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Catecholamine reuptake inhibition improves the performance of male volunteers exercising in warm conditions, but sex differences in thermoregulation, circulating hormones, and central neurotransmission may alter this response. With local ethics committee approval, nine physically active women (mean ± SD age 21 ± 2 years; height 1.68 ± 0.08 m; body mass 64.1 ± 6.0 kg; VO2peak 51 ± 7 mL/kg/min) were recruited to examine the effect of pre-exercise administration of Bupropion (BUP; 4 × 150 mg) on prolonged exercise performance in a warm environment. Participants completed a VO2peak test, two familiarization trials, and two randomized, double-blind experimental trials. All trials took place during the first 10 days of the follicular phase of the menstrual cycle. Participants cycled for 1 h at 60% VO2peak followed by a 30-min performance test. Total work done was greater during the BUP trial (291 ± 48 kJ) than the placebo trial (269 ± 46 kJ, P = 0.042, d = 0.497). At the end of the performance test, core temperature was higher on the BUP trial (39.5 ± 0.4 °C) than on the placebo trial (39.2 ± 0.6 °C, P = 0.021; d = 0.588), as was heart rate (185 ± 9 vs 179 ± 13, P = 0.043; d = 0.537). The results indicate that during the follicular phase of the menstrual cycle, an acute dosing protocol of BUP can improve self-regulated performance in warm conditions.

This investigation quantified the effect of changes in plasma osmolality on the measurement of hematocrit (Hct) and the implications for the subsequent use of these data to calculate changes in plasma volume and application to the World Anti-Doping Agency Athlete Biological Passport.Two groups of eight male volunteers visited the laboratory after an overnight fast. In study 1, a 20-mL blood sample was collected and aliquoted into collection tubes containing saline of varying concentrations to alter the sample osmolality. In study 2, plasma osmolality was manipulated in vivo through prolonged exercise. Samples were analyzed for hemoglobin concentration and Hct using manual methods and using an automated hematology analyzer (AHA).Changes in blood, plasma, and red cell volumes were calculated. Although AHA Hct values did not change (P = 0.652), spun packed cell volume fell progressively as the osmolality of the sample increased (P0.001, study 1). Consequently, there was a significant increase in apparent plasma volume as osmolality increased (P0.001): regression analysis revealed that a 10 mOsm·kg change in plasma osmolality produced a difference of 0.8 Hct units and a 1.6% change in plasma volume. In study 2, exercise produced a 12 ± 3 mOsm·kg increase in plasma osmolality. No difference in Hct was apparent at rest (P = 0.659), but spun packed cell volume was 1.0 ± 0.9 Hct units lower during exercise compared with AHA data (P0.001). There was a difference in the degree of plasma volume change calculated, with a reduction of 8.7% ± 3.4% and 11.3% ± 3.5% reported with the manual and AHA methods, respectively (P = 0.002).Conditions or interventions that result in a marked change in plasma osmolality produce a discrepancy in Hct measured using an AHA, consequently introducing errors into any calculation of changes in plasma volume using these data. These findings may also have implications for the measurement of Hct by World Anti-Doping Agency-accredited laboratories.

This study examined effects of 4 weeks of caffeine supplementation on endurance performance. Eighteen low-habitual caffeine consumers ( 0.05). Before supplementation, all participants completed one VO2peak test, one practice trial and 2 experimental trials (acute 3 mg · kg−1 caffeine [precaf] and placebo [testpla]). During the supplementation period a second VO2peak test was completed on day 21 before a final, acute 3 mg · kg−1 caffeine trial (postcaf) on day 29. Trials consisted of 60 min cycle exercise at 60% VO2peak followed by a 30 min performance task. All participants produced more external work during the precaf trial than testpla, with increases in the caffeine (383.3 ± 75 kJ vs. 344.9 ± 80.3 kJ; Cohen’s d effect size [ES] = 0.49; P = 0.001) and placebo (354.5 ± 55.2 kJ vs. 333.1 ± 56.4 kJ; ES = 0.38; P = 0.004...

