Biomedical subjects

M C Morey

Publications and source records attributed to M C Morey.

14 recordsLinked to original sources

PubMed1999

Aerobic exercise training can reverse age-related peripheral circulatory changes in healthy older men.

BACKGROUND: The age-related decline in maximal oxygen consumption is attenuated by habitual aerobic exercise. However, the relative effects of training on central and peripheral responses to exercise in older subjects are not known. The present study assessed the contribution of central and peripheral responses to the age-associated decline in peak oxygen consumption and compared the effect of exercise training in healthy older and younger subjects. METHODS AND RESULTS: Ten older and 13 younger men underwent invasive measurement of central and peripheral cardiovascular responses during an upright, staged cycle exercise test before and after a 3-month period of exercise training with cycle ergometry. At baseline, cardiac output and AV oxygen difference during exercise were significantly lower in older subjects. With training, the older and younger groups increased maximal oxygen consumption by 17.8% and 20.2%, respectively. Peak cardiac output was unchanged in both groups. Systemic AV oxygen difference increased 14.4% in the older group and 14.3% in the younger group and accounted for changes in peak oxygen consumption. Peak leg blood flow increased by 50% in older subjects, whereas the younger group showed no significant change. There was no change in peak leg oxygen extraction in the older group, but in the younger group, leg AV oxygen difference increased by 15.4%. CONCLUSIONS: These findings suggest that the age-related decline in maximal oxygen consumption results from a reversible deconditioning effect on the distribution of cardiac output to exercising muscle and an age-related reduction in cardiac output reserve.

Adult↗

PubMed1999

Reliability of physical performance tests in four different randomized clinical trials.

OBJECTIVES: (1) To assess the test-retest reliability of physical performance tests in subject groups with different levels of impairment and disability, and (2) to assess the stability of these tests over different time intervals. DESIGN: Test-retest, repeated measures reliability design. SETTING: (1) A university's center for aging and research center, (2) a continuing care retirement community, and (3) an extended care and rehabilitation center at a Veterans Affairs medical center. SUBJECTS: Twenty-four community-dwelling elders, 15 community-dwelling elders with Parkinson disease, 12 older women with vertebral osteoporosis and compression fractures, and 14 elderly nursing home residents. MEASURES: Lower extremity isometric strength (ankle dorsiflexion, hip abduction), spinal configuration (thoracic kyphosis, lumbar lordosis), lumbosacral motion (flexion, extension), and timed measures of the ability to get in and to get out of bed at a usual pace. RESULTS: Most of the within-group intraclass correlation coefficients (ICCs) were good to excellent (.70 to .97). Overall, ICCs for all groups combined were between .70 and .96, and no decrement in reliability was noted after controlling for group membership. In addition, no decrement in the ICC was observed for short (1 day) vs. longer (1 week) intervals of testing. CONCLUSIONS: These performance-based measures may be used reliably across a wider range of testing environments and elderly populations than has been reported.

Ankle Joint↗

PubMed1999

Spinal-flexibility-plus-aerobic versus aerobic-only training: effect of a randomized clinical trial on function in at-risk older adults.

BACKGROUND: As exercise is associated with favorable health outcomes, impaired older adults may benefit from specialized exercise interventions to achieve gains in function. The purpose of this study was to determine the added benefit of a spinal flexibility-plus-aerobic exercise intervention versus aerobic-only exercise on function among community-dwelling elders. METHODS: We employed a randomized clinical trial consisting of 3 months of supervised exercise followed by 6 months of home-based exercise with telephone follow-up. A total of 210 impaired males and females over age 64 enrolled in this study. Of these, 134 were randomly assigned to either spinal flexibility-plus-aerobic exercise or aerobic-only exercise, with 116 individuals completing the study. Primary outcomes obtained at baseline, after 3 months of supervised exercise, and after 6 months of home-based exercise included: axial rotation, maximal oxygen uptake (VO2max); functional reach, timed-bed-mobility; and the Physical Function Scale (PhysFunction) of the Medical Outcomes Study SF-36. RESULTS: Differences between the two interventions were minimal. Overall change scores for both groups combined indicated significant improvement for: axial rotation (p=.001), VO2max (p=.0001), and PhysFunction (p=.0016). Secondary improvements were noted for overall health (p=.0025) and reduced symptoms (p=.0008). Differences between groups were significant only for VO2max (p=.0014) at 3 months with the aerobic-only group improving twice as much in aerobic capacity as the spinal flexibility-plus-aerobic group. Repeated measures indicated both groups improved during the supervised portion of the intervention but tended to return toward baseline following the home-based portion of the trial. CONCLUSIONS: Gains in physical functioning and perceived overall health are obtained with moderate aerobic exercise. No differential improvements were noted for the spinal flexibility-plus-aerobic intervention.

