Biomedical subjects

A W Gardner

Publications and source records attributed to A W Gardner.

At least 55 records · Page 3Linked to original sources

PubMed1996

Rates of free fatty acid appearance and fat oxidation in healthy younger and older men.

Alterations in the mobilization and oxidation of fat may partially account for age-related alterations in body composition. To investigate age-related alterations in fat metabolism, we compared basal rate of appearance of free fatty acids (FFAapp) and total body fat oxidation as measured by infusions of [14C] palmitate and indirect calorimetry, respectively, in 18 younger (23 +/- 1 yr) and 30 older (69 +/- 1 yr) men. We also examined whether age-related differences in body composition, body fat distribution, peak oxygen consumption, dietary intake, and/or fasting insulin levels may explain age-related variation in FFAapp and total body fat oxidation. The FFAapp showed a tendency to be higher in older compared with younger men (1,134 +/- 184 vs. 680 +/- 105 mu mol/min; P = 0.07), whereas total body fat oxidation was similar between groups (257 +/- 25 vs. 222 +/- 9 mu mol/min). The estimated rate of nonoxidative disposal of free fatty acids showed a tendency to be higher in the older (913 +/- 182 mu mol/min) than in younger men (423 +/- 103 mu mol/min; P = 0.06). Fat-free mass was the most significant predictor of FFAapp in younger (r = 0.63; P < 0.01) and older (r = 0.41; P < 0.05) men. These results suggest that older men recruit fatty acids from adipose tissue stores in excess of the energy needs of respiring tissue. However, variation in FFAapp between the age groups could not be explained by differences in body habitus or fasting insulin levels.

Adult↗

PubMed1996

Practical equations to predict claudication pain distances from a graded treadmill test.

Treadmill testing is used to estimate the severity of claudication, but routine use is not practical or cost-effective in all settings. Thus, the purposes of this study were: (1) to develop and cross-validate prediction equations for treadmill claudication pain distances in a heterogeneous cohort of peripheral arterial occlusive disease patients, and (2) to determine if the regression equations were more accurate in assessing claudication distances than self-reported distances of patients. Medical history, vital signs, resting ankle/brachial systolic pressure index (ABI), and claudication distances during a graded treadmill test were obtained on a validation group of 178 claudicants and on a cross-validation group of 94 claudicants. The independent predictors of claudication pain distances of the validation group were ABI, body mass index, gender, and current smoking status, with multiple correlation coefficients of R = 0.73 and R = 0.82 for the distances to onset and to maximal pain, respectively. These equations were successfully cross-validated on an independent group of claudicants, as the predicted distances to onset of claudication pain (167.2 +/- 102.6 m) and to maximal pain (354.6 +/- 154.3 m) were similar (p = 0.99) to measured distances (169.1 +/- 127.8 m and 356.6 +/- 181.0 m, respectively). However, the self-reported distances to onset (89.5 +/- 126.3) and to maximal claudication pain (189.2 +/- 284.3) were 1-2 blocks less than either the measured or predicted distances (p < 0.01). It is concluded that claudication pain distances during an incremental treadmill test can be more accurately estimated from a composite of variables obtained during medical screening than by relying on the self-report of patients. Consequently, in clinical settings where treadmill testing is impractical, the functional severity of claudication can be assessed without exercise testing.

Aged↗

PubMed1996

The effect of cigarette smoking on exercise capacity in patients with intermittent claudication.

