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Physical activity energy expenditure (PAEE) is a determinant of prognosis and fitness in older patients with coronary heart disease (CHD). PAEE and total energy expenditure (TEE) are closely related to fatness, physical function, and metabolic risk in older individuals. The goal of this study was to assess effects of resistance training on PAEE, TEE, and fitness in older women with chronic CHD and physical activity limitations ( N = 51, mean age: 72 + 5 yr). The study intervention consisted of a progressive, 6-mo program of resistance training vs. a control group condition of low-intensity yoga and deep breathing. The study interventions were completed by 42 of the 51 participants. The intervention group manifested a 177 ± 213 kcal/day (+9%) increase in TEE, pre- to posttraining, measured by the doubly labeled water technique during a nonexercise 10-day period ( P < 0.03 vs. controls). This was due to a 50 ± 74 kcal/day (4%) increase in resting metabolic rate measured by indirect calorimetry ( P < 0.01, P < 0.05 vs. controls) and a 123 ± 214 kcal/day (9%) increase in PAEE ( P < 0.03, P = 0.12 vs. controls). Resistance training was associated with significant increases in upper and lower body strength, but no change in fat-free mass, measured by dual X-ray absorptiometry, or left ventricular function, measured by echocardiography and Doppler. Women in the control group showed no alterations in TEE or its determinants. There were no changes between groups in body composition, aerobic capacity, or measures of mental depression. These results demonstrate that resistance training of 6-mo duration leads to an increase in TEE and PAEE in older women with chronic CHD.

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.

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)

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.

It is currently unclear whether age-specific equations should be used for assessing body composition from bioelectrical resistance. Kushner et al. (Am. J. Clin. Nutr. 56: 835#x2013;839, 1992) showed that the relationship between height2/resistance and total body water (TBW) is robust across a wide age range, although uncertainty remained over the relationship in preschool children. We therefore cross-validated the Kushner equation for predicting total body water in 4- to 6-yr-old children in two independent laboratories. TBW was measured from H2 18O dilution, and bioelectrical resistance and reactance were measured using an RJL 101A analyzer in 31 children (15 females, 16 males; 5 +/- 0.8 yr) studied in Burlington, Vermont, and 30 children (14 females, 16 males; 5 +/- 0.2 yr) studied in Phoenix, Arizona. There was no significant difference between TBW predicted from the Kushner equation and that measured in children in Burlington (11.76 +/- 2.00 vs. 11.91 +/- 2.46 kg; r = 0.94) or in Phoenix (11.53 +/- 1.64 vs. 11.66 +/- 1.90 kg; r = 0.94). The Kushner equation for TBW can be transformed into an equation for fat-free mass (FFM) by using published age- and gender-specific constants for the hydration of FFM: hydration of FFM = 76.9 - 0.25 age (yr) - 1.9 gender where female equals 0 and male equals 1. The intraclass reliability for estimates of fat mass and FFM with the use of bioelectrical resistance in an independent group of 26 children (5.0 +/- 0.8 yr, 20.2 +/- 3.0 kg) was > 0.99 for duplicate observations performed 2 wk apart.(ABSTRACT TRUNCATED AT 250 WORDS)

RE: Poehlman, Eric T., Andrew W. Gardner, Paul J. Arciero, Michael I. Goran, and Jorges Calles-Escandon. Effects of endurance training on total fat oxidation in elderly persons.