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Biomedical subjects

P A Rechnitzer

Publications and source records attributed to P A Rechnitzer.

At least 19 recordsLinked to original sources
PubMed1994

Ventilatory response to exercise in men and women 55 to 86 years of age.

This study examines the relationship between minute ventilation (VE) and carbon dioxide production (VCO2) during exercise in men (n = 128) and women (n = 96), 55 to 86 yr of age. The means for the slopes of VE-VCO2 (delta VE/delta VCO2), examined for graded exercise below the ventilation threshold (TVE), increased significantly for men (p < 0.0001), from 25.0 +/- 0.7 (SEM) at mean age 58 (55 to 59) yr to 32.2 +/- 1.8 at mean age 83 (80 to 86) yr, but did not change for women (p = 0.0812), from 22.3 +/- 0.9 at mean age 58 (56-59) yr to 24.2 +/- 2.4 at mean age 79 (75 to 85) yr. A correlation that was significantly greater than zero was found between delta VE/delta VCO2 and age. The increase in delta VE/delta VCO2 was 0.29/yr for men (r = 0.47, p < 0.001) and 0.20/yr for women (r = 0.28, p = 0.0051). In both cases, the explained variance was small (men = 22%; women = 8%). VE, tidal volume (VT), and breathing frequency (fb) were examined at VCO2 = 1.0 L/min, the highest intensity that most older men and women could exercise without exceeding TVE. VE was significantly higher by 14% in men 80 to 86 yr of age (38.2 +/- 1.4 L/min) compared with men 55 to 59 yr of age (33.5 +/- 0.8), whereas there were no differences in VE for the women.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Determinants of independence in the elderly.

The purpose of this study was to compare strength, flexibility, and cardiorespiratory fitness of the elderly living independently (n = 64) with those in rest or nursing homes (n = 61), and to identify those variables most strongly associated with an independent lifestyle. Quantitative levels of independence (Incapacity Index) and of activity were determined by questionnaires. Flexibility was measured using the Leighton Flexometer. Strength was measured using a modified sphygmomanometer. Cardiorespiratory fitness was measured using a self-paced walking test. Body size factors were also determined. Independent and dependent subjects were significantly different in age, which imposed a limitation on interpretation of these data. However, this factor was accounted for statistically in the analyses. Independent individuals compared to dependent ones showed significantly greater flexibility, activity levels, and choice of walking speed. Through multiple regression analysis, it was found that 40% of the variance in Incapacity Index was associated with participation in outdoor activities, greater shoulder flexibility, and a faster normal walking speed (> 1.0 m.s-1).

Activities of Daily Living↗
PubMed1993

Evaluation of the VMM turbine for spirometry in the applied physiology laboratory.

The volume measurement module turbine (VMM) was evaluated in 51 subjects for spirometry in applied physiology against the Stead-Wells spirometer (SW) and Wright peak flow meter (WM). The volume and flow ranges (VMM) were, FEV1 1.32 to 3.94 L (mean 2.62, confidence interval [CI] 2.46 to 2.78); forced vital capacity (FVC) 1.97 to 5.06 L (mean 3.50, CI 3.29 to 3.71); and peak expiratory flow rate (PEFR) 290 to 624 L.min-1 (mean 434, CI 407 to 461). The mean difference for FEV1 was 0.09 L (CI 0.05 to 0.14), FVC 0.04 L (CI -0.02 to 0.10), and PEFR 18.0 L min-1 (CI 8.7 to 27.3) less than SW or WM. Bias with FEV1 and FVC was not significant, though PEFR demonstrated a significant proportional error. The repeatability coefficients for FEV1 and FVC were 0.18 and 0.20, comparable to the SW; but for PEFR they were greater, 58.4 versus 33.8 L.min-1 by WM. The VMM turbine is accurate and reliable for the measurement of FEV1 and FVC over the ranges studied; however, care should be taken when interpreting PEFR.

Adult↗
PubMed1992

Age and sex effects on mobility of the human ankle.