Objectives The aim of this study was to examine the influence of octopamine supplementation on endurance performance and exercise metabolism. Design Double-blind cross-over study. Methods Ten healthy, recreationally active men (Mean ± SD; age: 24 ± 2 years; body mass: 78.4 ± 8.7 kg; VO2peak: 50.5 ± 6.8 mL kg−1 min−1) completed one VO2peak test, one familiarisation trial and two experimental trials. After an overnight fast, participants ingested either a placebo or 150 mg of octopamine 60 min prior to exercise. Trials consisted of 30 min of cycle exercise at 55% peak power output, followed by a 30 min performance task whereby participants completed as much work (kJ) as possible. Results Performance was similar between the experimental trials (placebo: 352.8 ± 39 kJ; octopamine: 350.9 ± 38.3 kJ; Cohen’s d effect size = 0.05; p = 0.380). Substrate oxidation and circulating concentrations of free fatty acids, prolactin and cortisol were similar between trial conditions (all p > 0.05). There were also no differences across trials for heart rate or perceived exertion during exercise (both p > 0.05). Conclusions Acute supplementation with a low dose of octopamine did not influence endurance cycle performance, substrate oxidation or circulating hormonal concentrations, which could be due to the low serum octopamine concentrations observed. Future studies should investigate the influence of larger doses of octopamine in recreationally active and well-trained individuals during prolonged exercise in temperate and high ambient conditions.

Introduction: This study examined the influence of a supplement matrix on the excretion pattern of nandrolone metabolites in response to ingestion of a trace amount of 19-norandrostenedione. Methods: Ten male and nine female volunteers (mean +/- SD: age = 26 +/- 3 yr, height = 1.71 +/- 0.09 m, body mass = 70.9 +/- 13.2 kg) were recruited. On two occasions, subjects entered the laboratory in the morning after an overnight fast. After an initial urine collection, subjects ingested either 500 mL of plain water or a commercially available energy bar; 10 [mu]g of 19-norandrostenedione was added to each. The volume of each urine sample passed during the next 24 h was measured, and an aliquot was retained for analysis. All samples were analyzed for the metabolites 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE) by gas chromatography-mass spectrometry. Results: The total volume of urine passed was higher in the water trial (2.10 +/- 0.52 L) than in the bar trial (1.85 +/- 0.55 L; P = 0.040). Baseline urinary 19-NA concentrations were all below the limit of quantification for the assay. Peak urinary 19-NA was lower (P = 0.002) in the water trial (4.80 +/- 2.84 ng[middle dot]mL-1) than in the bar trial (8.46 +/- 4.44 ng[middle dot]mL-1). The time elapsed between ingestion of the supplement and the peak urinary 19-NA concentration was longer (P = 0.023) on the bar trial (4.6 +/- 2.4 h) than on the water trial (2.8 +/- 1.9 h). There was no difference in the total recovery of 19-NA + 19-NE between the liquid and solid supplements (water 30 +/- 10%; bar 28 +/- 12%; P < 0.140). Conclusions: Peak 19-NA concentrations were higher, and occurred later, when the 19-norandrostenedione was added to a solid supplement. This may be due to a slower rate of absorption and/or a reduced diuresis, resulting in a longer period for the metabolites to accumulate in the urine

