Frequency of combined resistance and aerobic training in older women.

The aim of this study was to determine the optimal frequency of combined aerobic and resistance training for improving muscular strength (MS), cardiovascular fitness (CF), and functional tasks (FTs) in women older than 60 years. Sixty-three women were randomly assigned to 1 of 3 exercise training groups. Group 1 performed 1 resistance exercise training (RET) and 1 aerobic exercise training (AET) session per week (AET/RET 1 × wk); group 2 performed 2 RET and 2 AET sessions per week (AET/RET 2 × wk); and group 3 performed 3 RET and 3 AET sessions per week (AET/RET 3 × wk). MS, CF, and FT measurements were made pretraining and 16 weeks posttraining. Repeated-measures analysis of variance indicated a significant time effect for changes in MS, CF, and FT, such that all improved after training. However, there were no significant training group or training group × time interactions. Sixteen weeks of combined AET/RET (1 × wk, 2 × wk, or 3 × wk) lead to significant improvements in MS, CF, exercise economy, and FT. However, there were no significant differences for MS, CF, or FT outcomes between groups.

Weight loss and exercise training effect on oxygen uptake and heart rate response to locomotion.

Effects of resistance and aerobic training on the ease of physical activity during and after weight loss are unknown. The purpose of the study was to determine what effect weight loss combined with either aerobic or resistance training has on the ease of locomotion (net V[Combining Dot Above]O2 and heart rate). It is hypothesized that exercise training will result in an increased ease, lowers heart rate during locomotion. Seventy-three overweight premenopausal women were assigned to diet and aerobic training, diet and resistance training, or diet only. Subjects were evaluated while overweight, after diet-induced weight loss (average, 12.5 kg loss), and 1 year after weight loss (5.5 kg regain). Submaximal walking, grade walking, stair climbing, and bike oxygen uptake and heart rate were measured at all time points. Weight loss diet was 800 kcal per day. Exercisers trained 3 times per week during weight loss and 2 times per week during 1-year follow-up. Resistance training increased strength, and aerobic training increased maximum oxygen uptake. Net submaximal oxygen uptake was not affected by weight loss or exercise training. However, heart rate during walking, stair climbing, and bicycling was reduced after weight loss. No significant differences in reduction in heart rate were observed among the 3 treatment groups for locomotion after weight loss. However, during 1-year follow-up, exercise training resulted in maintenance of lower submaximal heart rate, whereas nonexercisers increased heart rate during locomotion. Results suggest that moderately intense exercise is helpful in improving the ease of movement after weight loss. Exercise training may be helpful in increasing the participation in free-living physical activity.

Physical activity in free-living, overweight white and black women: divergent responses by race to diet-induced weight loss.

BACKGROUND: Black women are at greater risk of obesity than are white women, perhaps because of their lower levels of physical activity. OBJECTIVE: We compared free-living activity energy expenditure (AEE) in sedentary white and black women (in overweight and normal-weight states) and in never-overweight control subjects. DESIGN: Subjects included 46 women (23 white, 23 black) studied while overweight and after reaching a normal weight and 38 female control subjects (23 white, 15 black). Diet, without exercise training, resulted in a mean weight loss of 13 kg and a body mass index (in kg/m(2)) < 25. Body composition, sleeping energy expenditure, free-living total energy expenditure, and the energy cost of activity and aerobic capacity were assessed before and after weight loss under 4-wk, diet-controlled, weight-stable conditions and in the control subjects. AEE was defined as above-sleep energy expenditure. RESULTS: No significant racial differences in body composition, before or after weight loss, were found. After weight loss, AEE and aerobic capacity increased in the white women and decreased in the black women (P < 0.05 and P < 0.02, respectively). After weight loss, but not before, the white women had a significantly higher mean AEE than did the black women (2448 +/- 979 and 1728 +/- 1373 kJ/d, respectively; P < 0.05), approximating AEEs in the white (2314 +/- 1105) and black (2310 +/- 1251) control subjects. CONCLUSIONS: Relative to the responses of the white women to diet-induced weight loss, the black women became less fit and less physically active. Induction of a normal body weight in overweight black women appeared to produce a more obesity-prone state, favoring weight relapse.

Influence of distribution of lean body mass on resting metabolic rate after weight loss and weight regain: comparison of responses in white and black women.

