Sedentary Premenopausal Women Research Articles

Effect of 6-month high-impact step aerobics and resistance training on BMD and tibial bending strength in sedentary premenopausal women.

To determine the effectiveness of 6months of high-impact step aerobics (SA) or moderate-intensity resistance training (RT) on areal bone mineral density (aBMD) and tibial bending strength in sedentary premenopausal women. Sixty-nine women (20-35years old) who were randomly assigned to RT (n = 22), SA (n = 26), or non-treatment control (CON, n = 21) groups completed the study. SA had a minimum of 50 high-impact landings each training session. RT had a periodized lower body resistance training program incorporating eight exercises (65-85% of 1 repetition maximum: 1-RM). Both RT and SA met 3 times weekly. aBMD was assessed using dual X-ray absorptiometry (DXA). Tibial bending strength was assessed using mechanical response tissue analysis (MRTA). Measurements at 6months were compared to baseline using ANCOVA, adjusted for baseline measures and covariates with α = 0.05. Calcaneus aBMD (0.0176 vs -0.0019 or -0.0009g/cm2 relative to RT, p < 0.004, and CON, p < 0.006, respectively), lower leg aBMD (0.0105 vs -0.0036g/cm2, relative to RT, p = 0.02), and lumbar spine 2 (L2) aBMD (0.0082 vs -0.0157g/cm2 relative to CON, p < 0.02) were significantly greater in the SA group after 6months. Tibial bending strength and bone resorption biomarkers were unchanged in all three groups after 6months. Sedentary premenopausal women engaging in 6months of high-impact aerobic exercise improved aBMD in the calcaneus, lower leg, and L2.

The Effects of Habitual Aquatic Walking on Arterial Stiffness and Body Composition in Postmenopausal Women: A Cross‑Sectional Study

PURPOSE: Menopause is associated with increased carotid–femoral pulse wave velocity (cfPWV), an indicator of arterial stiffness, which is an independent marker of cardiovascular risk. This study aimed to investigate the cfPWV, blood pressure, and body composition with habitual exercise for at least 1 year in postmenopausal women performing habitual aquatic walking versus age-matched sedentary postmenopausal and premenopausal women.METHODS: A total of 115 postmenopausal and premenopausal women were divided into the following groups: (1) postmenopausal women performing habitual aquatic walking (HAW; n=57), (2) sedentary postmenopausal women (SPO; n=41), and (3) sedentary premenopausal women (SPR, n=17). The HAW group participated 3 days per week, 60 minutes per day, for at least 1 year, whereas the SPO and SPR groups performed no regular exercise, for less than 2 days per week, 30 minutes per day, for at least 1 year. The cfPWV, BP, and body composition were assessed in all groups.RESULTS: The cfPWV (&lt;i&gt;p&lt;/i&gt;&lt;.05), augmentation pressure (&lt;i&gt;p&lt;/i&gt;&lt;.05), and DBP were significantly lower in the SPR group than in the SPO group. AIx@75, BMI, %BF, and SBP were significantly lower in the SPR group than in the SPO and HAW groups. Lean body mass was higher in the SPR group than in the SPO and HAW groups (&lt;i&gt;p&lt;/i&gt;&lt;.05). The cfPWV, AP, AIx@75, SBP, and %BF were lower in the HAW group than in the SPO group (&lt;i&gt;p&lt;/i&gt;&lt;.05). Furthermore, the cfPWV was significantly correlated with aging and SBP.CONCLUSIONS: This cross-sectional study indicates that sedentary postmenopausal women may be at a higher risk of cardiovascular disease than postmenopausal women who participate in habitual aquatic walking.

Circulating myokines IL-6, IL-15 and FGF21 response to training is altered by exercise type but not by menopause in women with obesity