We investigated whether values for passive resistive torque, dorsiflexion strength, and active mobility of the ankle joint varied with age in a randomly selected sample of middle-aged and elderly males and females. The main effects of sex and age group were significant, without an interaction effect, on values for passive resistive torque and voluntary strength. The trends indicated that females had lower values for both variables and that passive torque increased and strength decreased with respect to age. Dorsiflexion range of motion also showed a highly significant trend to decrease across age groups, and more so for females than males. Mean values for middle-aged men vs old men went from 20.0 to 13.5 degrees, while corresponding values for women decreased from 20.7 degrees of dorsiflexion to 10.1. Functional ankle movement thus becomes limited with age, but could be improved by strengthening weak dorsiflexor muscles.

Aged↗
PubMed1992

Forced expiratory volume, height, and demispan in Canadian men and women aged 55-86.

In a random cross-sectional study in London, Canada, forced expiratory volume in 1 second (FeV1.0), height, and demispan (fingerweb to central sternal notch) were measured on 182 men and 212 women of mean ages 70.4 (SD 8.5) and 71.3 (8.2). The mean FeV1.0 for men was 2.55 (0.66) l, and for women 1.80 (0.48) l and declined 29 ml.year-1 and 25 ml.year-1, respectively. The mean FeV1.0 standardized for measured height and calculated height for men was 2.54 (0.61) l and 2.55 (0.62) l in men, and 1.80 (0.46) l and 1.79 (0.45) l in women. There was no significant difference between the two methods of standardization, and the relationship of height to demispan in this independent elderly population was constant across age for both men (2.16) and women (2.17). Linear and proportional regression coefficients to predict FeV1.0 from height and demispan have been generated for this random sample aged 55 to 86 years.

Aged↗
PubMed1992

Response rates in a survey of physical capacity among older persons.

A representative sample of 420 subjects aged 55 to 84 was sought for participation in a study of the relationship between physical activity and health. A stratified random sample with 35 subjects in each of 12 age-gender categories was designed, using lists generated consecutively until the target number for each category was reached. Although the protocol required walking and treadmill tests, 60.3 percent of those eligible participated, a figure comparable to that of NHANES II and superior to that of the Canada Fitness Survey. Participants were younger, more likely to be male, less likely to be currently married, and more likely to have had a white-collar job and some postsecondary education than were nonparticipants. Difficulties of obtaining subjects and methods for avoiding these difficulties include offering many opportunities to attend and determining accurately the reason for nonparticipation.

Age Factors↗
PubMed1991

Personality. Type A behavior, and the effects of beta-blockade.

In a previous report, it was shown that a dimension of personality entitled dependence/independence could be used to distinguish the cardiovascular and catecholaminergic response to stress in type A individuals. This study is a continuation of the previous work. It examines the relative effects of beta-blockade on stress-induced changes in heart rate, blood pressure, and catecholamines in two groups of type A individuals who differ in reactivity. Sixty-six healthy, middle-aged men with type A behavior were classified as dependent (high reactivity) or independent (low reactivity). The effects of beta-blockade on the two groups were tested in a randomized, double-blind, crossover trial utilizing a mental stressor, a physical stressor, and work day monitoring. Results showed that, in comparison with the independent type As, those who had been classified as dependent had higher heart rates in all three stress conditions and had higher epinephrine levels during both the mental and physical stressors. For both groups, beta-blockade lowered the heart rate and systolic blood pressure but increased norepinephrine with the mental stressor and epinephrine and norepinephrine with the physical stressor. It also reduced the mean work day heart rate. For the dependent type As, the drug had a greater effect on increasing epinephrine during the physical stressor and by reducing the percent of the work day spent in high heart rate zones. The results are discussed from the point of view of identifying type As who may be particularly coronary prone and the potential effects of beta-blockade on the reactivity associated with type A behavior.

Adult↗
PubMed1990

Type A behavior, personality, and sympathetic response.

