EX Condition Research Articles

Obesity Promotes Marrow-Derived Myeloid Cell Accumulation while Exercise Reduces Proliferative Signaling in Colon Cancer.

Obesity increases colon cancer risk that has been previously linked to marrow-derived myeloid cells. We previously demonstrated that exercise training (EX) prevents colon cancer initiation, potentially through reduced myelopoiesis. However, it remains unknown whether early myeloid cell accumulation and inflammation in the colon precedes carcinogenesis with high-fat diet (HFD)-induced obesity, and if EX can attenuate these effects. We hypothesized that obesity would promote colon carcinogenesis that was preceded by myeloid cell accumulation and inflammation that would be attenuated by EX. C57BL/6 mice were randomized to a HFD or control (CON) diet for 8 weeks. The HFD mice switched to CON diet and all mice were given intraperitoneal injections of azoxymethane (AOM) to induce colon cancer and randomized into EX or sedentary (SED) conditions. HFD mice developed more aberrant crypt foci (ACF), a marker for early carcinogenesis, compared to CON (p < 0.01), and EX developed fewer ACF compared to SED (p < 0.0001). Marrow-derived (p < 0.001) CD206+ macrophages were elevated in HFD compared to CON at study week 16 (p < 0.01). Marrow-derived CD206- macrophages (p < 0.05) and marrow-derived (p < 0.05) CD206+ macrophages were more abundant in HFD compared to CON at study week 42. EX did not alter colon immune cell populations. β-Catenin protein was higher in HFD compared to CON at study week 42 (p < 0.05), and STAT3 protein content was lower at study week 28 with EX compared to SED (p < 0.05). The results suggest that obesity promotes colon ACF formation, potentially through early inflammatory myeloid cell accumulation. Despite attenuating ACF, EX did not alter myeloid cell accumulation in the colon, suggesting that EX inhibits ACF formation through alternative mechanisms which may include reduced β-Catenin and STAT3 signaling.

Executive function during exercise is diminished by prolonged cognitive effort in men

The speed and accuracy of decision-making (i.e., executive function (EF) domains) is an integral factor in many sports. At rest, prolonged cognitive load (pCL) impairs reaction time (RT). In contrast, exercise improves RT and EF. We hypothesized that RT and EF during exercise would be diminished by prolonged ‘dual tasking’ as a consequence of pCL. To test the hypothesis, twenty healthy male participants performed four conditions [resting control (Rest), pCL only (pCLRest), exercise only (EX), and pCL + exercise (pCLEX)] in a randomized-crossover design. Both exercise conditions utilized a 50-min cycling exercise protocol (60% VO2 peak) and the pCL was achieved via a 50-min colour-word Stroop task (CWST). Compared with Rest, pCLRest caused a slowed CWST RT (P < 0.05) and a large SD (i.e., intraindividual variability) of CWST RT (P < 0.01). Similarly, compared with EX, the slowed CWST RT (P < 0.05) and large SD of CWST RT (P < 0.01) were also observed in pCLEX. Whereas the reverse-Stroop interference was not affected in pCLRest (P = 0.46), it was larger (i.e., declined EF) in pCLEX than EX condition (P < 0.05). These observations provide evidence that the effort of pCL impairs RT and EF even during exercise.

The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.

The effects of short-term low energy availability, achieved through diet or exercise, on cognitive function in oral contraceptive users and eumenorrheic women

To date, no research has explored the effects of low energy availability (EA) on cognitive performance using dietary and exercise regimens relevant to athletes. Twenty female participants (10 eumenorrheic, 10 oral contraceptive [OC] users) completed three, 3-day conditions: 1) controlled-balanced EA without exercise (BAL; 45 kcal·kg·LBM-1·day-1), 2) diet-induced low EA without exercise (DIET; 15 kcal·kg·LBM-1·day-1) and 3) exercise-induced low EA (EX; 15 kcal·kg·LBM-1·day-1, including 30 kcal·kg·LBM-1·day-1 treadmill running at 70% V̇O2max). A cognitive test battery was completed before and after each 3-day condition. Mental rotation test accuracy improved in the BAL condition, but there was a decline in accuracy in the EX condition (BAL, +2.5%; EX, -1.4%; P = 0.042, d = 0.85). DIET (+1.3%) was not different to BAL or EX (P > 0.05). All other measures of cognitive performance were not affected by condition (P > 0.05) and OC use did not affect cognitive responses (P > 0.05). Accuracy in the mental rotation test was impaired when low EA was induced through increased exercise energy expenditure. All other aspects of cognition were unaffected by three days of low EA through diet or exercise. OC use did not mediate the effect of low EA on cognition. Novelty bullets • Cognitive function was not affected by 3 days diet-induced low energy availability (EA). • Only spatial awareness was impaired during 3 days exercise-induced low EA. • Reproductive hormones affected spatial awareness independent of EA.

