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Biomedical subjects

Dennis T Villareal

Publications and source records attributed to Dennis T Villareal.

At least 19 recordsLinked to original sources
PubMed2026

EffectS of Lifestyle Interventions in Older PEople With Obesity (Effective SLOPE): a Systematic Review With Network Meta-Analyses.

BACKGROUND/AIM: We conducted a systematic review with network meta-analyses (NMA) summarizing the effects and safety of lifestyle interventions containing nutrition (NUT; e.g., calorie restriction), exercise (EX; e.g., aerobic/resistance exercise) and behavior change interventions (BCI; e.g., behavioral therapy) on physical function, body composition, quality of life, psychosocial outcomes, health and adverse events in community-dwelling older adults with obesity. METHODS: We used the methodology proposed by Cochrane and searched six databases and one trial registry for eligible randomized controlled trials (RCTs; intervention duration ≥ 12 weeks) up to May 2022 with a full new search in MEDLINE and a re-assessment of previously identified eligible trial registry entries in October 2025. Random-effects NMA ((standardized) mean difference ((S)MD), 95% confidence intervals) were conducted if possible. RESULTS: We included 72 RCTs (n = 6716) for descriptive summaries and 54 RCTs (n = 4249) for NMA. NUT+EX+BCI improved physical function (performance batteries) compared to control (SMD 3.37 [1.76;4.97]; high certainty of evidence). NUT+EX+BCI may reduce body (MD -8.69 [-13.14;-4.25]) and fat mass (MD -6.58 [-10.44;-2.73]) while not negatively affecting fat-free mass (MD -1.38 [-3.52;0.76]) or bone mineral density (MD -0.01 [-0.05;0.02]) (evidence very uncertain). Other interventions (single/combined) may also be effective; however, effects were often imprecise. For psychosocial outcomes, quality of life, and health events, data were insufficient or too heterogeneous to derive clear results. CONCLUSION: The evidence suggests that NUT+EX+BCI interventions are most suitable for the management of obesity in older adults. Nevertheless, further RCTs-especially in frail populations and on patient-relevant outcomes-are needed.

Humans↗
PubMed2006

Lower extremity muscle size and strength and aerobic capacity decrease with caloric restriction but not with exercise-induced weight loss.

Caloric restriction (CR) results in fat loss; however, it may also result in loss of muscle and thereby reduce strength and aerobic capacity (VO2 max). These effects may not occur with exercise-induced weight loss (EX) because of the anabolic effects of exercise on heart and skeletal muscle. We tested the hypothesis that CR reduces muscle size and strength and VO2 max, whereas EX preserves or improves these parameters. Healthy 50- to 60-yr-old men and women (body mass index of 23.5-29.9 kg/m2) were studied before and after 12 mo of weight loss by CR (n = 18) or EX (n = 16). Lean mass was assessed by dual-energy X-ray absorptiometry, thigh muscle volume by MRI, isometric and isokinetic knee flexor strength by dynamometry, and treadmill VO2 max by indirect calorimetry. Both interventions caused significant decreases in body weight (CR: -10.7 +/- 1.4%, EX: -9.5 +/- 1.5%) and lean mass (CR: -3.5 +/- 0.7%, EX: -2.2 +/- 0.8%), with no significant differences between groups. Significant decreases in thigh muscle volume (-6.9 +/- 0.8%) and composite knee flexion strength (-7.2 +/- 3%) occurred in the CR group only. Absolute VO2 max decreased significantly in the CR group (-6.8 +/- 2.3%), whereas the EX group had significant increases in both absolute (+15.5 +/- 2.4%) and relative (+28.3 +/- 3.0%) VO2 max. These data provide evidence that muscle mass and absolute physical work capacity decrease in response to 12 mo of CR but not in response to a similar weight loss induced by exercise. These findings suggest that, during EX, the body adapts to maintain or even enhance physical performance capacity.

Adaptation, Physiological↗
PubMed2006

DHEA enhances effects of weight training on muscle mass and strength in elderly women and men.

