Post-exercise Recovery Period Research Articles

Active intervals between sets and exercise of resistance exercises potentiate the magnitude of post-exercise hypotension in middle-aged hypertensive women.

Walking/run promotes greater post-exercise hypotension (PEH) than resistance exercise (RE) which can be associated nitric oxide production. Then, we investigated if adding walking between RE increases PEH. Thirteen hypertensive women (48 ± 1.9years; 26.8 ± 0.3kg/m2) performed five experimental sessions: 1-traditional RE with passive interval (PIBS); 2-RE with active interval between sets (AIBS); 3-RE with active interval between exercises (AIEX); 4-aerobic exercise (AE); 5-no exercise. Blood pressure was measured before and immediately after exercise and every 10min of a 60-min post-exercise recovery period. Plasma nitrite (NO) and malondialdehyde (MDA) were also measured. AIBS, AIEX, and AE sessions promoted systolic PEH (12 ± 1.53; 16 ± 2.13; 18 ± 1.34mmHg, respectively) and diastolic PEH (8 ± 1.38; 8 ± 0.79; 8 ± 0.58mmHg). In AIBS, AIEX and AE sessions, significant PEH was noted at 10 or 20min; in PIBS, PEH was significant only at 40min. In the PIBS session, NO did not change, but presented higher values after AIBS, AIEX and AE sessions. MDA showed no changes between sessions. Passive or active intervals in resistance exercise promote PEH in hypertensive women. Active intervals shorten the PEH onset time as additional benefit.

A novel approach to the dual sugar test for the assessment of intestinal epithelium permeability in response to exertional heat stress and nutritional intervention

An acute increase in intestinal epithelium permeability is induced by prolonged exertion in the heat, resulting in the translocation of pathogenic bacteria and endotoxins from the lumen into the circulation, causing a systemic inflammatory response and debilitating symptoms(1). Acute exercise-induced gastrointestinal syndrome mimics chronic health conditions with which an impaired intestinal barrier function is associated, including coeliac disease, inflammatory bowel disease, diabetes, Alzheimer’s and liver diseases(2). Intestinal epithelium permeability is typically assessed using a dual sugar absorption test, by administering a drink containing non-metabolisable sugars (e.g. lactulose [L] and L-rhamnose [R]) that can enter the circulation by paracellular translocation when the epithelium is compromised, and are subsequently excreted and measured cumulatively in the urine(3). We aimed to demonstrate that our recently developed ion chromatography protocol(4) can be used to accurately quantify L/R ratio in the plasma of participants exercising in hot ambient conditions and to determine the impact of nutritional intervention on intestinal epithelium permeability. Further, we hypothesised that measuring L/R in plasma collected at intervals during the post-exercise recovery period would reveal more information about intestinal permeability compared to previously published cumulative urine L/R data(3). Endurance-trained participants completed a set of randomised crossover studies, consisting of 2 h running at 60% V˙O2max in temperate, warm and hot ambient conditions (n = 8) and/or in the heat while consuming water, carbohydrate or protein (n = 9). The dual sugar solution was ingested at 90 min of exercise and blood was sampled at 0, 1, 2 and 4 h post-exercise. Plasma sugars were quantified by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and L/R ratios were compared by two-way repeated measures ANOVA with Tukey’s multiple comparisons. Plasma L/R increased immediately post-exercise in the heat (0.15 ± 0.11) compared with temperate (0.06 ± 0.04, p<0.001) and warm (0.09 ± 0.08, p<0.01) conditions, while consuming glucose before and during exercise alleviated this (0.02 ± 0.02, p<0.001), and this novel information was otherwise missed when measuring urine L/R. Consuming glucose or whey protein hydrolysate during exercise attenuated intestinal permeability from exertional heat stress throughout recovery, with the mean plasma L/R over 4 h reduced from 0.11 ± 0.05 to 0.04 ± 0.03 (p<0.001) and 0.06 ± 0.04 (p<0.01) with glucose and protein, respectively. We recommend using the dual sugar test with quantification of plasma sugars at intervals by HPAEC-PAD to maximise intestinal permeability data collection in exercise gastroenterology research and beyond, as this gives additional acute response information compared to urinary measurements. Our approach can be employed to investigate and develop personalised nutrition strategies that prevent intestinal hyperpermeability during exertional heat stress. This has implications for athlete performance and safety, and can also build upon occupational health and safety practices and inform chronic disease management.

Effects of post-exercise intake of exogenous lactate on energy substrate utilization at rest.

