Bout Of Exhaustive Exercise Research Articles

Antioxidant effect of organic purple grape juice on exhaustive exercise

This study aimed to assess the potential protective effect of organic purple grape juice (PGJ) on oxidative stress produced by an exhaustive exercise bout in rats. To test this hypothesis, rats were acutely treated with organic PGJ (Vitis labrusca) and subsequently submitted to an exhaustive exercise bout. Parameters of oxidative stress, such as thiobarbituric acid reactive species (TBARS) levels, 2',7',-dichlorofluorescein diacetate (DCFH-DA) oxidation, and nonprotein sulfhydryl levels (NP-SH) in the brain, skeletal muscle, and blood, were evaluated. Enzyme activity of Na(+),K(+)-ATPase, Ca(2+)-ATPase, and δ-aminolevulinate dehydratase (δ-ALA-D) in the brain, skeletal muscle, and blood were also assayed. Statistical analysis showed that the exhaustive exercise bout increased TBARS levels and DCFH-DA oxidation, and decreased NP-SH levels in rat tissue. Ca(2+)-ATPase activity was increased in groups exposed to both exercise and PGJ treatment. The results indicate that organic PGJ intake was able to protect against the oxidative damage caused by an exhaustive exercise bout in different rat tissues.

Growth-Hormone Responses to Consecutive Exercise Bouts With Ingestion of Carbohydrate Plus Protein

Endocrine responses to repeated exercise have barely been investigated, and no data are available regarding the mediating influence of nutrition. On 3 occasions, participants ran for 90 min at 70% VO2max (R1) before a second exhaustive treadmill run at the same intensity (R2; 91.6 ± 17.9 min). During the intervening 4-hr recovery, participants ingested either 0.8 g sucrose · kg-1 · hr-1 with 0.3 g · kg-1 · hr-1 whey-protein isolate (CHO-PRO), 0.8 g sucrose · kg-1 · hr-1 (CHO), or 1.1 g sucrose · kg-1 · hr-1 (CHO-CHO). The latter 2 solutions therefore matched the former for carbohydrate or for available energy, respectively. Serum growth-hormone concentrations increased from 2 ± 1 μg/L to 17 ± 8 μg/L during R1 considered across all treatments (M ± SD; p ≤ .01). Concentrations were similar immediately after R2 irrespective of whether CHO or CHO-CHO was ingested (19 ± 4 μg/L and 19 ± 5 μg/L, respectively), whereas ingestion of CHO-PRO produced an augmented response (31 ± 4 μg/L; p ≤ .05). Growth-hormone-binding protein concentrations were unaffected by R1 but increased similarly across all treatments during R2 (from 414 ± 202 pmol/L to 577 ± 167 pmol/L; p ≤ .01), as was the case for plasma total testosterone (from 9.3 ± 3.3 nmol/L to 14.7 ± 4.6 nmol/L; p ≤ .01). There was an overall treatment effect for serum cortisol (p ≤ .05), with no specific differences at any given time point but lower concentrations immediately after R2 with CHO-PRO (608 ± 133 nmol/L) than with CHO (796 ± 278 nmol/L) or CHO-CHO (838 ± 134 nmol/L). Ingesting carbohydrate with added whey-protein isolate during short-term recovery from 90 min of treadmill running increases the growth-hormone response to a second exhaustive exercise bout of similar duration.

The sustainability of VO2max: effect of decreasing the workload

The study examined the maintenance of VO(2max) using VO(2max) as the controlling variable instead of power. Therefore, ten subjects performed three exhaustive cycling exercise bouts: (1) an incremental test to determine VO(2max) and the minimal power at VO(2max) (PVO(max)), (2) a constant-power test at PVO(max) and (3) a variable-power test (VPT) during which power was varied to control VO(2) at VO(2max). Stroke volume (SV) was measured by impedance in each test and the stroke volume reserve was calculated as the difference between the maximal and the average 5-s SV. Average power during VPT was significantly lower than PVO(max) (238±79 vs. 305±86W; p<0.0001). All subjects, regardless of their VO(2max) values and/or their ability to achieve a VO(2max) plateau during incremental test, were able to sustain VO(2max) for a significantly longer time during VPT compared to constant-power test (CPT) (958±368s vs. 136±81s; p<0.0001). Time to exhaustion at VO(2max) during VPT was correlated with the power drop in the first quarter of the time to exhaustion at VO(2max) (r=0.71; p<0.02) and with the stroke volume reserve (r=0.70, p=0.02) but was not correlated with VO(2max). This protocol, using VO(2max) rather than power as the controlling variable, demonstrates that the maintenance of exercise at VO(2max) can exceed 15min independent of the VO(2max) value, suggesting that the ability to sustain exercise at VO(2max) has different limiting factors than those related to the VO(2max) value.

