Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity.

Dehydration is a common event associated with exercise. However, few studies have examined the effects of dehydration on plasma redox status in humans. Eighty-two athletes were recruited and baseline anthropometrics and blood samples were obtained. Athletes then engaged in a dehydration protocol, training until 3% of preweight body mass was lost. Athletes returned to the lab and had postdehydration blood collected. Athletes then consumed an isotonic drink until pre-exercise body weight was reestablished. Blood was then recollected (1 h post full rehydration (PFR)). Samples were centrifuged and the plasma snap frozen in liquid nitrogen and stored at -80 °C. Lipid and protein oxidative stress was determined by measuring F2-isoprostanes and protein carbonyls (PC), respectively. Antioxidant capacity was determined by the ferric reducing ability of plasma (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. Plasma osmolality was determined using an osmometer. Statistical analysis utilized a 1-way ANOVA with posthoc testing. Values are reported as mean ± SD. Plasma osmolality was significantly elevated immediately postdehydration (p ≤ 0.001) but decreased to baseline at PFR. Plasma TEAC increased immediately postdehydration and at PFR (p ≤ 0.001). FRAP increased immediately postdehydration (p ≤ 0.001) and decreased to below baseline at PFR (p ≤ 0.05). Conversely, F2-isoprostanes declined significantly from baseline to immediately postdehydration and then significantly rose at PFR (p ≤ 0.001), whereas PC declined at PFR (p ≤ 0.01). This study indicates that dehydration and exercise cause a significant increase in plasma osmolality and antioxidant potential immediately postexercise. We propose dehydration significantly elevates antioxidant concentration which suppresses F2-isoprostanes and PC.

Tai Chi and Kung-Fu practice maintains physical performance but not vascular health in young versus old participants.

OBJECTIVES: Kung-Fu and Tai Chi along with other martial arts are gaining popularity but studies examining the benefits of martial arts on physical fitness, vascular health, nutrition, and psychological wellness are limited. Aging is associated with declines in these health components. The objectives of this study were to examine whether Tai Chi and Kung-Fu training would maintain physical fitness, vascular health, and psychological wellness components on older versus younger practitioners. METHODS: Seventeen subjects were recruited and divided into Young (age <40 years, n=9) and Old (age 40 years and above, n=8). Participants reported twice for health screens, vascular and nutrition assessment, and fitness tests. Mean differences were compared between groups for all tests using Student's t-tests. RESULTS: Age, months of practice, systolic blood pressure, and cardiovascular augmentation index were significantly greater in Old versus Young (p=0.001, p=0.007, p=0.049, and p=0.011, respectively). Psychologically, old practitioners experienced greater sleep interference (p=0.035) and overall pain (p=0.036). No other differences existed for any variable. CONCLUSION: Our study indicates that the practice of Tai Chi and Kung-Fu maintains physical fitness in older compared to younger practitioners. However, age associated changes in cardiovascular stiffness, systolic blood pressure, and pain were not prevented.

Six weeks daily ingestion of whole blueberry powder increases natural killer cell counts and reduces arterial stiffness in sedentary males and females.

Evidence suggests that berries contain bioactive compounds, which reduce certain cancers and hypertension. Our hypothesis was that daily blueberry (BB) consumption would increase natural killer (NK) cells and plasma redox capacity and reduce blood pressure, augmentation index (AIx), central pulse wave velocity, and aortic systolic pressures (ASPs). Twenty-five men and postmenopausal women aged 18 to 50 years were recruited and randomized to BB (n, 13) or placebo groups (n, 12). Participants were provided with BB (equivalent to 250 g berries) or placebo powders each day for 6 weeks. Blood pressure, vascular performance testing, and blood samples were taken at baseline (presupplementation). Participants returned after 6 weeks and repeated all procedures. Presupplementation to postsupplementation comparisons for the main effects of treatment, time, and treatment-time interaction were made using a 2 (treatment) × 2 (times) repeated-measures analysis of variance for all vascular measures, redox status, and NK cell counts. Anthropometric measures were compared using t tests. Body mass, composition, and overall blood pressures were not affected in either group. Overall, AIx and ASPs were decreased in BB (treatment effect, P = .024 and P = .046, respectively). Plasma redox was not affected. Absolute NK cells were increased in BB (time, P = .001 and interaction, P = .012). Subjects (n, 9) with prehypertensive pressures (≥120/80 mm Hg, respectively) were examined as a subset using t tests and exhibited significant reductions in diastolic pressure (P = .038) from presupplementation to postsupplementation in BB. We conclude that BB ingestion for 6 weeks increases NK cells and reduces AIx, ASP, and diastolic pressures in sedentary males and females.

