the knee extensors (CAR = 0.72 +/- 0.12) that was associated with weakness and decreased specific force. The reduced central activation was not associated with muscle area, body composition, aerobic capacity, CD4 count, or medication regimen. Those individuals with low central activation had higher HIV-1 viral loads and were more likely to have a history of AIDS-defining illness. These results suggest the possibility of a different mechanism contributing to muscle impairment in the current treatment era that is associated with impairment of central motor function rather than atrophy. Further investigation is warranted in a larger, more diverse population before more definitive claims are made.

Older Elite Football Players Have Reduced Cardiac and Osteoporosis Risk Factors

INTRODUCTION/PURPOSE

Aging with a sedentary lifestyle is associated with increased risk for developing cardiovascular disease (CVD), osteoporosis, and sarcopenia. The purpose of this study was to determine whether former professional football athleticism would be associated with reduced risk factors for CVD and osteoporosis, and higher muscle mass in later life.

METHODS

Maximal aerobic capacity (VO2max), body composition, and lipid and glucose risk factors for CVD were compared between 16 older former professional football players and never-athletic men matched for age, body mass index, current physical activity, and race. Regional bone mineral density of the football players was compared with age-matched reference norms.

RESULTS

Despite greater physical activity into middle age, the former football players had similar VO2max as the controls. Former football players had 26% lower total-body fat mass, 26% lower visceral adipose tissue area, and 13% higher muscle mass compared with the controls (P < 0.05). High-density lipoprotein cholesterol (HDL-C) levels were 37% higher (P < 0.001), HDL2-C levels were fourfold higher (P < 0.001), and triglycerides were 31% lower (P < 0.05) in the former football players than the controls. The former football players also had 20% and 6% higher total-body bone mineral content and density than the controls (P < 0.05) and higher lumbar spine, femoral neck, and greater trochanter bone mineral density than similar age-referenced norms (P < 0.05).

CONCLUSION

Elite athlete physical activity status in young adulthood, and remaining physically active in middle age, may confer body composition changes that are sustained in older adulthood. In this small sample of older men, former successful professional athletes who remained physically active in middle age have a favorable body composition and reduced risk factors for CVD and osteoporosis compared with healthy age- and BMI-matched older men.

Reduction in midthigh low-density muscle with aerobic exercise training and weight loss impacts glucose tolerance in older men

CONTEXT

Intramuscular lipid content increases with aging and obesity and is directly related to impaired glucose tolerance and insulin resistance.

OBJECTIVE

Our purpose was to determine the effects of aerobic exercise training (AEX) with and without weight loss (WL) on midthigh low-density muscle (LDM; a measure of im lipid) and whether changes in LDM impact glucose tolerance in sedentary older men.

DESIGN

Forty-six men (60.4 +/- 1.1 yr) completed 6 months of AEX (n = 34) or AEX + WL (n = 12) and had oral glucose tolerance tests (OGTTs) and computed tomography measures of LDM and regional abdominal and thigh fat depot areas.

RESULTS

At baseline, LDM area directly correlated with fasting plasma glucose (FPG), 120-min glucose (G(120)), and glucose area under the curve (G(AUC)) during an OGTT (r = 0.44, r = 0.51, and r = 0.54, respectively, P < 0.01). After the interventions, the AEX + WL group had greater decreases in LDM (-13.5 vs. +1.3%, respectively), FPG (-8.3 vs. +2.1%, respectively), G(120) (-22.5 vs. -3.6%, respectively), and G(AUC) (-17.3 vs. - 3.1%, respectively) than the AEX group. In the entire sample, the decreases in LDM correlated with reductions in FPG, G(120), and G(AUC) during an OGTT (r = 0.31, r = 0.34, and r = 0.41, P < 0.05). Changes in other regional fat depots did not independently correlate with glucose tolerance or insulin responses.

CONCLUSION

AEX + WL is more efficacious than AEX for reducing LDM and glucose tolerance. The improvement in glucose tolerance may be partially mediated by decreases in LDM in older men.

