Bout Of Strenuous Exercise Research Articles

95 - Changes in urinary excretion of oxidative nucleic acid modifications in the week following Copenhagen Marathon 2018, Denmark

Introduction The relationship between oxidative stress and physical activity is very complex. A single bout of exercise seems to induce oxidative stress, whereas regular exercise has been suggested to reduce oxidative stress. Here, we investigated the changes in oxidative RNA and DNA modifications in the week following a single bout of excessive exercise. Methods This observational study was conducted in relation to the Copenhagen Marathon 2018, Denmark. Male, non-professional runners (n=20) were examined before-, immediate after-, four days after-, and seven days after the marathon. Twenty-four-hour (24h) urine excretion of 8-oxo-7,8-dihydro-guanosine(8-oxoGuo) and 8-oxo-7,8-dihydro-2’-deoxyguanosine(8-oxodG) were determined using ultra performance liquid chromatography-tandem mass spectrometry as a measurement of oxidative RNA and DNA modifications, respectively. Results The runners were healthy, non-smokers with cardiorespiratory fitness level above average ((median (inter quartile range(IQR))): Age: 29.6(24.3;37.2) years, body mass index: 24.3(23.8;25.2) kg/m2, VO2max: 52.7(49.5;55.7) ml/min/kg). The baseline level of 8-oxoGuo and 8-oxodG were (median(IQR)): 33.9(29.2; 38.1) and 27.9(21.4; 30.8) nmol/24h, respectively. The level of 8-oxoGuo presented a marginal trend towards increase immediate after the marathon compared to baseline (Δmedian(IQR): 3.9 (-2.4;8.7) nmol/24h, P=0.12), no difference was found in 8-oxodG (-1.8(-4.3;2.6) nmol/24h, P=0.62). On day four, we observed a decrease in both 8-oxoGuo (-2.1(-8.4;0.1) nmol/24h, P=0.02) and 8-oxodG (-2.5(-4.0;0.1) nmol/24h, P Conclusion A single bout of strenuous exercise did not result in immediate increase in oxidative RNA and DNA modifications, however a marginal trend toward increased level of oxidative RNA modifications was observed. Both oxidative RNA and DNA modifications decreased four days after the marathon. The clinical implications of these results remain to be elucidated.

Vascular Nitric Oxide–Superoxide Balance and Thrombus Formation after Acute Exercise

An acute bout of strenuous exercise in humans results in transient impairment of nitric oxide (NO)-dependent function, but it remains unknown whether this phenomenon is associated with increased risk of thrombotic events after exercise. This study aimed to evaluate effects of a single bout of exhaustive running in mice on the balance of vascular NO/reactive oxygen species production, and on thrombogenicity. At different time points (0, 2, and 4 h) after exercise and in sedentary C57BL/6 mice, the production of NO and superoxide (O2) in aorta was measured by electron paramagnetic resonance spin trapping and by dihydroethidium/high-performance liquid chromatography-based method, respectively, whereas collagen-induced thrombus formation was analyzed in a microchip-based flow-chamber system (total thrombus-formation analysis system). We also measured pre- and postexercise plasma concentration of nitrite/nitrate and 6-keto-PGF1α. An acute bout of exhaustive running in mice resulted in decreased production of NO and increased production of O2 in aorta, with maximum changes 2 h after completion of exercise when compared with sedentary mice. However, platelet thrombus formation was not changed by exercise as evidenced by unaltered time to start of thrombus formation, capillary occlusion time, and total thrombogenicity (area under the flow pressure curve) as measured in a flow-chamber system. Strenuous exercise increased the plasma concentration of nitrite but did not affect nitrate and 6-keto-PGF1α concentrations. An acute bout of strenuous exercise in mice reduced NO and in parallel increased O2 production in aorta. This response was most pronounced 2 h after exercise. Surprisingly, the reduced NO and increased O2 production in mice after exercise did not result in increased platelet-dependent thrombogenicity. These results show that transient reduction in NO bioavailability does not modify thromboresistance in healthy mice after exercise.

Cardiovascular biomarkers modified by exercise

When managing patients with cardiovascular disease (CVD), clinical assessment has its limitations and clinicians usually need additional tools to help with the diagnosis. Cardiovascular biomarkers are one such tool to diagnose the condition promptly and accurately, and guide the therapeutic approach. While physical exercise is recommended for the prevention and therapy of several disorders including CVD, exercise can modify blood concentrations of several laboratory variables. In effect, the finding of abnormal levels of cardiac biomarkers after an acute bout of strenuous exercise has been a cause of concern. However, it is now starting to emerge that levels of some biomarkers outside the normal range in healthy physically active subjects, rather than reflecting an underlying disease, may indicate an adaptive response to exercise. This means that laboratory results in these individuals need to really be interpreted with caution.

