Exercise VO2max Research Articles

Acute salivary antimicrobial peptide secretion response to different exercise intensities and durations.

Antimicrobial peptides, key players of innate mucosal immunity in the oral cavity, exert antibacterial and bacteriolytic effects. This study aimed to clarify the effects of acute exercise at different intensities and durations on salivary antimicrobial peptide levels. In a randomized crossover trial, 14 young healthy untrained men performed intensity trials (cycling at 35%, 55%, and 75% of maximal oxygen uptake [VO2max] for 30 min) and duration trials (cycling at 55% VO2max for 30, 60, and 90 min). Saliva samples were collected at baseline and 0 and 60 min after exercise. In intensity trials, the change in salivary Lactoferrin levels from baseline to 0 min after 30-min exercise was greater at 75% VO2max exercise intensity compared to that at 35% VO2max. Furthermore, the change in salivary human beta defensin-2 (HBD-2) levels was greater at 75% VO2max compared to that at 35% and 55% VO2max. Salivary Lysozyme levels increased after exercise, independent of exercise intensity. However, salivary LL-37 levels did not change after exercise at any intensity. Additionally, in duration trials, the change in salivary levels of LL-37 and HBD-2 from baseline to 0 min after exercise at 55% VO2max was greater after 60 min and 90 min of exercise compared to that after 30 min of exercise. However, salivary Lactoferrin and Lysozyme levels increased after exercise, independent of exercise duration. Our findings suggest that secretory responses to acute exercise with exercise intensity and duration differ among salivary antimicrobial peptides.

The Utilization of Body Composition to Predict Cardiorespiratory Fitness and Determine Association with CKD Stage in Individuals with Mid-Spectrum CKD: A Pilot Study

Body composition (BC), a measure of body fat mass (FM), lean body mass (LBM), and bone mineral content (BMC), can be used as a predictor of cardiorespiratory fitness (CRF). Prior studies have established a relationship between BC and VO2max in healthy individuals over 35 years of age. However, this relationship is poorly understood in chronic disease populations. The focus of the study was to assess the relationship between BC, cardiorespiratory fitness, and chronic kidney disease (CKD). A cross-sectional analysis was conducted among 24 (9 males and 15 females) individuals diagnosed with mid-spectrum CKD (stages G2–G3b) who completed a health screening, dual-energy X-ray absorptiometry (DEXA) scan, and underwent a VO2max exercise test. Normality tests, descriptive statistics, Pearson’s correlations, t-tests, and ANOVAs were conducted in SAS v.9.4. The average percent body fat (%BF) was 36.28 ± 8.47%, LBM was 109.4 ± 29.1 lb, BMC was 2308.7 ± 735.1 g, and VO2max was 20.13 ± 5.04 mL/kg/min−1. BC was able to predict CRF via VO2max (R2 = 0.721, p < 0.001) and CKD stage (R2 = 0.390, p < 0.017). Positive correlations were observed in LBM (r = 0.750, p < 0.0018) and BMC (r = 0.647, p < 0.001), and negative correlations were observed with FM (r = −0.384, p < 0.032) and %BF (r = −0.802, p < 0.0001). BC was able to predict both CRF and CKD stages, with significant associations observed between BC, VO2max, and CKD stage. The progression of the CKD stage was associated with lower LBM, BMC, and VO2max values, indicating a graded effect of BC on CRF and CKD stage.

Lower mitochondrial respiration does not lead to decreased fat oxidation in young African American women without obesity.

The prevalence of type 2 diabetes in African American women (AAW) is nearly twice that of White women. Lower insulin sensitivity and decreased mitochondrial function may be contributing factors. The purpose of this study was to compare fat oxidation in AAW and White women. Participants were 22 AAW and 22 White women, matched for age (18.7-38.3 years) and BMI (< 28 kg/m2). Participants completed two submaximal (50% VO2max) exercise tests with indirect calorimetry and stable isotope tracers to assess total, plasma, and intramyocellular triglyceride fat oxidation. The respiratory quotientduring the exercise test was nearly identical in AAW and White women (0.813 ± 0.008 vs. 0.810 ± 0.008, p=0.83). Although absolute total and plasma fat oxidation was lower in AAW, adjusting for the lower workload in AAW eliminated these racial differences. There was no racial difference in plasma and intramyocellular triglyceride source of fat for oxidation. No racial differences were observed in rates of ex vivo fat oxidation. Exercise efficiency was lower in AAW when adjusted to leg fat free mass. The data suggest that fat oxidation is not lower in AAW compared with White women, but additional studies are needed across exercise intensity, body weight, and age to confirm these results.