Introduction: Acute bupropion (dopamine/noradrenaline reuptake inhibitor) administration significantly improved time trial performance and increased core temperature in the heat (30[degrees]C). Purpose: The present study was performed to examine the effect of a dopaminergic reuptake inhibitor on exercise capacity and thermoregulation during prolonged exercise in temperate and warm conditions. Methods: Eight healthy well-trained male cyclists participated in this study. Subjects ingested either placebo (PLA; 20 mg) or methylphenidate (MPH; Ritalin; 20 mg) 1 h before the start of exercise in temperate (18[degrees]C) or warm (30[degrees]C) conditions and cycled for 60 min at 55% Wmax, immediately followed by a time trial (TT; PLA18 and MPH18; PLA30 and MPH30) to measure exercise performance. Results: MPH did not influence TT performance at 18[degrees]C (P = 0.397). TT was completed 16% faster in MPH30 (38.1 +/- 6.4 min) than in PLA30 (45.4 +/- 7.3 min; P = 0.049). In the heat Tcore was significantly higher at rest (P = 0.009), and throughout the TT in MPH30 (P < 0.018), reaching values above 40[degrees]C. Throughout MPH30, heart rates were significantly higher (P < 0.05). Conclusions: These results show that MPH has a clear ergogenic effect that was not apparent in 18[degrees]C. The combination of a dopamine reuptake inhibitor and exercise in the heat clearly improved performance and caused hyperthermia without any change in the perception of effort or thermal stress compared with the PLA trial. This response may potentially increase the risk of developing heat illness during exercise in individuals taking drugs of this nature.

AB Purpose: Acute doses of Sinemet(R) (l-DOPA combined with carbidopa) previously failed to influence prolonged exercise performance in a temperate environment, but it is not known whether acute doses of l-DOPA timed to reach maximum plasma concentrations (Cmax) during exercise will improve prolonged cycling performance in warm conditions (30.2[degrees]C +/- 0.2[degrees]C, 50% +/- 1%). Methods: Ten physically active men (age, 26 +/- 4 yr; height, 1.76 +/- 0.08 m; body mass, 76.3 +/- 10.6 kg; V[spacing dot above]O2peak, 57 +/- 8 mL[middle dot]kg-1[middle dot]min-1) were recruited for this study. Participants cycled for 1 h at 60% V[spacing dot above]O2peak followed by a 30-min exercise test, during which they were instructed to complete as much work as possible. Heart rate, skin and core temperatures, as well as RPE and thermal stress were recorded throughout the exercise, and blood samples were collected at rest, at 15-min intervals during the first hour of exercise, and at the end of the exercise test. Finger tapping tests at the beginning and end of the exercise were conducted to examine fine motor control. Results: There was no significant difference in the work done on the placebo (314 +/- 43 kJ) and l-DOPA trials (326 +/- 48 kJ, P = 0.276). Prolactin concentrations were increased at the end of the exercise in all trials (P < 0.001), but this response was attenuated at the end of the exercise for the l-DOPA trial (11.4 +/- 5.5 ng[middle dot]mL-1) and placebo trials (20.8 +/- 3.3 ng[middle dot]mL-1, P = 0.003). No differences between trials were found for any other measure. Conclusions: The results suggest that increasing central catecholamine availability inhibits the normal prolactin response to exercise in the heat but does not alter performance, thermoregulation, or sympathetic outflow

Previous investigations have suggested that exercise at intensities greater than 70% maximal oxygen uptake (VO2max) reduces gastric emptying rate during exercise, but little is known about the effect of exercise intensity on gastric emptying in the postexercise period. To examine this, 8 healthy participants completed 3 experimental trials that included 30 min of rest (R), low-intensity (L; 33% of peak power output) exercise, or high-intensity (H; 10 × 1 min at peak power output followed by 2 min rest) exercise. Thirty minutes after completion of exercise, participants ingested 595 ml of a 5% glucose solution, and gastric emptying rate was assessed via the double-sampling gastric aspiration method for 60 min. No differences (p > .05) were observed in emptying characteristics for total stomach volume or test meal volume between the trials, and the quantity of glucose delivered to the intestine did not differ between trials (p > .05). Half-emptying times did not differ (p = .902) between trials and amounted to 22 ± 9, 22 ± 9, and 22 ± 7 min (M ± SD) during the R, L, and H trials, respectively. These results suggest that exercise has little effect on postexercise gastric emptying rate of a glucose solution.

