Prolonged Exercise Training Research Articles

Short-term high-intensity interval training exercise does not affect gut bacterial community diversity or composition of lean and overweight men.

What is the central question of this study? Does short-term high-intensity interval training alter the composition of the microbiome and is this associated with exercise-induced improvements in cardiorespiratory fitness and insulin sensitivity? What is the main finding and its importance? Although high-intensity interval training increased insulin sensitivity and cardiovascular fitness, it did not alter the composition of the microbiome. This suggests that changes in the composition of the microbiome that occur with prolonged exercise training might be in response to changes in metabolic health rather than driving exercise training-induced adaptations. Regular exercise reduces the risk of metabolic diseases, and the composition of the gut microbiome has been associated with metabolic function. We investigated whether short-term high-intensity interval training (HIIT) altered the diversity and composition of the bacterial community and whether there were associations with markers of insulin sensitivity or aerobic fitness. Cardiorespiratory fitness ( ) and body composition (dual energy X-ray absorptiometry scan) were assessed and faecal and fasted blood samples collected from 14 lean (fat mass 21±2%, aged 29±2years) and 15 overweight (fat mass 33±2%, aged 31±2years) men before and after 3weeks of HIIT training (8-12×60s cycle ergometer bouts at power output interspersed by 75s rest, three times per week). Gut microbiome composition was analysed by 16S rRNA gene amplicon sequencing. The HIIT significantly increased the aerobic fitness of both groups (P<0.001) and improved markers of insulin sensitivity (lowered fasted insulin and HOMA-IR; P<0.001) in the overweight group. Despite differences in the abundance of several bacterial taxa being evident between the lean and overweight group, HIIT did not affect the overall bacterial diversity or community structure (α-diversity or β-diversity). No associations were found between the top 50 most abundant bacterial genera and cardiorespiratory fitness markers; however, significant associations (P<0.05) were observed between the abundance of the bacterial species Coprococcus_3, Blautia, Lachnospiraceae_ge and Dorea and insulin sensitivity markers in the overweight group. Our results suggest that short-term HIIT does not greatly impact the overall composition of the gut microbiome, but that certain microbiome genera are associated with insulin sensitivity markers that were improved by HIIT in overweight participants.

The Impact of Moderate-Intensity Continuous or High-Intensity Interval Training on Adipogenesis and Browning of Subcutaneous Adipose Tissue in Obese Male Rats.

This study compares the effect of two types of exercise training, i.e., moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) on the browning of subcutaneous white adipose tissue (scWAT) in obese male rats. Effects on fat composition, metabolites, and molecular markers of differentiation and energy expenditure were examined. Forty male Wistar rats were assigned to lean (n = 8) or obese (n = 32) groups and fed either a standard chow or high-fat obesogenic diet for 10 weeks. Eight lean and obese rats were then blood and tissue sampled, and the remaining obese animals were randomly allocated into sedentary, MICT, or HIIT (running on a treadmill 5 days/week) groups that were maintained for 12 weeks. Obesity increased plasma glucose and insulin and decreased irisin and FGF-21. In scWAT, this was accompanied with raised protein abundance of markers of adipocyte differentiation, i.e., C/EBP-α, C/EBP-β, and PPAR-γ, whereas brown fat-related genes, i.e., PRDM-16, AMPK/SIRT1/PGC-1α, were reduced as was UCP1 and markers of fatty acid transport, i.e., CD36 and CPT1. Exercise training increased protein expression of brown fat-related markers, i.e., PRDM-16, AMPK/SIRT1/PGC-1α, and UCP1, together with gene expression of fatty acid transport, i.e., CD36 and CPT1, but decreased markers of adipocyte differentiation, i.e., C/EBP-α, C/EBP-β, and plasma glucose. The majority of these adaptations were greater with HIIT compared to MICT. Our findings indicate that prolonged exercise training promotes the browning of white adipocytes, possibly through suppression of adipogenesis together with white to beige trans-differentiation and is dependent on the intensity of exercise.

Postexercise cooling impairs muscle protein synthesis rates in recreational athletes.