EFEITOS DO EXERCÍCIO SOBRE O METABOLISMO ENERGÉTICO HUMANO EM AMBIENTES DE ALTA TEMPERATURA E UMIDADE

ABSTRACT Introduction Many exercise enthusiasts have started participating in sports in the high-temperature environment in recent years due to the increasing popularity of these sports habits. However, their scientific studies still have a gap in their safety and effectiveness. Objective Measure the energy supply characteristics of fat and sugar oxidation during exercise in different high-temperature and humidity environments. Methods 20 healthy adult subjects were exposed to fixed-intensity exercise for 20 minutes at 30-33 oC, 20% relative humidity (RH), and 50% RH, respectively. Results Under the silent exposure condition, compared with RH 20% and RH 50% under high temperature, sugar oxidation was significantly increased (P&lt;0.01), while fat oxidation was significantly reduced (P&lt;0.01), and total energy consumption was significantly increased (P&lt;0.01). Under the condition of 65% VO2 max exercise, compared with RH 20% and RH 50% at high temperatures, the amount of sugar oxidation was significantly reduced (P&lt;0.05), and the total energy consumption was significantly reduced (P&lt;0.05). Conclusion Under 65% exercise under VO2 max in the high temperature and humidity-controlled environment, the high temperature and medium humidity (RH 50%) environment consumes more energy, and there is a greater amount of sugar oxidation. Level of evidence II; Therapeutic studies - investigating treatment outcomes.

Maximum Aerobic Exercise Induces Common Carotid Vasoconstriction And Increased Vascular Resistance

Michael Diaz, Zaria Opara, Heysel Morales, Steven Hawkins, Louise Kelly, Allan Knox PURPOSE: Low-to-moderate intensity aerobic exercise has been reported to elicit changes in systemic hemodynamics. Recent evidence suggests that the cerebral circulation reacts independently to systemic circulations to the same physiological stimuli. The aim of this is to determine the influence of high-intensity aerobic exercise on common carotid artery (CCA) hemodynamics. METHODS: Hemodynamic measurements were recorded before and following the cessation of a maximum oxygen uptake test (VO2max). One minute video of the CCA by Doppler ultrasound were recorded and used to determine peak systolic velocity (PSV), end diastolic velocity (EDV), time averaged mean blood velocity (TAMEAN), timed average maximum velocity (TAMAX), pulsatility index (PI), and resistance index (RI). CCA diameters were calculated by commercially available vessel tracking software. Carotid stiffness index (β), Peterson’s pressure modulus (Ep), arterial compliance (AC) was also calculated. RESULTS: A total of 29 individuals, 14 male and 15 females, participated in this study (21.9 ± 3.9 years). Following the cessation of exercise, PSV (p < 0.001), TAMAX (p = 0.0085), RI (p < 0.001), and PI (p = 0.0032) significantly increased whilst the minimum diameter (p = 0.005), and maximum diameter (p = 0.020) decreased. No changes were observed for β (p = 0.491), Ep (p = 0.834) or AC (p = 0.535). CONCLUSION: The results show hemodynamic changes in the CCA following VO2max exercise. Specifically, increases in vascular resistance are likely due to the reductions in arterial diameter, which may be evident downstream of the CCA. Acute maximal aerobic exercise does not change CCA stiffness parameters.

Analysis Of The Effect Of Different Exercise Intensities On Blood Glucose

PURPOSE: To examine the changes in blood glucose(GLu) before and after different intensities-based exercise interventions in healthy university students, and provide a reference for the development of precise exercise prescriptions. METHODS: Nine healthy male college students without regular exercise habits were recruited. using a power bike (Monark 839E) with built-in Astrand to test VO2max and then to formulate 70%, 80%, and 90% VO2max intensities. Before each experiment, a high degree of consistency in each subject's meal was ensured. Exercise intervention was performed at 40 min postprandial (one week interval between each exercise intervention). First, fasting Plasma Glucose(FPG)was tested, then GLu was tested before exercise, and instant, 30 min, 60 min, and 120 min after exercise. RESULTS: (1) 40 min postprandial, instant after exercise and 60 min after exercise compared with FPG for the three intensities (P < 0.05), but not significant for 60 min after exercise at 80% VO2max intensity (p > 0.05). (2) 30 min and 60 min after exercise compared with immediate after exercise GLu (P < 0.01); 120 min after exercise (P < 0.05), but not significant at 70% VO2max intensity 120 min after exercise(p > 0.05). (3) There was no significant difference (p > 0.05) between the time points of the three intensities and the interaction measurements of exercise intensity, which proved that the changes in GLu under the three intensity exercise interventions were basically in the same direction. GLu changes within 120 min after different intensity exercise were consistent, i.e. GLu decreased instant after exercise, increased 30 min after exercise, and then decreased with time. But, there was no significant difference (p > 0.05) among the various time points of the changes in GLu for 70%, 80% and 90% VO2max exercise. CONCLUSIONS: (1) GLu changes in a similar trend, first decreased, increased and then decreased after different exercise intensities. (2) There is a certain trend of GLu changing with exercise intensity after exercise, that is, the greater the intensity of exercise, the more obvious the GLu drop after exercise, but there is no statistical significance, but there is a trend that the greater the intensity of intervention exercise, the more obvious the GLu drop.