This study investigated the effects of exogenous lactate intake on energy metabolism during 1 h of rest after acute exercise. Eight-week-old ICR mice were randomly divided into four groups: SED (no treatment), EXE (exercise only), LAC (post-exercise oral lactate administration), and SAL (post-exercise saline administration) (n=8 per group). The exercise intensity was at VO2max 80% at 25 m/min and 15° slope for 50 min. After acute exercise, the LAC and SAL groups ingested lactate and saline orally, respectively, and were allowed to rest in a chamber. Energy metabolism was measured for 1 h during the resting period. LAC and SAL group mice ingested lactate and saline, respectively, after exercise and the blood lactate concentration was measured 1 h later through tail blood sampling. Blood lactate concentration was not significantly different between the two groups. Energy metabolism measurements under stable conditions revealed that the respiratory exchange ratio in the LAC group was significantly lower than that in the SAL group. Additionally, carbohydrate oxidation in the LAC group was significantly lower than that in the SAL group at 10-25 min. No significant difference was observed in the fat oxidation level between the two groups. We found that post-exercise lactate intake modified the respiratory exchange ratio after 1 h of rest. In addition, acute lactate ingestion inhibits carbohydrate oxidation during the post-exercise recovery period.

Impact of Caffeine Intake Strategies on Heart Rate Variability During Post-Exercise Recovery: A Systematic Review and Meta-Analysis.

The objective of this systematic review and meta-analysis is to evaluate the influence of caffeine (CAF) intake strategies, taking into account their form, timing, and dosage, on heart rate variability (HRV) indices in the post-exercise recovery period. The meta-analysis adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and is registered in the PROSPERO database (CRD42023425885). A comprehensive literature search was carried out across MEDLINE, Web of Science, LILACS, and SCOPUS, concluding in May 2023. We concentrated on randomized clinical trials comparing CAF supplementation effects to placebo on HRV indices post-exercise in active adults aged 18 and above. The primary endpoint was the assessment of HRV indices, measured both prior to and following exercise. Of the 10 studies included, 7 were used for the meta-analysis, and all contributed to the systematic review. The research explored a variety of CAF strategies, spanning different forms (capsule, drink, gum), times (10, 45, 60 min) and doses (2.1 to 6.0 mg/kg). The outcomes revealed no substantial variations between the placebo and CAF conditions in terms of both the square root of the average of successive squared differences between adjacent RR intervals (RMSSD) (standardized mean difference (SMD) -0.03, 95% CI -0.265 to 0.197, p=0.77) and high frequency (HF) index (SMD -0.061, 95% CI -0.272 to 0.150, p=0.57). Furthermore, metaregression analysis, employing a fixed-effects model and accounting for the administered CAF doses, revealed no significant correlation between caffeine doses and HRV indices (p>0.05). In conclusion, there is moderate-certainty evidence suggesting that different CAF intake strategies, encompassing aspects such as form, time, and dose, do not have a significant impact on HRV indices recovery post-exercise (i.e., vagal modulation).

Acute and short-term beetroot juice nitrate-rich ingestion enhances cardiovascular responses following aerobic exercise in postmenopausal women with arterial hypertension: A triple-blinded randomized controlled trial

BackgroundThe increase in blood pressure (BP) levels in the postmenopausal period can be partly explained by the decrease in nitric oxide synthases (NOS). ObjectiveTo investigate the acute and one-week effects of beetroot juice nitrate-rich (BRJ-NO3−rich) ingestion on cardiovascular and autonomic performance in response to submaximal aerobic exercise in postmenopausal women with systemic arterial hypertension (SAH) who are physically inactive. MethodsFourteen postmenopausal women with SAH [mean (SD) age: 59(4) y; BMI (kg/m2): 29.2(3.1)] completed submaximal aerobic exercise bouts after an acute and a one-week intervention with BRJ in a placebo-controlled, randomized, triple-blind, crossover design. Participants ingested either BRJ (800 mg of NO3−) or placebo acutely and drank either BRJ (400 mg of NO3−) or placebo every day for the next six days. After two and ½ hours, they performed a session of aerobic submaximal aerobic exercise, and their systolic BP (SBP) and diastolic BP (DBP), flow-mediated dilation (FMD), heart rate (HR) recovery, and HR variability were measured. ResultsIn the post-exercise recovery period, SBP dropped significantly in the BRJ-NO3−rich group (−9.28 mmHg [95%CI: −1.68 to −16.88] ES: −0.65, p = 0.019) compared to placebo after acute ingestion. The FMD values increased after acute BRJ-NO3−rich on post-exercise (3.18 % [0.36 to 5.99] ES: 0.87, p = 0.031). After the one-week intervention, FMD values were higher in the BRJ-NO3−rich group before (4.5 % [1.62 to 7.37] ES: 1.21, p = 0.005) and post-exercise measurements (4.2 % [1.52 to 6.87] ES: 1.22, p = 0.004) vs. placebo. HRV indices with remarkable parasympathetic modulation to heart recovered faster on the BRJ-NO3−rich group than placebo group. No between-group differences were identified in values of HR post-exercise recovery in the 30s, 60s, 120s, 180s, and 300s. ConclusionsAcute and short-term BRJ-NO3−rich ingestion may enhance cardiovascular and autonomic behavior in response to aerobic exercise in postmenopausal women diagnosed with SAH. Clinical trial registry numberhttps://clinicaltrials.gov/ct2/show/NCT05384340.

