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Biomedical subjects

M A Fiatarone

Publications and source records attributed to M A Fiatarone.

At least 19 recordsLinked to original sources
PubMed1995

Long-term effects of a high-carbohydrate diet and exercise on insulin action in older subjects with impaired glucose tolerance.

Carbohydrate metabolism was assessed in 20 glucose-intolerant subjects before and after 12 wk on a high-carbohydrate diet (HC) or the diet combined with exercise training (HC-EX). The diet provided 60% of energy as carbohydrate and 20% as fat. Neither treatment altered fasting glucose or insulin concentrations or their response to a meal. During a glucose clamp (216 pmol insulin/L) glucose disposal increased from 13.2 +/- 0.83 to 14.6 +/- 0.83 mumol.kg fat-free mass-1.min-1 (P < 0.05) in both groups. During more pronounced hyperinsulinemia (654 pmol/L) glucose disposal did not change significantly (49.9 +/- 3.8 to 50.7 +/- 3.8 mumol.kg fat-free mass-1.min-1). Muscle glycogen increased in the HC-EX group (78.5 +/- 8.1 to 161.1 +/- 15.7 mmol glucose/kg muscle), with no changes in the HC group. These results do not support the recommendation to increase the dietary carbohydrate content for improving postprandial glucose metabolism or insulin action in glucose-intolerant adults unless combined with exercise training, which promotes muscle glycogen storage.

Aged↗
PubMed1995

Factors associated with low body mass index and weight loss in nursing home residents.

BACKGROUND: Undernutrition in nursing home residents is a significant and possibly modifiable public health problem. We evaluated the hypothesis that some potentially modifiable factors are associated with resident undernutrition. METHODS: This study is a cross-sectional, secondary data analysis of 6,832 community nursing home residents sampled from 202 nursing homes in 7 states. Data were from the Minimum Data Set (MDS), and HCFA-mandated resident assessment instrument used in U.S. community nursing homes. Two dependent variables represented undernutrition: (a) low body mass index (BMI), defined as the lowest quartile BMI of the sample (19.42 kg/m2 and below); and (b) weight loss, an MDS measure defined as 5% decrease in weight in 30 days, or a 10% decrease in 180 days (9.9% of the sample). Independent variables included resident demographics, eating-related variables, variables measuring functional, cognitive, and affective statuses, and medical conditions. Separate logistic regression models were estimated for low BMI and weight loss to test multivariate associations. RESULTS: Poor oral intake, eating dependency, decubiti, and chewing problems increase the likelihood of both low BMI and weight loss. Female gender, age 85 or older, bedfast, and hip fracture increase the odds of low BMI only; depressed behaviors and two or more chronic diseases increase the odds of weight loss only. CONCLUSION: Undernutrition in nursing home residents is a multifactorial syndrome. Improved oral feeding methods and treatment of depression are potentially important ways to counteract undernutrition in nursing home residents by targeting reversible features.

Activities of Daily Living↗
PubMed1995

Relationship between physical performance and self-perceived physical function.

OBJECTIVE: The objective of this study was to compare two methods of measuring physical function in subjects with a broad range of abilities and to evaluate the effects of cognitive, social, educational, and age factors on the relationship between the two methods. DESIGN: Multiple regression analysis was used to compare self-perceived (dependent variables) with performance measures (independent variables). Covariates included age, gender, Mini-Mental State Exam score, education, living status, and depression score. SETTING: Five community-dwelling and two nursing home sites. PARTICIPANTS: 417 community-dwelling subjects and 200 nursing home residents aged 62-98 years. MEASUREMENTS: Self-perceived physical function was assessed with the physical dimension summary score of the Sickness Impact Profile, which comprises three subscales: ambulation, mobility, and body care and movement. Physical performance was evaluated by self-selected gait speed, chair-stand time, maximal grip strength, and a balance score. RESULTS: Nursing home residents and community-dwellers were significantly different (P < .0001) in all variables except age and gender. Self-perceived and performance-based measures were moderately correlated, with a range from r = -.194 to r = -.625 (P < .05). Gait speed was the strongest independent predictor of self-perceived physical function in both groups. Symptoms of depression were also an independent predictor of self-perceived function in nursing home residents; subjects who had such symptoms report more self-perceived dysfunction than would be predicted based on performance tests. CONCLUSIONS: Self-selected gait speed is a global indicator of self-perceived physical function over a broad range of abilities. External determinants (depressive symptoms, cognitive function, marital status, etc.) affect self-perceived function in both groups, but gait speed is the greatest single predictor of self-perceived function. In nursing home residents depressive symptomatology is related to self-perceived.

