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African American (AA) and European American (EA) women often exhibit differences in hemoglobin (Hb) and 25-hydroxyvitamin D [25(OH)D], both of which can be altered by calorie restriction leading to weight loss. Given these known differences, it is of clinical interest to examine the potential for race-specific, adverse responses to weight loss. Sixty-four overweight (BMI 27-29.9 kg/²), premenopausal women consumed a standardized, very-low calorie diet to reduce BMI < 25 kg/². Ancestry informative markers provided estimates of African admixture, an objective mean of expressing race. Blood sampling and anthropometric measures were performed at baseline and upon meeting target BMI. At baseline, in the overweight state, Hb (g/dL) (AA, 11.7 ± 0.9 vs. EA, 12.5 ± 0.8; p < .01) and 25(OH)D (nmol/L) (AA, 35.7 ± 12.9 vs. EA, 57.0 ± 20.0; p < .01) were lower in AAs. After weight loss, Hb decreased (AA, -0.5 ± 0.7 vs. EA, -0.4 ± 0.6; p = .48) to a similar extent among races. Conversely, 25(OH)D increased (AA, 43.4 ± 14.0 vs. EA 68.2 ± 24.3; p < .01) though the magnitude of change (Δ) was not different (AA, +7.8 ± 13.5 vs. EA,+11.2 ± 16.7;p = .37) between races. Multiple linear regression revealed a positive association between ΔHb and Δ25(OH)D (r = .386; p < .01) adjusted for African admixture, Δtestosterone, and Δbody fat%. Path analyses revealed a significant indirect effect of Δbody fat% on ΔHb through Δ25(OH)D, β =-0.023, CI [-0.06, -0.004]. Following 15% weight loss, participants with the largest increase in serum 25(OH)D exhibited the smallest decrease in Hb. Future research should clarify the optimal degree of calorie restriction to stimulate weight loss while mitigating the potential risk of anemia associated with dieting efforts. [ABSTRACT FROM AUTHOR]

Aerobic capacity is negatively related to locomotion economy. The purpose of this paper is to determine what effect aerobic exercise training has on the relationship between net cycling oxygen uptake (inverse of economy) and aerobic capacity [peak oxygen uptake (...o2peak)], as well as what role mitochondrial coupled and uncoupled respiration may play in whole body aerobic capacity and cycling economy. Cycling net oxygen uptake and ...o2peak were evaluated on 31 premenopausal women before exercise training (baseline) and after 8-16 wk of aerobic training. Muscle tissue was collected from 15 subjects at baseline and post-training. Mitochondrial respiration assays were performed using high-resolution respirometry. Pre- (r = 0.46, P < 0.01) and postexercise training (r = 0.62, P < 0.01) ...o2peak and cycling net oxygen uptake were related. In addition, uncoupled and coupled fat respiration were related both at baseline (r = 0.62, P < 0.01) and post-training (r = 0.89, P < 01). Post-training coupled (r = 0.74, P < 0.01) and uncoupled carbohydrate respiration (r = 0.52, P < 05) were related to cycle net oxygen uptake. In addition, correlations between ...o2peak and cycle net oxygen uptake persist both at baseline and after training, even after adjusting for submaximal cycle respiratory quotient (an index of fat oxidation). These results suggest that the negative relationship between locomotion economy and aerobic capacity is increased following exercise training. In addition, it is proposed that at least one of the primary factors influencing this relationship has its foundation within the mitochondria. Strong relationships between coupled and uncoupled respiration appear to be contributing factors for this relationship. [ABSTRACT FROM AUTHOR]

Exercise is known to improve insulin sensitivity (SI); however, studies to date have been confounded by negative energy deficits after exercise. Purpose: The primary objective of this study was to assess the effect of 8 to 16 wk of aerobic exercise training on the SI of untrained women under rigorously controlled energy-balanced conditions. The secondary objective was to determine if one acute bout of moderate-intensity continuous (MIC) or high-intensity interval (HII) exercise further affected SI. Methods: Insulin sensitivity was assessed in 28 untrained women at baseline, after 8 to 16 wk of training with no-exercise (NE) before assessment, 22 h after MIC (50% V˙O2peak), and 22 h after HII (84% V˙O2peak) using a hyperinsulinemic–euglycemic clamp. Participants were in a whole-room indirect calorimeter during each condition, and food intake was adjusted to ensure energy balance across 23 h before each clamp. Results: There were no significant differences in acute energy balance between each condition. Results indicated a significant main effect of time, such that SI was higher during the HII condition compared with both baseline and NE (P < 0.05). No significant differences in SI were observed after NE or MIC. Conclusions: Widely reported improvements in SI in response to chronic exercise training may be mediated in part by shifts in energy balance. However, an acute bout of HII exercise may increase SI even in the context of energy balance. [ABSTRACT FROM AUTHOR]

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The purpose of this investigation was to determine if differences in inflammatory cytokines exist between fat-free mass responders versus non-responders following a combined resistance/aerobic training program in older women. Fifty women over 60 years old, mean BMI 27 ± 4 (kg/m2) and physically untrained, participated in a combined training program for 16-weeks. Body composition, muscle strength, and serum inflammatory markers (TNF-α, CRP, and IL-6) were assessed at baseline and 16-weeks post-training. A significant time effect was observed for weight, %fat, fat mass, and all strength measures (p < 0.05). A group interaction was observed for TNF-α (p < 0.05), which revealed higher concentrations of circulating TNF-α at baseline (18%) and post-exercise training (24%) in non-responders compared to responders (p < 0.05). In conclusion, this study revealed a significantly greater concentration of circulating TNF-α in older women that do not increase fat-free mass following training. [ABSTRACT FROM AUTHOR]

The article discusses a study which was aimed 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. The study included 63 women who were randomly assigned to 1 of 3 exercise training groups. The study found no significant differences for MS, CF, or FT outcomes between groups.