BACKGROUND: Little is known about the effect of weight change on regional lean body mass (LBM) distribution or on racial differences in resting metabolic rate (RMR). OBJECTIVE: The study compared total and regional LBM patterns in white and black women after weight loss and regain and assessed the influence of regional LBM on variances in RMR. DESIGN: Eighteen white and 22 black women who did not differ in age, weight, and height were studied 3 times: in the overweight state, after weight reduction to the normal-weight state, and after 1 y without intervention. Total and regional lean and fat masses were assessed by dual-energy X-ray absorptiometry. RESULTS: White and black women did not differ significantly in mean (+/- SD) weight loss (13.4 +/- 3.6 and 12.7 +/- 3.2 kg, respectively) and regain (6.1 +/- 5.5 and 6.4 +/- 5.4 kg, respectively). Black subjects had significantly less trunk LBM and significantly more limb LBM at each time point (P < 0.05). In both races, weight regain was associated with significant increases in limb LBM (P < 0.05) but not in trunk LBM (P = 0.21). RMR, adjusted for total LBM and fat mass, was significantly higher in white women after weight loss (P < 0.01) and regain (P < 0.01). However, no racial difference was found when RMR was adjusted for LBM distribution. CONCLUSIONS: In both races, trunk LBM decreased with weight loss and remained lower, despite significant weight regain, which potentially reflected decreased organ mass. Regional LBM distribution explained the racial difference in RMR.

Free-living activity energy expenditure in women successful and unsuccessful at maintaining a normal body weight.

BACKGROUND: Although physical inactivity is believed to contribute to the rising prevalence of obesity, the role and magnitude of its contribution to weight gain are unknown. OBJECTIVE: We compared total free-living activity energy expenditure (AEE) and physical activity level in women successful and unsuccessful at maintaining a normal body weight. DESIGN: Premenopausal, generally sedentary women were studied at their normal weight and 1 y later after no intervention. Two groups were identified on the basis of extreme weight changes: maintainers (n = 27) had a weight gain of less-than-or-equal 3% of their initial body weight ( less-than-or-equal 2 kg/y) and gainers (n = 20) had a weight gain of >10% (>6 kg/y). At baseline and follow-up, evaluations were conducted during 4 wk of diet-controlled, energy-balance conditions. Free-living AEE and physical activity were assessed with the use of doubly labeled water, exercise energy economy and muscle strength with the use of standardized exercise tests, and sleeping EE and substrate utilization with the use of chamber calorimetry. RESULTS: Maintainers lost a mean (plus minusSD) of 0.5 plus minus 2.2 kg/y and gainers gained 9.5 plus minus 2.1 kg/y. Gainers had a lower AEE (P < 0.02), a lower physical activity level (P < 0.01), and less muscle strength (P < 0.001); these differences between groups remained significant from baseline to follow-up. Sleeping EE, exercise economy, and sleeping or 24-h substrate utilization were not significantly different between the 2 groups. A lower AEE in the gainers explained approximately 77% of their greater weight gain after 1 y. CONCLUSION: The general US population should increase their daily physical activity levels to decrease the rising prevalence of obesity.

Resistance training and intra-abdominal adipose tissue in older men and women.

PURPOSE: Little is known concerning the effects of resistance-exercise training (RT) on older adult's intra-abdominal adipose tissue (IAAT). The purpose of this study was to determine the effects of RT on fat distribution in 12 women and 14 men, aged 61-77 yr. METHODS: Computed tomography IAAT and abdominal subcutaneous adipose tissue (SAT), densitometry-determined body composition, one-repetition maximum (1-RM), and isometric strength were measured before and after 25 wk of RT. Training consisted of two sets of 10 repetitions at 65-80% of 1-RM, three times each week. RESULTS: There were similar increases in strength for both the men and women. Women improved 22% and 38% in the isometric strength test and 1-RM test, respectively, whereas the men improved 21% and 36%, respectively. A significant increase in fat-free mass (FFM) was found for both men and women. However, there was a significant gender x time interaction, which indicated that men increased FFM more than women (2.8 kg vs 1.0 kg, respectively). Similar decreases in fat mass (FM) were found for the men (1.8 kg) and women (1.7 kg). However, women lost a significant amount of IAAT (131 to 116 cm2), whereas the men did not (143 to 152 cm2). Similarly, women also lost a significant amount of SAT (254 to 239 cm2), but men did not (165 to 165 cm2). CONCLUSION: Despite similar decreases in FM after a 25-wk RT program, older women lost significant amounts of IAAT and SAT, whereas the older men did not.

Increased strength and decreased flexibility are related to reduced oxygen cost of walking.

Purpose was to determine effects resistance training/weight loss induced changes in muscular strength and flexibility have on net walking oxygen uptake (netVO(2)). Sixty-seven premenopausal women lost 12 kg. Before weight loss subjects were assigned to diet (WL) or diet/3 days per week resistance training (WLRT). Resting energy expenditure, oxygen uptake while walking at 4.84 km h(-1) on the flat and up 2.5% grade, isometric knee extension strength, and flexibility of the knee extensors and plantar flexors were measured. Strength increased in WLRT (+36 N) but not in WL (-24 N). NetVO(2) decreased significantly while flat walking (7.3%) and 2.5% grade walking (5.7%) in WLRT, but not in WL. Delta strength was negatively while delta knee extensor and plantar flexor flexibility were positively related to delta netVO(2). Decreases in walking and grade netVO(2) were independently and positively related to increased knee extension strength and decreased knee extensor and plantar flexor flexibility.