Association of comorbidity with physical disability in older HIV-infected adults

Comorbidity, aging, and their impact on physical functioning will play an increasingly greater role in HIV medical care as the number of infected adults over 50 years of age grows. The study objective was to investigate the relationship of comorbidity and age with physical functioning in HIV-infected and HIV-negative patients. Eight hundred eighty-nine HIV-infected veterans and 647 HIV-negative veterans from the Veterans Aging Cohort Study conducted between September 2001 and June 2002 were included in the study. Physical functioning was measured by self-reported difficulty with various physical activities. Regression analyses were performed to examine demographic and clinical factors associated with physical functioning. Separate models were used for HIV-infected and HIV negative subjects since these groups differed in demographic makeup. In both patient groups, chronic lung disease, coronary artery disease, hypertension, smoking, and major depression were independently associated with reduced physical functioning in age and race adjusted regression models. Increased age was associated with reduced physical functioning in both HIV-infected and HIV-negative patients. However, when comorbid conditions were entered into the models for both HIV-infected and HIV-negative patients, age coefficients were reduced and were no longer statistically significant. Among the HIV-infected patients, results remained unchanged after controlling for the impact of antiretroviral therapy and HIV disease stage. Our findings demonstrate the important role of general medical comorbidity in physical functioning in both HIV-infected and HIV-negative patients. This suggests the importance of effectively treating comorbid conditions in persons with HIV, in order to reduce the overall impact of disease on physical functioning.

Reduced aerobic capacity and physical functioning in older HIV-infected men

Aerobic capacity and physical functioning decline with age and chronic illness. The extent of physical disability is unknown in older HIV-infected adults, who represent a rapidly growing proportion of HIV/AIDS patients in the United States. We performed functional performance testing including treadmill testing in 32 HIV-infected male veterans aged 40-69 years. Controls were 47 healthy male subjects tested previously in the same exercise laboratory. HIV-infected subjects were classified as younger (40-49 years, n = 12) or older age (50+ years, n = 20). Peak aerobic capacity (VO2peak) was significantly reduced in the older vs. younger HIV subjects [19.1 mL/kg/min +/- 5.7 (mean, SD) vs. 25.2 +/- 4.2, p = 0.01]. VO2peak was reduced 41% +/- 15% (mean, SD) in HIV-infected subjects compared to expected values from age-matched healthy controls. Regression analyses show a similar decline in VO2peak with age in HIV-infected and healthy controls. Mean 6-min walk distance was not significantly different between the HIV-infected age groups, and was reduced only 8% compared to expected values for healthy adults. Current CD4 count and HAART exposure were similar in the two age groups and were not significantly associated with VO2peak. Anemia (HCT <35%) was significantly associated with reduced VO2peak (p = 0.02), but this association was not independent of the effect of age (p = 0.1). We conclude that older HIV-infected adults have markedly impaired aerobic capacity but maintain the capacity to undertake day-to-day activities. Additional physiologic and metabolic testing is needed to measure the effect of HAART toxicity and primary aging on aerobic capacity, and to determine if older HIV-infected adults are at greater risk.

Diagnosis of hypertension and high blood pressure levels negatively affect cognitive function in older adults

BACKGROUND

Hypertension is associated with diminished performance on tests of cognitive function. The degree to which those diagnosed with hypertension have controlled blood pressure (BP) levels may be a critical determinant of cognitive outcomes. Persons with hypertension and poorly controlled BP are likely to display the worst performance on cognitive tests.

PURPOSE

The purpose is to examine potential interactive relations of hypertension diagnostic status and current BP levels to cognitive function.

METHODS

Participants were 101 healthy older adults (ages 53-84, 62% male, 90% White, 29% diagnosed with hypertension) who engaged in biomedical and neuropsychological assessment.

RESULTS

After statistical adjustment for age and education, persons with high BP performed more poorly than those with normal BP on the Visual Reproductions-Immediate and Delayed Recall and the Grooved Pegboard tests. Diagnosed hypertension was related to poorer performance on the Grooved Pegboard tests. An interaction of diagnosed hypertension and BP level revealed that those diagnosed with hypertension and also having poorly controlled BP levels performed least well on the Grooved Pegboard tests and the Trail Making Test-Part A.

CONCLUSION

Irrespective of prior diagnostic status, individuals with high BP displayed compromised performance on tests of nonverbal memory, motor speed, and manual dexterity. However, as compared to the other groups, those diagnosed with hypertension and also having poorly controlled BP elevation were most vulnerable to difficulties on tests of perceptuo-motor speed, motor speed, and manual dexterity. These findings suggest the need for increased attention to preventative efforts with respect to BP assessment and control in older adults to help preserve cognitive function.

Interactive relations of central versus total obesity and blood pressure to cognitive function

OBJECTIVE

To examine the potential interactive relations of central versus total obesity and blood pressure (BP) to cognitive function.