Activities of Daily Living↗
PubMed1995

Aging and dietary modulation of elastase and interleukin-1 beta secretion.

Aging is associated with diminished immune function that may stem from alterations in arachidonic acid metabolism and lipid peroxidation. This study sought to determine if dietary modification of fatty acids influenced neutrophil and monocyte secretion after an in vivo inflammatory stress in older human subjects. Volunteers participated in protocols that forced their quadriceps muscles to lengthen during tension development (eccentric stress). These protocols can cause inflammatory foci in the muscle as well as alterations in circulating leukocyte function. In this study, in vivo neutrophil degranulation was assessed by plasma elastase concentrations, and mononuclear cell function was assessed by interleukin-1 beta (IL-1 beta) secretion in vitro. In response to eccentric stress, older subjects (> 60 yr old) taking a placebo had no apparent elastase response, whereas those taking fish oil supplements responded with a 142% increase in plasma elastase (P = 0.011), similar to responses of younger reference subjects (< 33 yr old) taking no supplement. Overall, elastase responses correlated with individual plasma arachidonic acid-to-eicosapentaenoic acid ratios (r = -0.881, P = 0.004). Thus apparent age-related differences in elastase release were reconciled by individual differences in fatty acid nutriture. No significant temporal changes in urinary lipid peroxide excretion or IL-1 beta secretion were observed; however, age-associated differences were found.

Adult↗
PubMed1995

Military body fat standards and equations applied to middle-aged women.

Military circumference equations are used to assess compliance of military personnel with body fat (BF) standards. The purpose of the present study was to determine the ability of military equations to correctly classify 62 women aged 40-60 yr (50.9 +/- 6.2, mean +/- SD) as overfat or underfat using underwater weighing (UWW) as the reference method and military BF standards as diagnostic cutoffs. Values for the mean +/- SD percent BF from UWW, Army, Marine Corps, and Navy equations were 29.5 +/- 7.1, 27.3 +/- 4.7, 25.7 +/- 5.8, and 30.3 +/- 5.1, respectively. The Army and Marine Corps equations underpredicted percent BF compared to UWW, P < 0.05. Bland-Altman plots showed a lack of agreement in predicting percent BF in women 40-60 yr between equation and UWW-derived percent BF. This finding was supported by the low agreement in correctly classifying an individual as meeting or exceeding the BF standards, range 25%-57%, Cohen's kappa. The low sensitivities (range 20%-74%) and higher specificities (range 80%-98%) of the equations indicated they identified individuals who met the BF standards better than those who exceeded them. Caution must be exercised when using military prediction equations to assess compliance with military BF standards in healthy middle-aged women.

Adipose Tissue↗
PubMed1995

Strength improvements with 1 yr of progressive resistance training in older women.

Thirty-nine healthy women (59.5 +/- 0.9 yr) were randomized to either a control group (CON) or a progressive resistance training group (PRT) that trained twice weekly for 12 months. PRT trained at 80% or more (average of 84%) of their most recent one repetition maximum (1RM) on the lateral pull-down (LPD), knee extensor (KE), and double leg press (DLP) apparatus. One RM was measured for each exercise once monthly in PRT and at baseline, midstudy, and end of study in CON. One RM significantly increased in PRT for all muscle groups trained compared to CON (P < 0.0001). Increases of 73.7 +/- 12%, 35.1 +/- 3%, and 77.0 +/- 5%, respectively, for KE, DLP, and LPD in PRT and 12.7% +/- 8%, 3.7% +/- 3%, and 18.4% +/- 4%, respectively, in CON were observed. Approximately 50% of the gains in KE and LPD and 40% in the DLP were seen in the first 3 months of the study. In all three exercises, strength gains in PRT continued over the entire 12-month period. These data indicate that high-intensity strength training results in substantial, continual increases in strength in postmenopausal women for at least 12 months, with the greatest gains seen in the first 3 months of training.

Exercise↗
PubMed1994

Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures. A randomized controlled trial.