ABSTRACT To examine the effects of a time-matched endurance vs. concurrent training on circulating IL-6, IL-13, IL-15, IL-15Ra, FGF21 levels in postmenopausal women with obesity, and to determine these myokines response to endurance training pre- and postmenopause. Thirty-five sedentary postmenopausal women with obesity were randomly divided into endurance training (EN1, N = 10), concurrent training (CON, N = 13) or no training group (CT, N = 12). Additionally, twelve sedentary premenopausal women with obesity were added to an endurance training group (EN2, N = 12). Participants took part in a 12-week supervised intervention, performing 3 sessions/week of 60 min/session. Before and after the interventions, body composition and fitness were assessed, and blood samples obtained to measure serum myokines levels. Total fat mass decreased in all exercised groups (CON,−5.2%; EN1,−5.3%; EN2,−5.6%). In postmenopausal women, serum IL-6, IL-15 and IL-15Ra decreased after training (P<0.01), finding a pronounced reduction in IL-6 (−42% vs. −16%) and IL-15 (−50% vs. −31%) when comparing EN1 to CON (P<0.05). Serum FGF21 was only reduced in the EN1 (−27%; P=0.012). While EN1 and EN2 comparison, reported differences for IL-15Rα concentration (−28% vs. −40%; P=0.023). Finally, in EN2, the delta change of fat mass and IL-6, IL-15 and IL-15Rα were associated (r = 0.605; r = 0.546; r = 0.515; P<0.05). IL-13 showed undetected concentrations. Circulating IL-6, IL-15 and FGF21 response to training is altered by exercise type but not by menopause in women with obesity. Endurance training promotes a higher reduction of these myokines, potentially activating their intricate immune and fat mass regulation roles in postmenopausal women with obesity.

The effect of acute step-aerobic exercise on adiponectin and leptin levels in premenopausal women.

It is well known that the prevalence of obesity, cardiovascular disease and metabolic syndrome is increasing during the transition to menopausal stages. The aim of this study was to investigate the effects of acute step-aerobic exercise on levels of leptin and adiponectin, which are adipose tissue-derived adipocytokines, associated with obesity, hypertension and other diseases in sedentary premenopausal women. Twenty-four sedentary premenopausal volunteer women between the ages of 40-45 (premenopause group) and 24 healthy adults between the ages of 21-39 (control group) were enrolled in this study. Moderate intensity step-aerobic exercise (50-60% of HR<inf>max</inf>) was applied for 60 min to the premenopausal subjects. Venous blood samples were obtained before and after the exercise. Adiponectin and leptin levels were determined using the ELISA method. No statistically significant difference was found in terms of BMI values, and leptin levels between the premenopause and control group, while differences of adiponectin were statistically significant. Plasma leptin levels of the premenopausal women decreased whereas adiponectin levels increased meaningfully after the acute aerobic exercise (P<0.05). When the premenopausal women were grouped according to BMI, there were no significant differences between BMI≤30 and >30 groups in terms of leptin and adiponectin levels measured before and after exercise. Our results may suggest that acute step aerobic exercise in premenopausal women alters leptin and adiponectin levels in favor of the organism. However, further studies are needed.

Muscle ion transporters and antioxidative proteins have different adaptive potential in arm than in leg skeletal muscle with exercise training.

It was evaluated whether upper‐body compared to lower‐body musculature exhibits a different phenotype in relation to capacity for handling reactive oxygen species (ROS), H+, La−, Na+, K+ and also whether it differs in adaptive potential to exercise training. Eighty‐three sedentary premenopausal women aged 45 ± 6 years (mean ± SD) were randomized into a high‐intensity intermittent swimming group (HIS, n = 21), a moderate‐intensity swimming group (MOS, n = 21), a soccer group (SOC, n = 21), or a control group (CON, n = 20). Intervention groups completed three weekly training sessions for 15 weeks, and pre‐ and postintervention biopsies were obtained from deltoideus and vastus lateralis muscle. Before training, monocarboxylate transporter 4 (MCT4), Na+/K+ pump α 2, and superoxide dismutase 2 (SOD2) expressions were lower (P < 0.05) in m. deltoideus than in m. vastus lateralis, whereas deltoid had higher (P < 0.05) Na+/H+ exchanger 1 (NHE1) expression. As a result of training, Na+/K+ pump α 2 isoform expression was elevated only in deltoideus muscle, while upregulation (P < 0.05) of the α 1 and β 1 subunits, phospholemman (FXYD1), NHE1, and superoxide dismutase 1 expression occurred exclusively in vastus lateralis muscle. The increased (P < 0.05) expression of MCT4 and SOD2 in deltoid muscle after HIS and vastus lateralis muscle after SOC were similar. In conclusion, arm musculature displays lower basal ROS, La−, K+ handling capability but higher Na+‐dependent H+ extrusion capacity than leg musculature. Training‐induced changes in the ion‐transporting and antioxidant proteins clearly differed between muscle groups.