The plasma levels of dehydroepiandrosterone (DHEA) and its sulfated form (DHEAS) decline approximately 80% between the ages of 25 and 75 yr. Muscle mass and strength also decrease with aging. Published data on the effects of DHEA replacement on muscle mass and strength are conflicting. The goals of this study were to determine whether DHEA replacement increases muscle mass and strength and/or enhances the effects of heavy resistance exercise in elderly women and men. We conducted a randomized, double-blind, placebo-controlled study of the effects of 10 mo of DHEA replacement therapy with the addition of weightlifting exercise training during the last 4 mo of the study (DHEA + exercise group, n = 29; placebo + exercise group, n = 27). DHEA alone for 6 mo did not significantly increase strength or thigh muscle volume. However, DHEA therapy potentiated the effect of 4 mo of weightlifting training on muscle strength, evaluated by means of one-repetition maximum measurement and Cybex dynamometry, and on thigh muscle volume, measured by magnetic resonance imaging. Serum insulin-like growth factor concentration increased in response to DHEA replacement. This study provides evidence that DHEA replacement has the beneficial effect of enhancing the increases in muscle mass and strength induced by heavy resistance exercise in elderly individuals.

Adjuvants, Immunologic↗
PubMed2006

Effect of weight loss and exercise on frailty in obese older adults.

BACKGROUND: Obesity exacerbates the age-related decline in physical function and causes frailty in older persons. However, appropriate treatment for obese older persons is unknown. We evaluated the effects of weight loss and exercise therapy on physical function and body composition in obese older persons. METHODS: We screened 40 obese older volunteers and eventually randomized 27 frail obese older volunteers to treatment or control groups. Treatment consisted of 6 months of weekly behavioral therapy for weight loss in conjunction with exercise training 3 times per week. Physical function was evaluated with measurements of frailty (Physical Performance Test, peak oxygen consumption, and Functional Status Questionnaire); strength, gait, and balance tests; body composition with dual-energy x-ray absorptiometry; and quality of life using the Medical Outcomes Survey 36-Item Short-Form Health Survey. Results are reported as mean +/- SD. RESULTS: Two subjects in the treatment group did not comply with the intervention, and 1 subject in the control group withdrew. Analyses included all 27 subjects originally randomized to the treatment and control groups. The treatment group lost 8.4% +/- 5.6% of body weight, whereas weight did not change in the control group (+0.5% +/- 2.8%; P<.001). Compared with the control group, fat mass decreased (-6.6 +/- 3.4 vs +1.7 +/- 4.1 kg; P<.001), without a change in fat-free mass (-1.2 +/- 2.1 vs -1.0 +/- 3.5 kg; P = .75) in the treatment group. The Physical Performance Test score (2.6 +/- 2.5 vs 0.1 +/- 1.0; P = .001), peak oxygen consumption (1.7 +/- 1.6 vs 0.3 +/- 1.1 mL/min per kilogram; P = .02), and Functional Status Questionnaire score (2.9 +/- 3.7 vs -0.2 +/- 3.9; P = .02) improved in treated subjects compared with control subjects. Treatment also improved strength, walking speed, obstacle course, 1-leg limb stance time, and health survey physical subscale scores (all P<.05). CONCLUSION: These findings suggest that weight loss and exercise can ameliorate frailty in obese older adults. Trial Registration clinicaltrials.gov Identifier: NCT00146133.

Activities of Daily Living↗
PubMed2006

Improvements in glucose tolerance and insulin action induced by increasing energy expenditure or decreasing energy intake: a randomized controlled trial.

BACKGROUND: Weight loss, through calorie restriction or increases in energy expenditure via exercise, improves glucose tolerance and insulin action. However, exercise-induced energy expenditure may further improve glucoregulation through mechanisms independent of weight loss. OBJECTIVE: The objective was to assess the hypothesis that weight loss through exercise-induced energy expenditure improves glucoregulation and circulating factors involved in insulin action to a greater extent than does similar weight loss through calorie restriction. DESIGN: Sedentary men and women aged 50-60 y with a body mass index (kg/m(2)) of 23.5-29.9 were randomly assigned to 1 of 2 weight-loss interventions [12 mo of exercise training (EX group; n = 18) or calorie restriction (CR group; n = 18)] or to a healthy lifestyle (HL) control group (n = 10). The insulin sensitivity index and areas under the curve for glucose and insulin were assessed with an oral-glucose-tolerance test. Adiponectin and tumor necrosis factor alpha concentrations were measured in fasting serum. Fat mass was measured by dual-energy X-ray absorptiometry. RESULTS: Yearlong energy deficits were not significantly different between the EX and CR groups, as evidenced by body weight and fat mass changes. The insulin sensitivity index increased and the glucose and insulin areas under the curve decreased in the EX and CR groups, remained unchanged in the HL group, and did not differ significantly between the EX and CR groups. Marginally significant increases in adiponectin and decreases in the ratio of tumor necrosis factor alpha to adiponectin occurred in the EX and CR groups but not in the HL group. CONCLUSIONS: Weight loss induced by exercise training or calorie restriction improves glucose tolerance and insulin action in nonobese, healthy, middle-aged men and women. However, it does not appear that exercise training-induced weight loss results in greater improvements than those that result from calorie restriction alone.