METHOD

In all, 90 healthy, stroke, and dementia-free middle-aged and older adults (ages 54-81 years; 63% male; 93% White) underwent biomedical and neuropsychological assessment. Relations of central obesity (assessed by waist circumference (WC)) and systolic or diastolic BP to cognitive function were examined in multiple regression models. Next, body mass index (BMI) was substituted for WC in the models.

RESULTS

After statistical adjustment for age, education, gender, and other potential confounders including components of the metabolic syndrome (depending on the model), significant interactions of WC and systolic (or diastolic) BP were noted for the Grooved Pegboard - Dominant Hand and Stroop Interference scores, with marginally significant results for Grooved Pegboard - Nondominant Hand. In general, individuals with greater WC and higher BP performed most poorly on these measures. Similar results were obtained for BMI.

CONCLUSION

Independent of other confounders including facets of the metabolic syndrome, the combination of greater WC (or BMI) and higher (systolic or diastolic) BP was associated with diminished performance on tests of motor speed and manual dexterity, and executive function (i.e. response inhibition) accounting for 3-13% of the variance in these measures. In healthy older adults, there are similar, negative relations of central and total obesity to cognitive function that are potentiated by higher BP levels.

Treadmill Exercise Rehabilitation Improves Ambulatory Function and Cardiovascular Fitness in Patients With Chronic Stroke

BACKGROUND AND PURPOSE

Physical inactivity propagates disability after stroke through physical deconditioning and learned nonuse. We investigated whether treadmill aerobic training (T-AEX) is more effective than conventional rehabilitation to improve ambulatory function and cardiovascular fitness in patients with chronic stroke.

METHODS

Sixty-one adults with chronic hemiparetic gait after ischemic stroke (>6 months) were randomized to 6 months (3x/week) progressive T-AEX or a reference rehabilitation program of stretching plus low-intensity walking (R-CONTROL). Peak exercise capacity (Vo2 peak), o2 consumption during submaximal effort walking (economy of gait), timed walks, Walking Impairment Questionnaire (WIQ), and Rivermead Mobility Index (RMI) were measured before and after 3 and 6 months of training.

RESULTS

Twenty-five patients completed T-AEX and 20 completed R-CONTROL. Only T-AEX increased cardiovascular fitness (17% versus 3%, delta% T-AEX versus R-CONTROL, P<0.005). Group-by-time analyses revealed T-AEX improved ambulatory performance on 6-minute walks (30% versus 11%, P<0.02) and mobility function indexed by WIQ distance scores (56% versus 12%, P<0.05). In the T-AEX group, increasing training velocity predicted improved Vo2 peak (r=0.43, P<0.05), but not walking function. In contrast, increasing training session duration predicted improved 6-minute walk (r=0.41, P<0.05), but not fitness gains.

CONCLUSIONS

T-AEX improves both functional mobility and cardiovascular fitness in patients with chronic stroke and is more effective than reference rehabilitation common to conventional care. Specific characteristics of training may determine the nature of exercise-mediated adaptations.

The effect of exercise intensity on the response to exercise rehabilitation in patients with intermittent claudication

PURPOSE

The purpose of this randomized trial was to compare the efficacy of a low-intensity exercise rehabilitation program vs a high-intensity program in changing physical function, peripheral circulation, and health-related quality of life in peripheral arterial disease (PAD) patients limited by intermittent claudication.

METHODS

Thirty-one patients randomized to low-intensity exercise rehabilitation and 33 patients randomized to high-intensity exercise rehabilitation completed the study. The 6-month exercise rehabilitation programs consisted of intermittent treadmill walking to near maximal claudication pain 3 days per week at either 40% (low-intensity group) or 80% (high-intensity group) of maximal exercise capacity. Total work performed in the two training regimens was similar by having the patients in the low-intensity group exercise for a longer duration than patients in the high-intensity group. Measurements of physical function, peripheral circulation, and health-related quality of life were obtained on each patient before and after the rehabilitation programs.

RESULTS

After the exercise rehabilitation programs, patients in the two groups had similar improvements in these measures. Initial claudication distance increased by 109% in the low-intensity group (P < .01) and by 109% in the high-intensity group (P < .01), and absolute claudication distance increased by 61% (P < 0.01) and 63% (P < .01) in the low-intensity and high-intensity groups, respectively. Furthermore, both exercise programs elicited improvements (P < .05) in peak oxygen uptake, ischemic window, and health-related quality of life.