The purposes of this study were: (1) to determine whether peripheral arterial occlusive disease (PAOD) patients who smoked had more severe claudication pain, reduced peripheral circulation, and poorer cardiopulmonary measurements at peak exercise than non-smoking patients, and (2) to determine whether the differences between the smoking and non-smoking patients persisted after controlling for the resting ankle/brachial systolic pressure index (ABI). Thirty-eight PAOD patients (ABI = 0.59 +/- 0.15, mean +/- SD) who smoked an average of 1.5 packs of cigarettes per day over 42 years and 100 PAOD patients (ABI = 0.74 +/- 26) who had quit smoking for an average of 7 years were recruited. Smokers refrained from smoking on the day of testing. Claudication pain times, oxygen uptake, ventilation, leg oximetry, and ankle systolic pressure responses to peak exercise were recorded. The smoking group had more severe claudication pain, as maximal pain occurred 1:37 min:s sooner during exercise (p < 0.05), and the pain took 2:21 min:s longer to subside (p < 0.01) compared to the non-smoking group. Additionally, at peak exercise the smoking group had a lower oxygen uptake (12.8 +/- 2.6 vs 13.9 +/- 2.4 ml/kg/min, p < 0.01), a higher ventilation (31.7 +/- 9.2 vs 27.9 +/- 7.1 liters/min, p < 0.05), and a higher oximeter electrode power (409 +/- 55 vs 385 +/- 37 mW, p < 0.01) than the non-smoking group. Differences between the groups persisted (p < 0.05) after adjusting for resting ABI. It is concluded that cigarette smokers with PAOD had more severe claudication pain, reduced peripheral circulation, and poorer cardiopulmonary measurements at peak exercise than non-smoking patients. These differences were independent of resting ABI. Thus, cigarette smoking reduces the exercise capacity of claudicants, placing patients who smoke at an even greater risk of living a functionally dependent lifestyle.

Adult↗

PubMed1995

Changes in energy balance and body composition at menopause: a controlled longitudinal study.

OBJECTIVE: To describe the effects of menopause on resting metabolic rate, body composition, fat distribution, physical activity during leisure time, and fasting insulin levels. DESIGN: A longitudinal comparison of metabolic changes in women who experienced menopause with changes in age-matched women who did not experience menopause. SETTING: General clinical research center. PATIENTS: An initial cohort of 35 sedentary healthy premenopausal women (age range, 44 to 48 years). After 6 years of follow-up, 18 women had spontaneously stopped menstruating for at least 12 months and 17 women remained premenopausal. No women received hormone replacement therapy. RESULTS: Women who experienced menopause lost more fat-free mass than women who remained premenopausal (-3.0 +/- 1.1 kg and -0.5 +/- 0.5 kg, respectively), had greater decreases in resting metabolic rate (-103 +/- 55 kcal/d and -8 +/- 17 kcal/d) and physical activity during leisure time (-127 +/- 79 kcal/d and 64 +/- 60 kcal/d), and had greater increases in fat mass (2.5 +/- 2 kg and 1.0 +/- 1.5 kg), fasting insulin levels (11 +/- 9 pmol/L and -2 +/- 5 pmol/L), and waist-to-hip ratios (0.04 +/- 0.01 and 0.01 +/- 0.01) (P < or = 0.01 for all comparisons). Menopause did not affect energy intake, fasting glucose levels, or peak oxygen consumption. CONCLUSIONS: Natural menopause is associated with reduced energy expenditure during rest and physical activity, an accelerated loss of fat-free mass, and increased central adiposity and fasting insulin levels. These changes may indicate a worsening cardiovascular and metabolic risk profile.

Adipose Tissue↗

PubMed1995

Exercise rehabilitation programs for the treatment of claudication pain. A meta-analysis.