OBJECTIVE: To determine how multiple risk factors for osteoporotic fractures could be modified by high-intensity strength training exercises in postmenopausal women. DESIGN: Randomized controlled trial of 1-year duration. SETTING: Exercise laboratory at Tufts University, Boston, Mass. POPULATION: Forty postmenopausal white women, 50 to 70 years of age, participated in the study; 39 women completed the study. The subjects were sedentary and estrogen-deplete. INTERVENTIONS: High-intensity strength training exercises 2 days per week using five different exercises (n = 20) vs untreated controls (n = 19). MAIN OUTCOME MEASURES: Dual energy x-ray absorptiometry for bone status, one repetition maximum for muscle strength, 24-hour urinary creatinine for muscle mass, and backward tandem walk for dynamic balance. RESULTS: Femoral neck bone mineral density and lumbar spine bone mineral density increased by 0.005 +/- 0.039 g/cm2 (0.9% +/- 4.5%) (mean +/- SD) and 0.009 +/- 0.033 g/cm2 (1.0% +/- 3.6%), respectively, in the strength-trained women and decreased by -0.022 +/- 0.035 g/cm2 (-2.5% +/- 3.8%) and -0.019 +/- 0.035 g/cm2 (-1.8% +/- 3.5%), respectively, in the controls (P = .02 and .04). Total body bone mineral content was preserved in the strength-trained women (+2.0 +/- 68 g; 0.0% +/- 3.0%) and tended to decrease in the controls (-33+77 g; -1.2% +/- 3.4%, P = .12). Muscle mass, muscle strength, and dynamic balance increased in the strength-trained women and decreased in the controls (P = .03 to < .001). CONCLUSIONS: High-intensity strength training exercises are an effective and feasible means to preserve bone density while improving muscle mass, strength, and balance in postmenopausal women.

Aged↗
PubMed1994

Exercise training and nutritional supplementation for physical frailty in very elderly people.

BACKGROUND: Although disuse of skeletal muscle and undernutrition are often cited as potentially reversible causes of frailty in elderly people, the efficacy of interventions targeted specifically at these deficits has not been carefully studied. METHODS: We conducted a randomized, placebo-controlled trial comparing progressive resistance exercise training, multinutrient supplementation, both interventions, and neither in 100 frail nursing home residents over a 10-week period. RESULTS: The mean (+/- SE) age of the 63 women and 37 men enrolled in the study was 87.1 +/- 0.6 years (range, 72 to 98); 94 percent of the subjects completed the study. Muscle strength increased by 113 +/- 8 percent in the subjects who underwent exercise training, as compared with 3 +/- 9 percent in the nonexercising subjects (P < 0.001). Gait velocity increased by 11.8 +/- 3.8 percent in the exercisers but declined by 1.0 +/- 3.8 percent in the nonexercisers (P = 0.02). Stair-climbing power also improved in the exercisers as compared with the nonexercisers (by 28.4 +/- 6.6 percent vs. 3.6 +/- 6.7 percent, P = 0.01), as did the level of spontaneous physical activity. Cross-sectional thigh-muscle area increased by 2.7 +/- 1.8 percent in the exercisers but declined by 1.8 +/- 2.0 percent in the nonexercisers (P = 0.11). The nutritional supplement had no effect on any primary outcome measure. Total energy intake was significantly increased only in the exercising subjects who also received nutritional supplementation. CONCLUSIONS: High-intensity resistance exercise training is a feasible and effective means of counteracting muscle weakness and physical frailty in very elderly people. In contrast, multi-nutrient supplementation without concomitant exercise does not reduce muscle weakness or physical frailty.

Aged↗
PubMed1994

Lipoprotein response to exercise training and a low-fat diet in older subjects with glucose intolerance.

The purpose of this study was to determine the effect of aerobic exercise training (Ex), a low-fat diet (LF, 19% fat), or combined interventions (LF-Ex) on lipoprotein cholesterol (LDL, HDL, and VLDL) and triglyceride (TG) concentrations in glucose-intolerant subjects while their weight was maintained. Baseline dietary fat and carbohydrate composition, body composition, body mass index, age, and lipoprotein cholesterol were not different among groups. Aerobic capacity increased in both exercise groups (P < 0.01) and remained unchanged in the LF group. Body composition was unaltered and change in body weight (kg) was small: Ex, -0.8 +/- 0.4, (P < 0.05); LF, +0.4 +/- 0.4; (NS); LF-Ex, -1.4 +/- 0.4 (P < 0.01). Exercise alone did not significantly affect lipoprotein cholesterol or TG concentrations. In LF and LF-Ex, respectively, decreases (P < 0.02) in total cholesterol (-0.66 +/- 0.24 and -0.42 +/- 0.21 mmol/L), HDL (-0.14 +/- 0.07 and -0.26 +/- 0.04), and LDL (-0.60 +/- 0.25 and -0.23 +/- 0.13) were seen after 12 wk, whereas VLDL and TG remained unchanged. Our data indicate that beneficial effects of exercise training on lipid indexes are not observed in subjects with impaired glucose tolerance on either an average US diet or a low-fat diet if substantial changes in weight or body composition do not occur.

Aged↗
PubMed1994

Aging and stress-induced changes in complement activation and neutrophil mobilization.

