Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Eur J Sport Sci ; 24(7): 870-877, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38956805

RESUMO

Cannabidiol (CBD) is a non-intoxicating phytocannabinoid which has been proposed to possess anti-inflammatory and analgesic properties. Given the potential for perceptions of pain to limit exercise performance, the aim of the present study was to investigate if 3 weeks of daily CBD supplementation (150 mg day-1) improved performance in a 10-min performance-trial on a cycle ergometer. In a randomized, double-blind and placebo-controlled study, 22 healthy participants (n = 11 male and n = 11 female) completed two 10-min performance trials on a WattBike cycle ergometer interspersed with a 3-week supplementation period. Supplementation involved either 150 mg day-1 oral CBD or 150 mg day-1 of a visually identical placebo (PLA). During trials, ratings of perceived exertion (RPE [6-20]), heart rate (HR) and blood lactate (BLa) were collected every 2 min. Mean power (W) was also taken throughout the exercise at each time point. All data were analyzed using two-way ANOVAs. There were no significant differences (P > 0.05) between CBD or PLA groups for mean power (W) during the 10-min performance trial. There were also no significant differences (P > 0.05) in any of the physiological or perceptual parameters (HR, BLa and RPE) between conditions. Three weeks supplementation of a broad-spectrum CBD supplement did not improve performance via any change in RPE during a 10-min time trial on a cycle ergometer, and as such, this evidence does not support the claim that broad-spectrum CBD supplements could be performance-enhancing in this exercise modality.


Assuntos
Desempenho Atlético , Canabidiol , Suplementos Nutricionais , Frequência Cardíaca , Ácido Láctico , Humanos , Canabidiol/administração & dosagem , Canabidiol/farmacologia , Masculino , Método Duplo-Cego , Feminino , Frequência Cardíaca/efeitos dos fármacos , Adulto , Desempenho Atlético/fisiologia , Adulto Jovem , Ácido Láctico/sangue , Teste de Esforço , Esforço Físico/fisiologia , Esforço Físico/efeitos dos fármacos
2.
Echo Res Pract ; 10(1): 19, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-38053157

RESUMO

BACKGROUND: Image and performance enhancing drugs (IPEDs) are commonly used in resistance trained (RT) individuals and negatively impact left ventricular (LV) structure and function. Few studies have investigated the impact of IPEDs on atrial structure and function with no previous studies investigating bi-atrial strain. Additionally, the impact of current use vs. past use of IPEDs is unclear. METHODS: Utilising a cross-sectional design, male (n = 81) and female (n = 15) RT individuals were grouped based on IPED user status: current (n = 57), past (n = 19) and non-users (n = 20). Participants completed IPED questionnaires, anthropometrical measurements, electrocardiography, and transthoracic echocardiography with strain imaging. Structural cardiac data was allometrically scaled to body surface area (BSA) according to laws of geometric similarity. RESULTS: Body mass and BSA were greater in current users than past and non-users of IPEDs (p < 0.01). Absolute left atrial (LA) volume (60 ± 17 vs 46 ± 12, p = 0.001) and right atrial (RA) area (19 ± 4 vs 15 ± 3, p < 0.001) were greater in current users than non-users but this difference was lost following scaling (p > 0.05). Left atrial reservoir (p = 0.008, p < 0.001) and conduit (p < 0.001, p < 0.001) strain were lower in current users than past and non-users (conduit: current = 22 ± 6, past = 29 ± 9 and non-users = 31 ± 7 and reservoir: current = 33 ± 8, past = 39 ± 8, non-users = 42 ± 8). Right atrial reservoir (p = 0.015) and conduit (p = 0.007) strain were lower in current than non-users (conduit: current = 25 ± 8, non-users = 33 ± 10 and reservoir: current = 36 ± 10, non-users = 44 ± 13). Current users showed reduced LV diastolic function (A wave: p = 0.022, p = 0.049 and E/A ratio: p = 0.039, p < 0.001) and higher LA stiffness (p = 0.001, p < 0.001) than past and non-users (A wave: current = 0.54 ± 0.1, past = 0.46 ± 0.1, non-users = 0.47 ± 0.09 and E/A ratio: current = 1.5 ± 0.5, past = 1.8 ± 0.4, non-users = 1.9 ± 0.4, LA stiffness: current = 0.21 ± 0.7, past = 0.15 ± 0.04, non-users = 0.15 ± 0.07). CONCLUSION: Resistance trained individuals using IPEDs have bi-atrial enlargement that normalises with allometric scaling, suggesting that increased size is, in part, associated with increased body size. The lower LA and RA reservoir and conduit strain and greater absolute bi-atrial structural parameters in current than non-users of IPEDs suggests pathological adaptation with IPED use, although the similarity in these parameters between past and non-users suggests reversibility of pathological changes with withdrawal.