Key points Protein ingestion and cooling are strategies employed by athletes to improve postexercise recovery and, as such, to facilitate muscle conditioning. However, whether cooling affects postprandial protein handling and subsequent muscle protein synthesis rates during recovery from exercise has not been assessed.We investigated the effect of postexercise cooling on the incorporation of dietary protein‐derived amino acids into muscle protein and acute postprandial (hourly) as well as prolonged (daily) myofibrillar protein synthesis rates during recovery from resistance‐type exercise over 2 weeks.Cold‐water immersion during recovery from resistance‐type exercise lowers the capacity of the muscle to take up and/or direct dietary protein‐derived amino acids towards de novo myofibrillar protein accretion. In addition, cold‐water immersion during recovery from resistance‐type exercise lowers myofibrillar protein synthesis rates during prolonged resistance‐type exercise training.Individuals aiming to improve skeletal muscle conditioning should reconsider applying cooling as a part of their postexercise recovery strategy. We measured the impact of postexercise cooling on acute postprandial (hourly) as well as prolonged (daily) myofibrillar protein synthesis rates during adaptation to resistance‐type exercise over 2 weeks. Twelve healthy males (aged 21 ± 2 years) performed a single resistance‐type exercise session followed by water immersion of both legs for 20 min. One leg was immersed in cold water (8°C: CWI), whereas the other leg was immersed in thermoneutral water (30°C: CON). After water immersion, a beverage was ingested containing 20 g of intrinsically (l‐[1‐13C]‐phenylalanine and l‐[1‐13C]‐leucine) labelled milk protein with 45 g of carbohydrates. In addition, primed continuous l‐[ring‐2H5]‐phenylalanine and l‐[1‐13C]‐leucine infusions were applied, with frequent collection of blood and muscle samples to assess myofibrillar protein synthesis rates in vivo over a 5 h recovery period. In addition, deuterated water (2H2O) was applied with the collection of saliva, blood and muscle biopsies over 2 weeks to assess the effects of postexercise cooling with protein intake on myofibrillar protein synthesis rates during more prolonged resistance‐type exercise training (thereby reflecting short‐term training adaptation). Incorporation of dietary protein‐derived l‐[1‐13C]‐phenylalanine into myofibrillar protein was significantly lower in CWI compared to CON (0.016 ± 0.006 vs. 0.021 ± 0.007 MPE; P = 0.016). Postexercise myofibrillar protein synthesis rates were lower in CWI compared to CON based upon l‐[1‐13C]‐leucine (0.058 ± 0.011 vs. 0.072 ± 0.017% h−1, respectively; P = 0.024) and l‐[ring‐2H5]‐phenylalanine (0.042 ± 0.009 vs. 0.053 ± 0.013% h−1, respectively; P = 0.025). Daily myofibrillar protein synthesis rates assessed over 2 weeks were significantly lower in CWI compared to CON (1.48 ± 0.17 vs. 1.67 ± 0.36% day−1, respectively; P = 0.042). Cold‐water immersion during recovery from resistance‐type exercise reduces myofibrillar protein synthesis rates and, as such, probably impairs muscle conditioning.

Session RPE During Prolonged Exercise Training.

Although the session rating of perceived exertion (sRPE) is primarily a marker of internal training load (TL), it may be sensitive to external TL determining factors, such as duration and volume. Thus, sRPE could provide further information on accumulated fatigue not available from markers of internal TL. Therefore, the purpose of this study was to investigate sRPE during heavy training bouts at relatively constant intensity. Eleven university swimmers performed a high-volume training session consisting of 4 × 10 × 100-yd (4 × 10 × 91.4m). Repetition lap time and heart rate were measured for each repetition and averaged for each set. Blood lactate concentration was measured after each set. At the end of each set, a 10-minute rest period was allowed, during which sRPE values were obtained, as if the training bout had ended. There were no differences between sets for lap time (P = .096), heart rate (P = .717), and blood lactate concentration (P = .466), suggesting that the subjects were working at the same external and internal intensity. There was an increase (P = .0002) in sRPE between sets (first 4 [1.2], second 5 [1.3], third 7 [1.3], and fourth 8 [1.5]), suggesting that even when maintaining the same intensity, the perception of the entire workload increased with duration. Increases in duration, although performed with a consistent internal and external intensity, influences sRPE. These findings support the concept that sRPE may provide additional information on accumulated fatigue not available from other markers of TL.