Resistance training conserves fat-free mass and resting energy expenditure following weight loss.

OBJECTIVE: To determine what effect diet-induced approximately 12 kg weight loss in combination with exercise training has on body composition and resting energy expenditure (REE) in premenopausal African-American (AA) and European-American (EA) women. METHODS AND PROCEDURES: This study was a longitudinal, randomized weight loss clinical intervention, with either aerobic (AT), resistance (RT), or no exercise training (NT). Forty-eight AA and forty-six EA premenopausal overweight (BMI between 27 and 30) women underwent weight loss to a BMI<25. Body composition (densitometry), REE (indirect calorimetry), maximal oxygen uptake (VO2max), and muscular strength (isometric elbow flexion) were evaluated when subjects were in energy balance. RESULTS: AA women lost less fat-free mass (FFM, P

IAAT, catecholamines, and parity in African-American and European-American women.

OBJECTIVE: We have recently reported that parous European-American (EA) women have disproportionately more intra-abdominal adipose tissue (IAAT) than their nulliparous counterparts. Mediating mechanisms for IAAT accumulation remain unknown; however, some evidence suggests a possible catecholamine link. The objective of this study was to determine whether the IAAT-parity relationship found in EA women exists in African-American (AA) women and to determine whether catecholamines play a mediating role. METHODS AND PROCEDURES: Subjects included 44 EA and 47 AA premenopausal women. Free-living physical activity by doubly labeled water (activity-related time equivalent (ARTE)), body composition (air plethysmography, computed tomography), and 24-h fractionated urinary catecholamines were measured. RESULTS: Repeated measures ANOVA revealed parous EA and AA women had significantly higher IAAT than their nulliparous counterparts (100.1 +/- 28.5 and 76.2 +/- 34.8 cm(2) vs. 75.9 +/- 29.1 and 59.6 +/- 15.0 cm(2)). In AA women and nulliparous women, 24-h urinary dopamine was significantly higher (AA parous 260.8 +/- 88; EA parous 197.2 +/- 78.8; AA nulliparous 376.5 +/- 81; EA nulliparous 289.6 +/- 62). Multiple regression analysis for modeling IAAT indicated that race, parity, dopamine, ARTE, and VO(2max) were all significant and independent contributors to the model (Unstandardized betas: race -32.6 +/- 7.4; parity (number of births) 10.0 +/- 3.4; 24-h urinary dopamine 0.08 +/- 0.04; ARTE (min/day) -0.09 +/- 0.04; VO(2max) (ml/kg/min) -2.8 +/- 1.0). DISCUSSION: Independent of the potential confounders: age, race, percent body fat, IAAT, 24-h fractionated urinary catecholamines, physical activity, and VO(2max), parous EA and AA women had more IAAT than their nulliparous counterparts. Of the catecholamines, dopamine was found to be significantly lower in parous women and higher in AA's. Dopamine, however, did not explain racial or parity differences in IAAT.

Low resting and sleeping energy expenditure and fat use do not contribute to obesity in women.

OBJECTIVE: Determine whether sleeping and resting energy expenditure and sleeping, resting, and 24-hour fuel use distinguish obesity-prone from obesity-resistant women and whether these metabolic factors explain long-term weight gain. RESEARCH METHODS AND PROCEDURES: Forty-nine previously overweight but currently normal-weight women were compared with 49 never-overweight controls. To date, 87% of the 98 women have been re-evaluated after 1 year of follow-up, without intervention, and 38% after 2 years. Subjects were studied at a General Clinical Research Center after 4 weeks of tightly controlled conditions of energy balance and macronutrient intake. Forty-nine obesity-prone weight-reduced women were group-matched with 49 never-overweight obesity-resistant controls. All were premenopausal, sedentary, and normoglycemic. Energy expenditure and fuel use were assessed using chamber calorimetry. Body composition was assessed using DXA. RESULTS: At baseline, percent body fat was not different between the obesity-prone and control women (33 +/- 4% vs. 32 +/- 5%, respectively; p = 0.22). Analysis of covariance results show that after adjusting for lean and fat mass, sleeping and resting energy expenditure of obesity-prone women was within 2% of controls. Neither sleeping nor resting energy expenditure nor sleeping, resting, or 24-hour fuel use was significantly different between the groups (p > 0.25). None of the metabolic variables contributed significantly to patterns of weight gain at 1 or 2 years of follow-up. DISCUSSION: The results suggest that when resting and sleeping energy expenditure and fuel use are assessed under tightly controlled conditions, these metabolic factors do not distinguish obesity-prone from obesity-resistant women or explain long-term weight changes.