Effect of resveratrol and quercetin supplementation on redox status and inflammation after exercise.

Resveratrol and quercetin function as antioxidants and anti-inflammatories in vitro, but these mechanisms have been minimally examined in combination in exercising humans. The purpose of this investigation was to examine supplementation as a countermeasure against oxidative stress and inflammation in response to exercise. Fourteen athletes were randomly assigned, in a double-blind crossover design, to a resveratrol and quercetin combination (RQ) (120 mg resveratrol and 225 mg quercetin for 6 days and 240 mg resveratrol and 450 mg quercetin on day 7 just prior to exercise) or to placebo (P). There was a 1-week washout between trials. Blood was taken at baseline, pre-exercise, immediately after exercise, and 1 h after exercise. Plasma was analyzed for oxidative stress (F2-isoprostanes and protein carbonyls), antioxidant capacity (ferric-reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorptive capacity (ORAC)), and inflammation (cytokine interleukin (IL)-8 and C-reactive protein (CRP)). Statistical design utilized a 2 × 3 ANOVA and Student's t test. Pre-exercise values were not different from baseline for any measure. The postexercise increase in F2-isoprostanes was significantly less (p = 0.039 interaction) with RQ (68%) than with P (137%). Protein carbonyls, FRAP, ORAC, and TEAC significantly increased after exercise but were not affected by treatment. IL-8 and CRP increased significantly immediately after exercise but were not affected by treatment. These data indicate that RQ significantly reduces exercise-induced lipid peroxidation without associated changes in inflammation or plasma antioxidant status.

Effect of blueberry ingestion on natural killer cell counts, oxidative stress, and inflammation prior to and after 2.5 h of running.

Blueberries are rich in antioxidants known as anthocyanins, which may exhibit significant health benefits. Strenous exercise is known to acutely generate oxidative stress and an inflammatory state, and serves as an on-demand model to test antioxidant and anti-inflammatory compounds. The purpose of this study was to examine whether 250 g of blueberries per day for 6 weeks and 375 g given 1 h prior to 2.5 h of running at ∼72% maximal oxygen consumption counters oxidative stress, inflammation, and immune changes. Twenty-five well-trained subjects were recruited and randomized into blueberry (BB) (N = 13) or control (CON) (N = 12) groups. Blood, muscle, and urine samples were obtained pre-exercise and immediately postexercise, and blood and urine 1 h postexercise. Blood was examined for F2-isoprostanes for oxidative stress, cortisol, cytokines, homocysteine, leukocytes, T-cell function, natural killer (NK), and lymphocyte cell counts for inflammation and immune system activation, and ferric reducing ability of plasma for antioxidant capacity. Muscle biopsies were examined for glycogen and NFkB expression to evaluate stress and inflammation. Urine was tested for modification of DNA (8-OHDG) and RNA (5-OHMU) as markers of nucleic acid oxidation. A 2 (treatment) × 3 (time) repeated measures ANOVA was used for statistical analysis. Increases in F2-isoprostanes and 5-OHMU were significantly less in BB and plasma IL-10 and NK cell counts were significantly greater in BB vs. CON. Changes in all other markers did not differ. This study indicates that daily blueberry consumption for 6 weeks increases NK cell counts, and acute ingestion reduces oxidative stress and increases anti-inflammatory cytokines.