Effect of essential amino acid supplementation and aerobic exercise on insulin sensitivity in healthy older adults: A randomized clinical trial

The combination of prolonged essential amino acid (EAA) supplementation and aerobic exercise training (Ex) improves muscle protein metabolism, strength and function in healthy older adults. However, excess EAA intake may worsen insulin sensitivity. Here we report the effects of EAA supplementation (EAA, n=11), placebo (PLA, n=10), aerobic exercise with placebo (Ex+PLA, n=11) or Ex with EAA supplementation (Ex+EAA, n=10) for 22 weeks on insulin sensitivity in non-diabetic older adults. A 2×2 design with block randomization and double blinding for supplement or placebo was used. Subjects ingested EAA (15g) or placebo daily. Exercising subjects participated in supervised progressive vigorous treadmill walking 3 times weekly. Measures of insulin sensitivity by oral glucose tolerance testing were collected at baseline and 22 weeks. Dietary intakes of protein and specific amino acids were determined in a subset of subjects. Overall, exercise improved insulin sensitivity, while EAA supplementation had no effect. In the dietary subset, post-intervention insulin sensitivity did not correlate significantly with the total intake of EAA, anti-angiogenic amino acids (cysteine, methionine), or branched-chain amino acids (isoleucine, leucine, valine). Overall, we conclude that in healthy older adults with moderate protein intake, EAA supplementation is metabolically safe as it does not decrease insulin sensitivity regardless of its combination with aerobic exercise. Thus, daily protein intake should be controlled for when modeling insulin sensitivity. Future studies should explore the role of increased blood flow as a potential explanatory factor for the observed interaction between aerobic exercise and supplementation. NCT00872911.

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.

Post-exercise Cooling Impairs Muscle Protein Synthesis Rates In Healthy Young Males

Protein ingestion and cooling are strategies employed by athletes to improve post-exercise recovery and, as such, to facilitate muscle reconditioning following exercise. However, whether post-exercise cooling affects postprandial protein handling and subsequent muscle protein synthesis rates during recovery from exercise has not been studied. PURPOSE: This study assessed the impact of post-exercise cooling on acute postprandial (hourly) and prolonged (daily) myofibrillar protein synthesis rates during recovery from resistance-type exercise over a 2-week period. METHODS: Twelve healthy, male adults (age: 21±1 y) performed a single session of resistance-type exercise followed by water immersion of both legs for 20 min. One leg was immersed in cold water (8°C: CWI) while the other leg was immersed in thermoneutral water (30°C: CON). After water immersion, a beverage was ingested containing 20 g intrinsically L-[1-13C]-phenylalanine and L-[1-13C]-leucine labelled milk protein with 45 g of carbohydrates. In addition, primed continuous L-[ring-2H5]-phenylalanine and L-[1-13C]-leucine infusions were applied, with frequent collection of blood samples and muscle biopsies to assess myofibrillar protein synthesis rates in vivo over a 5-h recovery period. In addition, deuterated water (2H2O) was ingested with the collection of saliva, blood and muscle biopsies over 2 weeks to assess the effects of post-exercise cooling with protein intake on myofibrillar protein synthesis rates during more prolonged resistance-type exercise training. RESULTS: Incorporation of dietary protein-derived L-[1-13C]-phenylalanine into myofibrillar protein was significantly lower in CWI compared to CON (0.016±0.002 vs 0.021±0.002 MPE; P=0.016). Post-exercise myofibrillar protein synthesis rates were lower in CWI compared to CON based upon L-[1-13C]-leucine (0.058±0.003 vs 0.072±0.005%·h-1, respectively; P=0.024) and L-[ring-2H5]-phenylalanine (0.042±0.003 vs 0.053±0.004%·h-1, respectively; P=0.025). Daily myofibrillar protein synthesis rates assessed over 2 weeks were significantly lower in CWI when compared to CON (1.48±0.05 vs 1.67±0.11%·d-1, respectively; P=0.042). CONCLUSION: Cold-water immersion during recovery from resistance-type exercise impairs myofibrillar protein synthesis rates.

Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men.