CONCLUSION

The efficacy of low-intensity exercise rehabilitation is similar to high-intensity rehabilitation in improving markers of functional independence in PAD patients limited by intermittent claudication, provided that a few additional minutes of walking is accomplished to elicit a similar volume of exercise.

Stress-induced blood pressure reactivity and cognitive function

OBJECTIVE

To examine the relation of stress-induced blood pressure (BP) reactivity to cognitive function.

METHODS

Ninety-four healthy stroke- and dementia-free middle-aged and older adults (ages 54 to 79; 62% male; 90% white) completed biomedical, psychophysiological, and neuropsychological assessment procedures.

RESULTS

After statistical adjustment for age, education, state anxiety, fasting glucose levels, and resting systolic or diastolic BP (depending on the model), greater systolic BP reactivity was associated with decreased performance on Logical Memory-Immediate Recall (r2 = 0.08; p < 0.007), Logical Memory-Delayed Recall (r2 = 0.06; p < 0.02), and Stroop interference scores (r2 = 0.04; p < 0.05). Enhanced diastolic BP reactivity was similarly associated with decreased performance on Logical Memory-Immediate Recall (r2 = 0.06; p < 0.02) and Stroop interference scores (r2 = 0.06; p < 0.02).

CONCLUSIONS

Independent of resting clinic blood pressure (BP), systolic and diastolic BP reactivity was associated with diminished performance on tests of immediate and delayed verbal memory and executive function (i.e., response inhibition), accounting for 3 to 8% of the variance in these measures.

Relationship between objective measures of peripheral arterial disease severity to self-reported quality of life in older adults with intermittent claudication

OBJECTIVES

The aim of this study was to determine the relation between functional measures of peripheral arterial disease (PAD) severity with both disease-specific and generic self-reported health-related quality-of-life (HR-QOL) measures, as well as the relation between the two types of HR-QOL measures.

METHODS

This was a cross-sectional observation of participants from the community and primary care or vascular surgery clinics in an academic Veterans Administration medical center. Eighty patients with symptomatic Fontaine stage II PAD provided physiologic measures and self-response questionnaires. Objective measures included the ankle-brachial index (ABI), time to maximum claudication pain on a graded exercise test, and a 6-minute floor-walking distance. Self-reports included the Walking Impairment Questionnaire (WIQ), a disease-specific HR-QOL measure and the Medical Outcomes Study (MOS) Short-Form 36 (SF-36), a generic HR-QOL measure.

RESULTS

Patients (mean age 70 +/- 8 [+/- SD] and 85% men) exhibited moderate-to-severe PAD by objective measures of ABI (0.65 +/- 0.19) and time in minutes to maximal claudication on a graded exercise test (7:54 +/- 4:58). Significant correlations were found between these measures and the WIQ distance, MOS-Physical Function, and MOS-Role Limitations due to physical dysfunction. The SF-36 and the WIQ subscales were significantly correlated.

CONCLUSION

In older PAD patients with intermittent claudication, objective measures of disease severity are correlated with a self-reported, disease-specific and generic HR-QOL.

Stress-Induced Blood Pressure Reactivity and Silent Cerebrovascular Disease

Background and Purpose— Exaggerated blood pressure (BP) responses to mental stress, an index of autonomic dysregulation, have been related to enhanced risk for stroke. This study examined cross-sectional relations of stress-induced BP reactivity to silent cerebrovascular disease assessed by magnetic resonance imaging (MRI) in healthy older adults.

Methods— Sixty-seven nondemented, community-dwelling older adults (ages 55 to 81; 75% male) free of major medical, neurological, or psychiatric disease, engaged in: (1) clinical assessment of resting systolic and diastolic BP; (2) assessment of systolic and diastolic BP responses to 3 laboratory-based mental stressors; and (3) MRI. MRIs were rated for small silent infarcts (≥3 mm), infarct-like lesions (<3 mm), and periventricular and deep white matter hyperintensities (WMH).

Results— After adjustment for age, gender, resting clinic BP, and fasting glucose levels, higher systolic BP reactivity was associated with an increased number of small silent infarcts (r 2 =0.14; P =0.004) and greater severity ratings of periventricular (r 2 =0.08; P <0.04) and deep WMH (r 2 =0.06; P <0.05). Higher diastolic BP reactivity was similarly associated with an increased number of small silent infarcts (r 2 =0.08; P <0.04), and greater severity ratings of periventricular (r 2 =0.08; P <0.04) and deep WMH (r 2 =0.11; P =0.009).