Effect of mixed flavonoids, n-3 fatty acids, and vitamin C on oxidative stress and antioxidant capacity before and after intense cycling.

Consumption of plant flavonoids, antioxidants, and n-3 fatty acids is proposed to have many potential health benefits derived primarily through antioxidant and anti-inflammatory activities. This study examined the effects of 1,000 mg quercetin + 1,000 mg vitamin C (QC); 1,000 mg quercetin, 1,000 mg vitamin C, 400 mg isoquercetin, 30 mg epigallocatechin gallate, and 400 mg n-3 fatty acids (QFO); or placebo (P), taken each day for 2 wk before and during 3 d of cycling at 57% W(max) for 3 hr, on plasma antioxidant capacity (ferricreducing ability of plasma [FRAP], oxygen-radical absorbance capacity [ORAC]), plasma oxidative stress (F(2)-isoprostanes), and plasma quercetin and vitamin C levels. Thirty-nine athletes were recruited and randomized to QC, QFO, or P. Blood was collected at baseline, after 2 wk supplementation, immediately postexercise, and 14 hr postexercise. Statistical design used a 3 (groups) × 4 (times) repeated-measures ANOVA with post hoc analyses. Plasma quercetin was significantly elevated in QC and QFO compared with P. Plasma F(2)-isoprostanes, FRAP, and vitamin C were significantly elevated and ORAC significantly decreased immediately postexercise, but no difference was noted in the overall pattern of change. Post hoc analyses revealed that the QC and QFO groups did not exhibit a significant increase in F(2)-isoprostanes from baseline to immediately postexercise compared with P. This study indicates that combining flavonoids and antioxidants with n-3 fatty acids is effective in reducing the immediate postexercise increase in F(2)-isoprostanes. Moreover, this effect occurs independently of changes in plasma antioxidant capacity.

Effect of n-3 fatty acids and antioxidants on oxidative stress after exercise.

PURPOSE: n-3 fatty acids are known to exert multiple beneficial effects including anti-inflammatory actions that may diminish oxidative stress. Supplementation with antioxidant vitamins has been proposed to counteract oxidative stress and improve antioxidant status. Therefore, this project investigated the effects of daily supplementation in 48 trained cyclists over 6 wk and during 3 d of continuous exercise on F2-isoprostanes (oxidative stress), plasma n-3 fatty acids, and antioxidant status (oxygen radical absorption capacity and ferric-reducing antioxidant potential). METHODS: Cyclists were randomized into n-3 fatty acids (N3) (n = 11) (2000 mg of eicosapentaenoic acid and 400 mg of docosahexaenoic acid), a vitamin-mineral (VM) complex (n = 12) emphasizing vitamins C (2000 mg), E (800 IU), A (3000 IU), and selenium (200 microg), a VM and n-3 fatty acid combination (VN3) (n = 13), or placebo (P) (n = 12). Blood was collected at baseline and preexercise and postexercise. A 4 x 3 repeated-measures ANOVA was performed to test main effects. RESULTS: After exercise, F2-isoprostanes were higher in N3 (treatment effect P = 0.014). Eicosapentaenoic acid and docosahexaenoic acid plasma values were higher after supplementation (interaction effect P = 0.001 and 0.006, respectively) in both n-3 supplemented groups. Oxygen radical absorption capacity declined similarly among all groups after exercise. Ferric-reducing antioxidant potential exhibited significant interaction (P = 0.045) and significantly increased after exercise in VN3 and VM (P < 0.01). CONCLUSIONS: This study indicates that supplementation with n-3 fatty acids alone significantly increases F2-isoprostanes after exhaustive exercise. Lastly, antioxidant supplementation augments plasma antioxidant status and modestly attenuates but does not prevent the significant n-3 fatty acid associated increase in F2-isoprostanes postexercise.

Quercetin's effect on cycling efficiency and substrate utilization.