No Sex Differences In Common Carotid Artery Stiffness Response Following Maximal Oxygen Consumption Test

No Sex Differences in Common Carotid Artery Stiffness Response Following Maximal Oxygen Consumption Test HEYSEL MORALES, MICHAEL DIAZ, ZARIA OPARA, STEVEN HAWKINS, LOUISE KELLY, ALLAN KNOX. PURPOSE: Previous investigations have reported sex differences in the time course of age-related arterial stiffness, with postmenopausal women presenting increased risk of cardiovascular diseases. Using sex as a biological variable has identified differences between males and females in physiological responses to equivalent doses of exercise. The purpose of this study was to determine if sex differences exist in arterial stiffness response to a maximum oxygen consumption (VO2max) exercise test. METHODS: VO2max was measured by indirect calorimetry. Body composition was measured by air displacement plethysmography (BODPOD). Indices of common carotid artery (CCA) stiffness (Peterson’s elastic modulus [Ep], Beta stiffness [B1], distensibility [DIST], and diameter compliance [DC]) were calculated before and within 5 minutes following VO2max. CCA’s were imaged for 1 minute by duplex Doppler ultrasound approximately 2-3cm below bifurcation and stored for offline analysis of velocities and diameters. Brachial blood pressures were captured by automated cuff. RESULTS: Males (n=14) and females (n=15) were matched for age (p=0.549), fat mass (p =0.775), body fat percentage (p=0.08), fat free mass percentage (p=0.087), and VO2max (p=0.349). Males had higher body mass (p < 0.001) and fat free mass (p<0.001). No sex differences were observed before or after exercise for Ep, B1, DIST, and DC (p >0.05 for all). No sex differences were identified for delta changes in any CCA stiffness indices (p >0.05). CONCLUSION: The CCA response to VO2max test is equivalent in males and females who are matched for baseline VO2max, despite males presenting high fat free masses. Previously reported sex differences in response to equivalent exercise dose may not be evident in the CCA stiffness characteristics.

EFFECTS OF STATINS ON SUBSTRATE UTILIZATION DURING EXERCISE

PURPOSE: Statin is the most prescribed medicine worldwide to lower cardiovascular risk. Its blood triglyceride lowering effect, may limit fat mobilization/oxidation during exercise. METHODS: Nine individuals with metabolic syndrome, chronically treated with statins to correct their dyslipidemia exercised at three increasing intensities (40, 70, and 85% VO2 MAX) while taking statins or placebo using a randomized double-blind crossover design. Indirect calorimetry and stable isotope tracer techniques were combined to assess plasma substrate kinetic and oxidation. RESULTS: As expected, statin use lowered resting plasma triglyceride concentration (i.e., PLAC 1.4±0.7 vs STAT 1.1±0.5 mmol·L-1, p = 0.003), and also plasma triglyceride concentration during exercise (i.e., PLAC 1.7±0.8 vs STAT 1.2±0.5 mmol·L-1; p < 0.001). Ra glycerol (i.e., index of whole-body lipolysis) increased along with exercise intensity but the increase was attenuated by statins (p < 0.014) at the 85% VO2 MAX exercise intensity (i.e., PLAC 7.4±1.9 vs STAT 5.8±2.2 mM·kg·min-1; p = 0.046). This 21% lower lipolysis during STAT did not limit fat oxidation that was similarly low in PLAC and STAT (i.e., PLAC 0.7±2.1 vs STAT 0.8±2.2 mM·kg·min-1; p = 0.459). STAT increased resting plasma glucose concentration (i.e., PLAC 6.6±1.6 vs STAT 6.8±1.6 mmol·L-1, p = 0.036) but did not affect exercise glucose or insulin plasma. Rates of glucose appearance (i.e., Ra glucose, index of liver glucose output) were similar during PLAC and STAT at rest and during exercise. Glucose disappearance rates increased during the first two exercise intensities (i.e., 40 and 70% VO2 MAX), but decreased in both groups at 85% VO2 explaining the ensuing hyperglycaemia at this intensity. CONCLUSIONS: Statin reduces exercise lipolysis during high intensity exercise, without affecting the already low rates of fat oxidation at that intensity. However, statin use does not affect plasma glucose kinetics or carbohydrate oxidation during exercise in a wide range of intensities in individuals chronically medicated with this drug.