Oxidative capacity and glycogen content increase more in arm than leg muscle in sedentary women after intense training

The hypothesis that the adaptive capacity is higher in human upper- than lower-body skeletal muscle was tested. Furthermore, the hypothesis that more pronounced adaptations in upper-body musculature can be achieved by "low-volume high-intensity" compared with "high-volume low-intensity" exercise training was evaluated. A group of sedentary premenopausal women aged 45 ± 6 yr (± SD) with expected high adaptive potential in both upper- and lower-extremity muscle groups participated. After random allocation to high-intensity swimming (HIS, n = 21), moderate-intensity swimming (MOS, n = 21), soccer (SOC, n = 21) or a nontraining control group (CON, n = 20), the training groups completed three workouts per week for 15 wk. Resting muscle biopsies were obtained from the vastus lateralis muscle and deltoideus muscle before and after the intervention. After the training intervention, a larger (P < 0.05) increase existed in deltoideus muscle of the HIS group compared with vastus lateralis muscle of the SOC group for citrate synthase maximal activity (95 ± 89 vs. 27 ± 34%), citrate synthase protein expression (100 ± 29 vs. 31 ± 44%), 3-hydroxyacyl-CoA dehydrogenase maximal activity (35 ± 43 vs. 3 ± 25%), muscle glycogen content (63 ± 76 vs. 20 ± 51%), and expression of mitochondrial complex II, III, and IV. Additionally, HIS caused higher (P < 0.05) increases than MOS in deltoideus muscle citrate synthase maximal activity, citrate synthase protein expression, and muscle glycogen content. In conclusion, the deltoideus muscle has a higher adaptive potential than the vastus lateralis muscle in sedentary women, and "high-intensity low-volume" training is a more efficient regime than "low-intensity high-volume" training for increasing the aerobic capacity of the deltoideus muscle.

Effect Of Exercise Training Mode On Oxidative Capacity In Human Arm And Leg Skeletal Muscle

The exercise-induced adaptation pattern in oxidative capacity in human skeletal is highly dependent on the type of training performed. However, information on the impact of different exercise training protocols on muscle responses in arm versus leg is sparse. PURPOSE: To examined effects of different whole-body exercise training modes on oxidative capacity in arm and leg human skeletal muscle. METHODS: Sedentary premenopausal women (n=83; age; 45±2 (±SEM) yrs, height; 165±1 cm, weight; 79.2±1.5 kg, body fat; 42.9±0.6 %) were randomized into high-intensity swimming (HIS, n=21), moderate-intensity swimming (MOS, n=21), football training intervention-groups (FTG, n=21), and control (CON, n=20). Intervention-groups completed 3 sessions/wk for 15 wks. Pre and post-intervention muscle biopsies were obtained at rest from arm (m. deltoideus) and leg (m. vastus lateralis). RESULTS: Maximal citrate synthase (CS) activity in intervention-groups increased by 44±59% overall (P<0.001; n=82), with only HIS displaying a higher (P<0.05) increase in arm than leg muscle (95±89% vs. 52±80%, respectively). In leg, CS protein expression increased in intervention-groups (31-55%, P<0.05), while arm, CS protein expression was increased in FTG and HIS (49-100%, P<0.01) only. Maximal arm 3-Hydroxyacyl-CoA Dehydrogenase (HAD) activity post-training was elevated in FTG, MOS and HIS (20-35%), while only HIS had an increase (18±30%, P<0.05) in leg. HIS and MOS increased (P<0.05) arm mitochondrial respiratory chain complex 1-5, and FTG only had an increase (P<0.05) in complex 5, while groups-specific adaptations occurred in the leg muscle. In HIS the increase in arm complex 2 and 4 was higher (P<0.05) than in leg. Resting muscle glycogen was elevated post-HIS in arm only (63±76%, P<0.001). CONCLUSION: In conclusion, markers of oxidative capacity in arm and leg human skeletal muscle respond differently to exercise training. In general, Krebs cycle capacity, marked by CS, increased in both arm and leg muscle, while the increase in β-oxidation capacity primarily occurred in arm. The greatest improvement in mitochondrial electron-transport capacity was in arm muscles after swim-training, with the overall greatest effect after high-intensity swim-training. Supported by a grant (ST-05710) from The Faroese Research Council.

Predictors of fat mass changes in response to aerobic exercise training in women.