3.
Andrologia ; 53(4): e14001, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33559971

RESUMO

Eurycoma longifolia supplementation increases testosterone levels in humans via activation of the hypothalamic-pituitary-gonadal axis and/or the hypothalamic-pituitary-adrenal axis mainly in older adults and nonhealthy populations. This study aimed to assess the impact of Eurycoma longifolia on the hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal axes in healthy young males since this might promote functional testosterone prowess. Thirty-two males (24.4 ± 4.7 years; 1.74 ± 0.07 m; 73.7 ± 8.4 kg) in a placebo-controlled, double-blind, matched-paired study received 600 mg/day Eurycoma longifolia or placebo for two weeks. Blood analysis using repeated measures analysis of variance showed significant interaction and time effects for testosterone (F1,30  = 9.04, p = .005), free testosterone (F1,30  = 7.13, p = .012) and estradiol (F1,30  = 8.07, p = .008) levels in favour of the treatment group, while luteinising hormone, follicle-stimulating hormone and sexual hormone-binding globulin did not. The lack of changes in luteinising hormone and follicle-stimulating hormone levels suggests that a lesser role played by Eurycoma longifolia in activating the hypothalamic-pituitary-gonadal axis in the young adults. The raised testosterone level may be due to a greater rate of hormone production via the hypothalamic-pituitary-adrenal axis. The supplementation of Eurycoma longifolia for two weeks demonstrates steroidogenic effects on young men were dose-related. Consequently, the raised testosterone following Eurycoma longifolia supplementations could benefit muscle and strength gain in young adults.


Assuntos
Eurycoma , Idoso , Método Duplo-Cego , Humanos , Sistema Hipotálamo-Hipofisário , Masculino , Sistema Hipófise-Suprarrenal , Extratos Vegetais/farmacologia , Testosterona , Adulto Jovem
4.
Med Sci Sports Exerc ; 52(9): 1966-1975, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32168106

RESUMO

PURPOSE: This study aimed to quantify net glycogen utilization in the vastus lateralis (VL) and gastrocnemius (G) of male (n = 11) and female (n = 10) recreationally active runners during three outdoor training sessions. METHODS: After 2-d standardization of carbohydrate intakes (6 g·kg body mass per day), glycogen was assessed before and after 1) a 10-mile road run (10-mile) at lactate threshold, 2) 8 × 800-m track intervals (8 × 800 m) at velocity at V˙O2max, and 3) 3 × 10-min track intervals (3 × 10 min) at lactate turnpoint. RESULTS: Resting glycogen concentration was lower in the G of female compared with males (P < 0.001) runners, although no sex differences were apparent in the VL (P = 0.40). Within the G and VL of male runners, net glycogen utilization differed between training sessions where 10 miles was greater than both track sessions (all comparisons, P < 0.05). In contrast, net glycogen utilization in female runners was not different between training sessions in either muscle (all comparisons, P > 0.05). Net glycogen utilization was greater in male than in female runners in both VL (P = 0.02) and G (P = 0.07) during the 10-mile road run. With the exception of male runners during the 3 × 10-min protocol (P = 0.28), greater absolute glycogen utilization was observed in the G versus the VL muscle in both male and female runners and during all training protocols (all comparisons, P < 0.05). CONCLUSION: Data demonstrate that 1) prolonged steady-state running necessitates a greater glycogen requirement than shorter but higher-intensity track running sessions, 2) female participants display evidence of reduced resting muscle glycogen concentration and net muscle glycogen utilization when compared with male participants, and 3) net glycogen utilization is higher in the G muscle compared with the VL.