Plasma measurements of the dual sugar test reveal carbohydrate immediately alleviates intestinal permeability caused by exertional heat stress.

The aim of this set of randomised cross-over studies was to determine the impact of progressive heat exposure and carbohydrate or protein feeding during exertional stress on small intestine permeability using a dual sugar test. In our previous work, and typically in the field, recovery of lactulose and l-rhamnose is measured cumulatively in urine. This follow-up study exploits our novel high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) protocol to accurately quantify the sugars in plasma. Endurance-trained participants completed experimental trial A (ET-A; n=8), consisting of 2h running at 60% in temperate, warm and hot ambient conditions, and/or experimental trial B (ET-B; n=9), consisting of 2h running at 60% in the heat while consuming water, carbohydrate or protein. Blood samples were collected and plasma lactulose (L) and l-rhamnose (R) appearance, after dual sugar solution ingestion at 90min of exercise, was quantified by HPAEC-PAD to measure plasma L/R and reveal new information about intestinal permeability immediately post-exercise and during recovery. In ET-A, plasma L/R increased immediately post-exercise in hot compared with temperate and warm conditions, while, in ET-B, carbohydrate alleviated this, and this information was otherwise missed when measuring urine L/R. Consuming carbohydrate or protein before and during exercise attenuated small intestine permeability throughout recovery from exertional heat stress. We recommend using the dual sugar test with quantification of plasma sugars by HPAEC-PAD at intervals to maximise intestinal permeability data collection in exercise gastroenterology research, as this gives additional information compared to urinary measurements. KEY POINTS: Intestinal permeability is typically assessed using a dual sugar test, by administering a drink containing non-metabolisable sugars (e.g. lactulose (L) and l-rhamnose (R)) that can enter the circulation by paracellular translocation when the epithelium is compromised, and are subsequently measured in urine. We demonstrate that our recently developed ion chromatography protocol can be used to accurately quantify the L/R ratio in plasma, and that measuring L/R in plasma collected at intervals during the post-exercise recovery period reveals novel acute response information compared to measuring 5-h cumulative urine L/R. We confirm that exercising in hot ambient conditions increases intestinal epithelial permeability immediately after exercise, while consuming carbohydrate or protein immediately before and during exercise attenuates this. We recommend using our dual sugar absorption test protocol to maximise intestinal epithelial permeability data collection in exercise gastroenterology research and beyond.

Astaxanthin supplementation counters exercise-induced decreases in immune-related plasma proteins.

Astaxanthin is a dark red keto-carotenoid found in aquatic animals such as salmon and shrimp, and algae (Haematococcus pluvialis). Astaxanthin has a unique molecular structure that may facilitate anti-oxidative, immunomodulatory, and anti-inflammatory effects during physiological stress. The primary objective of this study was to examine the efficacy of 4-week ingestion of astaxanthin in moderating exercise-induced inflammation and immune dysfunction using a multi-omics approach. This study employed a randomized, double blind, placebo controlled, crossover design with two 4-week supplementation periods and a 2-week washout period. Study participants were randomized to astaxanthin and placebo trials, with supplements ingested daily for 4 weeks prior to running 2.25 h at close to 70%VO2max (including 30 min of 10% downhill running). After the washout period, participants repeated all procedures using the counterbalanced supplement. The astaxanthin capsule contained 8 mg of algae astaxanthin. Six blood samples were collected before and after supplementation (overnight fasted state), immediately post-exercise, and at 1.5, 3, and 24 h-post-exercise. Plasma aliquots were assayed using untargeted proteomics, and targeted oxylipin and cytokine panels. The 2.25 h running bout induced significant muscle soreness, muscle damage, and inflammation. Astaxanthin supplementation had no effect on exercise-induced muscle soreness, muscle damage, and increases in six plasma cytokines and 42 oxylipins. Notably, astaxanthin supplementation countered exercise-induced decreases in 82 plasma proteins (during 24 h recovery). Biological process analysis revealed that most of these proteins were involved in immune-related functions such as defense responses, complement activation, and humoral immune system responses. Twenty plasma immunoglobulins were identified that differed significantly between the astaxanthin and placebo trials. Plasma levels of IgM decreased significantly post-exercise but recovered after the 24 h post-exercise recovery period in the astaxanthin but not the placebo trial. These data support that 4-week astaxanthin versus placebo supplementation did not counter exercise-induced increases in plasma cytokines and oxylipins but was linked to normalization of post-exercise plasma levels of numerous immune-related proteins including immunoglobulins within 24 h. Short-term astaxanthin supplementation (8 mg/day during a 4-week period) provided immune support for runners engaging in a vigorous 2.25 h running bout and uniquely countered decreases in plasma immunoglobulin levels.

The effect of insulin resistance on the heart rate recovery in healthy individuals with a low-to-moderate cardiovascular disease risk profile.