Skin Blood Flow Responses to Acetylcholine, Local Heating, and to 60% VO2max exercise with and without Nitric Oxide inhibition, in Boys vs. Girls.

To determine sex-related differences in the skin blood flow (SkBF) response to exercise, local heating, and acetylcholine (ACh) in children, and to assess nitric oxide contribution to the SkBF response. Forearm SkBF during local heating (44°C), ACh iontophoresis, and exercise (30-min cycling and 60% of maximum oxygen consumption) was assessed, using laser Doppler fluxmetry, in 12 boys and 12 girls (7-13y old), with and without nitric oxide synthase inhibition, using Nω-nitro-L-arginine methyl ester iontophoresis. Local-heating-induced and ACh-induced SkBF increase were not different between boys and girls (local heating: 1445% [900%] and 1432% [582%] of baseline, P = .57; ACh: 673% [434%] and 558% [405%] of baseline, respectively, P = .18). Exercise-induced increase in SkBF was greater in boys than girls (528% [290%] and 374% [192%] of baseline, respectively, P = .03). Nω-nitro-L-arginine methyl ester blunted the SkBF response to ACh and during exercise (P < .001), with no difference between sexes. SkBF responses to ACh and local heat stimuli were similar in boys and girls, while the increase in SkBF during exercise was greater in boys. The apparent role of nitric oxide was not different between boys and girls. It is suggested that the greater SkBF response in boys during exercise was related to greater relative heat production and dissipation needs at this exercise intensity. The response to body size-related workload should be further examined.

Changes in the Second Ventilatory Threshold Following Individualised versus Standardised Exercise Prescription among Physically Inactive Adults: A Randomised Trial.

The second ventilatory threshold (VT2) is established as an important indicator of exercise intensity tolerance. A higher VT2 allows for greater duration of higher intensity exercise participation and subsequently greater reductions in cardiovascular disease (CVD) risk. This study aimed to compare the efficacy of standardised and individualised exercise prescription on VT2 among physically inactive adults. Forty-nine physically inactive male and female participants (48.6 ± 11.5 years) were recruited and randomised into a 12-week standardised (n = 25) or individualised (n = 24) exercise prescription intervention. The exercise intensity for the standardised and individualised groups was prescribed as a percentage of heart rate reserve (HRR) or relative to the first ventilatory threshold (VT1) and VT2, respectively. Participants were required to complete a maximal graded exercise test at pre-and post-intervention to determine VT1 and VT2. Participants were categorised as responders to the intervention if an absolute VT2 change of at least 1.9% was attained. Thirty-eight participants were included in the analysis. A significant difference in VT2 change was found between individualised (pre vs. post: 70.6% vs. 78.7% maximum oxygen uptake (VO2max)) and standardised (pre vs. post: 72.5% vs. 72.3% VO2max) exercise groups. Individualised exercise prescription was significantly more efficacious (p = 0.04) in eliciting a positive response in VT2 (15/19, 79%) when compared to the standardised exercise group (9/19, 47%). Individualised exercise prescription appears to be more efficacious than standardised exercise prescription in eliciting a positive VT2 change among physically inactive adults. Increasing VT2 allows for greater tolerance to higher exercise intensities and therefore greater cardiovascular health outcomes.

492-P: Glucose Level Recommendations for Vo2 Max Exercise Testing in Adolescents with Type 1 Diabetes

Glucose level recommendations have yet to be established for adolescents diagnosed with type 1 diabetes (T1D) who participate in VO2 max exercise testing for clinical or strength and conditioning purposes. Although a decrease in glucose may be expected throughout, and immediately after exercise testing, a minimal pre-test glucose setpoint has not been established to reduce the risk of hypoglycemia. Retrospective medical and sports medicine chart reviews were conducted of clinical pediatric sports medicine and physical activity program patients with a diagnosis of T1D (N = 24; mean age = 15.5 ± 1.7 years; male = 14, 58.3%) who participated in a modified Bruce protocol for maximal oxygen uptake (VO2 max). The majority of the participants identified as non-Hispanic (n = 22, 91.7%) and white (n = 19, 79.2%). Their average body mass index (BMI) based on age and sex was in the 66th percentile ± 19.5 and their average hemoglobin A1c (HbA1c) was 8.8% ± 1.8. Almost 2/3 of the participants (n = 15, 62.5%) wore a continuous glucose monitor. Their average VO2 max peak was 43.7 ml/kg/min ± 7.1. A paired-samples t-test was employed to detect a statistically significant reduction in glucose levels between pretest (&amp;lt; 30 minutes, mean = 191.1 mg/dl ± 61.2) and post-test VO2 max (&amp;lt; 5 minutes, mean = 166.7 mg/dl ± 57.9); t(21) = 2.3, p &amp;lt;. 05). The American Diabetes Association recommends that glucose levels do not fall below 70 mg/dl in order to prevent symptoms of hypoglycemia. These results demonstrated a mean decrease in glucose of 24.4 mg/dl and provide further data which can be used to set safety parameters and expectations for adolescents with T1D participating in VO2 max testing. Disclosure K. King: None. B. J. Thrasher: None. T. E. Mckay: None. K. A. Wintergerst: None.