Assuntos
Glicogênio/metabolismo , Músculo Esquelético/metabolismo , Resistência Física/fisiologia , Corrida/fisiologia , Caracteres Sexuais , Adulto , Glicemia/metabolismo , Ácidos Graxos não Esterificados/sangue , Feminino , Glicerol/sangue , Humanos , Ácido Láctico/sangue , Masculino , Músculo Quadríceps/metabolismo , Fatores Sexuais , Adulto Jovem
5.
Artigo em Inglês | MEDLINE | ID: mdl-33419381

RESUMO

The aim of this study was to update the metabolic power (MP) algorithm (PV˙O2, W·kg-1) related to the kinematics data (PGPS, W·kg-1) in a soccer-specific performance model. For this aim, seventeen professional (Serie A) male soccer players (V˙O2max 55.7 ± 3.4 mL·min-1·kg-1) performed a 6 min run at 10.29 km·h-1 to determine linear-running energy cost (Cr). On a separate day, thirteen also performed an 8 min soccer-specific intermittent exercise protocol. For both procedures, a portable Cosmed K4b2 gas-analyzer and GPS (10 Hz) was used to assess the energy cost above resting (C). From this aim, the MP was estimated through a newly derived C equation (PGPSn) and compared with both the commonly used (PGPSo) equation and direct measurement (PV˙O2). Both PGPSn and PGPSo correlated with PV˙O2 (r = 0.66, p < 0.05). Estimates of fixed bias were negligible (PGPSn = -0.80 W·kg-1 and PGPSo = -1.59 W·kg-1), and the bounds of the 95% CIs show that they were not statistically significant from 0. Proportional bias estimates were negligible (absolute differences from one being 0.03 W·kg-1 for PGPSn and 0.01 W·kg-1 for PGPSo) and not statistically significant as both 95% CIs span 1. All variables were distributed around the line of unity and resulted in an under- or overestimation of PGPSn, while PGPSo routinely underestimated MP across ranges. Repeated-measures ANOVA showed differences over MP conditions (F1,38 = 16.929 and p < 0.001). Following Bonferroni post hoc test significant differences regarding the MP between PGPSo and PV˙O2/PGPSn (p < 0.001) were established, while no differences were found between PV˙O2 and PGPSn (p = 0.853). The new approach showed it can help the coaches and the soccer trainers to better monitor external training load during the training seasons.


Assuntos
Algoritmos , Modelos Teóricos , Corrida , Futebol , Teste de Esforço , Humanos , Masculino , Consumo de Oxigênio , Futebol/fisiologia
6.
Int J Sports Physiol Perform ; 14(10): 1344-1349, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30958069

RESUMO

PURPOSE: To investigate the impact of twice-daily inhalation of 100 µg of salmeterol (SAL) or 12 µg of formoterol (FOR) in addition to a strength- and power-training program over a 5-wk period on a 30-m sprint, strength, power, mood, stress, and skinfold thickness. METHODS: In a randomized, single-blind study, 23 male and 15 female nonasthmatic, recreationally active individuals were recruited (mean [SD] age 26.3 [5.4] y, weight 76.2 [11.5] kg, height 176.9 [8.5] cm). Participants completed 3 standardized whole-body strength- and power-training sessions per week for 5 wk during which they were assigned to an SAL, FOR, or placebo group. Participants used their inhaler twice per day as instructed and completed assessments of sprint, strength, and power at baseline and 1 wk after cessation of the training program. The assessments included a 30-m sprint, vertical jump, 1-repetition-maximum (1RM) bench press, 1RM leg press, peak torque flexion and extension, anthropometric evaluation, and Rest-Q questionnaires. RESULTS: After 5 wk of strength and power training, 30-m sprint time reduced in the FOR (0.29 [0.11] s, P = .049) and SAL (0.35 [0.05] s, P = .040) groups compared with placebo (+0.01 [0.11] s). No significant change was found in other assessments of strength, mood, or skinfold thickness. CONCLUSIONS: When strength and power training are combined with the inhalation of FOR or SAL over a 5-wk period, moderately trained individuals experience an improvement in 30-m sprint performance.