The article reports on research conducted to investigate the impact weight loss and exercise training had on oxygen uptake and heart rate response during locomotion. Researchers evaluated 73 overweight women who were assigned to diet and aerobic training, diet and resistance training, or diet only. They found that resistance training increased strength, aerobic training increased maximum oxygen uptake and that no significant differences in reduction of heart rate were seen in any of the groups.

Purpose: To examine the effects of three different frequencies of combined resistance and aerobic training on total energy expenditure (TEE) and activity-related energy expenditure (AEE) in a group of older adults. Methods: Seventy-two women, 60-74 yr old, were randomly assigned to one of three groups: 1 d•wk-1 of aerobic training and 1 d•wk-1 of resistance training (1 + 1), 2 d•wk-1 of aerobic training and 2 d•wk-1 resistance training (2 + 2), or 3 d•wk-1 of aerobic training and 3 d•wk-1 of resistance training (3 + 3). Body composition (dual-energy x-ray absorptiometry), feeling of fatigue, depression, and vigor (questionnaire), strength (one-repetition maximum), serum cytokines (enzyme- linked immunosorbent assay), maximal oxygen uptake (progressive treadmill test), resting energy expenditure, and TEE were measured before and after 16 wk of training. Aerobic training consisted of 40 min of aerobic exercise at 80% maximum heart rate, and resistance training consisted of two sets of 10 repetitions for 10 different exercises at 80% of one repetition maximum. Results: All groups increased fat-free mass, strength, and aerobic fitness and decreased fat mass. No changes were observed in cytokines or perceptions of fatigue/depression. No time-group interaction was found for any fitness/body composition variable. TEE and AEE increased with the 2 + 2 group but not with the other two groups. Nonexercise training AEE (nonexercise training activity-related thermogenesis) increased significantly in the 2 + 2 group (+200 kcal•d-1), group 1 + 1 showed atrend for an increase (+68 kcal•d-1), and group 3 + 3 decreased significantly (-150 kcal•d-1). Conclusion: Results indicate that 3 + 3 training may inhibit nonexercise training activity- related thermogenesis by being too time consuming and does not induce superior training adaptations to 1 + 1 and 2 + 2 training. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Aerobic exercise training (AET) has been shown to improve mitochondrial bioenergetics and upregulate proteins related to lipid metabolism. However, it remains to be determined if these alterations associated with AET persist when measured in energy balance (EB) in the days after the last bout of training. The purpose of the study was to test the hypothesis that improvements in skeletal muscle mitochondrial function induced by AET observed in previous literature would persist when measured after restoring EB conditions 72 h removed from the last exercise bout. Methods: Participants were 14 premenopausal women (age = 31.2 ± 6.7 yr, BMI = 26.6 ± 5.1 kg·m−2). The AET program required three monitored training sessions per week for 8–16 wk. Skeletal muscle biopsies were obtained at baseline and after 8–16 wk of AET (≥72 h after the last exercise bout). All food was provided for 72 h before biopsies, and EB was managed 24 h before testing within ±100 kcal of measured energy requirements using a whole-room calorimeter. Mitochondrial oxidative capacity was quantified in permeabilized muscle fibers from the vastus lateralis. Results: We found that AET increased coupled respiration (154%) and uncoupled respiration (90%) rates using a fatty acid substrate (palmitoyl carnitine) (P < 0.05). However, when rates were normalized to complex IV activity (a marker of mitochondrial content), no significant differences were observed. In addition, there were no changes in proteins known to mediate mitochondrial biogenesis or lipid transport and metabolism after AET. Conclusion: Eight to 16 wk of AET improved mitochondrial capacity under fatty acid substrate when assessed in EB, which appears to be due to mitochondrial biogenesis. [ABSTRACT FROM AUTHOR]

Introduction: Resting energy expenditure (REE) increases after an intense exercise; however, little is known concerning mechanisms. Purpose: The purpose of this study was to determine effects of a single bout of moderate-intensity continuous (MIC) aerobic exercise, or high-intensity interval (HII) exercise on REE under energy balance conditions. Methods: Thirty-three untrained premenopausal women were evaluated at baseline, after 8-16 wk of training, 22 h after either MIC (50% peak VO2) or HII (84% peak ...O2). Participants were in a room calorimeter during and after the exercise challenge. Food intake was adjusted to obtain energy balance across 23 h. REE was measured after 22 h after all conditions. Twenty-three-hour urine norepinephrine concentration and serum creatine kinase activity (CrKact) were obtained. Muscle biopsies were obtained in a subset of 15 participants to examine muscle mitochondrial state 2, 3, and 4 fat oxidation. Results: REE was increased 22 h after MIC (64 ± 119 kcal) and HII (103 ± 137 kcal). Markers of muscle damage (CrKact) increased after HII (9.6 ± 25.5 U⋅L-1) and MIC (22.2 ± 22.8 U⋅L-1), whereas sympathetic tone (urine norepinephrine) increased after HII (1.1 ± 10.6 ng⋅mg-1). Uncoupled phosphorylation (states 2 and 4) fat oxidation were related to REE (r = 0.65 and r = 0.55, respectively); however, neither state 2 nor state 4 fat oxidation increased after MIC or HII. REE was not increased after 8 wk of aerobic training when exercise was restrained for 60 h. Conclusions: Under energy balance conditions, REE increased 22 h after both moderate-intensity and high-intensity exercise. Exercise-induced muscle damage/repair and increased sympathetic tone may contribute to increased REE, whereas uncoupled phosphorylation does not. These results suggest that moderate- to high-intensity exercise may be valuable for increasing energy expenditure for at least 22 h after the exercise. [ABSTRACT FROM AUTHOR]