Previous evidence suggests that quercetin supplementation increases performance in humans. We examined the effects of 3 weeks of quercetin supplementation on fuel utilization, gross efficiency (GE), and perceived effort during 3 h of cycling over 3 successive days. Forty cyclists were randomized into quercetin and placebo groups and tested for maximal oxygen consumption (53.2 +/- 1.2 and 54.7 +/- 1.1 mL.kg(-1).min(-1)). For 3 weeks following maximal oxygen consumption testing, subjects supplemented either 1000 mg.day(-1) quercetin or placebo during normal training. Following supplementation, subjects cycled at 57% maximum power for 3 h, on 3 successive days, using their own bicycles fitted to CompuTrainer Pro Model trainers (RacerMate, Seattle, Wash.). Metabolic measurements were taken every 30 min for each 3-h ride. Muscle biopsies obtained from the vastus lateralis immediately pre-exercise and postexercise on days 1 and 3 were analyzed for muscle glycogen content. Power output remained constant for all 3 exercise trials, but significant decreases over time were measured for GE, cadence, respiratory exchange ratio, blood glucose, and muscle glycogen. Significant increases were measured for heart rate and volume of oxygen consumption over time. No quercetin treatment effect was observed for any of the outcome measures in this study. These data indicate that GE is reduced during an exhausting 3-h bout of exercise. However, quercetin did not significantly affect any outcomes in these already well-trained subjects.

Successive bouts of cycling stimulates genes associated with mitochondrial biogenesis.

Exercise increases mRNA for genes involved in mitochondrial biogenesis and oxidative enzyme capacity. However, little is known about how these genes respond to consecutive bouts of prolonged exercise. We examined the effects of 3 h of intensive cycling performed on three consecutive days on the mRNA associated with mitochondrial biogenesis in trained human subjects. Forty trained cyclists were tested for VO(2max) (54.7 +/- 1.1 ml kg(-1) min(-1)). The subjects cycled at 57% watts(max) for 3 h using their own bicycles on CompuTrainer Pro Model trainers (RacerMate, Seattle, WA) on three consecutive days. Muscle biopsies were obtained from the vastus lateralis pre- and post-exercise on days one and three. Muscle samples were analyzed for mRNA content of peroxisome proliferator receptor gamma coactivator-1 alpha (PGC-1alpha), sirtuin 1 (Sirt-1), cytochrome c, and citrate synthase. Data were analyzed using a 2 (time) x 2 (day) repeated measures ANOVA. Of the mRNA analyzed, the following increased from pre to post 3 h rides: cytochrome c (P = 0.006), citrate synthase (P = 0.03), PGC-1alpha (P < 0.001), and Sirt-1 (P = 0.005). The following mRNA showed significant effects from days one to three: cytochrome c (P < 0.001) and citrate synthase (P = 0.01). These data show that exhaustive cycling performed on three consecutive days resulted in both acute and chronic stimuli for mRNA associated with mitochondrial biogenesis in already trained subjects. This is the first study to illustrate an increase in sirtuin-1 mRNA with acute and chronic exercise. These data contribute to the understanding of mRNA expression during both acute and successive bouts of prolonged exercise.

Quercetin does not affect rating of perceived exertion in athletes during the Western States endurance run.

The purpose of this study was to measure the influence of quercetin supplementation on ratings of perceived exertion in ultramarathon runners competing in the 160-km Western States Endurance Run (WSER). Sixty-three runners were randomized to quercetin (Q) and placebo (P) groups, and under double blinded methods ingested four supplements per day with or without 250 mg quercetin for 3 weeks before the WSER. Thirty-nine of the 63 subjects (quercetin N = 18, placebo N = 21) finished the race. At the completion of exercise ratings of perceived exertion (RPE) were assessed at aid stations located at 40, 90, 125, 150, and 160 km (finish line). The pattern of change in RPE over time was not significantly different between the Q and P groups. Ratings of perceived exertion (RPE) did not significantly increase throughout the race (15.2 +/- 2.9 at 40 km -14.2 +/- 4.0 at 160 km) for both groups combined. Race times were not different between the groups (Q = 26.4 +/- 0.7 h and P = 27.5 +/- 0.6 h). Significant time main effects (p < 0.001) were found for both serum glucose and cortisol throughout the race. Quercetin supplementation for 3 weeks prior to the WSER had no effect on RPE during competitive self-paced ultramarathon running. Ratings of perceived exertion (RPE) did not increase in a linear fashion but instead fluctuated nonmonotonically throughout the self-paced endurance running event.