7.
Int J Sports Physiol Perform ; 14(6): 822­828, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30569748

RESUMO

Terbutaline is a prohibited drug except for athletes with a therapeutic use exemption certificate; terbutaline's effects on endurance performance are relatively unknown. Purpose: To investigate the effects of 2 therapeutic (2 and 4 mg) inhaled doses of terbutaline on 3-km running time-trial performance. Methods: A total of 8 men (age 24.3 [2.4] y; weight 77.6 [8] kg; and height 179.5 [4.3] cm) and 8 women (age 22.4 [3] y; weight 58.6 [6] kg; and height 163 [9.2] cm) free from respiratory disease and illness provided written informed consent. Participants completed 3-km running time trials on a nonmotorized treadmill on 3 separate occasions following placebo and 2- and 4-mg inhaled terbutaline in a single-blind, repeated-measures design. Urine samples (15 min postexercise) were analyzed for terbutaline concentration. Data were analyzed using 1-way repeated-measures analysis of variance, and significance was set at P < .05 for all analyses. Results: No differences were observed for completion times (1103 [201] s, 1106 [195] s, 1098 [165] s; P = .913) for the placebo or 2- and 4-mg inhaled trials, respectively. Lactate values were higher (P = .02) after 4 mg terbutaline (10.7 [2.3] mmol·L-1) vs placebo (8.9 [1.8] mmol·L-1). Values of forced expiratory volume in the first second of expiration (FEV1) were greater after inhalation of 2 mg (5.08 [0.2]; P = .01) and 4 mg terbutaline (5.07 [0.2]; P = .02) compared with placebo (4.83 [0.5] L) postinhalation. Urinary terbutaline concentrations were mean 306 (288) ng·mL-1 and 435 (410) ng·mL-1 (P = .2) and peak 956 ng·mL-1 and 1244 ng·mL-1 after 2 and 4 mg inhaled terbutaline, respectively. No differences were observed between the male and female participants. Conclusions: Therapeutic dosing of terbutaline does not lead to an improvement in 3-km running performance despite significantly increased FEV1. The findings suggest that athletes using inhaled terbutaline at high therapeutic doses to treat asthma will not gain an ergogenic advantage during 3-km running performance.


Assuntos
Desempenho Atlético , Substâncias para Melhoria do Desempenho/administração & dosagem , Corrida , Terbutalina/administração & dosagem , Administração por Inalação , Adulto , Asma/tratamento farmacológico , Feminino , Volume Expiratório Forçado , Humanos , Ácido Láctico/sangue , Masculino , Método Simples-Cego , Adulto Jovem
8.
J Sports Sci Med ; 16(4): 581-588, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29238260