OBJECTIVE: To identify the components of exercise rehabilitation programs that were most effective in improving claudication pain symptoms in patients with peripheral arterial disease. DATA SOURCES: English-language articles were identified by a computer search using Index Medicus and MEDLINE, followed by an extensive bibliography review. STUDY SELECTION: Studies were included if they provided the mean or individual walking distances or times to the onset of claudication pain and to maximal pain during a treadmill test before and after rehabilitation. DATA EXTRACTION: Walking distances and times and characteristics of the exercise programs were independently abstracted by two observers. DATA SYNTHESIS: Thirty-three English-language studies were identified, of which 21 met the inclusion criteria. Overall, following a program of exercise rehabilitation, the distance (mean +/- SD) to onset of claudication pain increased 179% from 125.9 +/- 57.3 m to 351.2 +/- 188.7 m (P < .001), and the distance to maximal claudication pain increased 122% from 325.8 +/- 148.1 m to 723.3 +/- 591.5 m (P < .001). The greatest improvement in pain distances occurred with the following exercise program: duration greater than 30 minutes per session, frequency of at least three sessions per week, walking used as the mode of exercise, use of near-maximal pain during training as claudication pain end point, and program length of greater than 6 months. However, the claudication pain end point, program length, and mode of exercise were the only independent predictors (P < .001) for improvement in distances. CONCLUSIONS: The optimal exercise program for improving claudication pain distances in patients with peripheral arterial disease uses intermittent walking to near-maximal pain during a program of at least 6 months. Such a program should be part of the standard medical care for patients with intermittent claudication.

Exercise Test↗

PubMed1995

Training status, resting metabolic rate, and cardiovascular disease risk in middle-aged men.

We investigated differences in resting metabolic rate (RMR) and cardiovascular disease risk factors among 86 middle-aged men (36 to 59 years) classified as resistance-trained ([RT] n = 19), aerobic-trained ([AT] n = 37), or untrained ([UT], n = 30) according to habitual exercise patterns. RMR, body composition, body fat distribution, supine blood pressure, maximal aerobic capacity (VO2max), plasma lipid levels, and fasting levels of insulin, glucose, and thyroid hormones were measured. We found that RMR, adjusted for differences in fat-free mass, showed a tendency to be greater in AT men as compared with RT men (P = .09) and was greater in AT men as compared with UT men (P < .05). No differences in RMR were noted between RT and UT men. UT men had higher values for total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C), and the insulin to glucose ratio and lower values for high-density lipoprotein cholesterol (HDL-C) (all P < .01) as compared with RT and AT men, whereas no differences in these variables were noted between RT and AT men. Supine diastolic blood pressure was lower in RT men as compared with both AT and UT men. Stepwise regression analysis showed that variations in body fatness accounted for the greatest variation in fasting lipid profile, blood pressure, and the insulin to glucose ratio among groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1995

Predictors of the age-related increase in blood pressure in men and women.

BACKGROUND: The age-related increase in blood pressure frequently observed in men and women may be more related to deleterious alterations in physical fitness, body composition, and diet than to a true aging phenomenon. Our purposes were to: (a) characterize the relationship between age and blood pressure in normotensive men and women; (b) identify physiological predictors of the age-related increase in blood pressure; and (c) examine whether the relationship between age and blood pressure persists after controlling for differences in these predictor variables. METHODS: Three hundred and sixty four Caucasian men (17-80 yr) and 215 Caucasian women (18-81 yr) were characterized for supine resting blood pressure, peak oxygen consumption, body composition, body fat distribution, plasma insulin and glucose concentrations, and nutritional intake. RESULTS: In men, the relationship between age and mean arterial pressure (MAP) (r = .25, p < .01) was no longer significant (partial r = .07, p = .20; 0.03 mmHg increase per year) after four predictor variables of MAP (fat mass, sum of 9 skinfolds, alcohol intake, and supine heart rate) were statistically controlled. In women, the relationship between age and MAP (r = .44, p < .01) no longer existed in women younger than 62 years of age (partial r = .06, p = .46; .04 mmHg increase per year) after three predictor variables of MAP (waist-to-thigh ratio, supine heart rate, and alcohol intake) were held constant, whereas in women older than 62 the relationship persisted (partial r = .37, p < .01; 0.9 mmHg increase per year). CONCLUSION: In healthy Caucasian men and women between 17-81 years of age: (a) The relationship between MAP and age was stronger in women than in men, primarily due to an accelerated increase in MAP in women older than 62 years of age; (b) the age-related increase in MAP in men was primarily related to an increase in body fatness, whereas in women the distribution of fat was the primary factor; and (c) after the influence of the predictor variables of MAP were controlled, the relationship between MAP and age persisted in women beyond 62 years of age, but not in women younger than age 62 or in men of any age.