Adiponectin↗
PubMed2006

Effect of lifestyle intervention on metabolic coronary heart disease risk factors in obese older adults.

BACKGROUND: Coronary heart disease (CHD) risk factors increase with age and body mass index (BMI; in kg/m2). However, whether lifestyle intervention ameliorates metabolic CHD risk factors in obese older adults is unknown. OBJECTIVE: The objective was to determine whether lifestyle intervention improves metabolic CHD risk factors in obese older adults. DESIGN: A 6-mo outpatient randomized controlled trial was conducted in obese (BMI >or= 30) older (>or=65 y) adults randomly assigned to diet and exercise therapy (treatment group; n = 17) or no therapy (control group; n = 10). The main outcomes were CHD risk factors. RESULTS: Body weight decreased by 8.4% (8.2 kg) in the treatment group; weight did not change significantly (0.7 kg) in the control group (P < 0.001 between groups). Changes between the control and treatment groups, respectively, in waist circumference (1 and -10 cm), plasma glucose (4 and -4 mg/dL), serum triacylglycerols (0 and -45 mg/dL), and systolic (-2 and -10 mm Hg) and diastolic (0 and -8 mm Hg) blood pressure were different (P < 0.05 for all). The number of subjects with the metabolic syndrome decreased by 59% in the treatment group but did not change significantly in the control group (P < 0.05). Serum free fatty acids increased by 10 micromol/L in the control group and decreased by 99 micromol/L in the treatment group (P < 0.05). Changes between the control and treatment groups, respectively, in C-reactive protein (0.8 and -2.5 mg/L) and interleukin 6 (1.6 and -2.4 pg/mL) were different (P < 0.05 for both). CONCLUSIONS: Lifestyle intervention decreases multiple metabolic CHD risk factors simultaneously in obese older adults.

Age Factors↗
PubMed2006

One year of caloric restriction in humans: feasibility and effects on body composition and abdominal adipose tissue.

BACKGROUND: Caloric restriction (CR) increases maximal life span in short-lived organisms, and its effects are being explored in nonhuman primates. The objectives of this study were to determine the feasibility of prolonged CR in nonobese adults and to compare the effects of CR- and exercise-induced weight loss on body composition and abdominal adiposity. METHODS: A randomized, controlled trial was conducted with 48 healthy, nonobese women and men, aged 57 +/- 1 (mean +/- standard error [SE]) years, with body mass index 27.3 +/- 0.3 kg/m2. Participants were randomly assigned to a 20% calorically-restricted diet (CR, n = 19), exercise designed to produce a similar energy deficit (EX, n = 19), or a healthy lifestyle control group (HL, n = 10) for 1 year. Assessments included weight, body composition by dual-energy x-ray absorptiometry, abdominal adipose tissue by magnetic resonance imaging, and energy intake by doubly labeled water. RESULTS: The average level of CR achieved by the CR group was 11.5 +/- 2.1%, and the EX group completed 59 +/- 6.7% of their prescribed exercise. Weight changes were greater (p <or=.0005) in the CR (-8.0 +/- 0.9 kg) and EX (-6.4 +/- 0.9) groups as compared to the HL group (-1.3 +/- 0.9 kg), corresponding to reductions of 10.7%, 8.4%, and 1.7% of baseline weights, respectively. Whole-body fat mass and visceral and subcutaneous abdominal adipose tissue decreased significantly (p <.005) and comparably in the CR and EX groups, but did not change in the HL group. CONCLUSIONS: CR for 1 year was feasible, but the level of CR achieved was less than prescribed. CR and exercise were equally effective in reducing weight and adiposity.