Inhalation of hydrogen gas elevates urinary 8-hydroxy-2'-deoxyguanine in Parkinson's disease.

Hyposmia is one of the earliest and the most common symptoms in Parkinson’s disease (PD). The benefits of hydrogen water on motor deficits have been reported in animal PD models and PD patients, but the effects of hydrogen gas on PD patients have not been studied. We evaluated the effect of inhalation of hydrogen gas on olfactory function, non-motor symptoms, activities of daily living, and urinary 8-hydroxy-2′-deoxyguanine (8-OHdG) levels by a randomized, double-blinded, placebo-controlled, crossover trial with an 8-week washout period in 20 patients with PD. Patients inhaled either ~1.2–1.4% hydrogen-air mixture or placebo for 10 minutes twice a day for 4 weeks. Inhalation of low dose hydrogen did not significantly influence the PD clinical parameters, but it did increase urinary 8-OHdG levels by 16%. This increase in 8-OHdG is markedly less than the over 300% increase in diabetes, and is more comparable to the increase after a bout of strenuous exercise. Although increased reactive oxygen species is often associated with toxicity and disease, they also play essential roles in mediating cytoprotective cellular adaptations in a process known as hormesis. Increases of oxidative stress by hydrogen have been previously reported, along with its ability to activate the Nrf2, NF-κB pathways, and heat shock responses. Although we did not observe any beneficial effect of hydrogen in our short trial, we propose that the increased 8-OHdG and other reported stress responses from hydrogen may indicate that its beneficial effects are partly or largely mediated by hormetic mechanisms. The study was approved by the ethics review committee of Nagoya University Graduate School of Medicine (approval number 2015-0295). The clinical trial was registered at the University Hospital Medical Information Network (identifier UMIN000019082).

Oral Supplementation with Baker's Yeast Beta Glucan Is Associated with Altered Monocytes, T Cells and Cytokines following a Bout of Strenuous Exercise.

Exercise and physical labor in extreme environmental conditions causes transient decreases in immune cell and cytokine concentrations, likely increasing the susceptibility to opportunistic infection. Baker's yeast beta glucan (BYBG) has been previously demonstrated to be an effective countermeasure in athletes, but its effectiveness in individuals of average fitness under similar physical stress is unknown. The purpose of this study was to determine if 10 days of oral supplementation with BYBG could modify previously observed suppression of monocytes, T cells, circulating and whole blood LPS-stimulated cytokines due to strenuous exercise. Venous blood samples were collected from 109 healthy volunteers prior to, immediately after, 2 and 4 h post-exercise. Monocyte and T cell concentration, cell-surface receptor expression and serum and LPS-stimulated cytokines were assessed. BYBG significantly (P < 0.05) altered total and classic monocyte concentration and expression of CD38, CD80, CD86, TLR2, and TLR4 on monocyte subsets. BYBG also significantly increased CD4+ and CD8+ T cell concentration and the exercise response of CCR7+/CD45RA- central memory (TCM) cells. Likewise, BYBG significantly (P < 0.05) altered serum IFN-γ and IL-2, and LPS-stimulated IFN-γ, IL-2, IL-4, and IL-7. Taken together these data support the hypothesis that oral BYBG supplementation modulates the expected exercise response for individuals of average fitness. This may result in a decrease in susceptibility to opportunistic infections after strenuous exercise.

Rapid Communication: Dietary selenium improves skeletal muscle mitochondrial biogenesis in young equine athletes1

Exercise is known to promote mitochondrial biogenesis in skeletal muscle as well as enhance mitochondrial function and efficiency in human and rodent models. These adaptations help to decrease exercise-associated production of reactive oxygen species, which can negatively affect health and performance if antioxidant mechanisms are overwhelmed. Little is known about the adaptations of mitochondria in response to exercise training in the growing horse or if supplementation with a dietary antioxidant can improve mitochondrial function. To evaluate the separate and combined effects of selenium (Se) supplementation, training, and an acute strenuous exercise bout on mitochondrial adaptations in young horses, 30 American Quarter Horse yearlings were randomly assigned to an exercise training group or a no-training group and, within each group, received either 0.1 or 0.3 mg Se/kg DM for 14 wk. The study was split into 2 phases (wk 0 to 8 and wk 9 to 14), with half of the trained horses switched to the opposite dietary treatment in Phase 2. At the end of each phase, all horses underwent a 120-min submaximal exercise test (SET; SET 1 and SET 2). Biopsies of the middle gluteal muscle were collected before and after each phase of the study and in response to each SET and analyzed for markers of mitochondrial number and function. At rest, horses receiving 0.3 mg Se/kg DM had higher citrate synthase activity (P = 0.021) than horses receiving 0.1 mg Se/kg DM, indicating higher mitochondrial content. In contrast, cytochrome c oxidase (CCO) activity was not affected by dietary Se overall, but horses that were dropped from 0.3 mg Se/kg DM to 0.1 mg Se/kg DM during Phase 2 showed a decrease (P = 0.034) in integrated CCO activity from wk 9 to 14, suggesting impaired mitochondrial function. Mitochondrial enzyme activities were unaffected by an acute, strenuous exercise bout (SET 1 and SET 2). Our relatively low-intensity exercise training protocol did not appear to induce functional mitochondrial adaptations. However, elevated dietary Se may impart beneficial effects on mitochondrial biogenesis during growth and training. A more strenuous exercise training protocol should be investigated to determine the potential benefits of elevated dietary Se for elite equine athletes.