The association between insulin resistance (IR) and heart rate recovery index (HRRI) has been reported previously, but the cardiovascular disease (CVD) risk profile of the subjects was unclear in these studies. Therefore, we evaluated the association between IR and HRRI in apparently healthy individuals without metabolic syndrome who had a low-to-moderate CVD risk profile. A total of 182 eligible subjects were retrospectively included in the study. The subjects were divided into two groups according to the homeostasis model assessment of IR (HOMA-IR) value. HOMA-IR ≥2.5 was defined as IR (+) group (92 subjects), and <2.5 as IR (-) group (88 subjects). HRRI-2 was found by subtracting the heart rate at the second minute in the post-exercise recovery period from the maximum heart rate. Abnormal HRRI was defined as HRRI-2 that is ≤42 beats. The mean age of the patients was 41.91 ± 8.64 and 49.4% of them were female. Abnormal HRRI rates were significantly higher in the IR (+) group (37.2% vs 18.2%; p = 0.004). A negative correlation was detected between HRRI-2 and HOMA-IR (r = -0.416; p < 0.001). HOMA-IR (Odds Ratio (OR) = 1.57; confidence interval (CI) = 1.10-2.23; p = 0.013) and maximum heart rate during exercise (OR = 0.95; CI = 0.91-0.99; p = 0.013) as independent variables of abnormal HRRI. The HOMA-IR value of 2.82 was identified as an effective cutoff point for the prediction of abnormal HRRI (area under the curve: 0.658; CI: 0.570-0.746; p = 0.001). In this study, it was shown that IR without metabolic syndrome reduces HRRI in healthy individuals with a low-to-moderate CVD risk profile.

Effects of acute exercise on memory: Considerations of exercise intensity, post-exercise recovery period and aerobic endurance.

Accumulating research demonstrates that acute exercise can enhance long-term episodic memory. However, it is unclear if there is an intensity-specific effect of acute exercise on long-term episodic memory function and whether this is influenced by the post-exercise recovery period, which was the primary objective of this experiment. Another uncertainty in the literature is whether aerobic endurance influences the interaction between exercise intensity and post-exercise recovery period on long-term episodic memory function, which was a secondary objective of this study. With exercise intensity and post-exercise recovery period occurring as within-subject factors, and fitness as a between-subject factor, 59 participants (Mage = 20 years) completed 12 primary laboratory visits. These visits included a 20-min bout of exercise (Control, Moderate, and Vigorous), followed by a recovery period (1, 5, 10, and 15 min) and then a word-list episodic memory task, involving an encoding phase and two long-term recall assessments (20-min and 24-h delayed recall). The primary finding from this experiment was that moderate and vigorous-intensity exercise improved memory function when compared to a non-exercise control. A secondary finding was that individuals with higher levels of aerobic endurance, compared to their lesser fit counterparts, had greater memory performance after exercise (moderate or vigorous) when compared to after a control condition. Additionally, individuals with higher levels of aerobic endurance, compared to their lesser fit counterparts, generally performed better on the memory task with longer post-exercise recovery periods. Future research should carefully consider these parameters when evaluating the effects of acute exercise on long-term episodic memory.

Raw Eggs To Support Postexercise Recovery in Healthy Young Men: Did Rocky Get It Right or Wrong?

Egg protein is ingested during recovery from exercise to facilitate the postexercise increase in muscle protein synthesis rates and, as such, to support the skeletal muscle adaptive response to exercise training. The impact of cooking egg protein on postexercise muscle protein synthesis is unknown. We sought to compare the impact of ingesting unboiled (raw) compared with boiled eggs during postexercise recovery on postprandial myofibrillar protein synthesis rates. In a parallel design, 45 healthy, resistance-trained young men (age: 24 y; 95% CI: 23, 25 y) were randomly assigned to ingest 5 raw eggs (∼30 g protein), 5 boiled eggs (∼30 g protein), or a control breakfast (∼5 g protein) during recovery from a single session of whole-body resistance-type exercise. Primed continuous l-[ring-13C6]-phenylalanine infusions were applied, with frequent blood sampling. Muscle biopsies were collected immediately after cessation of resistance exercise and at 2 and 5 h into the postexercise recovery period. Primary (myofibrillar protein synthesis rates) and secondary (plasma amino acid concentrations) outcomes were analyzed using repeated-measures (time × group) ANOVA. Ingestion of eggs significantly increased plasma essential amino acid (EAA) concentrations, with 20% higher peak concentrations following ingestion of boiled compared with raw eggs (time × group: P < 0.001). Myofibrillar protein synthesis rates were significantly increased during the postexercise period when compared with basal, postabsorptive values in all groups (2-4-fold increase: P < 0.001). Postprandial myofibrillar protein synthesis rates were 20% higher after ingesting raw eggs [0.067%/h; 95% CI: 0.056, 0.077%/h; effect size (Cohen d): 0.63], and 18% higher after ingesting boiled eggs (0.065%/h; 95% CI: 0.058, 0.073%/h; effect size: 0.69) when compared with the control breakfast (0.056%/h; 95% CI: 0.048, 0.063%/h), with no significant differences between groups (time × group: P = 0.077). The ingestion of raw, as opposed to boiled, eggs attenuates the postprandial rise in circulating EAA concentrations. However, postexercise muscle protein synthesis rates do not differ after ingestion of 5 raw compared with 5 boiled eggs in healthy young men. This trial was registered at the Nederlands Trial Register as NL6506 (www.trialregister.nl).