We aimed to determine the effects of long-term collagen peptide (CP) supplementation and resistance exercise training (RET) on body composition, strength, and muscle fiber cross-sectional area (fCSA) in recreationally active men. Fifty-seven young men were randomly and double-blinded divided into a group receiving either collagen peptides (COL, 15 g/day) or a placebo (PLA). Strength testing, bioimpedance analysis, and muscle biopsies were used prior to and after an RET intervention. Food record protocols were performed during the RET intervention. The groups trained three times a week for 12 weeks. Baseline parameters showed no differences between groups, and the external training load and dietary food intake were also similar. COL showed a significant increase in fat-free mass (FFM) compared with the placebo group (p < 0.05). Body fat mass (BFM) was unchanged in COL, whereas a significant increase in BFM was observed in PLA. Both groups showed significant increases in all strength tests, with a trend for a slightly more pronounced effect in COL. The fCSA of type II muscle fibers increased significantly in both groups without differences between the two groups. We firstly demonstrated improved body composition in healthy, recreationally active men subsequent to prolonged CP supplementation in combination with RET. As the observed increase in FFM was not reflected in differences in fCSA hypertrophy between groups, we assume enhanced passive connective tissue adaptations in COL due to CP intake.

Changes of cardiac biomarkers after ultradistance and standard-distance triathlon.

Triathlon is becoming more popular sport due to recognition of the positive effects of triathlon. Generally, participants in these strenuous activities are well considered as healthy individuals pursuing a healthy lifestyle. However, there is still controversy on the beneficial effects of prolonged exercise training and endurance sport events. The duration of exercise required to elicit cardiac dysfunction and the mechanisms underlying this phenomenon have not been fully elucidated. There are only limited data in literature for exercise-induced changes of cardiac and muscle damage biomarkers in athletes participating in different triathlon distances. Monitoring cardiac and muscle damage biomarkers in triathletes participating in different triathlon distances will help researchers, coaches, and athletes better understand how to design training cycles minimizing overtraining and injury risk. Therefore, the purpose of the present study was to examine for evidence of blood biomarkers during triathlon events of two different distances such as standard- and ultradistance triathlon in male triathletes. The results of the present study showed that ultradistance showed greater muscle damage markers such as creatine kinase, myoglobin and lactate dehydrogenase than standard-distance. We also found that the distance of triathlon did not lead to an increase of troponin T in male triathletes.

Addition of the Aldose Reductase Inhibitor Benzofuroxane Derivative BF-5m to Prolonged and Moderate Exercise Training Enhanced Protection of the Rat Heart From Type-1 Diabetes.

Moderate exercise training may not be sufficient to exert beneficial effects on the cardiovascular system because of the long-term multifactorial etiology of diabetic complications. The addition of a proper pharmacological tool to the physical exercise should improve the outcomes of the diabetic damage. Here it is shown that 8 weeks exercise training of type 1 diabetic Sprague-Dawley (SD) rats resulted in a significantly increased heart rate, a 14% increase in the left ventricular ejection fraction (LVEF) increased plasma insulin levels and a 13% decrease in plasma glucose with respect to sedentary animals. The training also resulted in a 22% reduction in cardiac QT interval from a diabetic sedentary value of 185 ± 19 ms. Treatment of trained rats with the new antioxidant and NO-releasing aldose reductase 2 inhibitor 5(6)-(benzo[d]thiazol-2-ylmethoxy) benzofuroxane BF-5m, 20 mg/kg/day, added a further and significant (P < 0.01 vs. sedentary) increase of the LVEF up to 38% at 8 week time point. The long QT interval recorded in trained rats was reduced to further 12% by addition to the training of pharmacological treatment with 20 mg/kg/day BF-5m. At this time, the association of the two treatments improved the expression into the cardiac tissue of sarcoplasmic reticulum Ca2+ ATPase 2 (SERCA2) and manganese superoxide dismutase (MnSOD), and reduced the fibrosis.

A novel traditional Chinese medicine ameliorates fatigue-induced cardiac hypertrophy and dysfunction via regulation of energy metabolism.