The effects of hypoxia acclimation, exercise training and fasting on swimming performance in juvenile qingbo (Spinibarbus sinensis)

To investigate the effects of hypoxia acclimation, exercise training and fasting on the swimming performance of juvenile qingbo (Spinibarbus sinensis), we measured the critical swimming speed (U (crit)), resting and excess post-exercise oxygen consumption (EPOC) of control, hypoxia-acclimated, exercise-acclimated and fasting fish at 25°C. The muscle and plasma metabolites before and after a bout of exhaustive exercise (produced by chasing) were also measured. The fish were acclimated to hypoxia (48h at 1.0mgL(-1), 12.5% air saturation), exercise training (2weeks at 60% of U (crit), 6h daily) or fasting (2weeks). All treatments resulted in significantly lower resting oxygen consumption ([Formula: see text]O(2rest)) but had no effect on the magnitude of EPOC. Hypoxia acclimation had no effect on U (crit) or peak post-exercise oxygen consumption ([Formula: see text]O(2peak)) but produced a higher depletion of muscle [glycogen] post-chasing (P<0.05). Exercise training produced a significant increase in U (crit), higher liver [glycogen] pre-chasing and higher depletion of muscle [glycogen] post-chasing. Fasting resulted in a significant decrease in U (crit), [Formula: see text]O(2peak), muscle and liver [glycogen]. These results suggested that hypoxia acclimation had no effect on swimming performance in qingbo. Exercise training produced improved swimming performance by increasing the stored energy and the metabolic capacity of muscle. Fasting had a profound effect on swimming performance through both decreased respiratory capacity and a depleted energy store.

Adenosine-5'-triphosphate (ATP) supplementation improves low peak muscle torque and torque fatigue during repeated high intensity exercise sets

BackgroundIntracellular concentrations of adenosine-5’-triphosphate (ATP) are many times greater than extracellular concentrations (1–10 mM versus 10–100 nM, respectively) and cellular release of ATP is tightly controlled. Transient rises in extracellular ATP and its metabolite adenosine have important signaling roles; and acting through purinergic receptors, can increase blood flow and oxygenation of tissues; and act as neurotransmitters. Increased blood flow not only increases substrate availability but may also aid in recovery through removal of metabolic waste products allowing muscles to accomplish more work with less fatigue. The objective of the present study was to determine if supplemental ATP would improve muscle torque, power, work, or fatigue during repeated bouts of high intensity resistance exercise.MethodsSixteen participants (8 male and 8 female; ages: 21–34 years) were enrolled in a double-blinded, placebo-controlled study using a crossover design. The participants received either supplemental ATP (400 mg/d divided into 2 daily doses) or placebo for 15 d. After an overnight fast, participants underwent strength and fatigue testing, consisting of 3 sets of 50 maximal knee extensions performed on a Biodex® leg dynamometer.ResultsNo differences were detected in high peak torque, power, or total work with ATP supplementation; however, low peak torque in set 2 was significantly improved (p < 0.01). Additionally, in set 3, a trend was detected for less torque fatigue with ATP supplementation (p < 0.10).ConclusionsSupplementation with 400 mg ATP/d for 15 days tended to reduce muscle fatigue and improved a participant’s ability to maintain a higher force output at the end of an exhaustive exercise bout.