Aerobic exercise training in women typically results in minimal fat loss, with considerable individual variability. We hypothesized that women with higher baseline body fat would lose more body fat in response to exercise training and that early fat loss would predict final fat loss. Eighty-one sedentary premenopausal women (age: 30.7 ± 7.8 years; height: 164.5 ± 7.4 cm; weight: 68.2 ± 16.4 kg; fat percent: 38.1 ± 8.8) underwent dual-energy x-ray absorptiometry before and after 12 weeks of supervised treadmill walking 3 days per week for 30 minutes at 70% of (Equation is included in full-text article.). Overall, women did not lose body weight or fat mass. However, considerable individual variability was observed for changes in body weight (-11.7 to +4.8 kg) and fat mass (-11.8 to +3.7 kg). Fifty-five women were classified as compensators and, as a group, gained fat mass (25.6 ± 11.1 kg to 26.1 ± 11.3 kg; p < 0.001). The strongest correlates of change in body fat at 12 weeks were change in body weight (r = 0.52) and fat mass (r = 0.48) at 4 weeks. Stepwise regression analysis that included change in body weight and body fat at 4 weeks and submaximal exercise energy expenditure yielded a prediction model that explained 37% of the variance in fat mass change (R = 0.37, p < 0.001). Change in body weight and fat mass at 4 weeks were moderate predictors of fat loss and may potentially be useful for identification of individuals who achieve less than expected weight loss or experience unintended fat gain in response to exercise training.

High-intensity intermittent swimming improves cardiovascular health status for women with mild hypertension.

To test the hypothesis that high-intensity swim training improves cardiovascular health status in sedentary premenopausal women with mild hypertension, sixty-two women were randomized into high-intensity (n = 21; HIT), moderate-intensity (n = 21; MOD), and control groups (n = 20; CON). HIT performed 6–10 × 30 s all-out swimming interspersed by 2 min recovery and MOD swam continuously for 1 h at moderate intensity for a 15-week period completing in total 44 ± 1 and 43 ± 1 sessions, respectively. In CON, all measured variables were similar before and after the intervention period. Systolic BP decreased (P < 0.05) by 6 ± 1 and 4 ± 1 mmHg in HIT and MOD; respectively. Resting heart rate declined (P < 0.05) by 5 ± 1 bpm both in HIT and MOD, fat mass decreased (P < 0.05) by 1.1 ± 0.2 and 2.2 ± 0.3 kg, respectively, while the blood lipid profile was unaltered. In HIT and MOD, performance improved (P < 0.05) for a maximal 10 min swim (13 ± 3% and 22 ± 3%), interval swimming (23 ± 3% and 8 ± 3%), and Yo-Yo IE1 running performance (58 ± 5% and 45 ± 4%). In conclusion, high-intensity intermittent swimming is an effective training strategy to improve cardiovascular health and physical performance in sedentary women with mild hypertension. Adaptations are similar with high- and moderate-intensity training, despite markedly less total time spent and distance covered in the high-intensity group.

Effects of exercise combined with caloric restriction on inflammatory cytokines

Chronic inflammation has been implicated in the pathogenesis of several chronic diseases, such as atherosclerosis and diabetes, as well as certain types of cancers. It has been suggested that circulating biomarkers for inflammation may be modified by exercise; however, few laboratory-based studies have been conducted in nonobese premenopausal women. The purpose of this investigation was to determine the impact of a 4-month exercise training and caloric-restriction intervention with the goal of weight loss on circulating biomarkers of inflammation in sedentary premenopausal women aged 25- 40 years (weight, 57 ± 2 kg). Subjects were studied for 6 consecutive menstrual cycles: 1 Screening, 1 Baseline, then 4 interventions (Interventions 1-4). Supervised aerobic training, consisting primarily of treadmill running and elliptical machine exercise, was performed 4 times per week for 40-90 min at 79% ± 0.7% of maximal heart rate. Subjects also consumed 30% fewer calories vs. baseline (1863 ± 58 to 1428 ± 53 kcalday(-1) (1 kcal = 4.186 kJ), p < 0.0001). Circulating inflammatory biomarkers, including adiponectin, high-sensitivity (hs) C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interferon-gamma (IFN-γ), and leptin, as well as body composition, aerobic capacity, and energy balance, were measured before and after the intervention. Maximal aerobic capacity increased by 8.5 ± 1.7 mL kg(-1)min-1 (p < 0.001) and body mass declined by an average of 3.7 ± 0.5 kg (p < 0.001). Significant reductions in IL-6 (0.39 ± 0.04 to 0.30 ± 0.03 pgmL(-1), p = 0.025), IFN-γ (0.58 ± 0.83 to 0.42 ± 0.64 pgmL-1, p = 0.030), and leptin (13.18 ± 1.28 to 6.28 ± 0.71 pgmL(-1), p < 0.001) were detected in response to the intervention. No significant changes in adiponectin, hs-CRP, or TNF-α were found. Weight loss in response to exercise training and caloric restriction is effective in reducing inflammatory markers, specifically IL-6 and leptin.