Prolonged exercise and exercise training can adversely affect cardiac function in some individuals. QiShenYiQi Pills (QSYQ), which are a compound Chinese medicine, have been previously shown to improve pressure overload-induced cardiac hypertrophy. We hypothesized that QSYQ can ameliorate as well the fatigue-induced cardiac hypertrophy. This study was to test this hypothesis and underlying mechanism with a focus on its role in energy regulation. Male Sprague-Dawley rats were used to establish exercise adaptation and fatigue model on a motorized rodent treadmill. Echocardiographic analysis and heart function test were performed to assess heart systolic function. Food-intake weight/body weight and heart weight/body weight were assessed, and hematoxylin and eosin staining and immunofluorescence staining of myocardium sections were performed. ATP synthase expression and activity and ATP, ADP, and AMP levels were assessed using Western blot and ELISA. Expression of proteins related to energy metabolism and IGF-1R signaling was determined using Western blot. QSYQ attenuated the food-intake weight/body weight decrease, improved myocardial structure and heart function, and restored the expression and distribution of myocardial connexin 43 after fatigue, concomitant with an increased ATP production and a restoration of metabolism-related protein expression. QSYQ upgraded the expression of IGF-1R, P-AMPK/AMPK, peroxisome proliferator-activated receptor-γ coactivator-1α, nuclear respiratory factor-1, P-phosphatidylinositol 3-kinase (PI3K)/PI3K, and P-Akt/Akt thereby attenuated the dysregulation of IGF-1R signaling after fatigue. QSYQ relieved fatigue-induced cardiac hypertrophy and enhanced heart function, which is correlated with its potential to improve energy metabolism by regulating IGF-1R signaling. NEW & NOTEWORTHY Prolonged exercise may impact some people leading to pathological cardiac hypertrophy. This study using an animal model of fatigue-induced cardiac hypertrophy provides evidence showing the potential of QiShenYiQi Pills, a novel traditional Chinese medicine, to prevent the cardiac adaptive hypertrophy from development to pathological hypertrophy and demonstrates that this effect is correlated with its capacity for regulating energy metabolism through interacting with insulin-like growth factor-1 receptor.

Cardioprotective effect of a moderate and prolonged exercise training involves sirtuin pathway

AimTo investigate the cardioprotective effects of prolonged and moderate exercise training on cellular and molecular events early after myocardial infarction. Materials and methodsMale Wistar rats were divided in sedentary or exercised group; both groups underwent to a myocardial infarction. All the molecular and immunohistochemical analyses on hearts of sedentary and exercised rats were performed 48 h after surgical procedure. SIRT1 and SIRT3 expression were measured and two of the pathways activated by sirtuins, p53-induced apoptosis and Forkhead boxO (FOXO)3a-induced oxidative stress, were investigated. All the experiments were performed also in presence of the SIRT inhibitor, EX527. Key findingsFourty-eight hours post myocardial infarction, exercise training induced the activation of SIRT1 and SIRT3 pathway reducing cardiomyocytes apoptosis and oxidative damage. Molecular data were confirmed by immunohistochemical evaluations. These effects are more evident in border infarcted zone than in the remote myocardium. SignificanceExercise training is a non-pharmacological prevention strategy in cardiovascular diseases and the sirtuins family seems to be as novel and attractive target in cardioprotection.

Prolonged exercise training improves the acute type II muscle fibre satellite cell response in healthy older men.

Skeletal muscle stem cells, termed satellite cells, play a crucial role in repair and remodelling of muscle in response to exercise An age-related decline in satellite cell number and/or function has been hypothesized to be a key factor in the development of sarcopenia and/or the blunted muscle fibre adaptive response to prolonged exercise training in older persons We report that performing prolonged exercise training improves the acute type II muscle fibre satellite cell response following a single bout of resistance exercise in older men. The observed improvement in muscle satellite function is associated with an increase in muscle fibre capillarization following exercise training suggesting a possible functional link between capillarization and satellite cell function. Age-related type II muscle fibre atrophy is accompanied by a fibre type-specific decline in satellite cell number and function. Exercise training restores satellite cell quantity in older adults; however, whether it can restore the impaired satellite cell response to exercise in older adults remains unknown. Therefore we assessed the acute satellite cell response to a single exercise session before and after prolonged exercise training in older men. Fourteen older men (74±8years) participated in a 12-week exercise training programme (resistance exercise performed twice per week, high intensity interval training once per week). Before and after training, percutaneous biopsies from the vastus lateralis muscle were taken prior to and following 24 and 48h of post-exercise recovery. Muscle fibre characteristics were evaluated by immunohistochemistry and mRNA expression by RT-PCR. Whereas no changes were observed in type II muscle fibres, type I muscle fibre satellite cell content increased significantly at 24 and 48h after a single bout of resistance exercise before the exercise training programme (P<0.01). Following the exercise training programme, both type I and type II muscle fibre satellite cell content increased significantly at 24 and 48h after a single bout of resistance exercise (P<0.05). The greater acute increase in type II muscle fibre satellite cell content at 24 h post-exercise recovery after training was correlated with an increase in type II muscle fibre capillarization (r=0.671, P=0.012). We show that the acute muscle satellite cell response following exercise can be improved by prolonged exercise training in older men.