Beta-glucan, immune function, and upper respiratory tract infections in athletes.

PURPOSE: This study investigated the effects of oat beta-glucan (BG) supplementation on chronic resting immunity, exercise-induced changes in immune function, and self-reported upper respiratory tract infection (URTI) incidence in human endurance athletes. METHODS: Trained male cyclists were randomized to BG (N = 19) or placebo (P; N = 17) groups and under double-blind procedures received BG (5.6 g x d(-1)) or P beverage supplements for 2 wk before, during, and 1 d after a 3-d period in which subjects cycled for 3 h x d(-1) at approximately 57% maximal watts. URTI symptoms were monitored during BG supplementation and for 2 wk afterward. Blood samples were collected before and after 2 wk of supplementation (both samples, 8:00 a.m.), immediately after the 3-h exercise bout on day 3 (6:00 p.m.), and 14 h after exercise (8:00 a.m.) and were assayed for natural killer cell activity (NKCA), polymorphonuclear respiratory burst activity (PMN-RBA), phytohemagglutinin-stimulated lymphocyte proliferation (PHA-LP), plasma interleukin 6 (IL-6), IL-10, IL-1 receptor agonist (IL-1ra), and IL-8, and blood leukocyte IL-10, IL-8, and IL-1ra mRNA expression. RESULTS: Chronic resting levels and exercise-induced changes in NKCA, PMN-RBA, PHA-LP, plasma cytokines, and blood leukocyte cytokine mRNA did not differ significantly between BG and P groups. URTI incidence during the 2-wk postexercise period did not differ significantly between groups. CONCLUSIONS: An 18-d period of BG versus P ingestion did not alter chronic resting or exercise-induced changes in immune function or URTI incidence in cyclists during the 2-wk period after an intensified exercise.

Chronic quercetin ingestion and exercise-induced oxidative damage and inflammation.

Quercetin is a flavonoid compound that has been demonstrated to be a potent antioxidant in vitro. The objective of this study was to evaluate if quercetin ingestion would increase plasma antioxidant measures and attenuate increases in exercise-induced oxidative damage. Forty athletes were recruited and randomized to quercetin or placebo. Subjects consumed 1000 mg quercetin or placebo each day for 6 weeks before and during 3 d of cycling at 57% work maximum for 3 h. Blood was collected before and immediately after exercise each day, and analyzed for F2-isoprostanes, nitrite, ferric-reducing ability of plasma, trolox equivalent antioxidant capacity, and C-reactive protein. Statistical analyses involved a 2 (treatment) x 6 (times) repeated measures analysis of variance to test main effects. F2-isoprostanes, nitrite, ferric-reducing ability of plasma, trolox equivalent antioxidant capacity, and C-reactive protein were significantly elevated as a result of exercise, but no group effects were found. Despite previous data demonstrating potent antioxidant actions of quercetin in vitro, this study indicates that this effect is absent in vivo and that chronic quercetin ingestion does not exert protection from exercise-induced oxidative stress and inflammation.

Oral quercetin supplementation and blood oxidative capacity in response to ultramarathon competition.