Tibial And Radial Bone Strength In Women Is Predicted By Muscle Load And Sex Steroids

Mechanical loading and sex steroids are hypothesized to play an important role in bone metabolism and to influence bone health in premenopausal women. PURPOSE: To determine predictors of bone strength, geometry and volumetric bone mineral density (vBMD) in sedentary premenopausal women. METHODS: Baseline data was used from a subset of healthy, sedentary, premenopausal women (n = 67, aged 18-30 years; mean BMI 23.96 ± 3.1) enrolled in a study of physical activity and ovulation (WISER). Estrogen status was determined by 3-day urine collection. Menstrual cycle length (MCL) and luteal phase length (LPL) were assessed by questionnaire and confirmed with ovulation kits over 2 menstrual cycles. LPL was used as a surrogate of progesterone exposure. Total body lean mass (LM) and fat mass (FM) were measured by dual energy x-ray absorptiometry (DXA). Volumetric bone mineral density (vBMD), bone geometry (total and cortical area), estimated bone strength (polar strength strain index, SSIp, and bone strength index, BSI) and muscle cross-sectional area (MCSA) were assessed by pQCT (XCT 3000) at the distal (4, 8%) sites and midshaft (50, 66%) sites of the tibia and radius. Trabecular and total vBMD, total area and BSI were reported for distal sites; cortical vBMD, total and cortical area, and SSI were reported for midshaft sites. Linear regression, adjusted for limb length and age, was used to determine predictors of bone variables. RESULTS: The primary determinant of SSI and geometry at the midshaft tibia was LM while FM was the primary predictor of vBMD (P < 0.01). At the distal tibia, LM was the primary determinant of BSI, bone geometry, and vBMD (P < 0.01). MCSA was the primary determinant of both bone strength and geometry of the radius midshaft, while LPL predicted vBMD (P < 0.01). At the distal radius, menstrual cycle characteristics, MCSA and LM were the primary predictors of all bone variables (P < 0.05). CONCLUSION: Since sedentary premenopausal women likely have lower MCSA and LM compared to active women, these data suggest bone health may be compromised in this population. Also, luteal phase length and menstrual cycle length may significantly affect bone health. Thus, less muscle along with subtle alterations in menstrual cycle characteristics may lead to compromised bone strength in sedentary women. Supported by NCI Grant NCT00393172

Basal adipose tissue and hepatic lipid kinetics are not affected by a single exercise bout of moderate duration and intensity in sedentary women.

Hypertriacylglycerolaemia is an important risk factor for cardiovascular disease. In men, we have shown that the effects of evening exercise on basal VLDL (very-low-density lipoprotein) metabolism are dose-dependent: a single prolonged bout of aerobic exercise [2 h at 60% of VO(2 peak) (peak oxygen consumption)] reduces fasting plasma TAG [triacylglycerol (triglyceride)] concentrations, via enhanced clearance of VLDL-TAG from the circulation, whereas the same exercise performed for 1 h has no effect on VLDL-TAG metabolism and concentration. We hypothesized that women are more sensitive to the TAG-lowering effect of exercise because they reportedly use more intramuscular TAG as an energy source during exercise, and depletion of muscle TAG stores has been linked to reciprocal changes in skeletal muscle LPL (lipoprotein lipase) activity. To test our hypothesis, we measured basal VLDL-TAG and VLDL-apoB-100 (apolipoprotein B-100), and plasma NEFA [non-esterified fatty acid ('free fatty acid')] kinetics, by using stable isotope-labelled tracer techniques, on the morning after a single session of evening exercise of moderate duration and intensity (1 h at 60% of VO(2 peak)) in eight sedentary pre-menopausal women (age, 28+/-3 years; body mass index, 27+/-2 kg/m(2); body fat, 34+/-3%; values are means+/-S.E.M.). Compared with an equivalent period of evening rest, exercise had no effect on post-absorptive NEFA concentrations and the rate of appearance in plasma, VLDL-TAG and VLDL-apoB-100 concentrations, hepatic VLDL-TAG and VLDL-apoB-100 secretion and plasma clearance rates (all P>0.05). We conclude that, in women, as in men, a single session of exercise of moderate intensity and duration is not sufficient to bring about the alterations in VLDL metabolism that have been linked to post-exercise hypotriacylglycerolaemia.