The impact of 2years of high-intensity exercise training on a model of integrated cardiovascular regulation.

Heart rate variability, a common and easily measured index of cardiovascular dynamics, is the output variable of complicated cardiovascular and respiratory control systems. Both neural and non-neural control mechanisms may contribute to changes in heart rate variability. We previously developed an innovative method using transfer function analysis to assess the effect of prolonged exercise training on integrated cardiovascular regulation. In the present study, we modified and applied this to investigate the effect of 2years of high-intensity training on circulatory components to tease out the primary effects of training. Our method incorporated the dynamic Starling mechanism, dynamic arterial elastance and arterial-cardiac baroreflex function. The dynamic Starling mechanism gain and arterial-cardiac baroreflex gain were significantly increased in the exercise group. These parameters remained unchanged in the controls. Conversely, neither group experienced a change in dynamic arterial elastance. The integrated cardiovascular regulation gain in the exercise group was 1.34-fold larger than that in the control group after the intervention. In these previously sedentary, otherwise healthy, middle-aged adults, 2 years of high-intensity exercise training improved integrated cardiovascular regulation by enhancing the dynamic Starling mechanism and arterial-cardiac baroreflex sensitivity. Assessing the effects of exercise training on cardiovascular variability is challenging because of the complexity of multiple mechanisms. In a prospective, parallel-group, randomized controlled study, we examined the effect of 2years of high-intensity exercise training on integrated cardiovascular function, which incorporates the dynamic Starling mechanism, dynamic arterial elastance and arterial-cardiac baroreflex function. Sixty-one healthy participants (48% male, aged 53years, range 52-54years) were randomized to either 2years of exercise training (exercise group: n= 34) or control/yoga group (controls: n= 27). Before and after 2years, subjects underwent a 6min recording of beat-by-beat pulmonary artery diastolic pressure (PAD), stroke volume index (SVindex), systolic blood pressure (sBP) and RR interval measurements with controlled respiration at 0.2Hz. The dynamic Starling mechanism, dynamic arterial elastance and arterial-cardiac baroreflex function were calculated by transfer function gain between PAD and SVindex; SVindex and sBP; and sBP and RR interval, respectively. Fifty-three participants (controls: n= 25; exercise group: n= 28) completed the intervention. After 2years, the dynamic Starling mechanism gain (Group× Time interaction: P= 0.008) and the arterial-cardiac baroreflex gain (P= 0.005) were significantly increased in the exercise group but remained unchanged in the controls. There was no change in dynamic arterial elastance in either of the two groups. The integrated cardiovascular function gain in the exercise group increased 1.34-fold, whereas there was no change in the controls (P= 0.02). In these previously sedentary, otherwise healthy middle-aged adults, a 2year programme of high-intensity exercise training improved integrated cardiovascular regulation by enhancing the dynamic Starling mechanism and arterial-cardiac baroreflex sensitivity, without changing dynamic arterial elastance.

Improved Metabolic Flexibility Postbreakfast after Exercise Intervention in People with T2DM