AB Purpose: Ingestion of tyrosine (TYR), a catecholamine precursor, has previously improved aspects of cognitive function and mood during acute stress, although there is limited research exploring the optimal dose relative to blood values. The serum responses of two doses of TYR were investigated (study 1), with the identified "optimal" dose assessed relative to cognitive and physical performance during a military-based protocol in the heat (study 2). Methods: For study 1, 21 participants were assigned to one of the following three groups: HIGH (two doses of 150 mg[middle dot]kg-1 body mass TYR), LOW (two doses of 75 mg[middle dot]kg-1 body mass TYR), and CON (sugar-free drink). Participants ingested TYR in two separate doses (0900 and 1300 h) and remained in the laboratory from 0800 to 1700 h, having blood drawn every hour. For study 2, eight participants completed a military-based load carriage protocol composed of a 60-min walk (6.5 km[middle dot]h-1) followed by a 2.4-km time trial carrying a 25-kg backpack (40[degrees]C; relative humidity, 30%) on two occasions (TYR/placebo) in a double-blind counterbalanced crossover design. Cognitive function was assessed before, during, and after exercise. Results: Study 1 demonstrated that ingestion of a single dose of 150 mg[middle dot]kg-1 body mass TYR was equally efficient at elevating serum TYR concentration relative to a double dose. In study 2, exercise heat stress impaired some aspects of cognitive function; however, TYR did not alleviate these decrements (P > 0.05). Furthermore, no difference was observed in any physiological variable between conditions (P > 0.05) or time trial completion time (P = 0.74) between TYR (19.78 +/- 3.44 min) and placebo (20.29 +/- 3.55 min). Conclusions: Despite marked elevations in serum TYR concentration, ingestion of TYR did not influence cognitive function or physical performance during exercise heat stress.

Purpose:Caffeine can be beneficial during endurance and repeated-sprint exercise in able-bodied individuals performing leg or wholebody exercise. However, little evidence exists regarding its effects during upper-body exercise. This study therefore aimed to investigate the effects of caffeine on sprint (SPR) and 4-min maximal-push (PUSH) performance in wheelchair sportsmen.Methods:Using a double-blind, placebo-controlled, crossover design, 12 male wheelchair rugby players (age 30.0 ± 7.7 y, body mass 69.6 ± 15.3 kg, training 11.1 ± 3.5 h/wk) completed 2 exercise trials, separated by 7–14 d, 70 min after ingestion of 4 mg/kg caffeine (CAF) or dextrose placebo (PLA). Each trial consisted of four 4-min PUSHes and 3 sets of 3 × 20-m SPRs, each separated by 4 min rest. Participants responded to the Felt Arousal (a measure of perceived arousal), Feeling (a measure of the affective dimension of pleasure/displeasure), and rating-of-perceived-exertion (RPE) scales. Salivary caffeine secretion rates were measured.Results:Average SPR times were faster during CAF than PLA during SPR 1 and SPR 2 (P = .037 and .016). There was no influence of supplementation on PUSHes 2–4 (P > .099); however, participants pushed significantly farther during PUSH 1 after CAF than after PLA (mean ± SD 677 ± 107 and 653 ± 118 m, P = .047). There was no influence of CAF on arousal or RPE scores (P > .132). Feeling scores improved over the course of the CAF trial only (P = .017) but did not significantly differ between trials (P > .167). Pre-warm-up (45 min postingestion) salivary CAF secretion rates were 1.05 ± 0.94 and 0.08 ± 0.05 μg/min for CAF and PLA, respectively.Conclusion:Acute CAF supplementation can improve both 20-m-sprint performance and a 1-off bout of short-term endurance performance in wheelchair sportsmen.