Circulating Bone Biomarkers Are Altered Following A Single Bout Of Strenuous Load Carriage Exercise

Military training creates a multi-stressor environment which has been associated with risk of stress fracture. Understanding the acute bone biomarker responses to exercise can provide a model to study how various stressors or interventions affect bone and its adaptation to physical training. PURPOSE: To characterize the effects of a militarily relevant exercise on circulating bone biomarkers. METHODS: 20 Soldiers (18 male, 2 female); age 21.2±0.9 y, performed a 60 min self-paced treadmill time trial at 1% grade while wearing 30% of body weight vest (EX) and a resting control trial (CON) in a randomized, crossover design. Fasted blood samples were collected at 0630 h (AM) and EX or CON trials commenced ~0900 h. Blood samples were collected before (PRE) and after (POST) exercise, and at +1, +2, and +4 h after EX or time-matched during CON. Additionally, fasted samples were collected for the next 3 mornings at 0630 h (AM Day +1 to +3). Parathyroid hormone (PTH), ionized calcium (iCa), osteocalcin (OCN), sclerostin (SOST), C terminal propeptide of type 1 collagen (CTX), N-terminal propeptide of type 1 collagen (P1NP), bone alkaline phosphatase (BAP), and tartrate resistant acid phosphatase (TRAP5b) were assayed and all samples except AM were adjusted for changes in plasma volume from PRE. Data were analyzed using repeated measured ANOVA. Data are mean ± SE. RESULTS: Compared to PRE, PTH was significantly higher (104±32%, p<0.01) and iCa was lower (-2.5±0.8%, p<0.01) at POST during EX but not during CON. OCN was higher at +1 through +4 h than PRE by 15.9±13.0-20.5±12.0% (p<0.01) during EX but unchanged during CON. SOST was elevated by 29.1±14.2% (p<0.01) at POST vs PRE EX but later time points were not different than CON. CTX was elevated vs PRE at +1 h (43.6±22.2%, p<0.01) in EX condition only; later time points were higher (p<0.01) than PRE under both conditions. P1NP, BAP, and TRAP5b were not different from PRE during EX or CON. There were no changes in the AM Day 1-3 samples except OCN was lower than CON on Day +2 and +3. CONCLUSIONS: Consistent with prior reports, iCa decreased and PTH increased immediately post EX. Some markers of bone resorption and OCN were increased post EX. In sum, the temporal pattern of these biomarkers suggest a transient post exercise increase in resorption, but these changes disappear within 24 h after exercise.

Predictors of treatment noninitiation, dropout, and response for cognitive behavioral therapy for trauma nightmares.

This report aims to extend previous findings on predictors of treatment dropout and response within nightmare treatment. Factors predicting treatment noninitiation, dropout, and response were examined in 70 trauma-exposed individuals treated in a randomized controlled trial of 2 conditions (exposure [EX] and nonexposure) of a therapy for trauma nightmares. Together, treatment noninitiation and dropout was predicted by younger age for the EX condition only and by fewer nights with nightmares at baseline for both conditions. Treatment noninitiation was predicted by fewer nights with nightmares. Treatment dropout was not predicted by any variables. For the EX condition, more baseline nightmares predicted more posttreatment nightmares, whereas more reported nights with nightmares at baseline predicted fewer nightmares at posttreatment. Baseline sleep quality and total posttraumatic stress disorder (PTSD) severity predicted posttreatment sleep quality and PTSD severity, respectively. In the nonexposure condition, more traumatic events predicted fewer nightmares at posttreatment, whereas more nightmares predicted more nightmares at posttreatment. Baseline daytime sleepiness predicted worse posttreatment sleep quality, and total PTSD symptom severity predicted posttreatment PTSD severity. Baseline symptom severity on constructs targeted in treatment are the best indicators of response. Treatment initiation appears to be more significant than dropout. Identifying reasons for treatment noninitiation is needed to maximize engagement. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The effects of feeding back experts’ own initial ratings in Delphi studies: A randomized trial