Physical Activity and Bone Turnover Markers: A Cross-Sectional and a Longitudinal Study

Strenuous physical activity in young individuals has an important effect on both bone mass and bone turnover but the effect of moderate physical activity in adults remains uncertain. In a large cohort (N = 530) of healthy premenopausal women, bone formation markers (osteocalcin and N-terminal propeptide of type 1 procollagen [P1NP]), but not serum C-telopeptide of type 1 collagen (sCTX), were found to be significantly associated with the level of physical activity, and this association remained significant after adjusting the data (ANCOVA) by age and body mass index. Mean spine and hip bone mineral density (BMD) values were positively associated with physical activity but this was statistically significant (P = 0.050) only for adjusted values of spine BMD. Twenty-four healthy sedentary premenopausal women, subscribing to participate in a community exercise program lasting a month, and 18 age-matched controls were included in the longitudinal study. Serum osteocalcin and P1NP, but not sCTX, rose significantly, by ca. 25%, only in the active group after a month of exercise. The changes in the two bone formation markers remained statistically significant for values adjusted for body weight, which fell significantly in the exercise group. In conclusion, both the cross-sectional and the longitudinal parts of our study demonstrate that even minor changes in physical activity are associated with a clear effect on bone formation markers.

Exercise for optimising peak bone mass in women

Physical activity is one of the major non-pharmacological methods for increasing and maintaining bone mineral density (BMD) and geometry. As such, it has an important role in maintaining peak bone mass and strength, thus reducing the risk of future osteoporotic fracture. However, not all exercise is effective, so a prescription in terms of optimal type, intensity, frequency and duration is required. Studies using animal models suggest that loading that is high in magnitude, rapidly applied and novel is most effective, whilst duration is less important beyond a threshold number of cycles. In human subjects cross-sectional studies comparing different athletic populations suggest that those who participate in high- or odd-impact sports have higher BMD; whilst impact exercise, strength training and brief high-impact-jump training interventions increase BMD in premenopausal women. In order to further elucidate exercise recommendations to optimise bone health in this population, the usefulness of brief high-impact unilateral exercises has been evaluated. Brief hopping exercises were shown to be feasible for sedentary premenopausal women, producing ground-reaction forces as high as those from jumping. Regularly performing these hopping exercises over 6 months was found to increase femoral-neck BMD of the trained leg relative to the control leg. Unilateral high-impact exercise may therefore improve bone strength of the trained limb and provide a useful model for comparing exercise prescriptions to help define the most efficient and effective exercise recommendations for the bone health of premenopausal women.

A Moderate-Intensity Exercise Program Fulfilling the American College of Sports Medicine Net Energy Expenditure Recommendation Improves Health Outcomes in Premenopausal Women

The purpose of this study was to assess and quantify the health outcomes associated with a moderate-intensity (50% VO2R) exercise program designed to achieve the American College of Sports Medicine net caloric expenditure guideline of 1,000 kcal x wk(-1). Fifteen apparently healthy but sedentary premenopausal women with the baseline characteristics (mean +/- SD age, height, weight, body composition, and VO2max: 37.4 +/- 6.3 yr, 166.2 +/- 6.2 cm, 72.1 +/- 11.2 kg, 32.5 +/- 5.8%, and 34.8 +/- 5.8 mL x kg(-1) x min(-1), respectively) participated in and completed the study. Exercise training was performed 3-4 days per week for 10 weeks in a progressive manner at moderate intensity (50% VO2R). There were significant (P < 0.05) improvements in VO2max (+2.5 mL x kg(-1) x min(-1)), systolic (-13.7 mm Hg) and diastolic (-6.4 mm Hg) blood pressure, high-density lipoprotein cholesterol (+3.2 mg x dL(-1)), fasting blood glucose (-4.9 mg x dL(-1)), and percent body fat (-1.6%). Although the American College of Sports Medicine specifies that the energy expenditure goal should be a net caloric expenditure of 1,000 kcal x wk(-1) and classifies relative moderate intensity as 40-59% of heart rate reserve or VO2R, we are unaware of any previous investigations that have examined the specific health outcomes associated with an exercise program fulfilling these requirements. Results indicate that significant health benefits will be conferred to previously sedentary, premenopausal women who engage in a moderate-intensity, 10-week exercise program designed to fulfill the net energy expenditure guideline of 1,000 kcal x wk(-1).