Conclusions— These results indicate that greater stress-induced BP reactivity is associated with enhanced silent cerebrovascular disease on MRI in healthy asymptomatic older adults independent of resting BP levels. Exaggerated stress-induced BP reactivity warrants further examination as a potential biobehavioral risk factor for cerebrovascular disease.

Response to exercise rehabilitation in smoking and nonsmoking patients with intermittent claudication

BACKGROUND

The purpose was to compare the changes in claudication pain, ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life following a program of exercise rehabilitation in smoking and nonsmoking patients with peripheral arterial disease (PAD) limited by intermittent claudication. Methods and results Thirty-nine smokers (63 +/- 4 pack-year smoking history; mean +/- SE) and 46 nonsmokers (former smokers who had a 51 +/- 7 pack-year smoking history who quit 14 +/- 2 years prior to investigation) completed the study. The 6-month exercise rehabilitation program consisted of intermittent treadmill walking to near maximal claudication pain 3 days per week, with progressive increases in walking duration and intensity during the program. Measurements were obtained on each patient before and after rehabilitation. Following exercise rehabilitation the smokers and nonsmokers had similar improvements in these measures, as initial claudication distance increased by 119% in the smokers (P <.001) and by 97% in the nonsmokers (P <.001), and absolute claudication distance increased by 82% (P <.001) and 59% (P <.001) in the smokers and nonsmokers, respectively. Furthermore, exercise rehabilitation improved (P <.05) ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life in the smokers and nonsmokers.

CONCLUSION

Exercise rehabilitation is an effective therapy to improve functional independence in both smoking and nonsmoking patients with PAD limited by intermittent claudication. Therefore, smokers with intermittent claudication are prime candidates for exercise rehabilitation because their relatively low baseline physical function does not impair their ability to regain lost functional independence to levels similar to nonsmoking patients with PAD.

Peripheral arterial disease and cognitive function

OBJECTIVE

Peripheral arterial disease (PAD) is associated with comorbid atherosclerosis of the coronary and carotid arteries and is a significant risk factor for stroke. However, cognitive function in PAD patients before clinically evident stroke remains poorly characterized. Here we hypothesized that, on neuropsychological testing, PAD patients would perform more poorly than healthy control subjects, and persons with mild cardiovascular disease (essential hypertension), but better than stroke patients, thus reflecting a continuum of cognitive impairment associated with increased severity of vascular disease.

METHOD

The cognitive performance of 38 PAD patients (mean ankle-brachial index=0.67, Fontaine Class II) was contrasted with that of 23 healthy normotensive controls, 20 essential hypertensives, and 26 anterior ischemic stroke patients on twelve neuropsychological tests.

RESULTS

PAD patients performed significantly more poorly than hypertensives and normotensives, but better than stroke patients, on seven tests of nonverbal memory, concentration, executive function, perceptuo-motor speed, and manual dexterity. Hypertensives displayed poorer performance than normotensives on tests of nonverbal memory and manual dexterity. These findings were independent of age, education, and depression scores. Higher diastolic blood pressure and plasma glucose levels predicted poorer performance of select cognitive tests by PAD patients. Eight to 67% of PAD patients displayed impaired performance (< 5(th) percentile of normotensive controls) on the seven aforementioned cognitive tests.

CONCLUSIONS

PAD patients exhibit diminished performance across a variety of domains of cognitive function. Findings also suggest a continuum of cognitive impairment associated with increasingly severe manifestations of cardiovascular disease, thus emphasizing the need for enhanced preventative measures to avert functional declines.

Cerebral blood flow and anxiety in older men: an analysis of resting anterior asymmetry and prefrontal regions

Asymmetric resting blood flow in prefrontal and hemispheric regions, assessed by single photon emission computed tomography (SPECT), was examined as a potential biological marker for enhanced trait and state anxiety in 30 older men (ages 55-81). Average and asymmetric perfusion in dorsolateral, medial, and orbital regions of the prefrontal lobes was also assessed. Results indicated a significant association between lower levels of resting dorsolateral blood flow and greater state anxiety responses to a series of stressful provocations (measured on a separate occasion). A significant curvilinear (U-shaped) relation between asymmetric dorsolateral perfusion and state anxiety was also identified; increased asymmetric blood flow favoring either the right or the left dorsolateral region related to higher levels of state anxiety. However, this association was attenuated by age and systolic blood pressure. Resting perfusion in the dorsolateral region may represent a more reliable biological marker for state anxiety than trait anxiety in older men.