Effects of Priming Exercise on V˙O2 Kinetics and the Power-Duration Relationship

This study aimed to investigate the influence of prior heavy- and severe-intensity exercise on the oxygen uptake (V·O₂) kinetics and the power-duration relationship. Ten cyclists performed 13 exercise tests during a 4-wk period, consisting of a ramp test to determine the gas exchange threshold (GET) and the peak V·O₂, followed by a series of square-wave tests to exhaustion under three conditions: no prior exercise (control), prior heavy exercise (6 min at a work rate above GET but below critical power [CP)], and prior severe exercise (6 min at a work rate above the CP). Pulmonary gas exchange was measured throughout the exhaustive exercise bouts and the parameters of the power-duration relationship (CP and the curvature constant, W') were determined from the linear work-time model. Prior heavy exercise increased the amplitude of the primary V·O₂ response (by ∼ 0.19 ± 0.28 L·min(-1), P = 0.001), reduced the V·O₂ slow component trajectory (by 0.04 ± 0.09 L·min(-2), P = 0.002), and increased the time to exhaustion (by ∼ 52 ± 92 s, P = 0.005). The CP was unchanged (control vs prior heavy: 284 ± 47 vs 283 ± 44 W; 95% confidence interval, -7 to 5 W), whereas the W' was increased by heavy-intensity priming (16.0 ± 4.8 vs 18.7 ± 4.8 kJ; 95% confidence interval, 0.3-5.2 kJ). Severe-intensity exercise had a similar effect on the V·O₂ kinetics but had no effect on the time to exhaustion, the CP (275 ± 45 W), or the W' (16.7 ± 4.7 kJ). Prior heavy-intensity exercise primes the V·O₂ kinetics and increases the amount of work that can be performed above the CP.

Effect of Zinc and Selenium Supplementation on Serum Testosterone and Plasma Lactate in Cyclist After an Exhaustive Exercise Bout

Zinc and selenium are essential minerals and have roles for more than 300 metabolic reactions in the body. The purpose of this study was to investigate how exhaustive exercise affects testosterone levels and plasma lactate in cyclists who were supplemented with oral zinc and selenium for 4weeks. For this reason, 32 male road cyclists were selected equally to four groups: PL group, placebo; Zn group, zinc supplement (30mg/day); Se group, selenium supplement (200μg/day); and Zn-Se group, zinc-selenium supplement. After treatment, free, total testosterone, and lactate levels of subjects were determined before and after exhaustive exercise. Resting total, free testosterone, and lactate levels did not differ significantly between groups, and were increased by exercise (P > 0.05). Serum total testosterone levels in Zn group were higher than in Se group after exercise (P < 0.05). Serum-free testosterone levels in the Zn group were higher than the other groups (P < 0.05).There was an insignificant difference between levels of lactate in the four groups after exercise (P > 0.05). The results showed that 4-week simultaneous and separately zinc and selenium supplementation had no significant effect on resting testosterone and lactate levels of subjects who consume a zinc and selenium sufficient diet. It might be possible that the effect of zinc supplementation on free testosterone depends on exercise.

Acute exercise activates AMPK and eNOS in the mouse aorta.

Exercise can prevent endothelial cell (EC) dysfunction and atherosclerosis even in the absence of improvements in plasma lipids. However, the mechanisms responsible for these effects are incompletely understood. In this study we examined in mice whether an acute bout of exercise activates enzymes that could prevent EC dysfunction, such as AMP-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS). We also examined whether exercise alters known regulators of these enzymes. C57BL/6 mice underwent a single bout of exhaustive treadmill exercise after which their aortas were analyzed for activation of AMPK, AMPK regulatory proteins, eNOS, and various enzymes that, like AMPK, activate eNOS. We found that such exercise acutely activates both AMPK and eNOS in the whole aorta and that the magnitude of these effects correlated with both the distance run and activation of the AMPK regulatory proteins silent information regulator-1 (SIRT1)-LKB1 and CaMKKβ. In contrast, Akt, PKA, PKG, and Src, other kinases known to activate eNOS, were unaffected. Immunohistochemical analysis revealed that AMPK and eNOS were both activated in the ECs of the aorta. This study provides the first evidence that an acute bout of exercise activates AMPK and eNOS in the endothelium of the aorta. The results also suggest that AMPK likely is the principal activator of eNOS in this setting and that its own activation may be mediated by both SIRT1-LKB1 and CaMKKβ.