The impact of exercise intensity on neurophysiological indices of food-related inhibitory control and cognitive control: A randomized crossover event-related potential (ERP) study

Food-related inhibitory control, the ability to withhold a dominant response towards highly palatable foods, influences dietary decisions. Food-related inhibitory control abilities may increase following a bout of aerobic exercise; however, the impact of exercise intensity on both food-related inhibitory control and broader cognitive control processes is currently unclear. We used a high-powered, within-subjects, crossover design to test how relative intensity of aerobic exercise influenced behavioral (response time, accuracy) and neural (N2 and P3 components of the scalp-recorded event-related potential [ERP]) measures of food-related inhibitory and cognitive control. Two hundred and ten participants completed three separate conditions separated by approximately one week in randomized order: two exercise conditions (35% VO2max or 70% VO2max) and seated rest. Directly following exercise or rest, participants completed a food-based go/no-go task and a flanker task while electroencephalogram data were recorded. Linear mixed models showed generally faster response times (RT) and improved accuracy following 70% VO2max exercise compared to rest, but not 35% VO2max; RTs and accuracy did not differ between 35% VO2max exercise and rest conditions. N2 and P3 amplitudes were larger following 70% VO2max exercise for the food-based go/no-go task compared to rest and 35% VO2max exercise. There were no differences between exercise conditions for N2 amplitude during the flanker task; however, P3 amplitude was more positive following 70% VO2max compared to rest, but not 35% VO2max exercise. Biological sex did not moderate exercise outcomes. Results suggest improved and more efficient food-related recruitment of later inhibitory control and cognitive control processes following 70% VO2max exercise.

Altered hemodynamics by 4D flow cardiovascular magnetic resonance predict exercise intolerance in repaired coarctation of the aorta: an in vitro study

BackgroundCoarctation of the aorta (CoA) is associated with decreased exercise capacity despite successful repair. Altered flow patterns have been identified due to abnormal aortic arch geometry. Our previous work demonstrated aorta size mismatch to be associated with exercise intolerance in this population. In this study, we studied aortic flow patterns during simulations of exercise in repaired CoA using 4D flow cardiovascular magnetic resonance (CMR) using aortic replicas connected to an in vitro flow pump and correlated findings with exercise stress test results to identify biomarkers of exercise intolerance.MethodsPatients with CoA repair were retrospectively analyzed after CMR and exercise stress test. Each aorta was manually segmented and 3D printed. Pressure gradient measurements from ascending aorta (AAo) to descending aorta (DAo) and 4D flow CMR were performed during simulations of rest and exercise using a mock circulatory flow loop. Changes in wall shear stress (WSS) and secondary flow formation (vorticity and helicity) from rest to exercise were quantified, as well as estimated DAo Reynolds number. Parameters were correlated with percent predicted peak oxygen consumption (VO2max) and aorta size mismatch (DAAo/DDAo).ResultsFifteen patients were identified (VO2max 47 to 126% predicted). Pressure gradient did not correlate with VO2max at rest or exercise. VO2max correlated positively with the change in peak vorticity (R = 0.55, p = 0.03), peak helicity (R = 0.54, p = 0.04), peak WSS in the AAo (R = 0.68, p = 0.005) and negatively with peak WSS in the DAo (R = − 0.57, p = 0.03) from rest to exercise. DAAo/DDAo correlated strongly with change in vorticity (R = − 0.38, p = 0.01), helicity (R = − 0.66, p = 0.007), and WSS in the AAo (R = − 0.73, p = 0.002) and DAo (R = 0.58, p = 0.02). Estimated DAo Reynolds number negatively correlated with VO2max for exercise (R = − 0.59, p = 0.02), but not rest (R = − 0.28, p = 0.31). Visualization of streamline patterns demonstrated more secondary flow formation in aortic arches with better exercise capacity, larger DAo, and lower Reynolds number.ConclusionsThere are important associations between secondary flow characteristics and exercise capacity in repaired CoA that are not captured by traditional pressure gradient, likely due to increased turbulence and inefficient flow. These 4D flow CMR parameters are a target of investigation to identify optimal aortic arch geometry and improve long term clinical outcomes after CoA repair.