RESUMO

The Objectives of the study were to investigate whether 400 µg inhaled salbutamol influences 3 km running time-trial performance and lung function in eucapnic voluntary hyperpnoea positive (EVH+ve) and negative (EVH-ve) individuals. Fourteen male participants (22.4 ± 1.6yrs; 76.4 ± 8.7kg; 1.80 ± 0.07 m); (7 EVH+ve; 7 EVH-ve) were recruited following written informed consent. All participants undertook an EVH challenge to identify either EVH+ve (↓FEV1>10%) or EVH-ve (↓FEV1<10%). Participants performed three separate 3 km running time-trials in a low-humidity (20-25%) environment on a non-motorized treadmill, 15 minutes following inhalation of salbutamol (400 µg), placebo (non-active inhalant) or control (no inhalant), in a randomized, single-blind, repeated measures design. Forced vital capacity maneuvers were performed at baseline, 10 minutes post inhalation and post time-trial. Time to complete 3 km and lung function data were analyzed using mixed model repeated measures ANOVA. Significance was assumed at p < 0.05. All EVH+ve participants had FEV1 falls from baseline between 10-25% post-challenge. There was no difference in performance time between trial conditions in EVH+ve (1012.7 ± 129.6s; 1002.4 ± 123.1s; 1015.9 ± 113.0s) (p = 0.774) and EVH-ve (962.1 ± 99.2s; 962.0 ± 76.2s; 950.8 ± 84.9s) (p = 0.401) groups for salbutamol, placebo and control trials, respectively. Exercising heart rate was significantly higher (p = 0.05) in the salbutamol trial (183 ± 8 beatsˑmin-1) compared to control (180 ± 9 beatsˑmin-1) with a trend towards significance (p=0.06) in the placebo trial (179 ± 9 beatsˑmin-1) for the pooled groups, no differences were seen between trials in groups individually. There was an increase in FEV1 in both EVH+ve (4.01 ± 0.8L; 4.26 ± 0.7L; 4.25 ± 0.5L) and EVH-ve (4.81 ± 0.4L; 5.1 ± 0.4L; 5.1 ± 0.5L) groups which was significant post-inhalation (p = 0.01; p = 0.02), but not post-time-trial (p = 0.27; p = 0.06), respectively, following salbutamol. EVH+ve participants did not demonstrate significant falls (>10% from baseline) in FEV1 following any time-trial. Administration of 400µg inhaled salbutamol does not improve 3 km time-trial performance in either mild EVH+ve or EVH-ve individuals despite significantly increased HR and FEV1.

9.
J Sports Sci Med ; 13(2): 271-9, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24790479

RESUMO

Whilst there appears to be no ergogenic effect from inhaled salbutamol no study has investigated the impact of the acute inhalation of 1600 µg, the World Anti-Doping Agency (WADA) daily upper limit, on endurance running performance. To investigate the ergogenic effect of an acute inhalation of short acting ß2-agonists at doses up to 1600 µg on 5 km time trial performance and resultant urine concentration. Seven male non-asthmatic runners (mean ± SD; age 22.4 ± 4.3 years; height 1.80 ± 0.07 m; body mass 76.6 ± 8.6 kg) provided written informed consent. Participants completed six 5 km time-trials on separate days (three at 18 °C and three at 30 °C). Fifteen minutes prior to the initiation of each 5 km time-trial participants inhaled: placebo (PLA), 800 µg salbutamol (SAL800) or 1600 µg salbutamol (SAL1600). During each 5 km time-trial HR, VO2, VCO2, VE, RPE and blood lactate were measured. Urine samples (90 ml) were collected between 30-180 minutes post 5 km time-trial and analysed for salbutamol concentration. There was no significant difference in total 5 km time between treatments (PLA 1714.7 ± 186.2 s; SAL800 1683.3 ± 179.7 s; SAL1600 1683.6 ± 190.7 s). Post 5 km time-trial salbutamol urine concentration between SAL800 (122.96 ± 69.22 ug·ml(-1)) and SAL1600 (574.06 ± 448.17 ug·ml(-1)) were not significantly different. There was no improvement in 5 km time-trial performance following the inhalation of up to 1600 µg of salbutamol in non-asthmatic athletes. This would suggest that the current WADA guidelines, which allow athletes to inhale up to 1600 µg per day, is sufficient to avoid pharmaceutical induced performance enhancement. Key pointsInhaling up to 1600 µg of Salbutamol does not result in improved 5 km time trial performance.The position of Salbutamol on the World Anti-Doping Agency list of prohibited appears justified.Athletes who use up to 1600 µg Salbutamol in one day need to review their therapy as it would suggest their respiratory condition is not under control.