This study examined the effects of feeding back experts’ initial ratings on three Delphi outcome measures: (1) the percentage of items on which experts changed their opinion; (2) the degree to which experts changed their ratings towards the group response; and (3) the increase in the level of agreement among experts. Additionally, two conformity indices were developed. Within a real-world Delphi study, experts were randomly assigned to one of two conditions: either their initial ratings were included in feedback (IN) or excluded from feedback (EX). Results showed that experts in the EX condition changed their opinion relatively more often than experts in the IN condition. Results also suggested that experts in the EX condition changed their ratings to a greater degree towards the group response than experts in the IN condition. No difference between conditions was found regarding the increase in the level of agreement.

Feasibility of Pairing Behavioral Activation With Exercise for Women With Type 2 Diabetes and Depression: The Get It Study Pilot Randomized Controlled Trial

Major depressive disorder is often comorbid with diabetes and associated with worse glycemic control. Exercise improves glycemic control and depression, and thus could be a parsimonious intervention for patients with comorbid diabetes and major depression. Because patients with diabetes and comorbid depression are often sedentary and lack motivation to exercise, we developed a group exercise intervention that integrates strategies from behavioral activation therapy for depression to increase motivation for and enjoyment of exercise. We conducted a 6-month pilot randomized controlled trial to test the feasibility of the behavioral activation exercise intervention (EX) for women with diabetes and depression. Of the 715 individuals who contacted us about the study, 29 participants were randomized to the EX condition or an enhanced usual care condition (EUC), which represents 4.1% of participants who initially contacted us. Inclusion criteria made recruitment challenging and limits the feasibility of recruiting women with diabetes and depression for a larger trial of the intervention. Retention was 96.5% and 86.2% at 3 and 6months. Participants reported high treatment acceptability; use of behavioral activation strategies and exercise class attendance was acceptable. No condition differences were observed for glycemic control, depressive symptoms, and physical activity, though depressive symptoms and self-reported physical activity improved over time. Compared to participants in the EUC condition, participants in the EX condition reported greater exercise enjoyment and no increase in avoidance behavior over time. Using behavioral activation strategies to increase exercise is feasible in a group exercise setting. However, whether these strategies can be delivered in a less intensive manner to a broader population of sedentary adults, for greater initiation and maintenance of physical activity, deserves further study.

Reduced neural response to food cues following exercise is accompanied by decreased energy intake in obese adolescents.

Acute exercise has been found to favor a transient anorexigenic effect in obese adolescents. Although the role of some gastro-peptides has been suggested as an explanation for this observed reduced energy intake after exercise, it is unknown whether neural pathways involved in the regulation of food intake are modulated in youth. Body composition (dual-energy X-ray absorptiometry) and aerobic capacities were assessed in 19 obese adolescent boys. Participants were randomized to remain at rest in a sitting position (CON condition) or to exercise 45 min at 65% of their maximal capacities (EX condition) by the end of the morning. An attentional computer task with electroencephalography recording was completed immediately after the exercise or sitting period to measure an event-related component (P3b) reflecting the level of cognitive engagement in the processing of food cues. A lunch test-meal was offered ad libitum and appetite feelings assessed at regular intervals using visual analog scales. The 45-min cycling exercise set at 65% VO2max induced a mean energy expenditure of 399±75 kcal. Both absolute (P<0.05) and relative (P<0.001) subsequent energy intake were significantly reduced after EX (1037±260 and 639±256 kcal, respectively) compared with CON (1116±243 and 1011±239 kcal, respectively). The energy ingested derived from each macronutrient and self-reported appetite remained unchanged. Although the amplitudes of the P3b component evoked by food and non-food visual stimuli were not significantly different during CON, the response to food cues was significantly reduced compared with non-food stimuli after exercise (P<0.01). An acute exercise favors decreased neural response to food cues compared with non-food ones in obese adolescents that may contribute to their subsequently reduced energy intake.

Verbal Instructions Acutely Affect Drop Vertical Jump Biomechanics--Implications for Athletic Performance and Injury Risk Assessments.