Abdominal Fat↗
PubMed2005

Low bone mass in subjects on a long-term raw vegetarian diet.

BACKGROUND: Little is known regarding the health effects of a raw food (RF) vegetarian diet. METHODS: We performed a cross-sectional study on 18 volunteers (mean +/- SD age, 54.2 +/- 11.5 years; male/female ratio, 11:7) on a RF vegetarian diet for a mean of 3.6 years and a comparison age- and sex-matched group eating typical American diets. We measured body composition, bone mineral content and density, bone turnover markers (C-telopeptide of type I collagen and bone-specific alkaline phosphatase), C-reactive protein, 25-hydroxyvitamin D, insulin-like growth factor 1, and leptin in serum. RESULTS: The RF vegetarians had a mean +/- SD body mass index (calculated as weight in kilograms divided by the square of height in meters) of 20.5 +/- 2.3, compared with 25.4 +/- 3.3 in the control subjects. The mean bone mineral content and density of the lumbar spine (P= .003 and P<.001, respectively) and hip (P = .01 and P<.001, respectively) were lower in the RF group than in the control group. Serum C-telopeptide of type I collagen and bone-specific alkaline phosphatase levels were similar between the groups, while the mean 25-hydroxyvitamin D concentration was higher in the RF group than in the control group (P<.001). The mean serum C-reactive protein (P = .03), insulin-like growth factor 1 (P = .002), and leptin (P = .005) were lower in the RF group. CONCLUSION: A RF vegetarian diet is associated with low bone mass at clinically important skeletal regions but is without evidence of increased bone turnover or impaired vitamin D status.

Absorptiometry, Photon↗
PubMed2005

Obesity in older adults: technical review and position statement of the American Society for Nutrition and NAASO, The Obesity Society.

Obesity causes serious medical complications and impairs quality of life. Moreover, in older persons, obesity can exacerbate the age-related decline in physical function and lead to frailty. However, appropriate treatment for obesity in older persons is controversial because of the reduction in relative health risks associated with increasing body mass index and the concern that weight loss could have potential harmful effects in the older population. This joint position statement from the American Society for Nutrition and NAASO, The Obesity Society reviews the clinical issues related to obesity in older persons and provides health professionals with appropriate weight-management guidelines for obese older patients. The current data show that weight-loss therapy improves physical function, quality of life, and the medical complications associated with obesity in older persons. Therefore, weight-loss therapy that minimizes muscle and bone losses is recommended for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss.

Aged↗
PubMed2005

Obesity in older adults: technical review and position statement of the American Society for Nutrition and NAASO, The Obesity Society.

Obesity causes serious medical complications and impairs quality of life. Moreover, in older persons, obesity can exacerbate the age-related decline in physical function and lead to frailty. However, appropriate treatment for obesity in older persons is controversial because of the reduction in relative health risks associated with increasing body mass index and the concern that weight loss could have potential harmful effects in the older population. This joint position statement from the American Society for Nutrition and the NAASO, The Obesity Society reviews the clinical issues related to obesity in older persons and provides health professionals with appropriate weight-management guidelines for obese older patients. The current data show that weight-loss therapy improves physical function, quality of life, and the medical complications associated with obesity in older persons. Therefore, weight-loss therapy that minimizes muscle and bone losses is recommended for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss.

Aged↗
PubMed2005

Aerobic power and insulin action improve in response to endurance exercise training in healthy 77-87 yr olds.