Adolescent↗

PubMed1995

Effects of caffeine ingestion on NE kinetics, fat oxidation, and energy expenditure in younger and older men.

Age-related differences in energy expenditure, fat oxidation, and norepinephrine (NE) kinetics after caffeine ingestion were examined using a placebo-controlled double-blind study in 10 older (O, 65-80 yr) and 10 younger (Y, 19-26 yr) men who were moderate consumers of caffeine. Caffeine ingestion resulted in similar increases in Y and O men for plasma caffeine levels (Y = 89 +/- 100 to 6,340 +/- 1,938 ng/ml, P < 0.05; O = 124 +/- 38 to 7,066 +/- 2,366 ng/ml, P < 0.05) and energy expenditure (Y = 11%, 1.38 +/- 0.15 to 1.52 +/- 0.22 kcal/min, P < 0.05; O = 9.5%, 1.15 +/- 0.13 to 1.26 +/- 0.20 kcal/min, P < 0.05). However, caffeine ingestion increased fatty acid concentrations (362 +/- 159 to 803 +/- 253 mumol/l, P < 0.05) and tended to increase rate of appearance of fatty acids (624 +/- 376 to 1,394 +/- 1,331 mumol/l, P = 0.07) in younger but not older men. Rates of fat oxidation and NE appearance and clearance did not significantly differ from baseline values in either group. In conclusion, older and younger men show a similar thermogenic response to caffeine ingestion, whereas older men show a smaller increase in fatty acid availability after a caffeine challenge. These metabolic differences are not related to alterations in NE kinetics or fat oxidation.

Administration, Oral↗

PubMed1995

Basal fat oxidation decreases with aging in women.

The present study tested the hypothesis that a decrease in basal fat oxidation in aging women is related to a loss of fat-free mass. Thirty-two nonsmoking women with a wide range of age (18-73 yr) were characterized for body composition (underwater weight), maximal aerobic capacity, and basal fat oxidation (indirect calorimetry). Results showed that fat oxidation was negatively correlated with age (r2 = 0.17, P = 0.017) but was positively correlated with the fat-free mass (r2 = 0.48, P < 0.0001) and with the level of aerobic fitness (maximal aerobic capacity) (r2 = 0.22, P = 0.007). Unexpectedly, fat oxidation had no relationship with fat mass (r2 = 0.07, P = 0.136). Partial correlation analysis showed that the decline in fat-free mass, and not the age or maximal O2 consumption, was the best single predictor of the decline in basal fat oxidation. These results support the theory that a decrease in fat oxidation with advancing age in healthy women is associated with a decrease in the fat-free mass and not age per se. Interventions that increase or preserve the quantity of fat-free mass (e.g., exercise training) may enhance fat oxidation and thus lessen the age-associated adiposity in women.

Adolescent↗

PubMed1995

Sympathetic nervous system activity, body fatness, and body fat distribution in younger and older males.

It was hypothesized that an increase in total and central body fatness is related to higher sympathetic nervous system activity (SNSA) in older men. Resting SNSA was measured from norepinephrine (NE) kinetics in 69 younger (18-36 yr) and 69 healthy older men (55-80 yr). Body fat distribution was estimated from the waist circumference, body composition from underwater weighing, peak oxygen consumption from a treadmill test to exhaustion, and dietary intake from food diaries. Plasma NE concentrations were 41% higher (P < 0.001) in older men due to a 27% increase (P < 0.001) in NE appearance rate and a tendency for a lower NE clearance rate (P = 0.08). NE appearance rate was higher in individuals of both age groups who exhibited a greater waist circumference and body fatness (range of r values 0.49-0.69; P < 0.01). The waist circumference, and not age, was the strongest predictor of the increase in NE appearance rate in older men. Statistically controlling for the waist circumference or body fatness diminished age-related differences in NE concentrations and in NE appearance rate. These findings suggest that an accumulation of total and central body fat is associated with higher levels of SNSA in older males.