Biomechanical quantities acquired during the drop vertical jump (DVJ) are used in the assessment of athletic performance and injury risk. The objective was to examine the impact of different verbal instructions on spatiotemporal, kinematic, and kinetic variables commonly included in such assessments. Ten men and 10 women from local varsity and club volleyball, basketball, figure skating, and track and field teams volunteered to participate. The athletes performed DVJs after given instructions to minimize ground contact time (CT), maximize jump height (HT), and synchronously extend the lower extremity joints (EX). Between the CT, HT, and EX conditions, body segment and joint angles were compared together with characteristics of vertical ground reaction force (GRF), whole-body power output, stiffness, and center-of-mass displacement time histories. Verbal instructions were found to influence nearly all of the spatiotemporal, body segment and joint kinematic, and kinetic variables that were statistically analyzed. Particularly noteworthy was the finding that athletic performance indices (e.g., jump height, power output, vertical stiffness, and reactive strength index) and lower extremity injury risk markers (e.g., peak vertical GRF and frontal plane knee angle) were significantly different (p ≤ 0.05) between the CT, HT, and EX conditions. The findings of this study suggest that verbal instructions should be controlled and/or clearly documented when using the DVJ to assess athletic performance potential and injury risk. Moreover, practitioners who devise performance enhancement and injury prevention strategies based on DVJ assessments are advised to consider that "coaching" or "cueing" during the task execution could impact conclusions drawn.

The Effect of Physical Activity on Post-Prandial Triglycerides and Airway Inflammation Following a High-Fat Meal

Recent studies have confirmed that a single high-fat meal (HFM) leads to increased triglycerides and airway inflammation, which may be attenuated by chronic exercise training or an acute bout of exercise. PURPOSE: To investigate whether an acute bout of moderate intensity exercise following a HFM would attenuate post-prandial lipemia (PPL) and airway inflammation in both inactive and active subjects. METHODS: Thirty-five, college-aged subjects took part in the study. Twenty subjects (13M/7F) exceeded physical activity (PA) guidelines (≥150 minutes moderate-vigorous PA/week) and fifteen subjects (5M/10F) did not meet PA guidelines. At the first visit, subjects underwent DEXA scans, pulmonary function tests, and an incremental test to exhaustion to determine VO2peak. On the second visit, subjects were randomized to the control condition ((ACT CON (n=10) or IN CON (n=6)) or the exercise condition ((ACT EX (n=10) or IN EX (n=9)). The EX condition performed the exercise bout (60%VO2peak; ∼30-135 minutes) on a treadmill 45 minutes post-HFM (63% fat, 10kcal/kg of body weight). Blood lipids and exhaled nitric oxide (eNO) were measured at baseline and 2 h and 4 h post-HFM. Sputum differential cell counts were performed at baseline and 4 h post-HFM to assess airway inflammation. RESULTS: Triglycerides increased significantly in ACT CON and ACT EX 2 h (∼54%, p=0.001; ∼66%, p=0.013, respectively) and 4 h (∼107%, p=0.001; ∼119%, p=0.004, respectively) post-HFM and also IN CON at 4 h (∼44%; p= 0.004) and IN EX (2 h, ∼62%, p= 0.001; 4 h, ∼93%, p=0.001) post-HFM. Area under the curve (AUC) was significantly lower in ACT EX (p<0.001) than ACT CON and IN EX, but was not significantly different in IN CON versus IN EX (p>0.05). Exhaled nitric oxide increased non-linearly from baseline to 2 and 4 h post-HFM in ACT (p<0.05, η2=0.36) and IN (<0.05), but was not dependent on condition. CONCLUSION: Preliminary findings suggest that in both active and inactive subjects, an exercise bout after a HFM did not reduce post-prandial airway inflammation. However, the exercise bout was effective in reducing PPL in active subjects, but not inactive subjects. Post-prandial airway inflammation occurred following a high-fat meal regardless of a reduction in post-prandial triglycerides.

Does Vo2peak Moderate The Association Between Dietary Fat Intake And Post-prandial Fat Oxidation?