Aged↗

PubMed1998

Physical fitness and functional limitations in community-dwelling older adults.

BACKGROUND: Conceptual models of disability have focused on disease-specific factors as the primary cause of disability. Functional limitations in the performance of basic tasks are considered primary mediators on the causal pathway from disease to disability. PURPOSE: The purpose of this study was to assess the association between three fitness components (cardiorespiratory, morphologic, and strength) and functional limitations. METHODS: Analyses employed data collected upon 161 older adults (72.5 +/- 5.1 yr) who agreed to undergo baseline testing in a clinical trial. RESULTS: After controlling for age, race, sex, education, depressive symptoms, and body mass index, all three fitness components were directly associated with functional limitations (P < 0.05). This study is the first to characterize a broad set of individual fitness components as they relate to functional limitations and the first to examine directly measured cardiorespiratory fitness within the context of existing disability models. CONCLUSION: These findings suggest that low fitness is a risk factor for functional decline independent of disease processes.

Activities of Daily Living↗

PubMed1998

Is there a threshold between peak oxygen uptake and self-reported physical functioning in older adults?

PURPOSE: Few studies have examined the relationship between directly measured oxygen uptake (VO2) and self-reported physical function (PF). The purpose of this study was: 1) to examine the relationship between peak V02 and PF and 2) to determine whether a threshold or cut point exist that distinguishes between individuals reporting required assistance in the performance of functional tasks (low PF) and those who report ability to perform tasks independently (high PF). METHODS: Participants were 161 community-dwelling adults, ages 65-90, who had a baseline evaluation for a clinical trail that included measurement of peak V02 and PF consisted of a summary score combining scores from the Older Americans Resources and Services Multidimensional Functional Assessment Questionnaire, Nagi Disability Study. Rosow-Breslau Scale, Physical Function Scale of the Medical Outcomes Study, and the Falls Efficacy Scale. Decision tree, cubic spline, and logistic regression analyses explored these relationships with age, gender, education, race, body mass index, depression, and total number of chronic diseases included as important covariates. RESULTS: Among all covariates examined, peak V02 was most strongly associated with (P = 0.004) with PF. There was not threshold effect. Decision tree analyses indicated that 18.3 mL.kg-1.min-1 was the optimal cut point distinguishing between low PF and High PG (P < 0.0001). Between-gender differences in PF (P = 0.002) were no longer significant when peak V02 was included in the PF model (P = 0.17). CONCLUSIONS: These data indicate that individuals with a V02 < 18 mL.kg-1min-1 report significant difficulty in the performance of daily tasks and that differences in peak V02 may explain, in part, why women report more impairment in PF.

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PubMed1996

Five-year performance trends for older exercisers: a hierarchical model of endurance, strength, and flexibility.

OBJECTIVE: To examine 5-year trends in measures of physical performance, and the impact of disease upon performance, in three domains: cardiovascular fitness, musculo-skeletal strength, and flexibility among older adults participating in a medically supervised exercise program. DESIGN: Longitudinal analyses of data obtained in an observational cohort study. SETTING: Department of Veterans Affairs Medical Center in Durham, North Carolina. PARTICIPANTS: Seventy-three community-dwelling veterans between 64 and 90 years of age. INTERVENTION: Voluntary participation in a medically supervised outpatient exercise program meeting 3 days per week for 90 minutes per session. MAIN OUTCOME MEASURES: Changes over time in cardiovascular fitness, musculoskeletal strength, and flexibility. RESULTS: Forty-nine percent of the original study participants remained in the program for a full 5 years. They had lower baseline rates of cardiorespiratory and musculoskeletal diseases than did the dropouts. Dropouts were significantly more impaired in baseline measures of cardiovascular fitness (P = .038) and strength (P = .007). Changes over time for cardiovascular fitness and strength were similar. Only linear (P < .05) and quadratic time (P < .001) were significant. Only linear time was significant for measures of flexibility (P < .05). Baseline cardiorespiratory disease, baseline musculoskeletal disease, and interaction terms were not significant. Overall, measures of physical performance demonstrated gradual improvement for 2 to 3 years, followed by a gradual decline in performance irrespective of baseline disease status. CONCLUSION: Older adults who exercise regularly, including those with multiple chronic diseases, can achieve significant gains in measures of physical performance, and these gains can be sustained for 2 to 3 years.