Critical Power Concept Adapted for the Specific Table Tennis Test: Comparisons Between Exhaustion Criteria, Mathematical Modeling, and Correlation with Gas Exchange Parameters

The purposes of this study were to determine and to compare the critical power concept adapted for the specific table tennis test (critical frequency - C F ) estimated from 5 mathematical models and using 2 different exhaustion criteria (voluntary and technical exhaustions). Also, it was an aim to assess the relationship between C F estimated from mathematical models and respiratory compensation point (RCP), peak oxygen uptake ( V˙O (2PEAK)) and minimal intensity at which V˙O (2PEAK) ( F V˙O (2PEAK)) appears. 9 male table tennis players [18(1) years; 62.3(4.4) kg] performed the maximal incremental test and 3-4 exhaustive exercise bouts to estimate C F s (balls · min (-1)). The exhaustion time and C F obtained were independent of the exhaustion criteria. The C F from 3-parameter model [45.2(7.0)-voluntary, 43.2(5.6)-technical] was lower than C F estimated by linear 2-parameter models, frequency-time (-1) [53.5(3.6)-voluntary, 53.5(3.5)-technical] and total ball thrown-time [52.2(3.5)-voluntary, 52.2(3.5)-technical] but significantly correlated. C F values from 2 linear models were significantly correlated with RCP [47.4(3.4) balls · min (-1)], and C F values of the linear and nonlinear models were correlated with F V˙O (2PEAK) [56.7(3.4) balls · min (-1)]. However, there were no significant correlations between C F values and V˙O (2PEAK) [49.8(1.1)ml · kg (-1) · min (-1)]. The results were not modified by exhaustion criteria. The 2 linear and non-linear 2-parameter models can be used to estimate aerobic endurance in specific table tennis tests.

Short-Term Treadmill Running as a Model for Studying Cell-Free DNA Kinetics In Vivo

Increased plasma concentrations of cell-free DNA (cf-DNA) are considered a hallmark of various clinical conditions. Despite intensive research in this field, limited data are available concerning the time course of release and clearance of cf-DNA in vivo. We extracted cf-DNA from plasma samples taken before and immediately after a 10-km cross-country run, and from samples taken before, immediately after, and 30 min after exhaustive short-term treadmill exercise. The contribution of nuclear (nDNA) and mitochondrial DNA (mtDNA) was measured by quantitative real-time PCR. The incremental treadmill exercise setup was exploited to delineate the precise sequencing and timing of cf-nDNA, lactate, and high-mobility group box 1 protein (HMGB1) release during the exercise and recovery phases. Postexercise plasma cf-nDNA concentrations in cross-country and treadmill runners were significantly increased, by 7.6-fold and 9.9-fold, respectively (P < 0.001). cf-nDNA concentrations were not correlated with age, sex, or body mass index. Plasma concentrations of cf-nDNA and HMGB1 in postexercise samples of treadmill runners were significantly correlated (r = 0.84; P = 0.004). cf-mtDNA concentrations were not affected by treadmill exercise. Time-course analyses demonstrated that cf-nDNA is released within minutes after the onset of exercise and is rapidly cleared from the circulation after the cessation of exercise. Nearly congruent kinetics for cf-nDNA, lactate, and HMGB1 were observed during the exercise phase. A single bout of exhaustive short-term treadmill exercise constitutes a versatile model system suitable for addressing basic questions about cf-DNA biology.

Effects of BCAA, Arginine and Carbohydrate Combined Drink on Post-Exercise Biochemical Response and Psychological Condition

This study investigated the effects of BCAA, arginine and carbohydrate combined beverage (BCAA Drink) on biochemical responses and psychological conditions during recovery after a single bout of exhaustive exercise. Fourteen healthy males were assigned to drink either BCAA Drink (BA trial) or placebo (PL trial) on two sessions separated by 2 weeks. Blood samples of each subject were collected before exercise, 0, 10, 20, 40, 60, 120 min and 24 h after exercise. No significant differences in the levels of lactate, ammonia, creatine kinase and glycerol between the two groups were observed at any of the time points. However, the levels of glucose and insulin were significantly higher in the BA trial as compared to those in the PL trial at the 40 and 60 min recovery points. Furthermore, the testosterone-to-cortisol ratio at the 120 min recovery point was significantly higher in the BA trial as compared to that in the PL trial. The results indicate the occurrence of anabolic response during the recovery period. The benefit of BCAA Drink was also performed by Profile of Mood States to assess the psychological condition. Fatigue score increased immediately at exhaustion in both groups, but the decrease in the fatigue score at 120 min recovery point was significant only in BA trial. These data indicate that a single bout of exhaustive exercise enhanced the feeling of fatigue. The detrimental consequence was reduced by an ingestion of BCAA Drink.