10.
Clin J Sport Med ; 24(6): 482-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24518370

RESUMO

OBJECTIVE: To examine the impact of dehydration, ethnicity, and gender on urinary concentrations of salbutamol in relation to the threshold stipulated by the World Anti-Doping Agency (WADA). DESIGN: Repeated measures open-label. PARTICIPANTS: Eighteen male and 14 female athletes (9 white males, 9 white females, 2 Afro-Caribbean males, 2 Afro-Caribbean females, 6 Asian [Indian subcontinent] males, and 4 Asian females) were recruited. All participants were nonasthmatic. INTERVENTIONS: After inhalation of 800 µg or 1600 µg of salbutamol, athletes exercised in a hot controlled environment (35°C, 40% relative humidity) at a self-selected pace until a target weight loss (2% or 5%) was achieved. MAIN OUTCOME MEASURES: Urine concentration of free salbutamol. RESULTS: After inhalation of 1600 µg salbutamol, 20 participants presented with a urine salbutamol concentrations above the current WADA limit (1000 ng/mL) and decision limit (1200 ng/mL) resulting in an adverse analytical finding. There were no differences according to gender or ethnic origin. CONCLUSIONS: Dehydration equivalent to a body mass loss greater than 2% concomitant to the acute inhalation of 1600 µg of salbutamol may result in a urine concentration above the current WADA limit and decision limit leading to a positive test finding independent of gender or ethnic origin. CLINICAL RELEVANCE: Asthmatic athletes using salbutamol should receive clear dosing advise and education to minimize the risk of inhaling doses of salbutamol that may produce urine concentrations of salbutamol above 1200 ng/mL.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2/urina , Albuterol/urina , Desidratação , Dopagem Esportivo , Grupos Raciais , Detecção do Abuso de Substâncias/métodos , Administração por Inalação , Agonistas de Receptores Adrenérgicos beta 2/administração & dosagem , Albuterol/administração & dosagem , Exercício Físico , Feminino , Temperatura Alta , Humanos , Masculino , Fatores Sexuais
11.
Clin J Sport Med ; 24(6): 474-81, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24451697

RESUMO

OBJECTIVE: Investigate the effect of inhaling 1600 µg salbutamol for 6 weeks on endurance, strength, and power performances. DESIGN: Randomized double-blind, mixed-model repeated measures. PARTICIPANTS: Sixteen male athletes (mean ± SD: age, 20.1 ± 1.6 years; height, 179.9 ± 8.2 cm; weight, 74.6 ± 9.1 kg). INTERVENTIONS: Participants were assigned to either a placebo inhaler (PLA) or inhaled 1600 µg salbutamol group (SAL). Over 6 weeks, participants inhaled PLA or SAL and completed 4 training sessions per week that focused on endurance, strength, and power. MAIN OUTCOME MEASURES: Participants completed the assessments of peak oxygen consumption (V[Combining Dot Above]O2peak), 3-km time trial, vertical jump height, 1 repetition maximum (1RM) bench and leg press, and peak torque knee flexion and extension. Assessments were undertaken at baseline, week 3, and week 6. RESULTS: Over the 6 weeks, PLA and SAL groups improved V[Combining Dot Above]O2peak (51.7 ± 4.7 vs 56.8 ± 7.1 mL·min·kg; 53.1 ± 6.1 vs 55.0 ± 6.7 mL·min·kg); 3-km running time trial (988.6 ± 194.6 vs 947.5 ± 155.5 seconds; 1040.4 ± 187.4 vs 1004.2 ± 199.4 seconds); 1RM bench press (65.7 ± 15.4 vs 70.3 ± 13.8 kg; 64.3 ± 14.0 vs 72.5 ± 15.3 kg); and leg press (250.0 ± 76.4 vs 282.5 ± 63.6 kg; 217.9 ± 54.0 vs 282.8 ± 51.9 kg). The SAL group did not improve significantly greater in any endurance or strength and power measure when compared with the PLA group. CONCLUSIONS: Inhaling 1600 µg salbutamol daily over 6 weeks does not result in significant improvements in endurance, or strength and power performances. CLINICAL RELEVANCE: Athletes using inhaled salbutamol to treat bronchoconstriction during exercise on a daily basis will not gain an advantage over nonasthmatic athletes not using inhaled salbutamol.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2/farmacologia , Albuterol/farmacologia , Atletas , Força Muscular/efeitos dos fármacos , Resistência Física/efeitos dos fármacos , Administração por Inalação , Agonistas de Receptores Adrenérgicos beta 2/administração & dosagem , Adulto , Albuterol/administração & dosagem , Desempenho Atlético , Relação Dose-Resposta a Droga , Método Duplo-Cego , Esquema de Medicação , Teste de Esforço , Humanos , Masculino , Dinamômetro de Força Muscular , Consumo de Oxigênio/efeitos dos fármacos , Corrida
12.
Br J Sports Med ; 46 Suppl 1: i78-84, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23097484