Introduction: This study examined changes in serum S100s concentration, a peripheral marker of BBB permeability, in response to exercise in the heat with and without fluid ingestion. Methods: Eight physically active males completed up to 90 min of intermittent exercise at a power output corresponding to 55% V?O2peak in a warm environment (35°C, 56% rh). Trials were completed with (F trial) and without (NF trial) the replacement of sweat losses. During the fluid trial, an aliquot of plain water was ingested at 15-min intervals to match the volume of sweat lost during the previous period of exercise. Results: Exercise time was 80.7 ± 13.0 min in the NF trial and 85.1 ± 9.5 min in the F trial (P = 0.107). Fluid ingestion resulted in a smaller rise in core temperature (P = 0.050) and heart rate (P = 0.027) during the latter stages of exercise. Serum S100s concentrations were 0.08 ± 0.02 µg·L-1 at rest, increasing to 0.20 ± 0.06 µg·L-1 at the end of exercise in the NF trial, with this response attenuated by the ingestion of fluid (0.13 ± 0.03 µg·L-1; P = 0.046). Both serum sodium concentration (P < 0.001) and serum osmolality (P = 0.003) were significantly lower at the end of exercise in the F trial than in the NF trial. Conclusion: The results of this study demonstrate that water ingestion can limit exercise-induced increases in serum S100s, consistent with the preservation of BBB integrity. It is possible that this response was mediated through the maintenance of lower extracellular osmolality late in exercise, thus potentially limiting the osmotically driven movement of fluid across the BBB.

Eight males were recruited to examine the effect of branched-chain amino acid (BCAA) supplementation on exercise capacity in a glycogen-depleted state in a warm environment. Following a exercise and dietary regimen designed to reduce glycogen availability, subjects returned to the laboratory the following morning and remained seated for 2 h, before cycling to volitional exhaustion at 50% VO2 peak in a warm environment [30.0 (0.2) degrees C; mean (SD)]. Four 250 ml aliquots of a 12 g l(-1) BCAA solution or placebo were ingested at 30 min intervals prior to exercise, with an additional 150 ml consumed every 15 min throughout exercise. BCAA ingestion had no effect on exercise capacity [placebo 103.9 (26.9) min; BCAA 111.0 (29.2) min; P = 0.129). No difference in heart rate (P = 0.345), core temperature (P = 0.628), or weighted mean skin temperature (P = 0.114) was apparent between trials. Ingestion of the BCAA solution produced a marked increase in plasma BCAA immediately prior to exercise [+ 1126 (158) micromol l(-1); P0.001) with this difference maintained throughout. Consequently, a significant reduction in the plasma concentration ratio of free tryptophan to BCAA was observed during the BCAA trial when compared to the placebo (P0.001). Plasma ammonia concentration was significantly elevated during exercise throughout the BCAA trial (P0.001), with no change from rest apparent during the placebo trial (P = 0.608). Blood glucose (P = 0.114) and lactate (P = 0.836) concentrations were not different between trials. Ingestion of a BCAA solution prior to, and during, prolonged exercise in glycogen-depleted subjects did not influence exercise capacity in a warm environment.

Eight young men were recruited to a study designed to examine the effect of tyrosine (TYR) supplementation on the capacity to perform prolonged exercise in a warm environment. Subjects entered the laboratory in the morning and remained seated for 1 hr before cycling to exhaustion at 70% VO2peak. Two 250-ml aliquots of a placebo (PLA ) or a TYR solution were ingested at 30-min intervals before exercise, with an additional 150 ml consumed every 15 min throughout exercise (total TYR dose: 150 mg/kg BM). Cognitive function was assessed before drink ingestion, at the end of the rest period, and at exhaustion. TYR ingestion had no effect on exercise capacity (PLA 61.4 ± 13.7 min, TYR 60.2 ± 15.4 min; p = .505). No differences in heart rate (p = .380), core temperature (p = .554), or weighted mean skin temperature (p = .167) were apparent between trials. Ingestion of TYR produced a marked increase in serum TYR concentrations (+236 ± 46 μmol/L; p < .001), with this difference maintained throughout exercise. No change was apparent during the PLA trial (p = .924). Exercise caused an increase in error rate during the complex component of the Stroop test (p = .034), but this response was not influenced by the drink ingested. No other component of cognitive function was altered by the protocol (all p > .05). Ingestion of a TYR solution did not influence time to exhaustion or several aspects of cognitive function when exercise was undertaken in a warm environment.