Exercise provides many metabolic benefits for people with type 2 diabetes; nevertheless, the ability to switch substrate oxidation from fat to carbohydrate and back, known as metabolic flexibility (MetFlex), in response to prolonged exercise training has not been thoroughly explored. Purpose: The goal of this analyses was to investigate changes in MetFlex after an exercise intervention. We enrolled healthy sedentary participants with obesity (HSO) and participants with type 2 diabetes (T2DM) in a 10-week aerobic exercise intervention. Methods: Seventeen participants with T2DM (8 females; 52.9 years; BMI= 36.9 kg/m2 and 9 males; 48.8 years; BMI= 33.3 kg/m2) and seven HSO (5 females; 44.8 years, BMI= 37.6 kg/m2 and 2 males; 46.5 years, BMI= 36.2 kg/m2) completed the intervention. MetFlex was assessed as the respiratory quotient (RQ) kinetic response after ingesting a standard high CHO breakfast during a 24-h energy expenditure measurement in a whole-room respiratory chamber. Briefly, the kinetics between the lowest RQ and highest RQ points were analyzed by a simple linear regression between time (1-minute resolution) and RQ units (RQUnits). Individual data were time-aligned and averaged for each group and moments (PRE and POST intervention), then slopes and intercepts for T2DM vs. HSO groups and PRE vs. POST were compared using a multiple regression model. Results: At PRE-intervention, HSO group had a significantly lower intercept than T2DM (HSO=0.737 vs. T2DM=0.705; P&amp;lt;0.001) and slower RQ kinetics as demonstrated by a greater slope (HSO=0.00448 RQUnits/min vs. T2DM=0.00332 RQUnits/min; F=18.1, P=0.001). After the exercise intervention only T2DM significantly increased their slope (POST= 0.003944 RQUnits/min; F=6.47, P=0.013). Conclusions: Our results indicate that participants with diabetes significantly improve MetFlex following a prolonged aerobic exercise intervention. Disclosure E.A. Carnero: None. C.P. Bock: None. N. Stephens: None. R.E. Pratley: Other Relationship; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eisai Inc., GlaxoSmithKline plc., Janssen Pharmaceuticals, Inc., Lexicon Pharmaceuticals, Inc., Ligand Pharmaceuticals, Inc., Eli Lilly and Company, Merck &amp; Co., Inc., Novo Nordisk Inc., Pfizer Inc., Sanofi-Aventis, Takeda Development Center Americas, Inc.. S.R. Smith: None. L.M. Sparks: None.

Attenuated strength gains during prolonged resistance exercise training in older adults with high inflammatory status

ObjectivesChronic systemic low grade inflammation is associated with the age-related loss of muscle mass. Resistance exercise has been suggested to reduce or lower chronic systemic low grade inflammation. However, systemic chronic low-grade inflammation may adversely affect the adaptive response to exercise training. We investigated the effect of resistance exercise training on systemic chronic low-grade inflammation in older adults. In addition, we studied the association between systemic chronic low-grade inflammation and the adaptive response to exercise training. Design/setting/participantsFrail and pre-frail older adults (61 subjects) performed 24 weeks of progressive resistance exercise training. Frailty was assessed using the Fried frailty criteria. MeasurementsLean body mass (DXA), strength (1RM), circulating levels of IL-1β, IL-6, IL-8 and TNF-α were measured prior to exercise training, after 12 weeks of training, and after 24 weeks of training. ResultsProlonged progressive resistance exercise training did not affect circulating levels of IL-6, IL-8 and TNF-α. However, exercise training led to a small but significant increase of 0.052 pg/mL in IL-1β. Higher circulating levels of TNF-α, IL-8 and IL-6 during the training period were negatively associated with strength gains for the leg press. A doubling of plasma TNF-α, IL-8 or IL-6 resulted in reduced strength gains for leg press with coefficients of −3.52, −3.42 and −1.54 respectively. High levels of circulating TNF-α were also associated with decreased strength gains for the leg extension (coefficient −1.50). Inflammatory cytokines did not appear to have an effect on gains in lean mass. ConclusionOur findings suggest that increased levels of plasma cytokines (TNF-α, IL-6 and IL-8) are associated with lower strength gains during resistance exercise training.

Effect of Protein or Essential Amino Acid Supplementation During Prolonged Resistance Exercise Training in Older Adults on Body Composition, Muscle Strength, and Physical Performance Parameters: A Systematic Review

Objectives: Loss of muscle mass and strength with aging, sarcopenia, burdens many older adults, making identification of strategies on how to counteract it very relevant—especially to health care providers working in rehabilitation. The aim of this systematic review was to determine the effect of protein or essential amino acid (EAA) supplementation during prolonged resistance exercise training (RT) in older adults. No known stimulants of muscle protein synthesis, or ingredients with an effect on muscle strength/physical function, were allowed with the supplementation, differentiating this systematic review from others. Data sources and methods: In January 2017, 4 electronic databases and reference lists were searched for randomized controlled trials investigating the effect of protein or EAA supplementation during RT in older adults (mean age &gt;60 years) on outcomes of body composition, muscle strength, and physical performance. Study selection and data extraction were performed by 2 independent reviewers. Results Sixteen studies (1107 participants) fulfilled the eligibility criteria. Methodologic differences between the studies disallowed a meta-analysis. Of the 16 studies, 6 found significant effects on body composition (3 studies), muscle strength (3 studies), and physical performance (2 studies) measures. Conclusions The evidence is weak and inconsistent, as benefit of protein or EAA supplementation during RT in older adults is only shown in some studies. The findings indicate that frail/sarcopenic older adults might benefit more than healthy older adults. Further research is needed to allow an interpretation on the importance of study population and design. Trial registration: PROSPERO, Reg. no.: CRD42017063808. Registered April 14, 2017.