Exercise Effect on Oxidative Stress Is Independent of Change in Estrogen Metabolism

The effect of exercise training on lipid peroxidation and endogenous estrogens is not well understood in premenopausal women. Exercise effects on these variables could mediate observed associations of exercise with hormonally related cancers, including breast cancer. The purpose of the study is to determine the effect of 15 weeks of aerobic exercise on lipid peroxidation, endogenous estrogens, and body composition in young, healthy eumenorrheic women. Fifteen sedentary premenopausal women (18-25 years) participated. Pre- and post-exercise training urine collection (three 24-h samples) started 48 h after most recent exercise session for analysis of a marker of lipid peroxidation (F(2)-isoprostane) and endogenous estrogens, including 2-hydroxyestrogens, 4-hydroxyestrogens, 16-alpha-hydroxyestrone, and ratios of these metabolites (2:16, 2:4). Body composition was measured by dual-energy X-ray absorptiometry, and F(2)-isoprostanes and estrogens were measured by gas chromatography-mass spectrometry. Aerobic exercise resulted in a 34% decrease in F(2)-isoprostane (P = 0.02), a 10% increase in fitness (P = 0.004), a 1.2 kg decrease in body mass (P = 0.007), and a 1.8 kg decrease in fat mass (P = 0.04). No significant changes were noted in estrogens. The effect of exercise training on oxidative stress may be relevant to risk for hormonally related cancers.

Large and Small Arterial Elasticity in Healthy Active and Sedentary Premenopausal Women

PURPOSE: To compare large and small arterial elasticity in apparently healthy sedentary and recreationally active adult women, and to examine if age affects large and small arterial elasticity. METHODS: The subjects for this cross-sectional study consisted of 43 premenopausal women without overt cardiovascular disease (age = 43.4 ± 4.7 yrs; mean ± SD). Activity level and menopausal status was based on self-report. The subjects were grouped into a sedentary group or a leisurely active group (30 min, 3d wk of moderate intensity) in addition to the following age groups: 35–40 years, n = 13; 41 −45 years, n = 14; 46–54 years, n = 16. Subjects rested supine while pulse contour analysis was measured from the radial artery using an HDI/Pulsewave CR-2000 instrument (Hypertension Diagnostic, Inc.) to examine arterial elasticity in the large and small arteries. RESULTS: There were no differences in large (14.5 ± 1.0 ml/mmHg × 10; 14.9 ± 0.9 ml/mmHg × 10; mean ± SD) and small (5.5 ± 0.5 ml/mmHg × 100; 6.4 ± 0.4 ml/mmHg × 100) arterial elasticity between the sedentary group and the recreationally active group, respectively. Large (12.8 ± 0.9 ml/mmHg × 10) arterial elasticity was lower in the oldest group (p = 0.008) compared to the youngest group (17.6 ± 5.9 ml/mmHg × 10). After adjusting for body mass index, large arterial elasticity (p = 0.022) remained lower in the oldest group. Small arterial elasticity was lower in the older group compared to the young group, but did not reach level of significance (p = 0.063). CONCLUSION: There is no difference in large and small arterial elasticity between healthy sedentary and recreationally active premenopausal women. This suggests that more strenuous physical activity may be necessary to gain beneficial effects on the vasculature. Large arterial elasticity is decreasing with advancing age independent of body mass index.

Adiponectin is a predictor of bone mineral density in middle-aged premenopausal women

Adipose-modulated biochemical signal that explains some of the association between fat mass and bone mineral density (BMD) is adiponectin. The results demonstrated an independent association between adiponectin and BMD, while the influence of adiponectin on bone mineral content is mediated by fat free mass in middle-aged women. Positive association between fat mass (FM) and bone mineral density (BMD) is mediated by biochemical factors. The relationship between plasma adiponectin concentration and BMD in 98 sedentary premenopausal women aged 38-49 years with a body mass index range of 20.0-42.1 kg/m(2) was examined. Different body composition and blood biochemical parameters were measured to adjust for possible confounding variables. The association between adiponectin and BMD values (total BMD: beta = -0.919; p = 0.0001, femoral neck BMD: beta = -0.925; p = 0.0001 and lumbar spine BMD: ss = -0.912; p = 0.0001) was independent of the influences that measured body composition, hormonal and insulin resistance factors may exert on BMD (p < 0.02). However, adiponectin explained only 3-12% of the variations in measured BMD variables. Similarly, adiponectin was associated with total bone mineral content (BMC; beta = -0.911; p = 0.0001) and remained associated in different analyses that controlled for possible confounding parameters (p < 0.01). However, the association between adiponectin and total BMC was no longer significant when adjusted for fat free mass (FFM; p > 0.21). Adiponectin is an independent predictor of BMD, while its independent contribution to the interindividual variance in measured values is only modest. The influence of adiponectin on total BMC is mediated or confounded by FFM in middle-aged premenopausal women.