Previous studies have demonstrated that frail octogenarians have an attenuated capacity for cardiovascular adaptations to endurance exercise training. In the present study, we determined the magnitude of cardiovascular and metabolic adaptations to high-intensity endurance exercise training in healthy, nonfrail elderly subjects. Ten subjects [8 men, 2 women, 80.3 yr (SD2.5)] completed 10-12 mo (108 exercise sessions) of a supervised endurance exercise training program consisting of 2.5 sessions/wk (SD 0.2), 58 min/session (SD 6), at an intensity of 83% (SD 5) of peak heart rate. Primary outcomes were maximal attainable aerobic power [peak aerobic capacity (Vo(2peak))]; serum lipids, oral glucose tolerance, and insulin action during a hyperglycemic clamp; body composition by dual-energy X-ray absorptiometry, and energy expenditure using doubly labeled water and indirect calorimetry. The training program resulted in an increase in Vo(2peak) of 15% (SD 7) [22.9 (SD 3.3) to 26.2 ml.kg(-1).min(-1) (SD 4.0); P < 0.0001]. Favorable lipid changes included reductions in total cholesterol (-8%; P = 0.002) and LDL cholesterol (-10%; P = 0.003), with no significant change in HDL cholesterol or triglycerides. Insulin action improved, as evidenced by a 29% increase in glucose disposal rate relative to insulin concentration during the hyperglycemic clamp. Fat mass decreased by 1.8 kg (SD 1.4) (P = 0.003); lean mass did not change. Total energy expenditure increased by 400 kcal/day because of an increase in physical activity. No change occurred in resting metabolism. In summary, healthy nonfrail octogenarians can adapt to high-intensity endurance exercise training with improvements in aerobic power, insulin action, and serum lipid and lipoprotein risk factors for coronary heart disease; however, the adaptations in aerobic power and insulin action are attenuated compared with middle-aged individuals.

Adaptation, Physiological↗
PubMed2004

Effect of CYP1A1 gene polymorphisms on estrogen metabolism and bone density.

UNLABELLED: In this study, we evaluated the effect of polymorphisms of the CYP1A1 gene, linked to hormone-related cancers, on estrogen metabolism and BMD. We found that variants carrying the A allele (CA and AA) for the C4887A polymorphism have a significantly higher degree of estrogen catabolism and lower femoral BMD. INTRODUCTION: Polymorphisms of the CYP1A1 gene, one of the key enzymes that metabolize estrogen, have been linked with hormone-related cancers. We investigated the impact of these polymorphisms on estrogen metabolism and BMD, which is another hormone-dependent health issue. MATERIALS AND METHODS: One hundred seventy postmenopausal women (mean age, 63.5 +/- 0.6 years) participated in the study, but analysis was limited to 156 white women. Genotyping was performed by restriction fragment length polymorphism analysis, urinary estrogen metabolites by enzyme immunoassay, serum estradiol by ultrasensitive radioimmunoassay, serum sex hormone-binding globulin by immunoradiometric assay, and BMD by DXA. Differences in the levels of urinary metabolites and BMD among the different variants were analyzed by analysis of covariance, whereas differences in free estradiol index, urinary N-telopeptide of type 1 collagen (NTx), and bone size were compared by one-way ANOVA. RESULTS: We found that subjects carrying the A allele (CA or AA) for the C4887A polymorphism of the CYP1A1 gene have significantly lower free estradiol index (0.323 +/- 0.08 versus 0.506 +/- 0.04; p = 0.04; pmol/nmol) and higher levels of total urinary estrogen metabolites (ng/mg Cr) than CC subjects (27.92 +/- 2.03 versus 21.15 +/- 1.04; p = 0.03), suggestive of an accelerated estrogen catabolism in these (CA + AA) individuals. They also had significantly lower BMD (g/cm2) in all regions of the femur than subjects with the CC genotype, (total hip: 0.809 +/- 0.02 versus 0.865 +/- 0.01; neck: 0.671 +/- 0.02 versus 0.722 +/- 0.01; trochanter: 0.614 +/- 0.02 versus 0.656 +/- 0.01; and intertrochanter: 0.969 +/- 0.03 versus 1.039 +/- 0.01; all p < 0.05). No significant effect of this gene polymorphism was detected on lumbar spine BMD. Urinary NTx, a marker for bone resorption, was also significantly higher in the CA + AA compared with the CC variants (186.09 +/- 16.15 versus 124.00 +/- 11.87 nmol of bone collagen equivalent/mmol of creatinine; p = 0.003). Genotype frequencies for this polymorphism showed CC as the most common genotype (127/156), followed by CA (28/156), whereas AA was rare (1/156). CONCLUSION: Women with the A allele seem to have increased estrogen catabolism, as indicated by higher urinary estrogen metabolites and lower free estradiol index. This is associated with increased bone resorption and lower femoral BMD in those with the A allele. Our data, therefore, suggest that, through its effect on the rate of estrogen catabolism, the C4887A polymorphism of the CYP1A1 gene may represent a possible genetic risk factor for osteoporosis.