Stanozolol treatment decreases the mitochondrial ROS generation and oxidative stress induced by acute exercise in rat skeletal muscle

Anabolic androgenic steroids are used in the sport context to enhance muscle mass and strength and to increase muscle fatigue resistance. Since muscle fatigue has been related to oxidative stress caused by an exercise-linked reactive oxygen species (ROS) production, we investigated the potential effects of a treatment with the anabolic androgenic steroid stanozolol against oxidative damage induced on rat skeletal muscle mitochondria by an acute bout of exhaustive exercise. Mitochondrial ROS generation with complex I- and complex II-linked substrates was increased in exercised control rats, whereas it remained unchanged in the steroid-treated animals. Stanozolol treatment markedly reduced the extent of exercise-induced oxidative damage to mitochondrial proteins, as indicated by the lower levels of the specific markers of protein oxidation, glycoxidation, and lipoxidation, and the preservation of the activity of the superoxide-sensitive enzyme aconitase. This effect was not due to an enhancement of antioxidant enzyme activities. Acute exercise provoked changes in mitochondrial membrane fatty acid composition characterized by an increased content in docosahexaenoic acid. In contrast, the postexercise mitochondrial fatty acid composition was not altered in stanozolol-treated rats. Our results suggest that stanozolol protects against acute exercise-induced oxidative stress by reducing mitochondrial ROS production, in association with a preservation of mitochondrial membrane properties.

Cardiac remodelling, blood chemistry, haematology and oxygen consumption of Atlantic cod, Gadus morhua L., induced by experimental haemolytic anaemia with phenylhydrazine

Anaemia is a common pathology associated with many infectious and non-infectious diseases. The effects of haemolytic anaemia induced by i.p. injection of phenylhydrazine (PHZ) were studied in Atlantic cod. Phenylhydrazine injection (0.3mgkg(-1)) in a DMSO and saline vehicle induced a reproducible and stable anaemia reducing haematocrit, (Hct) by 62% over 3weeks. Controls consisted of fish injected with saline and DMSO/saline vehicle with minimal effects on Hct or whole blood haemoglobin (Hb). Although anaemia resulted in reduced blood lactate and glucose in PHZ injected fish, there were no effects of anaemia on blood, sodium, chloride or potassium. Similarly, there were no changes in the relative proportions of leucocytes in the blood although an increase in the number of immature erythrocytes was observed in the anaemic fish. Anaemic fish showed a 29 and 22% increase in cardiac somatic index (CSI) relative to saline and vehicle controls, respectively, although there were no significant differences in the linear dimensions of the ventricle. Changes in cardiac somatic and ventricular somatic index correlated positively and significantly with Hct but not with whole blood Hb concentration. Anaemic fish had significantly reduced resting routine oxygen consumption compared with vehicle controls but were not able to increase oxygen consumption following a bout of exhaustive exercise. Plasma lactate concentrations increased significantly after exercise to a greater extent in anaemic fish compared with vehicle control fish. Phenylhydrazine is a useful model for studying haemolytic anaemia in Atlantic cod with minimal effects on blood biochemistry and haematology and clearly reduces the aerobic capacity in Atlantic cod.

Changes in Blood Lipoproteins, Inflammation Response and Tissue Damage After a Single Bout of Exhaustive Exercise