The effect of high-fat diet and exercise on KISS-1/GPR54 expression in testis of growing rats

PurposeTo find the expression of KISS-1 and G protein-coupled receptor 54 in rats testis from PND 21st to 56th.Method128 three-week-old weaned rats underwent high-fat diet and exercise (60–70% VO2max, 1 h/day, 5 days/week) intervention and were randomly divided into group C, CE, HC, or HE. Sample time points were set on the PND 21st, 35th, 43rd, and 56th. The testicular testosterone and the mRNA content, and protein content of KISS-1 and GPR54 in testis tissue were detected by ELISA, RT-qPCR, and Western blotting.Result(1) The protein of KISS-1 and GPR54 increased gradually during the growing period. KISS-1 mRNA peaked at 35D and GPR54 peaked at 43D. (2) High-fat diet affected the expression of the KISS-1/GPR54 system in rat testis and reduced the expression level of KISS-1 protein. (3) 60–70% VO2max exercise decreased the KISS-1/GPR54 expression level. Exercise intervention improved testicular development in rats with a high-fat diet.ConclusionThe expression of KISS-1/GPR54 increased during the growing period. High-fat diet can downregulate the protein and gene expression of KISS-1/GPR54 and change the expression trend. 60–70% VO2max exercise decreased the expression of KISS-1/GPR54, which may be involved in the effects of exercise on high-fat dietary sex hormone disorders.

The combined effect of Sacubitril-valsartan treatment on right ventricular function and cardiorespiratory response in patients with chronic heart failure

Abstract Cardiorespiratory response, right ventricular and global diastolic function is known to deteriorate the clinical course of patients with chronic heart failure with reduced ejection fraction (HFrEF), even under optimal treatment. In this work we sought to evaluate the impact of sacubitril/valsartan initiation in patients with chronic HFrEF in NYHA clinical status II-III, under optimal medical and invasive treatment. Methods 180 patients (85% male, mean age 62±9 years old, 60% ischemic heart failure, 73% with ICD, 45%with CRT and 45% with diabetes mellitus) in NYHA classification II-III-, who were prescribed Sacubitril-Valsartan were evaluated. Clinical status, biochemical parameters, cardiorespiratory exercise response and bi-ventricular Doppler indices were evaluated at first visit and 6 months after. The pulsed tissue Doppler imaging of the systolic and diastolic function of mitral and tricuspid annulus was characterized by the systolic waves Smv and Stv, and the diastolic waves: Emv and Amv; E was the early filling wave in transmitral velocity. Left atrial maximal volume and global longitudinal strain of the left ventricle (GLPS) were measured. In cardiorespiratory exercise Vo2max, VE/VCO2 and Mets achieved were evaluated. All of them received b-blockers, 90% eplerenone or spironolactone, 25% ivabradine and 90% diuretic treatment. Seventy percent of them started with the dose of 50mg of sacubitril/valsartan; while 80% finally received the full dose of 200 mg bid. One third of them were on clinical status NYHA III. Results Eight of the patients discontinued the medication due to hypotension or renal function worsening. All patients expressed improvement in clinical status; while diuretic therapy was down titrated in all of them and discontinued in 30%. As compared with the initial examination, tricuspid annulus systolic wave velocity increased by 5% (p=0.04); maximum volume of left atrium was decreased by 6% (p=0.004); GLPS average was improved by 41% (p=0.001) and E/Emv ratio was decreased by 22% (p=0.04). Moreover, improvement in Stv was more prominent in DCM as compared to IHF patients; In cardio respiratory exercise VE/VCO2 decreased by 5% (p=0.05); while VO2 max showed a trend in improvement (p=0.06), with no difference detected between DCM and ICM patients; although there was a significant increase (47%) in METS achieved (p=0.02). Conclusion Sacubitril/valsartan initiation was associated with improved left diastolic function and right ventricular function, along with functional status improvement in patients with HFrEF. These finding underline the beneficial role of sacubitril/valsartan initiation on the hemodynamic course of patients with systolic heart failure and clinical status deterioration. Funding Acknowledgement Type of funding source: None

The Effect of Interval and Continuous Training on Angiogenesis Factor in Type2 Diabetic Wistar Rats