Absorptiometry, Photon↗
PubMed2004

Effect of DHEA on abdominal fat and insulin action in elderly women and men: a randomized controlled trial.

CONTEXT: Dehydroepiandrosterone (DHEA) administration has been shown to reduce accumulation of abdominal visceral fat and protect against insulin resistance in laboratory animals, but it is not known whether DHEA decreases abdominal obesity in humans. DHEA is widely available as a dietary supplement without a prescription. OBJECTIVE: To determine whether DHEA replacement therapy decreases abdominal fat and improves insulin action in elderly persons. DESIGN AND SETTING: Randomized, double-blind, placebo-controlled trial conducted in a US university-based research center from June 2001 to February 2004. PARTICIPANTS: Fifty-six elderly persons (28 women and 28 men aged 71 [range, 65-78] years) with age-related decrease in DHEA level. INTERVENTION: Participants were randomly assigned to receive 50 mg/d of DHEA or matching placebo for 6 months. MAIN OUTCOME MEASURES: The primary outcome measures were 6-month change in visceral and subcutaneous abdominal fat measured by magnetic resonance imaging and glucose and insulin responses to an oral glucose tolerance test (OGTT). RESULTS: Of the 56 men and women enrolled, 52 underwent follow-up evaluations. Compliance with the intervention was 97% in the DHEA group and 95% in the placebo group. Based on intention-to-treat analyses, DHEA therapy compared with placebo induced significant decreases in visceral fat area (-13 cm2 vs +3 cm2, respectively; P = .001) and subcutaneous fat (-13 cm2 vs +2 cm2, P = .003). The insulin area under the curve (AUC) during the OGTT was significantly reduced after 6 months of DHEA therapy compared with placebo (-1119 muU/mL per 2 hours vs +818 muU/mL per 2 hours, P = .007). Despite the lower insulin levels, the glucose AUC was unchanged, resulting in a significant increase in an insulin sensitivity index in response to DHEA compared with placebo (+1.4 vs -0.7, P = .005). CONCLUSION: DHEA replacement could play a role in prevention and treatment of the metabolic syndrome associated with abdominal obesity.

Abdomen↗
PubMed2004

Physical frailty and body composition in obese elderly men and women.

OBJECTIVE: To evaluate the prevalence of frailty and interrelationships among body composition, physical function, and quality of life in community-dwelling obese elderly (OE) persons. RESEARCH METHODS AND PROCEDURES: Fifty-two OE, 52 nonobese frail, and 52 nonobese nonfrail subjects, matched for age and sex, were studied. Subjective and objective measures of functional status were evaluated by using the physical performance test, exercise stress test, lower extremity (LE) strength, gait speed, static and dynamic balance, functional status questionnaires, and health-related quality-of-life questionnaire (Medical Outcomes Short Form). Body composition was evaluated by using DXA, and muscle quality was evaluated by determining the ratio of LE strength to LE lean mass. RESULTS: Among OE subjects, 96% met our standard criteria for mild to moderate frailty. Compared with the nonobese nonfrail group, the OE and nonobese frail groups had lower and similar scores in physical performance test, peak aerobic power, and functional status questionnaire, and exhibited similar impairments in strength, walking speed, balance, and health-related quality of life. Although absolute fat-free mass (FFM) was greater, the percentage body weight as FFM and muscle quality was lower in the OE group than in the other two groups. DISCUSSION: Physical frailty, which predisposes to loss of independence, is common in community-living OE men and women. Physical frailty in OE subjects was associated with low percentage FFM, poor muscle quality, and decreased quality of life. These findings suggest that weight loss therapy may be particularly important in OE persons to improve physical function, in addition to improving the medical complications associated with obesity.

Aged↗
PubMed2004

Absence of left ventricular and arterial adaptations to exercise in octogenarians.