We measured the extent of complement activation and neutrophil mobilization after eccentric exercise to determine whether these responses were age dependent and whether they were associated with changes in plasma creatine kinase (CK), a marker for muscle membrane integrity. Repeated forced lengthening of a muscle as it develops tension causes immediate ultrastructural damage to sarcomeres, followed by delayed-onset muscle soreness and release of myocellular enzymes. This can be accomplished in quadriceps muscles by running downhill or by resisting bicycle pedals driven backward by a motor. Twelve older (61-72 yr) and 9 younger (20-32 yr) subjects performed one of these activities for 45 min at an intensity of 78 +/- 2% of maximum heart rate. For all subjects, a median increase of 21% in plasma des-Arg-C3a levels occurred immediately after the protocol, circulating neutrophils increased 66 +/- 10% by 4-6 h, and plasma CK increased 135 +/- 25% by 24 h. The peak increases in neutrophils correlated with the peak increases in des-Arg-C3a (rho = 0.662, P = 0.006), and the peak increases in CK correlated with the rise in neutrophils (rho = 0.523, P = 0.027). The increases in neutrophils and plasma CK were significantly smaller in the older subjects (P < 0.05). The results indicate that increased concentrations of circulating CK after muscle injury are associated with a sequential cascade of inflammatory mediators. Furthermore, neutrophil mobilization, but not complement activation, was diminished in older subjects in response to this stress.

Adult↗
PubMed1993

Exercise increases muscle GLUT-4 levels and insulin action in subjects with impaired glucose tolerance.

A decline in insulin sensitivity is associated with aging, inactivity, and obesity. The effects of exercise training on glucose homeostasis independent of weight loss in older glucose-intolerant individuals are not well established. We examined the effects of exercise training on oral glucose tolerance, insulin action, and concentration of the GLUT-4 glucose transporters in skeletal muscle. Exercise training at 50 and 75% of heart rate reserve was performed for 12 wk in 18 individuals (age = 64 +/- 2, body fat = 37.0 +/- 1.5%). Peripheral insulin action was determined 96 h after the last exercise bout using a two-step hyperinsulinemic-euglycemic glucose clamp (insulin = 192 and 708 pmol/l). Percent body fat and fat-free mass (FFM) were unchanged with training. Diet composition, assessed by diet record, did not change over the 12 wk. Improved oral glucose tolerance was observed, as exhibited by lower plasma glucose concentrations after training (P < 0.05), whereas plasma insulin response remained unchanged. The rate of glucose disposal was unchanged during the low insulin concentration but increased 11.0% at the high insulin concentration (P < 0.05) after training (54.4 +/- 4.4 vs. 60.4 +/- 5.5 mumol.kg FFM-1.min-1). Skeletal muscle glycogen and GLUT-4 concentration increased 24 and 60%, respectively, with training. There was no direct relationship between the change in GLUT-4 protein and the change in glucose disposal rate. These findings demonstrate that chronic exercise training without changes in body composition improves peripheral insulin action in subjects with impaired glucose tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1993

Acute phase response in exercise. III. Neutrophil and IL-1 beta accumulation in skeletal muscle.

Nine untrained men (22-29 yr) performed 45 min of downhill running (16% incline, 70% of maximum heart rate). Needle biopsies of the vastus lateralis were performed before, 45 min after, and 5 days after exercise. Immunohistochemical staining of muscle cross sections revealed a 135% increase in muscle interleukin-1 beta (IL-1 beta) immediately after and a 250% increase (P < 0.03) 5 days after exercise. Using a rating scale (0-3) for the presence of neutrophils, light microscopic examination showed a significant accumulation of neutrophils in muscle biopsies taken 45 min after and 5 days after exercise [before: 0.5 +/- 0.2, 45 min after: 1.5 +/- 0.3 (P < 0.01), and 5 days after: 1.2 +/- 0.2 (P < 0.04)]. In addition, electron microscopic analysis showed an increase in the percentage of damaged Z-bands relative to total Z-bands [before: 4.8 +/- 3.5%, 45 min after: 32.5 +/- 8.6% (P < 0.05), and 5 days after: 14.1 +/- 3.2%]. Neutrophil accumulation was positively correlated to intracellular Z-band damage (rho = 0.66, P < 0.001). Immunohistochemical staining for IL-1 beta was related to neutrophil accumulation in muscle (rho = 0.38, P < 0.06) and to plasma creatine kinase levels (rho = 0.416, P < 0.04). These data indicate that after eccentric exercise ultrastructural damage to skeletal muscle is associated with neutrophil infiltration and muscle IL-1 beta accumulation.

Acute-Phase Reaction↗
PubMed1992

Leg extensor power and functional performance in very old men and women.