Previous research indicates that ultramarathon exercise can result in blood oxidative stress. The purpose of this investigation was to examine the efficacy of oral supplementation with quercetin, a naturally occurring compound with known antioxidant properties, as a potential countermeasure against blood oxidative stress during an ultramarathon competition. In double-blind fashion, 63 participants received either oral quercetin (250 mg, 4x/day; 1,000 mg/day total) or quercetin-free supplements 3 weeks before and during the 160-km Western States Endurance Run. Blood drawn before and immediately after (quercetin finishers n = 18, quercetin-free finishers n = 21) the event was analyzed for changes in blood redox status and oxidative damage. Results show that quercetin supplementation did not affect race performance. In response to the ultramarathon challenge, aqueous-phase antioxidant capacity (ferric-reducing ability of plasma) was similarly elevated in athletes in both quercetin and quercetin-free treatments and likely reflects significant increases in plasma urate levels. Alternatively, trolox-equivalent antioxidant capacity was not altered by exercise or quercetin. Accordingly, neither F2-isoprostances nor protein carbonyls were influenced by either exercise or quercetin supplementation. In the absence of postrace blood oxidative damage, these findings suggest that oral quercetin supplementation does not alter blood plasma lipid or aqueous-phase antioxidant capacity or oxidative damage during an ultramarathon challenge.

Influence of carbohydrate, intense exercise, and rest intervals on hormonal and oxidative changes.

This study compared effects of carbohydrate (CHO) and rest on oxidative stress during exercise. Cyclists (N = 12) completed 4 randomized trials at 64% Wattsmax under 2 conditions (continuous cycling for 2 h [C] and cycling with 3-min rest every 10 min for 2.6 h [R]). Subjects cycled under each condition while receiving 6% CHO and placebo (PLA). CHO and PLA were given preexercise (12 mL/kg) and during exercise (4 mL x kg(-1) x 15 min(-1)). Blood was collected preexercise, postexercise, and 1 h postexercise and assayed for F2-isoprostanes, hydroperoxides (LH), nitrite, antioxidant capacity, glucose, insulin, cortisol, and epinephrine. F2-isoprostanes and LH were lower in CHO. Glucose, cortisol, and epinephrine exhibited significant effects, with postexercise levels of glucose higher and cortisol and epinephrine lower in CHO during the R condition. This pattern was identical in the C condition (21). Oxidative stress during cycling was unaffected by use of short rest intervals but was diminished by CHO.

Quercetin reduces illness but not immune perturbations after intensive exercise.

PURPOSE: To investigate the effects of quercetin supplementation on incidence of upper respiratory tract infections (URTI) and exercise-induced changes in immune function. METHODS: Trained male cyclists (N=40) were randomized to quercetin (N=20) or placebo (N=20) groups and, under double-blind procedures, received 3 wk quercetin (1000 mg.d(-1)) or placebo before, during, and for 2 wk after a 3-d period in which subjects cycled for 3 h.d(-1) at approximately 57% Wmax. Blood and saliva samples were collected before and after each of the three exercise sessions and assayed for natural killer cell activity (NKCA), PHA-stimulated lymphocyte proliferation (PHA-LP), polymorphonuclear oxidative-burst activity (POBA), and salivary IgA output (sIgA). RESULTS: Pre- to postexercise changes in NKCA, PHA-LP, POBA, and sIgA did not differ significantly between quercetin and placebo groups. URTI incidence during the 2-wk postexercise period differed significantly between groups (quercetin=1/20 vs placebo=9/20, Kaplan-Meier analysis statistic=8.31, P=0.004). CONCLUSION: Quercetin versus placebo ingestion did not alter exercise-induced changes in several measures of immune function, but it significantly reduced URTI incidence in cyclists during the 2-wk period after intensified exercise.

Ratings of perceived exertion during intermittent and continuous exercise.

This investigation characterized the acute differentiated and undifferentiated perceptual responses to a prolonged intermittent and continuous stationary cycle exercise session. Throughout two 2.0-hr. test sessions, 12 subjects cycled at 64% Watts(max) and 73% VO2 peak continuously or with 3-min. rest intervals interspersed every 10 min. During both trials, oxygen uptake (VO2), ventilation (VE), respiratory rate, respiratory exchange ratio, heart rate, and three ratings of perceived exertion (OMNI) measurements were made every 30 min. During the intermittent protocol, the perceived exertion measures were taken during Min. 10 of every 10-min. interval. OMNI RPE-Overall body did not differ significantly between conditions. No significant differences were reported for OMNI RPE-Legs between conditions; however, a significant interaction was reported for OMNI RPE-Chest, which was significantly lower in the continuous condition at Min. 120. These data indicate that perception of exertion is similar during prolonged intermittent and continuous exercise when performed at the same relative intensities throughout 90 min. of exercise.