Whey Protein Supplementation Enhances Whole Body Protein Metabolism and Performance Recovery after Resistance Exercise: A Double-Blind Crossover Study.

No study has concurrently measured changes in free-living whole body protein metabolism and exercise performance during recovery from an acute bout of resistance exercise. We aimed to determine if whey protein ingestion enhances whole body net protein balance and recovery of exercise performance during overnight (10 h) and 24 h recovery after whole body resistance exercise in trained men. In a double-blind crossover design, 12 trained men (76 ± 8 kg, 24 ± 4 years old, 14% ± 5% body fat; means ± standard deviation (SD)) performed resistance exercise in the evening prior to consuming either 25 g of whey protein (PRO; MuscleTech 100% Whey) or an energy-matched placebo (CHO) immediately post-exercise (0 h), and again the following morning (~10 h of recovery). A third randomized trial, completed by the same participants, involving no exercise and no supplement served as a rested control trial (Rest). Participants ingested [15N]glycine to determine whole body protein kinetics and net protein balance over 10 and 24 h of recovery. Performance was assessed pre-exercise and at 0, 10, and 24 h of recovery using a battery of tests. Net protein balance tended to improve in PRO (P = 0.064; effect size (ES) = 0.61, PRO vs. CHO) during overnight recovery. Over 24 h, net balance was enhanced in PRO (P = 0.036) but not in CHO (P = 0.84; ES = 0.69, PRO vs. CHO), which was mediated primarily by a reduction in protein breakdown (PRO < CHO; P < 0.01. Exercise decreased repetitions to failure (REP), maximal strength (MVC), peak and mean power, and countermovement jump performance (CMJ) at 0 h (all P < 0.05 vs. Pre). At 10 h, there were small-to-moderate effects for enhanced recovery of the MVC (ES = 0.56), mean power (ES = 0.49), and CMJ variables (ES: 0.27–0.49) in PRO. At 24 h, protein supplementation improved MVC (ES = 0.76), REP (ES = 0.44), and peak power (ES = 0.55). In conclusion, whey protein supplementation enhances whole body anabolism, and may improve acute recovery of exercise performance after a strenuous bout of resistance exercise.

Efficacy of wearing compression garments during post-exercise period after two repeated bouts of strenuous exercise: a randomized crossover design in healthy, active males

BackgroundThe efficacy of wearing [a] compression garment (CG) between repeated bouts of exercise within a same day has not been fully understood. The present study determined the effect of wearing a CG after strenuous exercise sessions (consisting of sprint exercise, resistance exercise, drop jump) twice a day on exercise performance, muscle damage, and inflammatory responses.MethodsEleven physically active males (age, 22.7 ± 0.9 years; height, 175.7 ± 6.7 cm; body mass, 73.6 ± 10.2 kg; BMI, 23.8 ± 2.7 kg/m2) performed two trials (a randomized crossover design), consisting of the trial with either wearing a whole-body CG during post-exercise period (CG trial) or the trial with wearing a normal garment without specific pressure (CON trial). Two exercise sessions were conducted in the morning (09:00–10:00, Ex1) and afternoon (14:00–15:00, Ex2). Immediately after completing 60 min of each exercise, the subjects in the CG trial changed into a whole-body CG. Time-course changes in exercise performance (bench press power, jump performances, repeated sprint ability), blood variables (lactate, glucose, myoglobin, creatine kinase, interleukin-6, leptin), and scores of subjective feeling (fatigue, muscle soreness) were compared between the CG and CON trials before Ex1 (8:40), immediately before Ex2 (14:00, 4 h after Ex1), 4 h after Ex2 (19:00), and 24 h after the onset of Ex1 (9:00).ResultsTwo bouts of exercise significantly decreased performances of counter movement jump (main effect for time: P = 0.04, F = 3.75, partial η2 = 0.27) and rebound jump (main effect for time: P = 0.00, F = 12.22, partial η2 = 0.55), while no significant difference was observed between the two trials (interaction: P = 0.10, F = 1.96, partial η2 = 0.16 for counter movement jump, P = 0.93, F = 0.01, partial η2 = 0.001 for rebound jump). Repeated sprint ability (power output during 10 × 6 s maximal sprint, 30-s rest periods between sprints) did not differ significantly between the two trials at any time points. Power output during bench press exercise was not significantly different between the two trials (interaction: P = 0.46, F = 0.99, partial η2 = 0.09 for Ex1, P = 0.74, F = 0.38, partial η2 = 0.04 for Ex2, P = 0.22, F = 1.54, partial η2 = 0.13 for 24 h after the onset of Ex1). Serum myoglobin, creatine kinase, leptin, and plasma interleukin-6 were not significantly different between the two trials (interaction: P = 0.16, F = 2.23, partial η2 = 0.18 for myoglobin; P = 0.39, F = 0.81, partial η2 = 0.08 for creatine kinase; P = 0.28, F = 1.30, partial η2 = 0.13 for leptin; P = 0.34, F = 1.05, partial η2 = 0.12 for interleukin-6). Muscle soreness at 24 h during post-exercise period was significantly lower in the CG trial than in the CON trial for pectoralis major muscle (P = 0.04), while the value was inversely lower in the CON trial for hamstring (P = 0.047).ConclusionsWearing a whole-body CG during the post-exercise period after two bouts of strenuous exercise sessions separated with 4 h of rest did not promote recovery of muscle function for lower limb muscles nor did it attenuate exercise-induced muscle damage in physically active males.