This study examined, under two types of stress and during a typical workday, the moderating effects of the personality trait dependence/independence on the hemodynamic and catecholaminergic response in Type A individuals. During the mental stressor, Type As with strong dependency needs showed elevated heart rates and higher levels of epinephrine. During the physical stressor, they showed elevated heart rates and higher levels of norepinephrine. During the typical workday, both urinary catecholamines and mean daily heart rates were higher. It is suggested that these findings, which indicate greater sympathetic-adrenal response, are the result of a basic personality/behavior inconsistency and that Type A behavior may have an accentuated relationship to coronary disease when overlaid on a personality for which it is inconsistent.

Adult↗
PubMed1990

Effect of an exercise program on the perception of exertion in males at retirement.

To describe the association between perception of exertion and exercise, 138 men at retirement, mean age 62.7 years, were studied before and after a one-year program of exercise. VO2max and ratings of perceived exertion (RPE) using the Borg psychophysical scale were determined by a continuous exercise treadmill protocol to fatigue. The men were randomly assigned to an exercise program (n = 69) or control (n = 69). The program consisted of walking or jogging for 30 min, 3 times per week for one year. After training, the activity group showed a significant improvement in VO2max (12%). Linear regression analysis was used to relate RPE to selected physiological measurements for control and activity groups. The equations for the before and after training relationships were compared. Changes in the relationship of RPE vs VO2 and Ve, after training, were not significant for the activity group. However, the control group showed significant changes in these relationships at one year post retirement. For VO2 and Ve, ratings were 1-2 units higher than at time of retirement. Results indicate that perception of a physical task normally changes at retirement such that a given amount of exertion may seem subjectively greater. Results also suggest that a structured exercise program is successful at maintaining perception of task at pre-retirement levels. This maintenance of a low rating of perception may retard a reluctance to be physically active which often accompanies ageing.

Aged↗
PubMed1989

The self-selected walking pace test and beta blockade.

The self-selected walking pace test is a safe, simple and inexpensive test to measure an individual's perception of walking speed and is more strongly related to maximal oxygen uptake than to age. This study was carried out to determine whether beta blockade, which commonly causes fatigue, would affect the test. Twenty-three clinically healthy men with a mean age of 43 years completed the test both on and off 80 mg long-acting oxprenolol daily, a beta blocking drug with partial agonist activity. The men walked 80 m at three self-selected speeds (rather slow, normal and rather fast). There was a significant reduction in heart rate on the drug. The walking speed at the three paces on and off medication were 1.08 ms-1 and 1.07 ms-1 (slow), 1.32 ms-1 and 1.33 ms-1 (normal) and 1.63 ms-1 and 1.61 ms-1 (fast). None of these differences reached statistical significance. The stride length also did not change. It is concluded that beta blocking medication does not interfere with the self-selected walking pace test.

Adrenergic beta-Antagonists↗
PubMed1989

Strength in an elderly population.

Strengths of several upper- and lower-limb muscle groups were measured in an elderly population by using a simple, adaptable dynamometer. The bladder of a sphygmomanometer was modified by folding and surrounding it in a sewn cloth bag. It was then attached to a board for improved stability during the tests. Thirty-seven men and 81 women aged 62 to 102 years were tested. Four muscle groups were statistically determined to best represent strength-two for upper limb and two for lower limb. These strength measures were correlated with anthropometric indices, and a step-wise multiple regression was used to determine the degree of association between the variables. Men were significantly stronger than women in absolute strength, but were not different when strength was expressed relative to body weight. Within each sex, however, age was the most important variable related to loss of strength; body weight was secondary or not significant. These results suggest that age is the most important factor for relating differences in strength in an older elderly population (those aged 75 to 90 or more years). This factor must be accounted for just as body weight or cross-sectional muscle area often are, when comparing strengths in a younger population.

Aged↗
PubMed1989

Physical activity and our human potential: a contemporary perspective.

The beneficial response of post-infarct patients and elderly, clinically healthy individuals to exercise training programs has emphasized the very important role that rehabilitation plays in releasing undiscovered potential. Illness may sometimes provide a starting point, as a marker of our mortality, for using physical activity in rehabilitation as a powerful symbol for rediscovering, both physically and emotionally, our capacity to expand our potential as human beings.