Aged↗

PubMed1994

The Gerofit Program: a VA innovation.

In 1986 Gerofit, an exercise and health promotion program for older veterans, was established. This paper describes the program in detail by summarizing the patient assessment protocol, the exercise program, and program evaluation, as well as observational outcomes for up to 5 years of follow-up. Our data suggest that exercise provides older veterans with beneficial gains in function that are maintained for 5 years.

Aged↗

PubMed1993

Aerobic fitness, acute exercise and sleep in older men.

In the current study 12 aerobically fit and 12 sedentary older men underwent two nocturnal polysomnographic (PSG) studies. A control PSG was conducted following a day without aerobic activity, whereas a postexercise PSG study was conducted following an afternoon session of exhaustive aerobic exercise. In addition to deriving usual sleep parameters, a computer scoring program was used to count the number of individual electroencephalographic (EEG) slow waves in each PSG tracing. Multivariate and univariate analyses showed that the fit subjects had shorter sleep onset latencies, less wake time after onset, fewer discrete sleep episodes, fewer sleep stage shifts during the initial portion of the night, less stage 1 sleep, a higher sleep efficiency and more total slow waves during both PSGs than did the sedentary subjects. Although no main effects were found for the acute exercise challenge, post hoc analyses showed that high levels of body heating during exercise predicted increased sleep fragmentation for both fit and sedentary subjects. These findings provide initial support for the contention that exercise and fitness may have significant effects on the sleep of older men. However, results also suggest that high levels of body heating resulting from a single exercise challenge may have adverse effects. Implications of the study are discussed and suggestions for future research are provided.

Age Factors↗

PubMed1991

Two-year trends in physical performance following supervised exercise among community-dwelling older veterans.

The extent to which exercise can delay the normal decline in physical performance associated with aging is unknown. We examined the impact of 2 years of supervised exercise on cardiovascular fitness, flexibility, and strength in a group of elderly (age 65-74) veterans. Seventy-five patients exercised 3 days/week for 90-minute sessions emphasizing aerobic, flexibility, and strength development. Thirty-six (47%) completed 2 years of a voluntary supervised exercise program (n = 25 with complete data). Over a 2-year follow-up period, cardiovascular outcome variables improved significantly: metabolic equivalents increased 20% (7.4 +/- 2.2 to 9.0 +/- 2.4, P less than 0.001) and submaximal heart rate decreased 7% (68.5 +/- 8.0 to 63.6 +/- 8.4 beats/minute, P = 0.02). Resting heart rate decreased 8% (131.4 +/- 14.8 to 121.0 +/- 18.5 beats/minute, P = 0.06), but this difference did not reach statistical significance. Flexibility, measured by hamstring length, improved 11% (57.5 +/- 15.1 to 64.0 +/- 11.1 degrees, P = 0.02). Strength variables did not improve. The study indicates that improvements in cardiovascular function and flexibility achieved by the elderly in the early stages of an exercise program can be maintained for at least 2 years.

Aged↗

PubMed1991

Two-year trends in physical performance following supervised exercise among community-dwelling older veterans.

The extent to which exercise can delay the normal decline in physical performance associated with aging is unknown. We examined the impact of 2 years of supervised exercise on cardiovascular fitness, flexibility, and strength in a group of elderly (age 65-74) veterans. Seventy-five patients exercised 3 days/week for 90-minute sessions emphasizing aerobic, flexibility, and strength development. Thirty-six (47%) completed 2 years of a voluntary supervised exercise program (n = 16-25 with complete data). Over a 2-year follow-up period, cardiovascular outcome variables improved significantly: metabolic equivalents increased 20% (7.4 +/- 2.2 to 9.0 +/- 2.4, P less than 0.001) and submaximal heart rate decreased 7% (131.4 +/- 14.8 to 121.0 +/- 18.5 beats/minute, P = 0.06). Resting heart rate decreased 8% (68.5 +/- 8.0 to 63.6 +/- 8.4 beats/minute, P = 0.02) but this difference did not reach statistical significance. Flexibility, measured by hamstring length, improved 11% (57.5 +/- 15.1 to 64.0 +/- 11.1 degrees, P = 0.02). Strength variables did not improve. The study indicates that improvements in cardiovascular function and flexibility achieved by the elderly in the early stages of an exercise program can be maintained for at least 2 years.

Aged↗

PubMed1991

The impact of supervised exercise on the psychological well-being and health status of older veterans.