Adipose Tissue↗

PubMed1995

Body fatness and waist circumference are independent predictors of the age-associated increase in fasting insulin levels in healthy men and women.

OBJECTIVE: Elevated levels of fasting insulin increase the risk for coronary artery disease. In this study, we considered the independent contributions of age, total body fatness, abdominal fat distribution, peak aerobic capacity, leisure time physical activity, dietary intake, and fasting glucose levels to the age-associated increase in fasting insulin levels in healthy men and women. DESIGN: A cross-sectional analysis. SUBJECTS: A total of 427 healthy men and 293 healthy women age 18 to 90 years. MEASUREMENTS: Plasma glucose and insulin levels were measured in the fasted state and subjects were characterized for body fatness from underwater weighting, abdominal fat distribution from the waist circumference, peak VO2 from a treadmill test to exhaustion, leisure time physical activity from a structured interview and dietary intake from a 3-day food diary. The independent predictors of fasting insulin levels were determined by stepwise multiple regression analysis. RESULTS: Fasting insulin concentrations increased with age in both men (0.09 +/- 0.02 pmol/yr, unadjusted slope +/- SEE) and women (0.14 +/- 0.03 pmol/yr). In men, the major independent predictors of fasting insulin levels were percent body fat (r2 = 28%, P < 0.001) and waist circumference (r2 = 3% P < 0.001). Age, glucose concentration, and peak VO2 were small (1% each), but independent contributors to the variance in insulin levels. In women, the waist circumference (r2 = 18%, P < 0.001) and the fasting glucose concentration (r2 = 7%, P < 0.001) were the independent correlates of fasting insulin concentrations. CONCLUSIONS: Our data suggest that total adiposity and central body fat distribution are significant determinants of the increase in fasting insulin levels, whereas age, dietary intake, and levels of aerobic fitness and physical activity appear to be less important contributors to the variation in fasting insulin concentrations in healthy men and women.

Adolescent↗

PubMed1994

Leisure time physical activity is a significant predictor of body density in men.

The purposes were to: (a) develop and cross-validate a prediction equation for body density with leisure time physical activity (LTA) serving as a potential predictor, and (b) determine whether the addition of LTA to previously published regression equations would improve their prediction. Body density (hydrostatic weighing) was measured in a validation group of 193 men (18-78 years), and was predicted by age, body mass index, subscapular skinfold, abdominal skinfold, thigh skinfold, waist circumference, and LTA. This equation cross-validated on an independent group of men (N = 96). Consequently, groups were combined (N = 289) to yield a new equation that also included the same seven variables plus the waist/thigh circumference ratio (R = 0.90, R2 = 0.81, SEE = 0.0085 g/ml, p < 0.0001). Additionally, LTA improved the prediction of published equations obtained from men of various ages. In conclusion, LTA is an independent predictor of body density in healthy men comprising a wide age range.

Adult↗

PubMed1994

Effects of endurance training on total fat oxidation in elderly persons.