Adult↗
PubMed1988

Age-related changes in speed of walking.

Self-paced walking was used as a measure of the neuromuscular slowing observed with aging. The effects of age on the choice of speed of walking, stride length, and step frequency were described for 289 males and 149 females aged 19 to 102 yr. These subjects were asked to walk at three self-selected paces (slow, normal, and fast) over an 80-m indoor course. Sixty-two years coincided with an accelerated decline in speed of walking. Before 62 yr, there was a 1 to 2% per decade decline in normal walking speed. After 63 yr, females showed a 12.4% per decade decrease and males showed a 16.1% per decade decrease. The eldest group (63 yr and older) had a significantly slower speed of walking and smaller step length than the younger groups (19 to 39 and 40 to 62 yr) for all paces. Heart rate at the three paces was not changed across age. In a multiple regression analysis, the only significant independent variable for walking speed at all three paces was (age), which accounted for 19 to 38% of the variance. When the population was divided into two age ranges (19 to 62 and 63 to 102 yr), walking speed was associated with height before 62 yr and with height and age after 62 yr.

Adult↗
PubMed1987

Exercise training of men at retirement: a clinical trial.

The effects of one year of exercise training on cardiorespiratory fitness, levels of daily leisure activity, and blood lipids (cholesterol and high density lipoproteins) were studied in a prospective, randomized clinical trial. Two hundred and twenty-four men aged 55 to 65 years volunteered for the study and were randomly allocated to a control (n = 111) or an activity (n = 113) group with stratification on blue or white collar job classification. After the attrition due to loss to follow-up, 100 men remained in each of the control and activity groups. The exercising men met an average of 2.5 times per week over the year and their VO2 max or peak VO2 (ml X kg-1 X min-1) increased significantly (p = .001, 11%) compared with controls. There were no significant changes in maximal heart rate (155 bpm) and respiratory exchange ratio (1.1), although ventilation (80 to 90 l X min-1) increased significantly in the trained group. In addition, the VO2 at a heart rate of 125 bpm increased significantly (p less than .001) in the trained group (14.7%) over that observed in the control (1.9%). There were no significant differences between the groups with respect to the remaining end-points.

Blood Pressure↗
PubMed1986

Personality (hardiness) as a moderator of job stress and coronary risk in type A individuals: a longitudinal study.

This research study uses longitudinal data to determine if Type A individuals, initially classified as "hardy," show differential cardiovascular and biochemical responses in the encounter with a common job stressor. Role ambiguity was utilized as a job stressor and "hardiness" was defined using the second-order factor dependence/independence from the 16-personality factor (16PF) questionnaire. The results indicated that those individuals classified as Type A1 showed blood pressure and triglyceride elevations with increased ambiguity and that dependence/independence (hardiness) moderated this effect. When all Type A's (A1 + A2) were included in the analysis similar results were found only on systolic blood pressure. The results appear consistent with earlier findings concerning the cardiovascular reactivity of Type A's. In addition, it is suggested that dependence/independence is either a major component of the concept of "hardiness" or may be a dimension of personality which distinguishes two classes of Type A behavior. It is suggested that these results may raise the interesting possibility of providing a means of identifying greater or lesser susceptibility to the coronary effects of Type A behavior.

Adult↗
PubMed1986

The effects of personal interaction on triglyceride and uric acid levels, and coronary risk in a managerial population: a longitudinal study.

This two year longitudinal study of managers investigated whether the level of interaction with other individuals was a job stressor that influences coronary risk factors. The results presented here show that increased levels of interaction were associated with increased serum triglyceride and increased serum uric acid levels. It is suggested that past research positing stress effects from responsibility for people may be due to interaction levels rather than responsibility per se. It was also found that Type A behavior and physical activity levels moderated these effects. While it is difficult to say that personal interaction, as a job stressor, contributes very significantly to either coronary risk factors or coronary heart disease the evidence supports the hypothesis that the amount of interaction has some specific stress effects.

Administrative Personnel↗