Purpose: This evaluated the efficacy of drinks containing low concentrations of carbohydrate (CHO; 2-6%) on physical performance in cool and warm environments. Methods: In two separate, but related studies, 24 healthy males completed a familiarisation trial and four trials to volitional exhaustion (TTE) at 70% VO2max in cool conditions (10C, n = 12) or 60% VO2max in a warm environment (30C, n = 12). Subjects ingested 0%, 2%, 4% or 6% CHO solutions (sucrose, glucose and fructose in a ratio of 50:25:25) immediately before exercise and every 10 minutes during exercise. Results: TTE in 10C was 102.6 ± 33.9 minutes, 109.2 ± 33.9 minutes, 121.0 ± 25.7 minutes and 122.4 ± 29.9 minutes in the 0%, 2%, 4% and 6% trials respectively (P = 0.012). Compared to the 0% trial, TTE was longer on the 4% (P = 0.032; ES 0.72) and 6% (P = 0.044; ES 0.66) trials. In addition, TTE was longer on the 6% trial than the 2% trial (P = 0.025). TTE was also significantly influenced by drink CHO content at 30C (0% 94.5 ± 24.5 minutes, 2% 104.1 ± 20.1 minutes, 4% 105.5 ± 26.7 minutes, 6% 112.0 ± 28.7 minutes; P = 0.046). No differences in TTE were apparent between 0% and the 2% or 4% trials, but TTE was longer on the 6% compared to the placebo (P = 0.045; ES 0.62). Heart rate, core temperature or rates of substrate oxidation were not affected by drink CHO content. Conclusions: These results demonstrate significant improvements in exercise capacity over the placebo trial when 4% and 6% CHO solutions were ingested at 10C and a 6% CHO drink at 30C.

This study examined the influence of relative humidity on endurance exercise performance in a warm environment. Eight male volunteers performed four cycle exercise trials at 70% maximum oxygen uptake until volitional exhaustion in an environmental chamber maintained at 30.2 ± 0.2°C. Volunteers were tested under four relative humidity (rh) conditions: 24, 40, 60 and 80%. Core and weighted mean skin temperature, heart rate, skin blood flow, and cutaneous vascular conductance were recorded at rest and at regular intervals during exercise. Mean ± SD time to exhaustion was 68 ± 19, 60 ± 17, 54 ± 17, and 46 ± 14 min at 24, 40, 60, and 80% rh, respectively (P < 0.001); exercise time was significantly less at 60% (P = 0.013) and 80% (P = 0.005) rh than recorded at 24% rh. There were no differences in core temperature (P = 0.480) and heart rate (P = 0.097) between trials. Core temperature at exhaustion was 39.0 ± 0.3°C at 24, 40, and 60% rh and 39.1 ± 0.3°C at 80% rh (P = 0.159). Mean skin temperature at the point of exhaustion was higher at 80% rh than at 24% rh (P < 0.001). Total sweat loss was similar between trials (P = 0.345), but sweating rate was higher at 60 and 80% rh than at 24% rh (P < 0.001). The results suggest that exercise capacity at moderate intensity in a warm environment is progressively impaired as the relative humidity increases.

The aim of this study was to quantify changes in brain volume after exercise/heat-induced hypohydration in man.Eight active men completed intermittent exercise in a warm environment, until 2.9% ± 0.1% of body mass was lost. Subjects remained hypohydrated for 2 h after the end of exercise. Brain volume was measured before, immediately after, and 1 and 2 h after exercise using magnetic resonance imaging (Philips 3T Achieva, AE Eindhoven, The Netherlands). Measures of subjective feelings and core body temperature were also monitored. Blood samples were drawn to determine serum electrolyte concentrations and osmolality and to allow calculation of changes in blood and plasma volumes.Brain volume was not influenced by hypohydration (0.2% ± 0.4%; effect size (ES) = 0.2, P = 0.310). Reductions in ventricular (4.0% ± 1.8%; ES = 4.6, P0.001) and cerebrospinal fluid (3.1% ± 1.9%; ES = 3.3, P = 0.003) volumes were observed after exercise. Compared with preexercise levels, serum osmolality was elevated throughout the 2-h postexercise period (+10 ± 2 mOsm·kg, P0.001). Core temperature increased from 37.1°C ± 0.3°C at rest to 39.3°C ± 0.5°C at the end of exercise (P = 0.001).These data demonstrate that brain volume remains unchanged in response to moderate hypohydration and presence of serum hyperosmolality, suggesting that mechanisms are in place to defend brain volume.