Exercise Selection and Common Injuries in Fitness Centers: A Systematic Integrative Review and Practical Recommendations.

Weight resistance training (RT) is an essential component of physical conditioning programs to improve the quality of life and physical fitness in different ages and populations. This integrative review aimed to analyze the scientific evidence on the relationship between exercise selection and the appearance of musculoskeletal injuries in physical fitness centers (PFC). The PubMed or Medline, EMBASE or Science Direct, Google Scholar and PEDro databases were selected to examine the available literature using a Boolean algorithm with search terms. The review process was performed using the five-stage approach for an integrative review and it was reported according to the PRISMA in Exercise, Rehabilitation, Sport Medicine and Sports Science (PERSiST) guidelines. A total of 39 peer-reviewed articles (Price index = 71.7%) met the inclusion criteria and evaluated the link between exercise selection and the incidence of injuries in exercisers who regularly attend PFC. Most injuries occur to the shoulders, elbows, vertebrae of the spine, and knees. Although the injury etiologies are multifactorial, the findings of the reviewed articles include the impacts of overuse, short post-exercise recovery periods, poor conditioning in the exercised body areas, frequent use of heavy loads, improper technique in certain exercises, and the abuse of performance- and image-enhancing drugs. Practical recommendations addressed to clinical exercise physiologists, exercise professionals, and health professionals are given in this paper. The exercise selection in RT programs requires professional supervision and adhering to proper lifting techniques and training habits that consider the anatomical and biomechanical patterns of the musculoskeletal structures, as well as genetic, pedagogical, and methodological aspects directly related to the stimulus–response process to mitigate the occurrence of RT-related injuries in PFC.

Effect of citrulline malate supplementation on muscle function and bioenergetics during short-term repeated bouts of fatiguing exercise

ABSTRACT Citrulline malate (CM) has been shown to improve muscle performance in healthy participants during a single exercise session. Yet, within the framework of exercises repeated at close time interval, the consequences of CM ingestion on mechanical performance are controversial and the bioenergetics side remains undocumented. The aim of this double-blind placebo-controlled study was to evaluate in vivo the effect of short-term (7 doses in 48 h) oral administration of CM upon gastrocnemius muscle function and bioenergetics using non-invasive multimodal NMR techniques in healthy rats. The experimental protocol consisted of two 6-min bouts of fatiguing exercise spaced by an 8-min recovery period. CM treatment did not affect the basal bioenergetics status and increased the half-fatigue time during the first exercise bout. With exercise repetition, it prevented PCr cost alteration and decreased both the glycolytic ATP production and the contractile ATP cost in working muscle, but these changes were not associated to any improvement in mechanical performance. In addition, CM did not influence the replenishment of high-energy phosphorylated compounds during the post-exercise recovery periods. Therefore, short-term CM administration enhances muscle bioenergetics throughout fatiguing bouts of exercise repeated at close time interval but this enhancement does not benefit to mechanical performance.

Effect Of Co-ingestion Of Carbohydrate With Milk Post-exercise In Women By Menstrual Cycle Phase

PURPOSE: The effect of the post-exercise milk ingestion or co-ingestion of carbohydrate with milk contributes to the recovery of substrate and exercise capacity. However, little information exists on the effect of post-exercise milk consumption on substrate responses and subsequent performance in women. Estrogen, levels of which change with the menstrual cycle, increases fat metabolism. Therefore, one must consider the menstrual cycle when examining the effect of post-exercise milk ingestion in women. Here we aimed to assess the effects of a milk-based beverage on substrate recovery and subsequent exercise performance in women by menstrual cycle phase. METHODS: Twelve women with regular menstrual cycles participated (age, 22.2 ± 2.0 years; height, 1.59 ± 0.55 m; weight, 55.1 ± 6.0 kg; body mass index, 21.7 ± 1.9 kg/m2). The subjects performed glycogen-depleting exercise in the early follicular phase (EF) or late follicular phase (LF), followed by a 240-min recovery period, during which they ingested a carbohydrate beverage (control [CON] group) or carbohydrate dissolved in milk (MILK group). After 240 min, the subjects completed a performance test to exhaustion at 90% maximal workload capacity. Baseline blood samples were taken for the analysis of estradiol and progesterone levels. At t = 0, 120, and 240 min post-exercise, blood samples were taken for the determination of blood glucose, lactate, free fatty acid (FFA), and insulin levels. RESULTS: Serum estradiol levels were significantly higher in the LF (CON and MILK) than in the EF (CON and MILK) (p < 0.01). Serum progesterone levels were not significantly in each group at baseline (p = 0.054). The area under the curve (AUC) of FFA from t = 120 to t = 240 was significantly greater in the MILK (EF and LF) than in the CON (EF and LF) group (12.9 ± 2.3, 13.3 ± 3.6, 18.9 ± 5.5, 18.7 ± 5.6 for the EF + CON, LF + CON, EF + MILK, and LF + MILK, respectively; p < 0.05). There was a significant positive correlation between performance test completion and the AUC of FFA from t = 0 to t = 240 in each group (EF + CON, r = 0.69, p < 0.05; LF + CON, r = 0.59, p < 0.05; EF + MILK, r = 0.83, p < 0.01; LF + MILK, r = 0.65, p < 0.05). CONCLUSION: Our results suggest that circulating substrate and hormone levels during the short post-exercise recovery period may be affected by differences in beverage intake but not the menstrual cycle.