Objective: The equilibrium of angiogenesis stimulus agents and angiogenesis inhibitory agents is an important factor in the increase of diabetic cardiomyopathy. This research aimed to survey the result of eight weeks of high-intensity interval training (HIIT) and moderate continuous (MICT) on the myocardium angiogenesis agent and histological alterations within male diabetic rats. Materials and Methods: 32 male Wistar rats did casually selected within 4 groups: health without exercise control, diabetic without exercise (D), D + HIIT, and D+ MICT groups. Diabetes type 2 produced with high-fat food for two weeks and an only dose of STZ. After approval of type 2 diabetes, subjects did direct to HIIT (90 -95 percent of VO2max), and MICT (50 to 65 percent of VO2max) exercise program five times per week during eight weeks. Western blotting methods were utilized for the exposure of protein synthesis of Vascular Endothelial Growth Factor (VEGF), Transforming Growth Factor-beta (TGF-β1), and Matrix Metalloproteinase-9 (MMP9) in the left ventricle. Besides, the base and ultimate blood glucose were estimated. Histological alterations assessed utilizing H&amp;E and Masson’s trichrome staining. Results: The installation of diabetes develops TGF-β1 (P-value= 0.001) and reduces MMP9 (P-value= 0.002) and VEGF (P-value= 0.002). But, eight weeks of MICT enhanced MMP9 (P-value= 0.002) and VEGF (P-value= 0.002), but the volume of TGF-β1 (P-value= 0.001) diminished significantly. Furthermore, the MICT did improve better than of HIIT in improving angiogenesis agents and adjust body mass, plasma glucose in the rats with diabetes. Conclusion: Not only eight weeks of interval and continuous exercise enhanced levels of MMP9 and VEGF, but also revealed a notable reduction in TGF-β1. Additionally, both training diminishes body weight and blood sugar.

Effect of exercise training on cardiac metabolism in rats with heart failure

Objectives. Heart failure (HF) impairs resting myocardial energetics, myocardial mitochondrial performance, and maximal oxygen uptake (VO2max). Exercise training is included in most rehabilitation programs and benefits HF patients. However, the effect of exercise intensity on cardiac mitochondrial respiration and concentrations of the key bioenergetic metabolites phosphocreatine (PCr), adenosine triphosphate (ATP), and inorganic phosphate (Pi) is unclear. This study aimed to investigate the effects of exercise training at different intensities in rats with HF. Methods. Rats underwent myocardial infarction or sham operations and were divided into three subgroups: sedentary, moderate intensity, or high intensity. The impact of HF and 6 weeks of exercise training on energy metabolism was evaluated by 31P magnetic resonance spectroscopy and mitochondrial respirometry. The concentrations of PCr, ATP, and Pi were quantified by magnetic resonance spectroscopy. VO2max was measured by treadmill respirometry. Results. Exercise training increased VO2max in sham and HF. PCr/ATP ratio was reduced in HF (p < .01) and remained unchanged by exercise training. PCr concentration was significantly lower in HF compared to sham (p < .01). Moderate and high-intensity exercise training increased ATP in HF and sham. HF impaired complex I (CI) and complex II (p = .034) respiration. High-intensity exercise training recovered CI respiration in HF rats compared to HF sedentary (p = .014). Conclusions. Exercise training improved cardiac performance, as indicated by increased VO2max and higher exercise capacity, without changing the myocardial PCr/ATP ratio. These observations suggest that the PCr/ATP biomarker is not suited to evaluate the beneficial effects of exercise training in the heart. The exact mechanisms require further investigations, as exercise training did increase ATP levels and CI respiration.

Protein Supplementation Does Not Further Augment Physiological Adaptations to Prolonged Endurance Exercise Training

PURPOSE: It has recently been speculated that protein supplementation may further augment the adaptations to prolonged endurance exercise training. We assessed the impact of protein supplementation during prolonged endurance exercise training on whole-body oxidative capacity (VO2max) and endurance exercise performance. METHODS: Sixty recreationally active males (age: 27±6 y; BMI: 23.8±2.6 kg·m-2, VO2max 47±6 mL·min-1·kg-1) were subjected to 12 weeks of triweekly endurance exercise training. After each session and each night prior to sleep, participants ingested either a protein supplement (PRO; 29 g casein protein) or an isocaloric carbohydrate placebo (PLA). Before and after the 12 weeks of training, VO2max and endurance exercise performance (~10-km time-trial) were assessed on a cycle ergometer. Muscular endurance (total workload achieved during 30 reciprocal isokinetic contractions) was assessed by isokinetic dynamometry and body composition by DXA. Dietary intake was assessed at baseline and during the intervention period. Repeated measures ANOVA was applied to assess whether training adaptations were different between groups. RESULTS: Protein intake increased in PRO (1.2±0.4 to 1.6±0.3 g·kg-1), but not in PLA (1.3±0.4 to 1.2±0.3 g·kg-1, time x treatment interaction, P<0.001). Endurance exercise training induced an 11±6% increase in VO2max (time effect, P<0.001), with no differences between groups (PRO: 48±6 to 53±7 mL·min-1·kg-1; PLA: 46±5 to 51±6 mL·min-1·kg-1; time x treatment interaction, P=0.50). Time to complete the time-trial was reduced by 14±7% (time effect, P<0.001), with no differences between groups (time x treatment interaction, P=0.15). Muscular endurance increased by 6±7% (time effect, P<0.001), with no differences between groups (time x treatment interaction, P=0.84). Whole body lean mass was unchanged over time (P=0.097). However, leg lean mass showed an increase following endurance exercise training (P<0.001), which tended to be greater in PRO (PRO: 0.5±0.7 kg; PLA: 0.2±0.6 kg; time x treatment interaction, P=0.073). CONCLUSION: Protein supplementation after exercise and before sleep does not further augment the gains in whole-body oxidative capacity and endurance exercise performance following prolonged endurance exercise training in healthy, young males.