WATSON, P., C. JUDKINS, E. HOUGHTON, C. RUSSELL, and R. J. MAUGHAN. Urinary Nandrolone Metabolite Detection after Ingestion of a Nandrolone Precursor. Med. Sci. Sports Exerc., Vol. 41, No. 4, pp. 766–772, 2009. Introduction: Quantities of various anabolic/androgenic steroids have been found in dietary supplements without their presence being disclosed on the label. The aim of this study was to quantify the excretion patterns of the diagnostic metabolites, 19-norandrosterone (19-NA), and 19-noretiocholanolone (19-NE) after ingestion of small doses of 19-nor-4-androstene-3,17-dione (19-norandrostenedione). Methods: Eleven males and nine females entered the laboratory in the morning after an overnight fast. An initial urine sample was collected, and volunteers then ingested 500 mL of water containing 5 g of creatine monohydrate and 1.0, 2.5, or 5.0 Kg of 19-norandrostenedione. The volume of each urine void was measured, and an aliquot was taken. Samples were analyzed for the metabolites 19-NA and 19-NE by GCMS. Results: Baseline urinary 19-NA concentrations were 0.19 T 0.14 ngImL j1 . Ingestion of the supplement resulted in peak mean urinary 19-NA concentrations of 0.68 T 0.36, 1.56 T 0.86, and 3.89 T 3.11 ngImL j1 in the 1.0-, 2.5-, or 5.0-Kg trials, respectively. Under current WADA regulations, ingestion of the 1.0-Kg dose produced 0 positive doping tests, 5 subjects (20%) tested positive in the 2.5-Kg trial, and 15 subjects (75%) had urinary 19-NA concentrations exceeding 2 ngImL j1 after ingesting creatine containing 5.0 Kg of the steroid. The recovery of the ingested dose was highly variable between individuals, with values ranging from 11% to 84% (mean T SD = 47% T 18%). Conclusions: Ingestion of trace amounts of 19-norandrostenedione can result in transient elevations of urinary 19-NA and 19-NE concentrations. The addition of as little as 2.5 Kg of 19-norandrostenedione to a supplement (0.00005% contamination) appears sufficient to result in a doping violation in some individuals. Key Words: 19-NORANDROSTENEDIONE, STEROIDS, DRUGS IN SPORT, WORLD ANTI DOPING AGENCY

Following a 2.0 +/- 0.1% body mass loss induced by intermittent exercise in the heat, seven male volunteers ingested either a carbohydrate-electrolyte solution (CE) or skimmed milk (M) in a volume equal to 150% of body mass loss. At the end of the 3 h recovery period, subjects were essentially in positive fluid balance on trial M (191 +/- 162 mL), and euhydrated on trial CE (-135 +/- 392 mL) despite being in negative sodium balance on both trials and negative potassium balance on trial CE. This difference of 326 +/- 354 mL or 0.4% body mass approached significance (P = 0.051). Subjects ingested 137 +/- 15 and 113 +/- 12 g of CHO during the CE and M trials, respectively, as well as 75 +/- 8 g of protein during the M trial. At the end of the 3 h recovery period, an exercise capacity test was completed at 61% VO(2peak) in warm (35.3 +/- 0.5 degrees C), humid (63 +/- 2%) conditions. HR (P = 0.020) and rectal temperature (P = 0.045) were higher on trial M, but no difference in exercise time to exhaustion was observed between trials (39.6 +/- 7.3 min vs. 39.7 +/- 8.1 min on trials CE and M, respectively). The results of the present study suggest that milk can be an effective post-exercise rehydration drink, with subjects remaining in net positive fluid balance throughout the recovery period. Despite the effect on fluid retention, exercise capacity was not different between skimmed milk and a commercially available carbohydrate-electrolyte drink 4 h following exercise/heat-induced body mass loss.