The initial delay to mitotic activity in primary cultures of equine satellite cells is reduced by combinations of growth factors.

Satellite cell (SC) activation is defined as the time frame during which the stem cell becomes poised to reenter G1 of the cell cycle. The growth factors and events leading to full mitotic activation in equine SCs remain largely unknown. Insulin-like growth factor I (IGF-I), hepatocyte growth factor (HGF), and fibroblast growth factor 2 (FGF2) are sequentially transcribed during the muscle repair and recovery period following strenuous exercise in adult horses. Expression of IGF-I occurs within 24 h of the postexercise recovery period suggesting it may affect early SC actions. As a first step, gluteus medius muscle cryosections from adult horses (n = 9) were examined for the presence of central nuclei (CN), a marker of SC addition to the fiber. Results demonstrate few CN fibers prior to exercise with a 3-fold increase (P = 0.05) 24 h postexercise. Cultures of SC (n = 4 isolates) were treated with 100 ng/mL IGF-I for varying times prior to measurement of myogenic events. Results demonstrate that IGF-I does not affect the initial lag period, proliferation, or subsequent differentiation of equine SC in vitro (P > 0.05). However, media containing a combination of IGF-I and 10 ng/mL FGF2 and 25 ng/mL HGF hastens (P < 0.05) the time to S-phase entry in fresh isolates of SCs. Media supplementation with optimal concentrations of FGF2, HGF, or a combination of HGF and FGF2 suppresses (P < 0.05) the percentage of myogenin immunopositive SCs to levels below that found in control- or IGF-I-treated SCs. These results provide new insight into the combinatorial roles growth factors play during equine SC myogenesis.

Prior aerobic exercise mitigates the decrease in serum osteoglycin and lipocalin-2 following high-glucose mixed-nutrient meal ingestion in young men.

Osteoglycin (OGN) and lipocalin-2 (LCN2) are hormones that can be secreted by bone and have been linked to glucose homeostasis in rodents. However, the endocrine role of these hormones in humans is contradictory and unclear. We examined the effects of exercise and meal ingestion on circulating serum OGN and LCN2 levels in eight healthy males {age: 28 [25, 30] years [median ± interquartile range (IQR)] and body mass index [BMI]: 24.3 [23.6, 25.5] kg/m2}. In a randomized crossover design, participants ingested a high-glucose (1.1 g glucose/kg body wt) mixed-nutrient meal (45% carbohydrate, 20% protein, and 35% fat) on a rest-control day and 3 and 24 h after aerobic cycling exercise (1 h at 70%-75% V̇o2peak). Acute aerobic exercise increased serum LCN2 levels immediately after exercise (∼61%), which remained elevated 3-h postexercise (∼55%). In contrast, serum OGN remained similar to baseline levels throughout the 3-h postexercise recovery period. The ingestion of a high-glucose mixed-nutrient meal led to a decrease in serum OGN at 90-min (approximately -17%) and 120-min postprandial (approximately -44%), and a decrease in LCN2 at 120-min postprandial (approximately -26%). Compared with the control meal, prior exercise elevated serum OGN and LCN2 levels at 120-min postprandial when the meal was ingested 3-h (OGN: ∼74% and LCN2: ∼68%) and 24-h postexercise (OGN: ∼56% and LCN2: ∼16%). Acute exercise increases serum LCN2 and attenuates the postprandial decrease in OGN and LCN2 following high-glucose mixed-nutrient meal ingestion. The potential endocrine role of circulating OGN and LCN2 in humans warrants further investigation.NEW & NOTEWORTHY We provide novel evidence that OGN and LCN2 decrease 120 min after ingesting a high-glucose mixed-nutrient meal in healthy adults. Acute aerobic exercise increases circulating LCN2 for up to 3-h postexercise, whereas circulating OGN remains similar to baseline. Despite differing postexercise responses, postprandial LCN2 and OGN are elevated when the high-glucose meal is ingested 3-h and 24-h postexercise. Findings support that OGN and LCN2 are dynamically linked to energy homeostasis in humans.

Promotion of the Glutathione Defense System From Aronia Berry Extract With Acute Aerobic Exercise: A Double-Blind Randomized Controlled Trial in Healthy Adults.