We examined the influence of 8 wk of endurance training on basal levels of fat oxidation and its association with changes in norepinephrine (NE) kinetics, resting metabolic rate (RMR), and body composition in 18 healthy elderly persons (66.1 +/- 1.4 yr; 10 men, 8 women). Fatty acid appearance rate and total body fat oxidation were determined from [14C]palmitate infusion and indirect calorimetry, NE kinetics were determined from infusions of [3H]NE, RMR was determined from the ventilated hood technique, and body composition was determined from underwater weighing. Endurance training increased peak oxygen consumption by 11% (1.9 +/- 0.1 to 2.1 +/- 0.1 l/min; P < 0.01) and increased RMR by 7% (1.20 +/- 0.02 to 1.28 +/- 0.02 kcal/min; P < 0.01). Endurance training increased NE appearance rate by 35% (0.51 +/- 0.04 to 0.69 +/- 0.04 micrograms/min; P < 0.01), whereas no change in NE clearance was noted. Endurance training increased fat oxidation by 22% (201.0 +/- 11.2 vs. 244.0 +/- 15.2 mumol/min; P < 0.01) but did not alter fatty acid appearance rate. Approximately two-thirds of the variation (r2 = 0.65) for the increase in fat oxidation was explained by increased NE appearance rate (r2 = 0.51; P < 0.01) and changes in fat-free weight (r2 = 0.14; P < 0.01). We conclude that 1) endurance training shifts in vivo basal substrate utilization toward greater fat oxidation in elderly individuals and 2) enhanced fat oxidation is associated with increased activity of the sympathetic nervous system and alterations in fat-free mass.

Aged↗

PubMed1994

Contribution of body composition and physical activity to age-related decline in peak VO2 in men and women.

We examined the contribution of variations in body composition and leisure time physical activity to the age-related decline in peak oxygen consumption (VO2) in men and women. Healthy males 17-80 yr old (n = 378) and females 18-81 yr old (n = 224) were characterized for peak VO2 from a treadmill test to exhaustion, fat-free mass and fat mass by underwater weighing, and leisure time physical activity. Peak VO2 showed a greater absolute decline (P < 0.05) with age in males (r = -0.70, slope = -0.034 l.min-1.yr-1; P < 0.01) than in females (r = -0.78, slope = -0.028 l.min-1.yr-1; P < 0.01). After statistically controlling for differences in fat-free mass and fat mass, the decline in peak VO2 was diminished in both sexes, although a greater rate of decline persisted in males (r = -0.47, slope = -0.016 l.min-1.yr-1; P < 0.01) than in females (r = -0.39, slope = -0.009 l.min-1.yr-1; P < 0.01). We found that the addition of leisure time physical activity (independent of body composition) to the regression model further attenuated the rate of decline in males (r = -0.40, slope = -0.013 l.min-1.yr-1; P < 0.01) but did not alter the age-related decline in peak VO2 in females (r = -0.39, slope = -0.009 l.min-1.yr-1; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗

PubMed1993

Influence of training on sleeping heart rate following daytime exercise.

The purpose of this investigation was to examine the influence of daytime exercise on heart rate during sleep. Nine, untrained male college students volunteered to participate. They cycled at 75% maximum oxygen uptake, (VO2max) 30 min.day-1 for 12 weeks. The exercise duration was increased by 5 min every 4 weeks from 30 to 40 min per session. Post-training VO2max [mean (SE): 48.9 (1.7) ml.kg-1.min-1] values were significantly (P < 0.01) higher than pre-training [45.5 (1.8) ml.kg-1.min-1] values. Before and after training, sleeping heart rate was assessed on two separate nights. Data were obtained during a night following 30 min of daytime cycling at 75 (6) % VO2max and on a night in which no daytime exercise was performed. A three-way repeated measures ANOVA [training status (pre-/post-training) x activity (exercise day/nonexercise day) x sleep time (18 epochs of 20 min each)] revealed a significant main effect for sleep time (P < 0.001) as well as a sleep time x training status interaction (P < 0.02). No significant difference in sleeping heart rate was noted when exercise and non-exercise days were compared both before and after training. It is concluded that endurance training in these young adult men: (1) hastens the achievement of baseline heart rate during sleep, and (2) does not moderate the relationship between an acute bout of daytime exercise and sleeping heart rate.

Adult↗

PubMed1993

A practical equation to predict resting metabolic rate in older men.