This study examined the impact of supervised exercise on the health status (measured by the Sickness Impact Profile [SIP]) and well-being (measured by the Psychological General Well-Being Index [PGWB]) of a sample of 43 elderly veterans. The intervention consisted of 90 minutes of exercise, 3 days per week at 70% of maximal capacity. Twenty-three (53%) participants completed a 1-year follow-up. The mean PGWB score increased significantly from 83.0 +/- 15.8 to 89.4 +/- 8.9 (p = .01). Cardiovascular fitness (measured by treadmill performance) increased significantly (p = .004). Baseline SIP scores were low (little dysfunction) and changed little. The study suggests that small but significant improvements in well-being accompany physiological benefits that the elderly experience with exercise.

Aged↗

PubMed1989

Evaluation of a supervised exercise program in a geriatric population.

Most studies that assess the effects of exercise in the elderly involve subjects who are in good health. The objective of this prospective longitudinal study was to examine the impact of exercise on cardiovascular fitness, flexibility, and strength in an elderly population that included chronically ill individuals. Patients were recruited initially from a population of veterans over 64 years of age who use a VA outpatient clinic as their regular source of care. The exercise intervention consisted of 90 minutes of exercise 3 days per week at 70% of the patient's maximal capacity. Activities included stationary cycling, stretching, weight training, and walking. Of 69 patients who began the program, 49 (71%) reached 4-month follow-up. Most patients completing follow-up (76%) had at least one chronic disease, such as arthritis, hypertension, or heart disease. Patients who dropped out were more likely to have multiple chronic illnesses than those who remained in the program. Average weekly attendance was 65% and was stable over time. Improvements in cardiovascular fitness at 4-month follow-up were significant: Metabolic equivalents increased from 7.1 +/- 2.3 to 8.3 +/- 2.6 (P less than .001), treadmill time increased from 8.5 +/- 3.8 to 11.2 +/- 4.2 minutes (P less than .001), submaximal heart rate decreased from 123.7 +/- 18.8 to 118.8 +/- 19.4 beats per minute (P less than .001) and resting heart rate decreased from 68.1 +/- 10.6 to 63.3 +/- 11.6 beats per minute (P = .005).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1988

1,2,4-Trioxanes as potential antimalarial agents.

A number of 1,2,4-trioxanes were prepared and tested for antimalarial activity in search of a simplified analogue of the naturally occurring antimalarial qinghaosu. The compounds were assayed in an in vitro system for antimalarial activity against chloroquine-susceptible and chloroquine-resistant strains of Plasmodium falciparum. The most active compounds were methyl 2-(2,4a-epidioxy-4a,5,6,7,8,8a-hexahydro-5,5,8a-trimethyl-2H-1-benzop yra n-2-yl) acetate (3b), which showed IC20's of 96 and 39 ng/mL, respectively, and 2,4a-epidioxy-3,4,4a,5,6,7,8,8a-octahydro-2-[2-(benzoyloxy)propyl]-5,5,8 a- trimethyl-2H-1-benzopyran (12), which showed IC50's of 24 and 99 ng/mL, respectively. For comparison, qinghaosu exhibits an IC50 of 1 ng/mL for both strains.

Animals↗

PubMedDate not supplied

Effect of exercise on cation transport in human red cells.

To test the hypothesis that environmental as well as genetic factors are important determinants of monovalent cation transport systems in humans, and to explore potential basic mechanisms of the alleged antihypertensive effects of habitual exercise, we studied the effects of a 12-week exercise program (45 minutes, 3-5 times per week) upon several membrane transport parameters in erythrocytes from a population of 63 adult men (30 normotensive subjects and 33 essential hypertensive patients). Subjects were randomly assigned into either an exercise group or a sedentary control group, and clinical and membrane transport parameters were measured at baseline and after 3 months. Exercising subjects demonstrated increases in maximal treadmill work capacity (p less than 0.001) and high-density lipoprotein cholesterol levels (p = 0.009) as well as decreases in heart rate at a fixed submaximal workload (p less than 0.05) and body weight (p less than 0.001) relative to the sedentary group. In conjunction with these well-described effects of exercise conditioning, the exercise group demonstrated a significant decrease in Na+-Li+ countertransport (p = 0.002), without significant changes in any other transport parameters measured. Blood pressure was not significantly altered in either group. We conclude that powerful environmental influences such as exercise training may act in concert with genetic factors to influence monovalent cation transport in humans and must be considered in further investigations of the pathophysiological linkage between altered monovalent cation transport and essential hypertension.

Adult↗