ObjectivesThis study aimed to examine the protective effects of Aronia melanocarna berry extract (ABE) supplementation against the acute aerobic exercise (AAE) – induced oxidative stress in healthy subjects.MethodsA 8-week, randomized, double-blind, parallel, placebo-controlled trial were conducted with 70 healthy middle-aged adults. We assessed a battery of AAE-induced oxidate stress biomarkers at pre-exercise, immediately post-exercise, and 30-min post-exercise. The AAE challenge model, as a treadmill exercise for 30 minutes at 60% VO2max, was applied to load oxidative stress at the end of the study. A linear mixed-effect model was used to test differences of safety and effectiveness between two groups and Pearson's correlation coefficients assessed the statistical association.ResultsThe AAE-induced time course-dependent oxidative stress was well-observed in the placebo group regarding the glutathione peroxidase activity and glutathione availability for antioxidant defense; and erythrocyte malondialdehyde, interleukin-6, and lactate levels for oxidative damage. Meanwhile, the ABE supplementation improved the glutathione defense system by increasing glutathione availability and glutathione peroxidase activity during exercise and post-exercise recovery periods. In addition, the scatter plot and linear regression analysis revealed strong negative correlations of GSH availability with oxidized LDL and erythrocyte malonaldehyde levels.ConclusionsThese finding suggest ABE supplementation might affect to improve antioxidant defense mechanism in healthy adults with low fruit and vegetable intake.Funding SourcesThis research was supported by the BK21 FOUR (Fostering Outstanding Universities for Research) funded by the Ministry of Education (MOE, Korea) and the National Research Foundation of Korea (NRF), and the Bio & Medical Technology Development Program of the National Research Foundation (NRF), funded by the Ministry of Science & ICT (2012M3A9C4048761).

The Immediate and Sustained Effects of Exercise-Induced Hemodynamic Response on Executive Function During Fine Motor-Cognitive Tasks Using Functional Near-Infrared Spectroscopy.

Several studies have shown that acute exercise has a small positive effect on cognitive performance. However, it is still unclear what type of exercise has a sustained impact on cognitive performance during post-exercise recovery. Therefore, the purpose of our study was to investigate cognitive performance at the behavioral level, and their neural correlates after a 10-minute post-exercise recovery period with two different types of exercise intervention (high-intensity interval exercise (HIIE) vs. Moderate-intensity continuous exercise (MCE)). A total of 29 healthy young adults (7 women) between the ages of 19 and 33 with fair to good cardiovascular fitness were submitted to two different exercise protocols and a recovery session. Cognitive function was assessed using a digital Trail-Making-Test (dTMT). Cortical activity in the prefrontal and the motor cortex using functional near-infrared spectroscopy (fNIRS) was measured before, after acute exercise, and during recovery. The statistical analysis of fNIRS data was performed by comparing the slope and mean of the hemodynamic response. High levels of hemodynamic responses were observed in the prefrontal and motor cortex on the brain during performing the dTMT while walking from pre- to post-exercise and decreased again in post-recovery, accompanied by improvement and maintenance of cognitive performance. Notably, a high hemodynamic response in the left motor area of the brain was maintained by HIIE in post-recovery compared with MCE. The high cortical activation in the left motor area from post-exercise to recovery for the HIIE group may be due to the additional availability of neural resources for fine motor and postural control by high-intensity exercise-induced fatigue. Additionally, the improved cognitive performance may have effectively utilized the available neural resources in the frontal lobe, depending on the condition (sitting and walking) and the two types of exercise protocol (HIIE and MCE).