Recent evidence suggests that octogenarians exhibit attenuated adaptations to training with a small increase in peak O2 consumption (VO2) that is mediated by a modest improvement in cardiac output without an increase in arteriovenous O2 content difference. This study was designed to determine whether diminished increases in peak VO2 and cardiac output in the octogenarians are associated with absence of left ventricular and arterial adaptations to exercise training. We studied 22 octogenarians (81.9 +/- 3.7 yr, mean +/- SD) randomly assigned a group that exercised at an intensity of 82.5 +/- 5% of peak heart rate for 9 mo and 14 (age 83.1 +/- 4.1) assigned to a control group. Peak VO2 increased 12% in the exercise group but decreased slightly (-7%) in the controls. The exercise group demonstrated significant but small decreases in the heart rate (6%, P = 0.002) and the rate-pressure product (9%, P = 0.004) during submaximal exercise at an absolute work rate. Training induced no significant changes in the left ventricular size, geometry (wall thickness-to-radius ratio), mass, and function assessed with two-dimensional echocardiography or in arterial stiffness evaluated with applanation tonometry. Data suggest that the absence of cardiac and arterial adaptations may in part account for the limited gain in aerobic capacity in response to training in the octogenarians.

Adaptation, Physiological↗
PubMed2003

Clinical outcomes of possible versus probable Alzheimer's disease.

OBJECTIVE: To determine whether Alzheimer's disease (AD) associated with comorbidities or atypical features (possible AD) is marked by differences in clinical course and outcomes compared with uncomplicated AD (probable AD). METHODS: Annual evaluations were made of patients with AD, for up to 11 years. Six hundred forty subjects with AD were clinically classified into two groups: 1) possible AD (n = 208), and 2) probable AD (n = 432). Data on demographics, Mini-Mental State Examination (MMSE), Short Blessed Test (SBT), psychometric performance, and Clinical Dementia Rating (CDR) were collected at baseline. Kaplan-Meier survival curves and Cox proportional hazards models were conducted to evaluate whether possible AD would have different outcomes on dementia progression, nursing home placement, and death compared with probable AD. RESULTS: The possible AD group was slightly younger and less well educated than the probable AD group, but there were no group differences at baseline in MMSE, SBT, and CDR scores. Controlling for age and education, the possible AD group had poorer baseline psychometric performance (p = 0.022). There were no group differences, however, for rate of dementia progression, nursing home admission, and death. CONCLUSIONS: Comorbidities and atypical features in this sample of patients with Alzheimer's disease did not substantially affect dementia outcomes. The primary determinant of the clinical course of dementia in this sample was the presence of clinically diagnosed Alzheimer's disease, independent of the presence or absence of comorbidities or atypical features. Therefore, patients with possible Alzheimer's disease may be considered for inclusion in investigations of Alzheimer's disease, including clinical trials, to improve the generalizability of the findings.

Aged↗
PubMed2003

Attenuation of cardiovascular adaptations to exercise in frail octogenarians.

To determine the mechanisms underlying increased aerobic power in response to exercise training in octogenarians, we studied mildly frail elderly men and women randomly assigned to an exercise group (n = 22) who participated in a training program of 6 mo of physical therapy, strength training, and walking followed by 3 mo of more intense endurance exercise at 78% of peak heart rate or a control sedentary group (n = 24). Peak O2 consumption (V(O2 peak)) increased 14% in the exercise group (P < 0.0001) but decreased slightly in controls. Training induced 14% increase (P = 0.027) in peak exercise cardiac output (Q), determined via acetylene re-breathing, and no change in arteriovenous O2 content difference. The increase in Q was mediated by increases in heart rate (P = 0.009) and probably stroke volume (P = 0.096). Left ventricular stroke work also increased significantly. In the men, the increase in V(O2 peak) was exclusively due to a large increase in peak Q (22%). In the women, the gain in V(O2 peak) was due to small increases in Q and O2 extraction from skeletal muscles. Pulse pressure normalized for stroke volume and arterial elastance during peak effort did not change with training. Controls showed no changes. The results suggest that, although frail octogenarians have a diminished capacity for improvement in aerobic power in response to exercise training, this adaptation is mediated mostly by an increase in Q during peak effort. Furthermore, Q likely plays a greater role in the adaptive increase in V(O2 peak) in old men than old women.

Adaptation, Physiological↗