Fluid balance and sweat electrolyte losses were measured in the players and substitutes engaged in an English Premier League Reserve competitive football match played at an ambient temperature of 6–8 °C (relative humidity 50–60%). Intake of water and/or sports drink and urine output were recorded, and sweat composition was estimated from absorbent swabs applied to 4 skin sites for the duration of the game. Body mass was recorded before and after the game. Data were obtained for 22 players (age 21 y, height 180 cm, mass 78 kg) and 9 substitutes (17 y, 181 cm, 72 kg). All were male. Two of the players were dismissed during the game, and none of the substitutes played any part in the game. Mean ± SD sweat loss of players amounted to 1.68 ± 0.40 L, and mean fluid intake was 0.84 ± 0.47 L (n = 20), with no difference between teams. Corresponding values for substitutes, none of whom played in the match, were 0.40 ± 0.24 L and 0.78 ± 0.46 L (n = 9). Prematch urine osmolality was 678 ± 344 mOsm/kg: 11 of the 31 players provided samples with an osmolality of more than 900 mOsm/kg. Sweat sodium concentration was 62 ± 13 mmol/L, and total sweat sodium loss during the game was 2.4 ± 0.8 g. These descriptive data show a large individual variability in hydration status, sweat losses, and drinking behaviors in a competitive football match played in a cool environment, highlighting the need for individualized assessment of hydration status to optimize fluid-replacement strategies.

Acute doses of Sinemet ® (L-DOPA combined with carbidopa) previously failed to change prolonged exercise performance in a temperate environment, but it is not known whether acute doses of L-DOPA timed to reach C max during exercise will improve prolonged cycling performance in warm conditions. 10 physically active men (age 26 ± 4 y; height 1.76 ± 0.08 m; body mass 76.3 ± 10.6 kg; V O 2 peak 57 ± 8 ml/kg/min) were recruited for this study. Participants cycled for 1 h at 60% V O 2 peak followed by a 30 min exercise test, during which they were instructed to complete as much work as possible. Heart rate, skin and core temperature, as well as ratings of perceived exertion and thermal comfort were recorded throughout exercise and blood samples were collected at rest, 15 min intervals during the first hour of exercise and the end of the exercise test. Finger tap tests at the beginning and end of exercise were employed to examine fine motor control. There was no significant difference in the work done on placebo (314 ± 43 kJ) and L-DOPA trials (326 ± 48 kJ; p = 0.08). Prolactin concentrations were increased at the end of exercise in all trials (p

This study systematically examined the influence of carbohydrate (sucrose), sodium, and caffeine on the fluid retention potential of beverages under euhydrated conditions, using the beverage hydration index method. Three cohorts, each of 12 young, healthy, active men, ingested 1 L of beverages containing four different concentrations of a single component (sucrose, sodium, or caffeine) in a double-blind, crossover manner. Urine output was collected for the subsequent 4 hr. Cumulative urine output was lower and net fluid balance was higher after 10 and 20% sucrose beverages than 0 and 5% sucrose beverages (p p p = .83). Consequently, the calculated beverage hydration index was greater in beverages with higher sucrose or sodium content, but caffeine had no effect. No difference was observed in arginine vasopressin or aldosterone between any trials. These data highlight that the key drivers promoting differences in the fluid retention potential of beverages when euhydrated are energy density, likely through slowed fluid delivery to the circulation (carbohydrate content effect), or electrolyte content through improved fluid retention (sodium content effect). These data demonstrate that beverage carbohydrate and sodium content influence fluid delivery and retention in the 4 hr after ingestion, but caffeine up to 400 mg/L does not. Athletes and others can use this information to guide their daily hydration practices.