Effects of a Second Bout of Strenuous Exercise on Appetite Regulating Hormones and Food Intake

Strenuous exercise typically shifts the hormonal milieu towards acute appetite suppression, which may persist for 30 min post‐exercise. Since no compensatory drive to eat occurs following exercise, a negative energy balance transpires. Although this exercise‐induced‐anorexia has been examined at different times of the day, it is still unclear whether a compensatory shift eventually occurs, or if this phenomenon is exacerbated with repeated exercise on the same day. This study investigated the effects of two bouts of strenuous exercise on appetite regulating hormones, perceptions of appetite, and food intake. In a randomized crossover design, 18 moderately fit (VO2max 44±6 ml·kg·min−1) Canadian Armed Forces members (14 male, 4 female) volunteered to complete two 8‐h trials. One trial involved completing two 2‐h circuits of military activities of varying intensities interspersed with 2 h of rest (EX), the other involved 8 h of rest (REST). Participants consumed military rations ad libitum during the trials, and were provided with a supper ration pack to consume at home. Visual analogue scales for appetite as well as venous plasma concentrations of GLP‐1, PYY, acylated ghrelin, and leptin were assessed throughout the trials. Participants expended significantly more energy during the EX trial, expending 1649±322 kcal during the 4 h of exercise vs. 404±68 kcal over the same time period during REST. Although the hormonal changes during EX favoured appetite suppression with: 1) elevated PYY levels during EX as compared to REST (53.9±13.8 pg/ml vs. 47.2±9.0 pg/ml), 2) supressed acylated ghrelin levels during EX as compared to REST (75.0±49.7 pg/ml vs. 109.6±59.4 pg/ml), and 3) larger increases in GLP‐1 levels from immediately following exercise to 1 h post‐exercise (3.3±2.7 pg/ml – 4.8±3.2 pg/ml), as compared to the equivalent time periods during the REST trial (3.6±1.6 pg/ml – 3.8±1.7 pg/ml); no significant differences were found between conditions for food energy consumed either during the eight hours in the lab (EX:2055±680 kcal vs. REST:1910±630 kcal), or during the subsequent meal consumed at home (EX:868±410 kcal vs. REST:1014±701 kcal). Similarly no significant trial effects emerged for any measure of appetite sensation. These results demonstrate that energy expenditure and energy intake remain uncoupled even following 2 bouts of arduous exercise. Hormonal responses following the second exercise bout were not significantly different from those found after the first exercise bout, suggesting the hormonal response following acute exercise can be reproduced throughout the day. Even when energy requirements increase by over 1200 kcal, energy intake over the entire day remains remarkably similar (EX: 2923±802 kcal vs. REST: 2924±1066 kcal). In the absence of a compensatory drive to eat, additional exercise bouts further augment the negative energy balance found during acute exercise.Support or Funding InformationThis research was funded in part by Defence Research &amp; Development Canada (DRDC).