1. Residents of a chronic care hospital (13 men of mean age 88.5 +/- 6 SD years and 13 women of mean age 86.5 +/- 6 SD years) who had multiple pathologies were assessed for leg extensor capability in several ways. 2. A custom-built rig was used to assess leg extensor power, that is, maximal power output over less than 1 s in a single extension of one leg. Performance measures were obtained by timing chair rises (from a standard chair 0.43 m high), stair climbing (four risers, total height 0.635 m) and a walk (6.1 m). For each measurement the best of several trials were recorded as definitive. 3. Leg extensor power was significantly correlated with all performance measures, but the performance measures were not related to each other except for chair rising and walking speed. 4. Women had significantly less extensor power than men, but their power explained more of the variance in performance, e.g. power accounted for 86% of the variance in walking speed. 5. There was no relation within the group between age and any of the variables measured. 6. Measurement of leg extensor power in frail elderly people may prove useful in focusing effective rehabilitation programmes.

Aged↗
PubMed1991

Acute phase response in exercise. II. Associations between vitamin E, cytokines, and muscle proteolysis.

Cytokines such as interleukin 1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), and interleukin 6 (IL-6) mediate a variety of host responses to trauma and infection, including skeletal muscle proteolysis. This investigation assesses the influence of damaging eccentric exercise on in vitro production and plasma concentrations of cytokines and their relationship to muscle protein breakdown. In a double-blind placebo-controlled protocol, 21 male subjects took vitamin E supplements (800 IU/day) for 48 days, then ran downhill on an inclined treadmill. Twenty-four hours after this single session of eccentric exercise, endotoxin-induced secretion of IL-1 beta was augmented 154% (P less than 0.01) in cells obtained from the placebo subjects, but no significant exercise-related changes were observed in cells from the vitamin E-supplemented subjects. TNF-alpha secretion was also significantly increased 24 h after exercise, but the response was not inhibited by vitamin E. In contrast, IL-6 secretion did not change after exercise, but dietary vitamin E supplementation significantly reduced IL-6 secretion throughout the 12-day period of observation (P = 0.023). Urinary 3-methylhistidine excretion correlated with mononuclear cell secretion of both IL-1 beta (P less than 0.05) and prostaglandin E2 (P less than 0.05), supporting the concept that these mononuclear cell products contribute to the regulation of muscle proteolysis.

Acute-Phase Reaction↗
PubMed1990

High-intensity strength training in nonagenarians. Effects on skeletal muscle.

Muscle dysfunction and associated mobility impairment, common among the frail elderly, increase the risk of falls, fractures, and functional dependency. We sought to characterize the muscle weakness of the very old and its reversibility through strength training. Ten frail, institutionalized volunteers aged 90 +/- 1 years undertook 8 weeks of high-intensity resistance training. Initially, quadriceps strength was correlated negatively with walking time (r = -.745). Fat-free mass (r = .732) and regional muscle mass (r = .752) were correlated positively with muscle strength. Strength gains averaged 174% +/- 31% (mean +/- SEM) in the 9 subjects who completed training. Midthigh muscle area increased 9.0% +/- 4.5%. Mean tandem gait speed improved 48% after training. We conclude that high-resistance weight training leads to significant gains in muscle strength, size, and functional mobility among frail residents of nursing homes up to 96 years of age.

Aged↗
PubMed1990

Energy expenditure and subsequent nutrient intakes in overfed young men.

We investigated the mechanisms of body weight regulation in young men of normal body weight leading unrestricted lives. Changes in total and resting energy expenditure, body composition, and subsequent voluntary nutrient intakes in response to overeating by 4,230 +/- 115 (SE) kJ/day (1,011 +/- 27 kcal/day) for 21 days were measured in seven subjects consuming a typical diet. On average, 85-90% of the excess energy intake was deposited (with 87% of this amount in fat and 13% in protein on average). There was no detectable difference between individuals in susceptibility to energy deposition. The resting metabolic rate, averaged for fasting and fed states, increased during overfeeding (mean +/- SE, 628 +/- 197 kJ/day, P less than 0.01), but at least some of this amount was obligatory expenditure associated with nutrient assimilation. No significant increase in energy expenditure for physical activity or thermoregulation resulted from overfeeding. Thus energy expenditure did not substantially adapt to increased energy intake. However, significant decreases in voluntary energy intake (1,991 +/- 824 kJ/day, P less than 0.05) and fat intake (48 +/- 11 g/day, P less than 0.01) followed overeating, indicating that adaptive changes in nutrient intakes can contribute significantly to body weight regulation after overeating.

Adult↗