Previous evidence suggests that individuals with low fat oxidation rates at rest may be prone to developing obesity and diabetes. Both exercise training and a high-fat diet are known to increase fat oxidation. It is unclear, however, whether exercise training influences the relationship between dietary fat intake and post-prandial (PP) fat oxidation. PUPROSE: The purpose of this study was to determine whether VO2peak moderates the association between dietary fat intake and PP fat oxidation after a high-fat meal. METHODS: Twenty-nine healthy young adults (17 M, aged 19–38 yrs) of varying aerobic capacities (VO2peak= 49.4±11.1 ml/kg/min) were randomized to either a moderate-intensity walking or sedentary condition. In the EX condition, walking was performed 60min PP (EX, energy expenditure 50% of breakfast kcals). After a 12hr fast, all participants consumed a high-fat breakfast (65% fat, 10 kcal/kgbw). Resting metabolic rate was assessed immediately after, and 200min following, consumption of the high-fat meal. Assessments included dietary fat via 3-day food log, VO2peak with a treadmill ramp protocol to exhaustion, indirect calorimetry with a ventilated hood system to determine fat oxidation at 0min and 200min PP, and %body fat via DEXA. RESULTS: Dietary fat intake was 798.6±235.4 kcal/day. Fat oxidation at baseline was not different from 200min PP (47.9±16.4 vs. 50.7±17.8 kcal/hr, p>0.05). There was a significant correlation between dietary fat intake and 200min PP fat oxidation (r=0.37, p<0.05) and between VO2peak and 200min PP fat oxidation (r=0.62, p<0.01). Moderation analysis examining the effect of VO2peak on the association between dietary fat intake and PP fat oxidation revealed no significant moderation (ΔR2=0.007, p=0.60). A subsequent linear regression, including VO2peak, dietary fat intake, %body fat, baseline fat oxidation, and energy balance PP (kcals); predicted 79% of the variance in PP fat oxidation (adjusted R2= 0.79, p<0.001). CONCLUSION: VO2peak did not moderate the association between dietary fat intake and PP fat oxidation. When examining additional factors thought to be associated with fat oxidation, however, 79% of the variance in PP fat oxidation was explained. These results indicate that post-prandial fat oxidation is a complex process with multiple contributing factors.

Effect of an exercise training intervention with resistance bands on blood cell counts during chemotherapy for lung cancer: a pilot randomized controlled trial.

PurposeChemotherapy for lung cancer can have a detrimental effect on white blood cell (WBC) and red blood cell (RBC) counts. Physical exercise may have a role in improving WBCs and RBCs, although few studies have examined cancer patients receiving adjuvant therapies. The purpose of this pilot trial was to examine the effects of an exercise intervention utilizing resistance bands on WBCs and RBCs in lung cancer patients receiving curative intent chemotherapy.MethodsA sample of lung cancer patients scheduled for curative intent chemotherapy was randomly assigned to the exercise intervention (EX) condition or usual care (UC) condition. The EX condition participated in a three times weekly exercise program using resistance bands for the duration of chemotherapy.ResultsA total of 14 lung cancer patients completed the trial. EX condition participants completed 79% of planned exercise sessions. The EX condition was able to maintain WBCs over the course of the intervention compared to declines in the UC condition (p = .008; d = 1.68). There were no significant differences in change scores in RBCs.ConclusionsExercise with resistance bands may help attenuate declines in WBCs in lung cancer patients receiving curative intent chemotherapy. Larger trials are warranted to validate these findings. Ultimately these findings could be informative for the development of supportive care strategies for lung cancer patients receiving chemotherapy.Trial registrationClinical Trials Registration #: NCT01130714.

Effect of Evening Postexercise Cold Water Immersion on Subsequent Sleep

This study investigated the effect of cold water immersion after evening exercise on subsequent sleep quality and quantity in trained cyclists. In the evenings (~1900 h) on three separate occasions, male cyclists (n = 11) underwent either no exercise (control, CON), exercise only (EX), or exercise followed by cold water immersion (CWI). EX comprised cycling for 15 min at 75% peak power, then a 15-min maximal time trial. After each condition, a full laboratory-based sleep study (polysomnography) was performed. Core and skin temperature, heart rate, salivary melatonin, ratings of perceived fatigue, and recovery were measured in each trial. No differences were observed between conditions for any whole night sleep measures, including total sleep time, sleep efficiency, sleep onset latency, rapid eye movement onset latency, wake after sleep onset, or proportion of the night spent in different sleep stages. Core temperature in EX and CWI trials was higher than CON, until it decreased below that of EX and CON until bedtime in CWI. After bedtime, core temperature was similar for all conditions throughout the night, except for a 90-min period where it was lower for CWI than EX and CON (3.5-4.5 h postexercise). Heart rates for EX and CWI were both significantly higher than CON postexercise until bedtime, whereas skin temperature after CWI was significantly lower than EX and CON, remaining lower than EX until 3 h postexercise. Melatonin levels and recovery ratings were similar between conditions. Fatigue ratings were significantly elevated after exercise in both CWI and EX conditions, with EX still being elevated compared with CON at bedtime. Whole night sleep architecture is not affected by evening exercise alone or when followed by CWI.