Effects of a single bout of strenuous exercise on platelet activation in female ApoE/LDLR−/− mice

Strenuous physical exercise leads to platelet activation that is normally counterbalanced by the production of endothelium-derived anti-platelet mediators, including prostacyclin (PGI2) and nitric oxide (NO). However, in the case of endothelial dysfunction, e.g. in atherosclerosis, there exists an increased risk for intravascular thrombosis during exercise that might be due to an impairment in endothelial anti-platelet mechanisms.In the present work, we evaluated platelet activation at rest and following a single bout of strenuous treadmill exercise in female ApoE/LDLR−/− mice with early (3-month-old) and advanced (7-month-old) atherosclerosis compared to female age-matched WT mice. In sedentary and post-exercise groups of animals, we analyzed TXB2 generation and the expression of platelet activation markers in the whole blood ex vivo assay. We also measured pre- and post-exercise plasma concentration of 6-keto-PGF1α, nitrite/nitrate, lipid profile, and blood cell count.Sedentary 3- and 7-month-old ApoE/LDLR−/− mice displayed significantly higher activation of platelets compared to age-matched wild-type (WT) mice, as evidenced by increased TXB2 production, expression of P-selectin, and activation of GPIIb/IIIa receptors, as well as increased fibrinogen and von Willebrand factor (vWf) binding. Interestingly, in ApoE/LDLR−/− but not in WT mice, strenuous exercise partially inhibited TXB2 production, the expression of activated GPIIb/IIIa receptors, and fibrinogen binding, with no effect on the P-selectin expression and vWf binding. Post-exercise down-regulation of the activated GPIIb/IIIa receptor expression and fibrinogen binding was not significantly different between 3- and 7-month-old ApoE/LDLR−/− mice; however, only 7-month-old ApoE/LDLR−/− mice showed lower TXB2 production after exercise. In female 4–6-month-old ApoE/LDLR−/− but not in WT mice, an elevated pre- and post-exercise plasma concentration of 6-keto-PGF1α was observed. In turn, the pre- and post-exercise plasma concentrations of nitrite (NO2−) and nitrate (NO3−) were decreased in ApoE/LDLR−/− as compared to that in age-matched WT mice.In conclusion, we demonstrated overactivation of platelets in ApoE/LDLR−/− as compared to WT mice. However, platelet activation in ApoE/LDLR−/− mice was not further increased by strenuous exercise, but was instead attenuated, a phenomenon not observed in WT mice. This phenomenon could be linked to compensatory up-regulation of PGI2-dependent anti-platelet mechanisms in ApoE/LDLR−/− mice.

Behavior of plasma interferon-gamma with graded exercise in individuals with varied body mass index and age: Risk stratification of predisposition to inflammation

Background: Increasing body mass index (BMI) and age predispose one to cardiometabolic disorders and their complications. Cardiometabolic disorders and their complications are associated with excessive inflammation leading to further exacerbation. Regular moderate exercise modulates inflammatory processes. Interferon-gamma (IFN-γ) is an anti-inflammatory cytokine which protects against excessive inflammation. We assessed the plasma levels of IFN-γ after different grades of exercise in normal healthy individuals with variable BMI and age. Aims and Objective: To study the behavior of plasma IFN-γ with graded exercise in individuals with varied BMI and age. Materials and Methods: A total of 40 healthy volunteers (21 males and 19 females) between the ages of 18 and 35 years were enlisted into the study. Each volunteer performed a bout of moderate exercise, a bout of severe exercise, and 1 month regular moderate exercise under supervision. Mean and standard deviation (SD) of BMI was 22.26 ?3.3 kg/m2. BMI ranged between 19 kg/m2 and 26 kg/m2. Blood samples from cubital vein were collected before a bout of moderate exercise (baseline), after moderate exercise, after a bout of severe exercise, and at the end of 1 month of regular moderate exercise. Plasma IFN-γ was measured by the enzyme-linked immunosorbent assay technique. Results: Mean and SD of IFN-γ at baseline (no exercise) was 10.54 ?2.21 pg/ml. After a bout of moderate exercise, its levels increased to 21.21 ?1.34 pg/ml. Mean and SD of IFN-γ after a bout of strenuous exercise was 8.32 ?1.45 pg/ml. The IFN-γ levels increased to 38.98 ?2.33 pg/ml at the end of 1 month of regular moderate exercise. Its levels were higher in healthy individuals with lower BMI and lower age. But on the performance of 1 month of regular moderate exercise, the IFN-γ levels of higher age group and higher BMI came closer to that of the lower age group with lower BMI. This indicates that regular physical activity confers protection against excessive inflammation in spite of higher BMI and age. Conclusion: Although an increase in physical stress, BMI and age predispose one to inflammation, regular physical activity of moderate nature protects against inflammation by increasing levels of anti-inflammatory cytokine, IFN-γ.

Rapid Communication: Dietary selenium improves skeletal muscle mitochondrial biogenesis in young equine athletes.