Systemic Cardiovascular Adjustments during Recovery from Passive Heat Stress

Much like exercise, heat stress elicits profound autonomic and hemodynamic responses which may persist in the post‐heating recovery period. In the same way that the post‐exercise recovery period contributes to vascular adaptation with exercise training, the post‐heating recovery period may potentiate beneficial vascular adaptation with chronic heat therapy. In contrast to the well‐studied post‐exercise recovery period, few studies have investigated the systemic cardiovascular adjustments accompanying recovery from whole‐body, passive heat stress. Hypothesis: We hypothesized that mean arterial pressure would be reduced in the post‐heating recovery period due to sustained post‐heating elevations in systemic vascular conductance and despite elevations in cardiac output.MethodsFour subjects (1 F, 27±5 yrs, BMI 26±3 kg/m2) completed two experimental visits (randomized, crossover design) comprising either 60 min of passive heating (HT) or a time‐matched thermoneutral control intervention (TN). Rectal temperature, skin temperature (six sites), brachial blood pressure, cardiac output (open‐circuit acetylene washin method), and heart rate were assessed at baseline, at the end of HT or TN interventions, and for 2 hours of recovery in a 21.4±0.4°C room (REC‐HT/TN). Values are reported as the change in each variable from pre‐intervention baseline and presented as means ± SD. Paired t tests were used to compare responses between conditions.ResultsHeating increased mean body temperature (HT +1.26±0.23°C, TN ‐0.04±0.07°C) (P &lt; 0.001). After 40 min of recovery, mean body temperature tended to remain elevated following heating (HT +0.48±0.18, TN +0.19±0.09°C, P = 0.06). There were no differences in mean body temperature between conditions at 80 min (P = 0.31) or 120 min of recovery (P = 0.37). Mean arterial pressure was reduced at the end of heating (HT ‐12±6, TN +5±4 mmHg, P &lt; 0.01) as elevations in systemic vascular conductance (HT +55±18, TN ‐6±6 mL·min‐1·mmHg‐1, P &lt; 0.01) were not offset by increases in cardiac output (HT +3.5±0.8, TN ‐0.2±0.6 L/min, P &lt; 0.01) sustained by an increased heart rate (HT +40±8, TN ‐2±6 bpm, P &lt; 0.01). Mean arterial pressure tended to remain reduced 40 min into the post‐heating recovery period (REC‐HT ‐6±6, REC‐TN +1±3 mmHg, P = 0.16) due to a tendency for elevations in systemic vascular conductance (REC‐HT +11±21, REC‐TN ‐6±15 mL·min‐1·mmHg‐1, P = 0.08). Cardiac output (REC‐HT +0.5±1.5, REC‐TN ‐0.5±1.1 L/min, P = 0.07) and heart rate (REC‐HT +6±9, REC‐TN ‐3±5 bpm, P = 0.07) also appeared to remain elevated 40 min into the post‐heating recovery period. Mean arterial pressure appeared similar between conditions from 80 minutes of recovery onward (P = 0.85) while systemic vascular conductance (P = 0.12) and cardiac output (P = 0.19) tended to remain elevated. These variables appeared similar between conditions after 120 min of recovery.ConclusionsRecovery from heat stress is marked by sustained hypotension, vasodilation, and elevations in cardiac output and heart rate. These post‐heating recovery responses may facilitate vascular adaptation with heat therapy.

The effect of beta-alanine supplementation on reducing blood lactate concentration and improving sports performance

Background and Objective: Dietary supplements are a common strategy used by athletes and adults to improve physical function and recovery, and muscle mass. Beta-alanine (βA) is an inessential amino acid that can improve the performance of athletes. βA is one of the dietary supplements involved in delaying or reducing fatigue and is of interest to athletes, coaches, and sports scientists. This study aimed to investigate the effect of 4-week βA supplementation on soccer athletes' onset of blood lactate accumulation (OBLA) in leg and chest press training volume and running time of 800 m. Materials and Methods: A total of 20 football athletes were randomly divided into two βA supplement and placebo groups. The supplement group (6.4 g of βA per day) and placebo group (6.4 g of starch per day) were eaten for 4 weeks after the briefing session and pretest on blood lactate concentration indices, leg and chest press volume training, and running time of 800 m. Functional evaluations and posttest blood samples were collected from the individuals on day 28. Results: The findings show that OBLA considerably rose right away following activity in both the supplement and placebo groups. It fell in both groups 15 min after activity, with the supplement group showing a significant difference (P ≥ 0.05). In either research group, as well as between pretest and posttest times, there was no statistically significant difference in the training volume of the chest press and leg press activity (P ≥ 0.05). There was a significant temporal interaction of 800 m between the supplement and placebo groups. Conclusion: Short-term βA supplementation reduced OBLA during the postexercise recovery period, while no effect on footballers' performance was observed in these tests.

Effects of carbohydrate-electrolyte dissolved alkaline electrolyzed water on physiological responses during exercise under heat stress in physically active men.

PurposeThis study investigated the effects of 1400 mL intake of alkaline electrolyzed water (AEW) or purified water (PW) into which carbohydrate-electrolyte (CE) was dissolved on improving physiological responses during exercise under heat stress.MethodsThis double-blinded, crossover randomized controlled trial included 10 male participants who completed two exercise trials in a hot environment (35 °C, ambient temperature, and 50% relative humidity) after consuming CE-dissolved PW (P-CE) or CE-dissolved AEW (A-CE). The exercise trial consisted of running for 30 min on a treadmill (at an intensity corresponding to 65% of heart rate reserve adjusted for heat stress conditions) and repeated sprint cycling (10 × 7-s maximal sprint cycling), with a 35-min rest interval between the two exercises, followed by a 30-min post-exercise recovery period. Before and after running, and after cycling, the participants drank P-CE (hydrogen concentration of 0 ppm, pH 3.8) or A-CE (0.3 ppm, pH 4.1). Blood samples were obtained before, during (rest interval between running and cycling), and post-exercise.ResultsRepeated sprint performance and oxidative stress response did not differ between the P-CE and A-CE trials. A-CE consumption significantly attenuated the increase in blood lactate concentration during the running exercise but not during repeated sprint cycling under heat stress conditions.ConclusionOur findings suggested that A-CE did not significantly affect repeated sprint performance; however, the attenuated elevation in blood lactate by A-CE ingestion implies a partial enhancement of endurance performance during submaximal exercise under heat stress.