Effect of aerobic training on plasma levels and subcutaneous abdominal adipose tissue gene expression of adiponectin, leptin, interleukin 6, and tumor necrosis factor α in obese women

Adipocytokines secreted by adipose tissue are suggested to play a role in the development of obesity-related complications. Regular aerobic exercise has been shown to reduce the risk of metabolic complications in obese subjects. The aim of this study was to investigate the effect of aerobic training on gene expression in subcutaneous abdominal adipose tissue (SCAAT) and on plasma levels of several adipocytokines in obese women. Twenty-five obese sedentary premenopausal women (body mass index, 32.18 ± 3.17 kg/m 2) underwent a 12-week aerobic exercise program, with a frequency of 5 d/wk and intensity corresponding to 50% of individual maximal oxygen consumption (V˙ o 2max) consisting of 2 sessions per week of supervised aerobic exercise and 3 sessions per week of home-based exercise on a bicycle ergometer. Before and after the aerobic training, V˙ o 2max and body composition were measured and plasma and SCAAT biopsy samples (in a subgroup of 8 subjects) were obtained for determination of plasma and messenger RNA levels of adipocytokines (leptin, adiponectin, interleukin 6, tumor necrosis factor α). The aerobic training resulted in an increase of subjects' V˙ o 2max by 12.8% (24.6 ± 3.9 vs 27.7 ± 4.8 mL · min −1 · kg −1, P < .05). Body weight and fat mass were reduced by 5.9% (88.5 ± 8.2 vs 83.3 ± 7.7 kg, P < .001) and 6.4% (38.8 ± 4.2% vs 36.3 ± 4.6%, P < .001), respectively, and the revised QUantitative Insulin sensitivity ChecK Index (QUICKI) increased (0.43 ± 0.06 vs 0.48 ± 0.06, P < .05) during the aerobic training. No aerobic training-induced changes in messenger RNA levels of the investigated genes in SCAAT were observed. A decrease of plasma leptin (24.3 ± 8.7 vs 18.1 ± 8.3 ng/mL, P < .05) was detected, whereas plasma levels of other cytokines remained unchanged. In moderately obese females, 3 months' aerobic training did not promote changes in the adipose tissue gene expression or plasma levels of the adipocytokines (except for leptin) involved in a regulation of lipid and carbohydrate metabolism.

Walking and Running Economy are Weakly Inversely Correlated to Maximal Oxygen Consumption In Healthy Males and Females

An inverse relationship has been shown between maximal oxygen uptake (VO2 max) and running and cycling economy. Furthermore, it has recently been reported that among sedentary premenopausal women VO2 max correlated inversely with walking economy at 3.0 mph (Hunter et al., Eur J Appl Physiol, 2005; 558–568, 2005). PURPOSE: To examine the relationship between VO2 max and walking and running economy in healthy men and women. We selected a range of typical walking speeds (2.0 – 4.0 mph), and one running speed (6.0 mph). METHODS: 19 healthy males (age 26.9 ± 6.4 yr.; ht: 179.7 ± 7.2 cm; wt: 79.5 ± 10.4 kg; % fat: 16.0 ± 7.4) and 26 healthy females (age 24.8 ± 4.8 yr.; ht: 166.1 ±5.2 cm; wt: 62.2 ± 8.9 kg; % fat: 25.9 ± 11.4) underwent two separate exercise sessions on different days that consisted of treadmill walking on a level grade at 2.0 mph (54 m/min), 3.0 mph (80 m/min), and 4.0 mph (107 m/min), and running at 6.0 mph (161 m/min). Subjects exercised for 5 min at each velocity, with 3 min rest in between each exercise bout. Pulmonary ventilation and gas exchange were measured breath-to-breath each minute of the test. The average of VO2 values obtained during the last two minutes of exercise for both exercise sessions was used for determination of exercise economy (corrected for resting VO2; RMR). V02 max was assessed during an inclined walking treadmill test to volitional fatigue. Linear regression was performed between 1/VO2 obtained during the submaximal tests and VO2max (in l/min, with and without correction for RMR; ml/kg/min; and ml/kg fat free mass/min). RESULTS: For both women and men linear regression generally revealed inverse relationships between walking/running economy and VO2max (regardless of how it was expressed). However, r2 values were routinely quite low: for walking: R2 0.01 – 0.13; for running: r2 0.03 – 0.24. CONCLUSIONS: Walking and running economy tend to vary inversely with VO2max; however, regression analysis suggests that very little of the variation in walking/running economy can be explained by maximal oxygen uptake.