Exercise is known to promote mitochondrial biogenesis in skeletal muscle as well as enhance mitochondrial function and efficiency in human and rodent models. These adaptations help to decrease exercise-associated production of reactive oxygen species, which can negatively affect health and performance if antioxidant mechanisms are overwhelmed. Little is known about the adaptations of mitochondria in response to exercise training in the growing horse or if supplementation with a dietary antioxidant can improve mitochondrial function. To evaluate the separate and combined effects of selenium (Se) supplementation, training, and an acute strenuous exercise bout on mitochondrial adaptations in young horses, 30 American Quarter Horse yearlings were randomly assigned to an exercise training group or a no-training group and, within each group, received either 0.1 or 0.3 mg Se/kg DM for 14 wk. The study was split into 2 phases (wk 0 to 8 and wk 9 to 14), with half of the trained horses switched to the opposite dietary treatment in Phase 2. At the end of each phase, all horses underwent a 120-min submaximal exercise test (SET; SET 1 and SET 2). Biopsies of the middle gluteal muscle were collected before and after each phase of the study and in response to each SET and analyzed for markers of mitochondrial number and function. At rest, horses receiving 0.3 mg Se/kg DM had higher citrate synthase activity ( = 0.021) than horses receiving 0.1 mg Se/kg DM, indicating higher mitochondrial content. In contrast, cytochrome oxidase (CCO) activity was not affected by dietary Se overall, but horses that were dropped from 0.3 mg Se/kg DM to 0.1 mg Se/kg DM during Phase 2 showed a decrease ( = 0.034) in integrated CCO activity from wk 9 to 14, suggesting impaired mitochondrial function. Mitochondrial enzyme activities were unaffected by an acute, strenuous exercise bout (SET 1 and SET 2). Our relatively low-intensity exercise training protocol did not appear to induce functional mitochondrial adaptations. However, elevated dietary Se may impart beneficial effects on mitochondrial biogenesis during growth and training. A more strenuous exercise training protocol should be investigated to determine the potential benefits of elevated dietary Se for elite equine athletes.

Antioxidant-induced reductive stress has untoward consequences on the brain microvasculature.

Antioxidant-induced reductive stress has untoward consequences on the brain microvasculature.

Exercise-induced hypoalgesia: Pain tolerance, preference and tolerance for exercise intensity, and physiological correlates following dynamic circuit resistance exercise

ABSTRACTPrevious research has demonstrated significant decreases in pain perception in healthy individuals following both aerobic and upper body resistance exercise, but research on circuit training has been limited. The purpose of the study was to determine the effects of a strenuous bout of dynamic circuit resistance exercise on pain threshold and pain tolerance in conjunction with changes in blood lactate levels, heart rate (HR), and perceived exertion. A sample of 24 college-age students participated in 2 sessions: (1) a maximal strength testing session and (2) a circuit training bout of exercise that consisted of 3 sets of 12 repetitions with a 1:1 work to rest ratio at 60% one-repetition maximum (1-RM) predicted from a three-repetition maximum (3-RM) for 9 exercises. Participants exhibited increases in pain tolerance, blood lactate levels, HR and perceived exertion following resistance exercise. Preference for exercise intensity was positively correlated with lactate post exercise and tolerance for exercise intensity was positively correlated with pain tolerance and lactate post exercise. In conclusion, this is the first study to demonstrate increases in pain tolerance following a dynamic circuit resistance exercise protocol and disposition for exercise intensity may influence lactate and pain responses to circuit resistance exercise.

A 10 km time trial running bout acutely increases the number of angiogenic Tcells in the peripheral blood compartment of healthy males.

What is the central question of the study? Are CD31+ angiogenic T (TANG ) cells preferentially mobilized in response to acute exercise? What is the main finding and its importance? Our study reveals that TANG cells are redistributed into the circulation in response to acute strenuous exercise, but to a lesser extent than CD31- Tcells. Of the TANG cells mobilized, TANG cells expressing CXCR4 show greater redistribution compared with CXCR4- TANG cells. Stromal-derived factor 1-α does not appear to play a role in the redistribution of TANG cells expressing CXCR4. The results suggest that a single bout of strenuous exercise might provide a short vasculogenic window, which could benefit the vascular system by redistributing CD31+ TANG cells. CD31+ Tcells have been documented to possess vasculogenic properties and have been termed 'angiogenic T cells' (TANG cells). No study to date has fully characterized the effect of acute exercise on TANG cells. Twelve male participants aged 24-45years undertook a running 10km time trial, with peripheral blood samples taken before, immediately after and 1h postexercise for quantification of TANG cells and subsequent CXCR4 cell surface expression by flow cytometry. The TANG cells demonstrated a 102% increase in number in the peripheral circulation immediately postexercise compared with pre-exercise levels, followed by a large egress (50%) from the circulation in total TANG cells 1h postexercise. This was due to changes in both CD4+ and CD8+ TANG cells, with CD8+ TANG cells displaying greater ingress (123%) and egress (52%) compared with CD4+ TANG cells (ingress, 83%; egress, 37%). The cell surface expression intensity of CXCR4 was affected only on CD8+ TANG cells, with a significant increase in cell surface expression immediately postexercise versus pre-exercise levels. The CD31- Tcells displayed greater redistribution than CD31+ TANG cells (119versus 102%). CXCR4-expressing TANG cells showed greater response to acute exercise than CXCR4- cells, which was accompanied by large changes in CXCR4 ligand SDF-1α. The results show that acute exercise increases TANG cells in the circulation in response to an acute exercise stressor. Additionally, CXCR4 cell surface expression appears to be increased in response to exercise, which may result from the direct upregulation of CXCR4 on the T-cell surface or could be due to CD31+ Tcells being redistributed into the blood expressing greater levels of CXCR4.