LANGUAGE NOTE | Document text in Chinese; abstract also in English. The objective of this study was to determine the effects on plasma lipoproteins, inflammation response and tissue-­damage markers level during their recovery following exhaustive run. These biochemical concentrations were measured before 30 min, immediately after, and 30 min, 1hr, 2hr, 24hr, 48hr, 72hr after an exhaustive run on treadmill in 15 health male subjects with 80%VO2max intensity. The result of one-way ANOVA with measure repeated analysis indicated that there were no significant changes in low-density lipoprotein cholesterol post run, and high-density lipoprotein cholesterol level was remain significant elevated (by 18%) until 2hr post run. The inflammatory marker of C-reactive protein level was significant elevated (by 42%) immediately and returned to baseline post 0.5hr. The neutrophils ratio remain significant increased (by 51%) during 0.5hr until 2hr and returned to baseline post 24hr. The tissue-damage markers were remain elevated by 23% immediately until 2hr in lactate dehydrogenase and only reach to peak (by 108%) significantly post 24hr in creatine kinase. It is concluded that an exhaustive exercise could induce the delay-onset damage and transient inflammatory response in tissue, and have enough rest or suitable antioxidant supplements for recovery. 目的：本研究旨在探討單次衰竭運動後恢復期對於血脂蛋白濃度變化與發炎損傷指標之影響。方法：受試者為15名健康男性(年齡22.8 ± 0.89歲，體重67. ± 1.81公斤)，以高強度(80%VO2max)的固定負荷運動至衰竭，並於運動前30分鐘、運動後立即、0.5hr、lhr、2hr、24hr、48hr、72hr等時間點靜脈採血進行生化值分析。結果：以單因子相依樣本變異數分析顯示，低密度脂蛋白膽固醇(low density lipoprotein-cholesterol, LDL-C)在運動後均無明顯變化；而高密度脂蛋白膽固醇(high den­sity lipoprotein-cholesterol, HDL-C)則在衰竭運動後2hr明顯持續增加約18.3% (p &lt; .05)；發炎指標：C-反應蛋白(C-reactive protein, CRP)於衰竭後立即顯著上升約42%，隨即0.5hr後恢復。嗜中性球比例(neutrophils, net-s%)在運動後0.5hr至2hr持續增加約51%，於24hr之後恢復。組織損傷情形，乳酸脱氫酶(lactate dehydrogenase, LDH)活性在衰竭後立即至2hr期間顯著增加約23%，而肌酸激酶(creatine kinase, CK)活性則在24hr後才明顯增加約108%的峰值反應。結論：本研究血脂蛋白與發炎、損傷等生化反應結果，意味著單次衰竭運動後可能誘發體內組織的延遲性損傷與組織的短暫發炎反應，需要有足夠的休息時間或運用適當的抗氧化增補劑來進行運動恢復。

Acute Exercise and Thioredoxin-1 in Rat Brain, and Alpha-Lipoic Acid and Thioredoxin-Interacting Protein Response, in Diabetes

Thioredoxin (TRX) is a protein disulfide reductase that plays an important role in many thiol-dependent cellular reductive processes, antioxidant protection, and signal transduction. Moreover, TRX reduces and maintains the function of many proteins during oxidative stress, which is increased in diabetes. The authors recently reported that diabetes impairs brain redox status and TRX response to exercise training. As a continuation of their studies, they hypothesized that alpha-lipoic acid, a natural thiol antioxidant, has a favorable effect on the brain TRX and glutathione (GSH) system in diabetes. Streptozotocin-induced diabetes was used as a chronic model and exhaustive exercise as an acute model for disrupted redox balance. Half the diabetic and nondiabetic animals were subjected to a bout of exhaustive exercise after 8 wk with or without lipoic acid and analyzed for key thiol antioxidants. Lipoic acid neither altered diabetes-induced oxidative stress as assessed by the increased ratio of oxidized to total GSH nor had any impact on the antioxidant protein response to exercise. However, lipoic acid increased mRNA of TRX-interacting protein, an inhibitor of TRX-1, and glutaredoxin-1 in diabetes. Exercise increased TRX-1 mRNA in both diabetic and nondiabetic animals but had no effect on TRX-1 protein. Cytosolic superoxide dismutase mRNA was only increased in diabetes, whereas exercise increased the protein levels in nondiabetic animals. The findings suggest that exhaustive exercise induces mRNA of TRX-1 in the brain and that lipoic acid cannot prevent diabetes-induced disturbances in GSH homeostasis. Because lipoic acid increased TRX-interacting protein transcription in diabetes, high doses may impair TRX-1 homeostasis.

Excess Postexercise Oxygen Consumption following Repeated Bouts of Anaerobic Exercise