Satiety, but not total PYY, Is increased with continuous and intermittent exercise

ObjectiveThis study determined the hormonal and subjective appetite responses to exercise (1-h continuous v. intermittent exercise throughout the day) in obese individuals.Design and MethodsEleven obese subjects (>30 kg/m2) underwent 3, 12-hour study days: control condition (sedentary behavior-SED), continuous exercise condition ((EX) 1-h exercise), and intermittent exercise condition ((INT) 12 hourly, 5-minute bouts). Blood samples (every 10 min) were measured for serum insulin and total peptide YY (PYY) concentrations, with ratings of appetite (visual analog scale-VAS: every 20 minutes). Both total area under the curve (AUC), 2-h AUC and AUC above baseline, and subjective appetite ratings were calculated.ResultsNo differences were observed in total PYY AUC between conditions, but hunger was reduced with INT (INT<EX; P<0.05), and satiety was increased with both SED and INT conditions (INT>EX and SED>EX; P<0.05). A correlation existed between the change in total PYY and insulin levels (r=−0.81; P<0.05), and total PYY and satiety (r=0.80; P<0.05) with the EX condition, not the SED and INT conditions.ConclusionThe total PYY response to meals is not altered over the course of a 12-h day with either intermittent or continuous exercise; however, intermittent exercise increased satiety and reduced hunger to a greater extent than continuous exercise in obese individuals.

Effects of Diets Supplemented with Branched-Chain Amino Acids on the Performance and Fatigue Mechanisms of Rats Submitted to Prolonged Physical Exercise

This study aimed to determine the effects of diets chronically supplemented with branched-chain amino acids (BCAA) on the fatigue mechanisms of trained rats. Thirty-six adult Wistar rats were trained for six weeks. The training protocol consisted of bouts of swimming exercise (one hour a day, five times a week, for six weeks). The animals received a control diet (C) (n = 12), a diet supplemented with 3.57% BCAA (S1) (n = 12), or a diet supplemented with 4.76% BCAA (S2) (n = 12). On the last day of the training protocol, half the animals in each group were sacrificed after one hour of swimming (1H), and the other half after a swimming exhaustion test (EX). Swimming time until exhaustion was increased by 37% in group S1 and reduced by 43% in group S2 compared to group C. Results indicate that the S1 diet had a beneficial effect on performance by sparing glycogen in the soleus muscle (p < 0.05) and by inducing a lower concentration of plasma ammonia, whereas the S2 diet had a negative effect on performance due to hyperammonemia (p < 0.05). The hypothalamic concentration of serotonin was not significantly different between the 1H and EX conditions. In conclusion, chronic BCAA supplementation led to increased performance in rats subjected to a swimming test to exhaustion. However, this is a dose-dependent effect, since chronic ingestion of elevated quantities of BCAA led to a reduction in performance.

The effect of physical (in)activity on blood pressure and splanchnic sympathetic nerve responses to inhibition of the RVLM

A sedentary lifestyle is a major risk factor for cardiovascular disease (CVD). CVD is often associated with enhanced activation of the sympathetic nervous system. The sympathetic nervous system is under tonic and phasic control by the rostral ventrolateral medulla (RVLM). In sedentary rats, there is enhanced sympathoexcitation in response to glutamatergic activation of the RVLM. Since the activity of RVLM is tonically restrained by γ‐amino‐butyric acid (GABA), we hypothesized that sedentary conditions may also lead to decreased responsiveness to GABA in RVLM when compared to physically active conditions. In Inactin anesthetized, sedentary (SED) or physically active (EX) rats, mean arterial pressure (MAP), heart rate (HR) and splanchnic sympathetic nerve activity (sSNA) were recorded during unilateral microinjection of GABA (30 nl, 0.3–600 mM) into the RVLM. Following GABA injections, the contralateral RVLM was inhibited with 90 nl of 2mM Muscimol and the GABA injections were repeated. There were no significant differences between SED or EX conditions for MAP, HR and sSNA responses to GABA both before and after contralateral blockade of the RVLM. Based on our results the enhanced sympathoexcitation seen in our sedentary model is not due to reduced responsiveness to GABA and may be due to enhanced responsiveness to excitatory neurotransmission. (Supported by R01‐HL096787; R01‐HL096787‐S1)