Individual responses in biomarkers of health after marathon and half-marathon running: is age a factor in troponin changes?

Although strenuous physical activity is known to cause notable perturbations in blood chemistries, only few studies exist observing exercise-induced simultaneous changes in biomarkers of health status. We compared markers of muscle, cardiovascular, renal, hepatic and inflammatory status at baseline and at 3-h and at 48-h postrace in recreational runners who successfully completed either a marathon (mean age 27 ± 13 years, finishing time 199 ± 8 min, n = 4) or half-marathon (mean age 38 ± 13 years, finishing time 131 ± 6 min, n = 6) race. Significant postrace changes occurred in myoglobin (p < .001), creatinine kinase (p < .01), CK-MB-mass (p < .01), high sensitivity troponin I (p < .05), high sensitivity troponin T (p < .05), brain natriuretic peptide (p < .001), creatinine (p < .01), aminotransferase enzymes (p < .001 for AST and p < .01 for ALT), uric acid (p < .001) cortisol (p < .01), C-reactive protein (p < .05), leukocytes (p < .001), haematocrit (p < .05) and mean corpuscular volume (p < .01). In comparison between the two types of exercise, marathon running lead to more pronounced responses in myoglobin, CK-MB-mass, ALT, AST, lactate and phosphate. Notable elevations in troponin levels were observed only in young participants (<30 years), most strikingly in those ≤20 years of age. The data indicates that prolonged running leads to distinct biomarker alterations, which should be considered in the assessment of health status after recent acute bouts of strenuous exercise. The observations suggesting more pronounced cardiac troponin responses in young individuals warrant further studies in larger populations.

Regional adaptation of collagen in skeletal muscle to repeated bouts of strenuous eccentric exercise.

This study investigated the injured region-specific alterations of factors related to the "repeated bout effect" (RBE), i.e., when the first bout of eccentric exercise generates resistance to injuries from the second bout of the same exercise. Wistar rats were divided into single injury (SI) and repeated injury (RI) groups. The right gastrocnemius muscle was subjected to a bout of eccentric contractions (ECs) at the age of 14weeks in the SI group and 10 and 14weeks in the RI group. The number of injured fibers after the last bout of ECs was lower in RI than in SI. In the SI group, injured fibers after ECs were mainly located in the superficial region of muscle and expressed myosin heavy chain (MHC) IIx and IIb. Prior to the second bout of ECs, the fiber-type composition in the RI group showed decreased MHC IIx and IIb fibers and increased MHC IIa fibers compared with those in the SI group. However, most regenerating fibers showed either MHC IIx or IIb expression. Heat shock protein 72 and total collagen contents in whole muscle were higher in the RI group than in the SI group; however, only the collagen expression in the RI group was more intense than that in the SI group in the superficial region of muscle. These findings suggest that increased collagen may play a more important role in the injured region of muscle than the other factors in RBE.

Endothelial glycocalyx integrity is preserved in young, healthy men during a single bout of strenuous physical exercise.

In the present study we aimed to evaluate whether oxidative stress and inflammation induced by strenuous exercise affect glycocalyx integrity and endothelial function. Twenty one young, untrained healthy men performed a maximal incremental cycling exercise - until exhaustion. Markers of glycocalyx shedding (syndecan-1, heparan sulfate and hyaluronic acid), endothelial status (nitric oxide and prostacyclin metabolites - nitrate, nitrite, 6-keto-prostaglandin F(1alpha)), oxidative stress (8-oxo-2'-deoxyguanosine) and antioxidant capacity (uric acid, non-enzymatic antioxidant capacity) as well as markers of inflammation (sVCAM-1 and sICAM-1) were analyzed in venous blood samples taken at rest and at the end of exercise. The applied strenuous exercise caused a 5-fold increase in plasma lactate and hypoxanthine concentrations (p<0.001), a fall in plasma uric acid concentration and non-enzymatic antioxidant capacity (p<10(-4)), accompanied by an increase (p=0.003) in sVCAM-1 concentration. Plasma 6-keto-prostaglandin F(1alpha) concentration increased (p=0.006) at exhaustion, while nitrate and nitrite concentrations were not affected. Surprisingly, no significant changes in serum syndecan-1 and heparan sulfate concentrations were observed. We have concluded, that a single bout of severe-intensity exercise is well accommodated by endothelium in young, healthy men as it neither results in evident glycocalyx disruption nor in the impairment of nitric oxide and prostacyclin production.