PURPOSE: Repeated anaerobic bouts are often used in training and observed in athletic competition. To our knowledge, the elevation in postexercise metabolism following exercise bouts of this nature has not been observed. The purpose of this study was to investigate excess postexercise oxygen consumption (EPOC) following repeated, exhaustive bouts of anaerobic exercise. METHODS: Four recreationally trained male subjects (age: 24.5 + 2.7 yrs), performed nine bouts of anaerobic exercise using the Wingate 30-second cycle protocol. The bouts were separated into sets of three, with a two minute rest after the first and second bout and a six minute forty-five second rest after the third bout, resulting in total test duration of thirty minutes. Prior to the third bout of the third set, subjects were fitted with an appropriate gas collection mask, and calculation of EPOC began immediately following that bout. Subjects reported to the laboratory rested and following a 12-hour fast. Each test was preceded by a 30-minute baseline test to determine resting metabolic rate. Postexercise VO2 was continuously monitored until baseline was re-established. RESULTS: EPOC magnitude and duration from repeated, exhaustive anaerobic exercise bouts was 10.6 + 4.3 L O2 and 58.5 + 38.8 mins, respectively. Heart rate at the completion of recovery was significantly elevated above rest (66.3 + 8.1 bts*min-1 vs. 84.8 + 13.7 bts*min-1, p=.01). CONCLUSIONS: These data indicate that EPOC, and thus caloric expenditure, during recovery from repeated, exhaustive anaerobic bouts of exercise is a noteworthy contributor to total caloric burn following this type of exercise, and is substantially greater than previously published EPOC values reported from aerobic exercise protocols. Heart rate remained significantly elevated above resting levels even after postexercise oxygen consumption returned to baseline. Further investigation of postexercise biomarkers, such as catecholamines, is warranted.

Effects Of Branch-chain Amino Acids And Arginine Drink On Post-exercise Metabolic Response

Chia-Jung Chung, Yi-An Lin, Mei-Chich Hsu National Taiwan Sport University, Taoyuan, Taiwan Branched-chain amino acid (BCAA) has been reported to increase the endurance exercise capacity, increase protein synthesis, decrease rating of perceived exertion and mental fatigue, attenuate muscle protein breakdown induced by exercise, and promote recovery from the damage. However, the effects of the combined BCAA and arginine beverage on post-exercise metabolic response have yet to be elucidated. PURPOSE: This study was to investigate the effects of branched-chain amino acid and arginine combined beverage (BA) on acute metabolic responses during recovery after a single bout of exhaustive exercise. METHODS: Fourteen healthy males were assigned to drink either BA or placebo (PL) on two sessions separated by 2 weeks. Blood samples of each subject were collected before exercise, and 0, 10, 20, 40, 60, 120 min and 24 hr after exercise, respectively. RESULTS: There were no significant differences in the levels of lactate, ammonia, creatine kinase, and glycerol between the two groups were observed at any of the time points. However, the blood glucose was significantly higher in the BA trial as compared to that in the PL trial at the 40 and 60-min recovery period (94.7 ± 4.5 mg/dL vs. 83.1 ± 2.8 mg/dL, p<0.05). The insulin concentration was higher in the BA trial as compared to that in the PL trial at the 40 and 60-min recovery period (31.6 ± 5.6 μU/mL vs. 15.5 ± 2.6 μU/mL, 30.1 ± 7.1 μU/mL vs. 10.6 ± 1.1 μU/ mL, p<0.05). Furthermore, the free fatty acid levels at the 60 and 120-min recovery period were significantly lower in the BA trial compared to that in the PL trial (0.18 ± 0.22 mmol/L vs. 0.3 ± 0.1 mmol/L, 0.4 ± 0.1 mmol/L vs. 0.6 ± 0.1 mmol/L, p<0.05). CONCLUSION: Consuming amino acid compound beverage during recovery period could increase blood glucose and insulin concentrations, and increase free fatty acid availability in muscle. Thus, branched-chain amino acid and arginine combined beverage supplementation may benefit recovery after exercise.

Maximal Exercise Significantly Affects Helper T-Cell (CD3+/CD4+) Count Compared to Rest and 1-h Post Exercise

Research has shown that maximal exercise has a significant effect on cells of the immune system. Specifically, the lymphocyte count increases with exercise and decreases to a value lower than baseline following an acute exhaustive bout of exercise. The overall lymphocyte response is well characterized, however, the ability of exercise to affect lymphocyte subfractions is unknown to our knowledge. PURPOSE: The purpose of this study was to determine the effect of maximal exercise on cell counts of two lymphocyte subfractions (helper T, and cytotoxic T cells). METHOD: Male subjects (ages 25-38 yrs old) completed a treadmill test to exhaustion. Blood was sampled at rest, immediately upon completion of maximal exercise, and at 60-min post exercise. Blood was incubated with antibodies specific to cell phenotype (helper T = CD3+/CD4+, cytotoxic T = CD3+/CD8+). Samples were analyzed for cell counts using flow cytometry. RESULTS: There was a significant difference in helper T cells between rest, maximal exercise and post 60 minute measurements (P=.038). Helper T cell count increased with exercise but returned to baseline within 60-min. The cytotoxic count had minimal changes with exercise (P=.149). These results show that helper T subfractions are affected more with exercise than cytotoxic cells. CONCLUSION: The potential implications of this finding are that functions carried out by helper T cells (antigen presentation, cytokine secretion, etc.) are effected to a greater extent by exercise than functions carried out by cytotoxic T cells (cell mediated killing, etc.).