Association of Reduction in Waist Circumference with Normalization of Mood in Obese Women Initiating Exercise Supported by the Coach Approach Protocol

Interrelations of exercise, mood, and weight reduction are unclear in the behavioral treatment of obesity. Obese women volunteers with high tension (anxiety) (T), depression (D), or total mood disturbance (TMD) scores, who were previously randomized into conditions of (1) exercise supported by The Coach Approach: a protocol based on social cognitive and self-efficacy theory (CA; n = 53, 66, and 60, respectively), (2) personal demonstration and follow up of exercise methods (EX; n = 27, 27, and 21, respectively), and (3) exercise suggested through written information only (INFO; n = 24, 28, and 20, respectively), were subjects. Identical nutrition information was provided to all subjects in a small group format. Minutes of exercise over the 6-month study were greatest in the CA condition, with minutes in the EX condition greater than the INFO condition. T, D, and TMD scores were reduced to normal levels mostly in the CA condition, with the EX condition having significantly more normalized D scores than the INFO. Across conditions, normalized mood scores generally predicted a greater reduction in waist circumference, with CA associated with additional benefits when D scores were considered. Properly accounting for exercise-induced mood change may be important in the behavioral treatment of obesity.

Nocturnal growth hormone secretory dynamics are altered after resistance exercise: deconvolution analysis of 12-hour immunofunctional and immunoreactive isoforms

To characterize the effects of daytime exercise on subsequent overnight growth hormone (GH) secretion and elimination dynamics, serum was sampled, and GH was measured every 10 min for 12 h (1800 to 0600) in a control (CON) condition and after a 50-set resistance exercise protocol (EX) from 1500 to 1700. GH was measured with a conventional immunoreactive (IR) and an immunofunctional (IF) assay, and values were analyzed via a multi-parameter deconvolution analysis. EX resulted in a higher overnight secretory burst frequency [CON: 7.6 (SD 2.4) < EX: 9.4 (2.2) bursts per 12 h, P = 0.005] but lower mean burst mass [CON: 9.2 (4.7) > EX: 6.0 (2.9) microg/l, P = 0.019] and secretory rate [CON: 0.68 (0.29) > EX: 0.48 (0.23) microg/l/min; P = 0.015; ANOVA main effect means presented]. Approximate entropy (ApEn) was greater after EX, indicating a less orderly GH release process than CON. The estimated half-life of IF GH was significantly lower than IR GH [IF: 15.3 (1.1) < IR 19.8 (1.6) min, P < 0.001] but similar between the CON and EX conditions (approximately 17 min). Despite the changes in secretory dynamics, 12-h mean and integrated GH concentrations were similar between conditions. The results suggest that although quantitatively similar total amounts of GH are secreted overnight in CON and EX conditions, resistance exercise alters the dynamics of secretion by attenuating burst mass and amplitude yet increasing burst frequency.

Effect of chronic supplementation with branched-chain amino acids on the performance and hepatic and muscle glycogen content in trained rats

The objective of this study was to evaluate the effects of a diet supplemented with branched-chain amino acids (BCAA; 3.57% and 4.76%) on the performance and glycogen metabolism of trained rats. Thirty-six adult male Wistar rats received the control diet (AIN-93M) ( n = 12) and two diets supplemented with BCAA (S1: AIN-93M + 3.57% BCAA, n = 12, and S2: AIN-93M + 4.76% BCAA, n = 12) for 6 weeks. The training protocol consisted of bouts of swimming exercise (60 min day −1) for 6 weeks at intensities close to the lactate threshold. On the last day of the experiment, all groups were trained for 1 h (1H) or were submitted to the exhaustion test (EX). The time to exhaustion did not differ between groups. The groups submitted to the exhaustion test presented a reduction in plasma glucose and an increase in plasma ammonia and blood lactate concentrations compared to the 1H condition. In the 1H condition, hepatic glycogen concentration was significantly higher in group S2 compared to the control diet and S1 groups (132% and 44%, respectively). Group S2 in the 1H condition presented a higher muscle glycogen concentration (45%) compared to the control diet group. In the EX condition, a significantly higher hepatic glycogen concentration was observed for group S2 compared to the control diet and S1 groups (262% and 222%, respectively). Chronic supplementation with BCAA promoted a higher hepatic and muscle glycogen concentration in trained animals, with this effect being dose dependent.