Acute Changes in Inflammatory Biomarker Levels in Recreational Runners Participating in a Marathon or Half-Marathon.

BackgroundStrenuous physical activity activates the participant’s immune responses; however, few studies exist, observing exercise-induced simultaneous changes in mediators of inflammation.MethodsWe examined individual responses in soluble urokinase-type plasminogen activator receptor (suPAR), a marker of immune activation, soluble endocytic receptor for haptoglobin-hemoglobin complexes (CD163), a marker of monocyte-macrophage activation, C-reactive protein (CRP), and pro- and anti-inflammatory cytokines from blood samples drawn at baseline, at 3- and 48-h post-races from recreational runners who successfully completed the marathon (199 ± 8 min, n = 4) or half-marathon (132 ± 4 min, n = 4) run. For comparisons, biomarkers reflecting muscle, heart, kidney, and liver functions were measured.ResultsSignificant 3-h post-race increases occurred in levels of suPAR (p < 0.01), CD163 (p < 0.05), white blood cells (p < 0.001), pro-inflammatory cytokines, interleukin-6 (IL-6) (p < 0.001), IL-8 (p < 0.05), and anti-inflammatory cytokine IL-10 (p < 0.05), whereas tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) remained relatively stable. Full-marathon running lead to more pronounced increases in suPAR, CD163, IL-8, and IL-10 than half-marathon running. In addition, 3-h post-race increases of all these parameters correlated significantly with changes in serum TNF-α and cortisol. The 48-h levels of serum suPAR and both pro- and anti-inflammatory cytokines had decreased to baseline levels, whereas CRP, a marker of acute phase response, increased in those with the most prominent IL-6 and IL-10 elevations in their preceding samples. The highest suPAR, CRP, IL-6, TNF-α, IL-10, and cortisol levels were noted in the individual with the most severe post-race fatigue.ConclusionsProlonged running increases mediators of inflammation in an exercise-dose-dependent manner which should be considered in the assessment of health status of physically active individuals after recent acute bouts of strenuous exercise.

Prolonged health benefits by alteration in plasma Interleukin-6 and fasting blood sugar with graded exercise in individuals with varied BMI

Background: Exercise confers good health. Unaccustomed exercise is stressful and has harmful effects. Interleukin-6 (IL-6) is a marker of inflammation which increases with physical stress. We observed the changes in plasma Interleukin-6 and Fasting blood Sugar with different grades of exercise in healthy individuals of varied BMI. Methods: Fifty four healthy volunteers (26 males and 28 females) in the age group 18 to 30 years not used to any form of exercise, were recruited. BMI of the subjects varied between 16.5 to 26.5 kg/m2. Subject performed a bout of moderate exercise; a bout of strenuous exercise, followed by one month regular moderate exercise using Shuttle Walk Test. Plasma IL-6 was estimated before and after exercise by Elisa technique. Exercise protocol used was Standardized Shuttle Walk. FBS was assessed just before moderate exercise on first day and 24 hours after moderate and strenuous exercise and on last day of one month of regular moderate exercise. Results: IL-6 level was significantly higher after a bout of moderate exercise compared to baseline (mean & SD: 32.6 1.9 pg/ml and 63.1 2.8 pg/ml respectively). It increased significantly after strenuous exercise (116.2 4.1pg/ml). IL-6 level dipped significantly after one month of regular moderate exercise (15.9 0.7pg/ml). FBS decreased 24 hours after a bout of moderate exercise (mean & SD: 92.9 mg/dl and 83.2 5.4 mg/dl respectively). It decreased further 24 hours after a bout of strenuous exercise (78.4 5.6 mg/dl). It was lowest after a month of regular moderate exercise (73.96 3.1 mg/dl). There was significant positive correlation between BMI and IL-6 for strenuous exercise for subjects above BMI of 23kg/m2. There was significant positive correlation between FBS and BMI for subjects of BMI above 23kg/m2. Conclusions: Unaccustomed physical stress in form of a bout of moderate or strenuous exercise increases IL-6 level. Regular moderate exercise has a buffering effect by preventing the shoot up of IL-6 when challenged with acute physical stress. Exercise has a good “after effect” on FBS even up to 24 hours. Positive correlation between higher BMI and FBS indicates the importance of maintaining BMI within prescribed limits. Key words: Interleukin-6, FBS, BMI, Exercise, Inflammation