The effects of acute and prolonged CRAM supplementation on reaction time and subjective measures of focus and alertness in healthy college students

BackgroundThe purpose of this study was to examine the effect of acute and prolonged (4-weeks) ingestion of a supplement designed to improve reaction time and subjective measures of alertness, energy, fatigue, and focus compared to placebo.MethodsNineteen physically-active subjects (17 men and 2 women) were randomly assigned to a group that either consumed a supplement (21.1 ± 0.6 years; body mass: 80.6 ± 9.4 kg) or placebo (21.3 ± 0.8 years; body mass: 83.4 ± 18.5 kg). During the initial testing session (T1), subjects were provided 1.5 g of the supplement (CRAM; α-glycerophosphocholine, choline bitartrate, phosphatidylserine, vitamins B3, B6, and B12, folic acid, L-tyrosine, anhydrous caffeine, acetyl-L-carnitine, and naringin) or a placebo (PL), and rested quietly for 10-minutes before completing a questionnaire on subjective feelings of energy, fatigue, alertness and focus (PRE). Subjects then performed a 4-minute quickness and reaction test followed by a 10-min bout of exhaustive exercise. The questionnaire and reaction testing sequence was then repeated (POST). Subjects reported back to the lab (T2) following 4-weeks of supplementation and repeated the testing sequence.ResultsReaction time significantly declined (p = 0.050) between PRE and POST at T1 in subjects consuming PL, while subjects under CRAM supplementation were able to maintain (p = 0.114) their performance. Significant performance declines were seen in both groups from PRE to POST at T2. Elevations in fatigue were seen for CRAM at both T1 and T2 (p = 0.001 and p = 0.000, respectively), but only at T2 for PL (p = 0.029). Subjects in CRAM maintained focus between PRE and POST during both T1 and T2 trials (p = 0.152 and p = 0.082, respectively), whereas significant declines in focus were observed between PRE and POST in PL at both trials (p = 0.037 and p = 0.014, respectively). No difference in alertness was seen at T1 between PRE and POST for CRAM (p = 0.083), but a significant decline was recorded at T2 (p = 0.005). Alertness was significantly lower at POST at both T1 and T2 for PL (p = 0.040 and p = 0.33, respectively). No differences in any of these subjective measures were seen between the groups at any time point.ConclusionResults indicate that acute ingestion of CRAM can maintain reaction time, and subjective feelings of focus and alertness to both visual and auditory stimuli in healthy college students following exhaustive exercise. However, some habituation may occur following 4-weeks of supplementation.

Comparison Of Two Strategies On Recovery After Exhaustive Exercise

The purpose of this study is to examine the effects of two recovery strategies on the ability to lower heart rate (HR) following an exhaustive exercise bout. Additionally, tidal volume (VT), respiratory rate (RR), and oxygen consumption (o2) were also collected. METHOD: Nine recreationally active males from the University of Northern Iowa volunteered for the study. Each subject participated in two test sessions with different recovery strategies. Both sessions involved the subjects warming up on a treadmill then being subjected to exhaustive exercise. Once exhaustion was achieved the subjects were instructed to place their hands on their head (HH) or knees (HK). Hotelling's T2 was rejected (F = 13.55, 4, 5, p = 0.007). Paired samples t-tests indicated that a significant treatment effect existed for HR (t = 3.619, 8, p = 0.007) and o2 (t = 2.747, 8, p = 0.025) but no significant effect for VT or RR. Though no significance was recorded, VT was higher and RR lower in HK. It appears that HK is a potentially superior recovery method, despite the historical usage of the HH method by coaches. When in a recovery phase of exhaustive exercise using the HK method maybe preferable if the goal is to lower HR more rapidly however it is unknown if this advantage in HR reduction will actually improve performance.