Sex-Specific Ventricular and Vascular Adaptations to Exercise.

Increasing data suggest that there are sex differences in ventricular and vascular adaptations to aerobic (endurance) exercise, which may be attributed to different physical and physiological features in men and women. Despite that cardiovascular control during acute exercise at the same relative work rate (e.g., the percentage of peak oxygen uptake) appears to be similar between the sexes, women have blunted responses or adaptations to prolonged (e.g., ≥1year) exercise training compared with men. Currently, there is little evidence to suggest that exercise-induced vascular adaptations are different between men and women. Furthermore, sex differences in skeletal muscle adaptations to exercise, and how this influences cardiovascular function, remain unclear. Identifying potential differences and the mechanisms behind such exercise-induced adaptations is important for the optimization of exercise interventions between men and women across the life span.

No evidence of white adipocyte browning after endurance exercise training in obese men

The phenomenon of adipocyte 'beiging' involves the conversion of non-classic brown adipocytes to brown-like adipose tissue with thermogenic, fat-burning properties, and this phenomenon has been shown in rodents to slow the progression of obesity-associated metabolic diseases. Rodent studies consistently report adipocyte beiging after endurance exercise training, indicating that increased thermogenic capacity in these adipocytes may underpin the improved health benefits of exercise training. The aim of this study was to determine whether prolonged endurance exercise training induces beige adipogenesis in subcutaneous adipose tissues of obese men. Molecular markers of beiging were examined in adipocytes obtained from abdominal subcutaneous (AbSC) and gluteofemoral (GF) subcutaneous adipose tissues before and after 6 weeks of endurance exercise training in obese men (n=6, 37.3±2.3 years, 30.1±2.3 kg m-2). The mRNAs encoding the brown or beige adipocyte-selective proteins were very lowly expressed in AbSC and GF adipose tissues and exercise training did not alter the mRNA expression of UCP1, CD137, CITED, TBX1, LHX8 and TCF21. Using immunohistochemistry, neither multilocular adipocytes, nor UCP1 or CD137-positive adipocytes were detected in any sample. MicroRNAs known to regulate brown and/or beige adipose development were highly expressed in white adipocytes but endurance exercise training did not impact their expression. The present study reaffirms emerging data in humans demonstrating no evidence of white adipose tissue beiging in response to exercise training, and supports a growing body of work demonstrating divergence of brown/beige adipose location, molecular characterization and physiological function between rodents and humans.

Athletes and the Aorta: Normal Adaptations and the Diagnosis and Management of Pathology.

Over a hundred years ago, physicians first recognized that participation in regular, vigorous training resulted in enlargement of the heart. Since that time, the term "athlete's heart" has entered the medical lexicon as a global expression encompassing the electrical, functional, and morphological adaptations that develop in response to physical training. Exercise-induced adaptations of the aorta, which is also exposed to large hemodynamic stresses during prolonged endurance exercise or resistance training, are less well recognized. Young athletes tend to have slightly larger aortas than their sedentary counterparts; however, this rarely exceeds normal ranges for the general population. A systematic approach is advised when presented with an athlete with aortic enlargement. The size of the aorta needs to be first put in the context of the athlete's age, sex, size, and sporting endeavors; however, even in the largest young athletes, the aortic root rarely exceeds 4cm in men or 3.4cm in women. A comprehensive evaluation is advised which includes a detailed family history and a thorough physical examination evaluating for signs of any defined connective tissue disorder associated with aortopathy. Downstream testing is then tailored for the individual and may include further tomographic imaging, opthalmology review, and genetic testing. This should ideally be performed at a specialist center. Management of athletes with an aortopathy includes tailoring athletic activity, medical management with strict impulse control, and, in some cases, prophylactic surgery. The issue of sporting eligibility should be individualized and if disqualification is necessary, this should be undertaken by a sports cardiologist or an expert in aortic disease with experience in dealing with an athletic population.