The accuracy of previous equations for predicting resting metabolic rate (RMR) in healthy older men is questionable because they are based on limited sample sizes and the absence of cross-validation procedures. The purposes of this study were to (1) examine biological predictors of RMR in healthy older men; (2) develop a practical equation to predict RMR from easily measured variables and examine its accuracy using cross-validation procedures; and (3) test the validity of existing equations in the literature to predict RMR in older men by comparison with measured RMR values. RMR, body composition, anthropometric measurements, leisure time activity (LTA), maximal aerobic power (VO2max), energy intake, and plasma thyroid hormone levels were determined in 89 healthy older men aged 50 to 78 years. Stepwise regression analysis showed that RMR was best predicted by fat-free weight ([FFW] R2 = 85%), free 3,5,3'-triiodothyronine (T3) level (R2 = 1%), and VO2max (R2 = 1%); these variables predicted RMR with a residual error of +/- 30 kcal/d. A practical equation was developed in a randomly selected subsample (N = 61) using easily measured variables as potential predictors, and was successfully cross-validated in a random subsample of older men (N = 28). The pooled equation to predict RMR is as follows: RMR (in kilocalories per day) = 9.7 (weight in kilograms) - 6.1 (chest skinfold thickness in millimeters) - 1.8 (age in years) + 0.1 (leisure time activity [LTA] in kilocalories per day) + 1,060. These variables accounted for 76% (R2) of the variation, and predicted RMR with a residual error of +/- 42 kcal/d.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Physical activity is a significant predictor of body density in women.

The purposes of this study were to 1) develop and cross-validate a prediction equation for body density with leisure-time physical activity (LTA) serving as a potential predictor, and 2) determine whether the addition of LTA to previously published equations would improve their prediction. Body density (hydrostatic weighing) was measured in a validation group of 111 women (aged 18-81 y) and was predicted by age, mass, body mass index (BMI), abdominal skinfold thickness, thigh skinfold thickness, and LTA. This equation was cross-validated on an independent group of women (n = 56). Consequently, groups were combined (n = 167) to yield a new equation that also included age, mass, BMI, abdominal skinfold thickness, thigh skinfold thickness, and LTA (R = 0.92, SEE = 7.9 g/L, P < 0.0001). LTA improved the prediction of equations published on women with relatively low body densities, but not on women with higher densities. In conclusion, LTA is an independent predictor of body density in healthy women and its prediction becomes stronger as body density decreases.

Adipose Tissue↗

PubMed1993

Claudication pain and hemodynamic responses to exercise in younger and older peripheral arterial disease patients.

BACKGROUND: Claudication patients who are candidates for exercise can frequently walk to maximal pain without experiencing exaggerated blood pressure and heart rate, as well as other clinical symptoms. However, these concomitant problems are more likely to become apparent as patients age. Consequently, this study compared the claudication and hemodynamic responses to exercise in younger and older peripheral arterial disease patients. METHODS: Forty younger (mean age 60.4 yr, range 55-62) and 51 older (mean age 75.5 yr, range 73-81) patients with stable claudication symptoms performed a progressive treadmill walking test to maximal leg pain. The times to onset and to maximal claudication pain, peripheral hemodynamic measurements (oximetry, ankle systolic pressure, and ankle-to-brachial systolic pressure index), and central hemodynamic measurements (heart rate and brachial blood pressures) were obtained. RESULTS: Onset and maximal claudication pain occurred 71 sec and 126 sec sooner (p < .05) in the older group, respectively. Greater reductions (p < .05) in foot transcutaneous oxygen tension, ankle systolic pressure, and ankle-to-brachial systolic pressure index were obtained during and following exercise in the older group. Furthermore, smaller increases (p < .05) in heart rate, brachial blood pressures, mean arterial pressure, and rate-pressure product were noted during exercise in the older group. CONCLUSIONS: Greater impairment in the peripheral hemodynamic measurements occurs without exaggerated heart rate and blood pressure responses in older claudication patients who walk to maximal leg pain compared with younger patients.

Age Factors↗