Dynamic cerebral carbon dioxide reactivity at rest and during exercise

The cerebral vasculature is highly sensitive to direct arterial carbon dioxide tension (PaCO2) changes. Hypocapnia causes cerebral vasoconstriction, while hypercapnia causes cerebral vasodilation to maintain the brain tissue PCO2 within narrow limits. The cerebral blood flow (CBF) responses to PaCO2 changes should be quick, but the cerebral vasculature sensitivity as cerebral CO2 is measured during steady‐state vascular responses. Therefore, the CBF time response to PaCO2 changes remains unknown. The purpose of this study was to examine dynamic cerebral CO2 reactivity at rest and during exercise using the frequency domain analysis.Seven healthy young subjects participated in the study. At rest and during exercise (30% VO2max and cycling exercise), the dynamic CO2 reactivity was calculated based on the transfer function analysis between the end‐tidal CO2 (PETCO2) and the middle cerebral artery mean blood velocity (MCAvm), using a binary white‐noise sequence (0%–7% inspired CO2 fraction). Dynamic characteristics of the respiratory controller showed a low‐pass filter characteristic for regulating ventilation, and the dynamic gain was decreased gradually to 0.7 at 0.02 Hz. However, the gain from PETCO2 to MCAvm (dynamic CO2 reactivity) remained reasonably constant up to 0.02 Hz. Moreover, it did not change during exercise.These findings suggest that the dynamic cerebral CO2 reactivity is reflected in slow to fast PaCO2 changes, and does not change during exercise. In terms of CO2 homeostasis, the cerebral CO2 reactivity may be a more important physiological mechanism to adapt to fast CO2 changes than the ventilatory response to PaCO2 changes.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Left Ventricular Volume is an Important Determinant of Exercise Capacity in Patients with Ebstein's Anomaly

Background: Mechanisms for impaired exercise capacity in Ebstein's anomaly (EA) remain unclear. We performed cardio-pulmonary exercise testing, rest and exercise cardiac magnetic resonance (CMR) to explore associations between disease severity and exercise capacity. Methods: In 13 un-operated EA patients (median age 13.5 years; M:F = 42:58%) percent predicted VO2 max (%VO2max) was determined. From rest CMR, indexed end diastolic volumes were calculated: right atrium (RA), atrialised RV (aRV), functional RV (fRVEDV), left atrium (LA), left ventricle (LVEDV). Three CMR based severity indices [A:(RA+aRV)/(fRVEDV+LA+LV), B:(RA+aRV+fRVEDV)/(LA+LV), C:(fRVEDV)/(LVEDV)] and tricuspid regurgitation fraction (TRF = fRV stroke volume-PA flow) were calculated. Pulmonary artery (PA) and aortic flow (AO) were measured at rest and peak exercise and cardiac index (CI) calculated. Results: Univariate associations were found between %VO2max and all measures of disease severity (A:r = −0.66, p = 0.02; B:r = −0.67, p = 0.02; C:r = −0.71, p = 0.01), TRF (r = −0.62; p = 0.03) and LVEDV (r = 0.76, p = 0.004) but not with fRVEDV (r = −0.31, p = 0.33) or age. LVEDV was associated with CI at rest (r = 0.84, p = 0.001) and exercise (r = 0.83, p = 0.001). fRVEDV and TRF were not associated with rest or peak exercise CI. aRV was associated with CI at peak exercise (r = −0.57, p = 0.05); RA was associated with CI at rest (r = −0.58; p = 0.05) and peak exercise (r = −0.53; p = 0.08). Only severity index C was associated with CI at rest (r = −0.61, p = 0.04) and peak exercise (r = −0.57, p = 0.05). LVEDV was the only variable independently associated with %VO2max, rest and peak exercise CI on multivariate analysis. Conclusions: Our data highlight the importance of maintenance of LV volume on exercise capacity in EA and suggest interactions between the RA, aRV and LV rather than between fRV and LV as seen in other congenital cardiac abnormalities.