Quercetin's influence on exercise-induced changes in plasma cytokines and muscle and leukocyte cytokine mRNA.

Trained male cyclists (n = 40) ingested quercetin (Q; n = 20) (1,000 mg/day) or placebo (P; n = 20) supplements under randomized, double-blinded methods for 3 wk before and during a 3-day period in which subjects cycled for 3 h/day at approximately 57% maximal work rate. Blood samples were collected before and after each exercise session and assayed for plasma IL-6, IL-10, IL-1ra, IL-8, TNF-alpha, and monocyte chemoattractant protein 1, and leukocyte IL-10, IL-8, and IL-1ra mRNA. Muscle biopsies were obtained before and after the first and third exercise sessions and assayed for NF-kappaB and cyclooxygenase-2 (COX-2), IL-6, IL-8, IL-1beta, and TNF-alpha mRNA. Postexercise increases in plasma cytokines did not differ between groups, but the pattern of change over the 3-day exercise period tended to be lower in Q vs. P for IL-8 and TNF-alpha (P = 0.094 for both). mRNA increased significantly postexercise for each cytokine measured in blood leukocyte and muscle samples. Leukocyte IL-8 and IL-10 mRNA were significantly reduced in Q vs. P (interaction effects, P = 0.019 and 0.012, respectively) with no other leukocyte or muscle mRNA group differences. Muscle NF-kappaB did not increase postexercise and did not differ between Q and P. Muscle COX-2 mRNA increased significantly postexercise but did not differ between Q and P. In summary, 1 g/day quercetin supplementation by trained cyclists over a 24-day period diminished postexercise expression of leukocyte IL-8 and IL-10 mRNA, indicating that elevated plasma quercetin levels exerted some effects within the blood compartment. Quercetin did not, however, influence any of the muscle measures, including NF-kappaB content, cytokine mRNA, or COX-2 mRNA expression across a 3-day intensified exercise period.

Ibuprofen use during extreme exercise: effects on oxidative stress and PGE2.

PURPOSE: Oxidative stress was examined with use (N = 29) or nonuse (N = 25) of ibuprofen in ultramarathoners after the Western States Endurance Run. METHODS: Oxidative stress was assessed by measuring plasma and urinary F2-isoprostanes, plasma nitrite, and plasma urate. A urinary prostaglandin E2 metabolite (PGE-M) was used as an end point to assess ibuprofen use. Ibuprofen users consumed 600 and 1200 mg of ibuprofen the day before and on race day, respectively, and nonusers avoided all antiinflammatory medications. Blood and urine were collected in the morning before the race and immediately after the race. RESULTS: Use compared with nonuse of ibuprofen significantly increased plasma (P

Carbohydrate attenuates perceived exertion during intermittent exercise and recovery.

PURPOSE: The purpose of this study was to examine the effect of carbohydrate supplementation on differentiated and undifferentiated ratings of perceived exertion (RPE) during prolonged intermittent exercise and recovery. METHODS: Twelve male subjects cycled for 2.0 h at 64% Wmax and 73% V O2peak with 3-min rest intervals interspersed every 10 min (2.6 h of total exercise time, including rest intervals) with placebo (P) or carbohydrate (C) beverages. RPE was assessed during the last minute of each 10-min exercise interval and then every 30 s during the 3-min recovery period. RESULTS: The pattern of change in RPE over time was significantly different between C and P ingestion (P < 0.05), with attenuated RPE responses found for both overall body (O) and legs (L). A significant main effect was found for recovery RPE-O between C and P ingestion (P < 0.05), with attenuated RPE responses found in the later part of the 2-h run. C relative to P ingestion was associated with higher respiratory exchange ratios and plasma levels of glucose and with lower levels of plasma cortisol. CONCLUSIONS: These data indicate that carbohydrate supplementation attenuates perceived exertion during prolonged intermittent exercise and recovery.