RESUMO

The use of performance-enhancing and social drugs by athletes raises a number of ethical and health concerns. The World Anti-Doping Agency was constituted to address both of these issues as well as publishing a list of, and testing for, banned substances in athletes. Despite continuing methodological developments to detect drug use and associated punishments for positive dope tests, there are still many athletes who choose to use performance and image enhancing drugs. Of primary concern to this review are the health consequences of drug use by athletes. For such a large topic we must put in place delimitations. Specifically, we will address current knowledge, controversies and emerging evidence in relation to cardiovascular (CV) health of athletes taking drugs. Further, we delimit our discussion to the CV consequences of anabolic steroids and stimulant (including amphetamines and cocaine) use. These drugs are reported in the majority of adverse findings in athlete drug screenings and thus are more likely to be relevant to the healthcare professionals responsible for the well-being of athletes. In detailing CV health issues related to anabolic steroid and stimulant abuse by athletes we critique current research evidence, present exemplar case studies and suggest important avenues for on-going research. Specifically we prompt the need for awareness of clinical staff when assessing the potential CV consequences of drug use in athletes.


Assuntos
Doenças Cardiovasculares/induzido quimicamente , Substâncias para Melhoria do Desempenho/efeitos adversos , Adulto , Anfetaminas/efeitos adversos , Anabolizantes/efeitos adversos , Atletas , Estimulantes do Sistema Nervoso Central/efeitos adversos , Transtornos Relacionados ao Uso de Cocaína/complicações , Angiografia Coronária , Dopagem Esportivo , Eletrocardiografia , Humanos , Fatores de Risco , Transtornos Relacionados ao Uso de Substâncias/complicações
13.
Int J Sport Nutr Exerc Metab ; 22(3): 225-31, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22693243

RESUMO

Professional jockeys are unique among weight-making athletes, as they are often required to make weight daily and, in many cases, all year-round. Common methods employed by jockeys include dehydration, severe calorie restriction, and sporadic eating, all of which have adverse health effects. In contrast, this article outlines a structured diet and exercise plan, employed by a 22-yr-old professional National Hunt jockey in an attempt to reduce weight from 70.3 to 62.6 kg, that does not rely on any of the aforementioned techniques. Before the intervention, the client's typical daily energy intake was 8.2 MJ (42% carbohydrate [CHO], 36% fat, 22% protein) consumed in 2 meals only. During the 9-wk intervention, daily energy intake was approximately equivalent to resting metabolic rate, which the athlete consumed as 6 meals per day (7.6 MJ, 46% CHO, 19% fat, 36% protein). This change in frequency and composition of energy intake combined with structured exercise resulted in a total body-mass loss of 8 kg, corresponding to reductions in body fat from 14.5% to 9%. No form of intentional dehydration occurred throughout this period, and mean urine osmolality was 285 mOsm/kg (SD 115 mOsm/kg). In addition, positive changes in mood scores (BRUMS scale) also occurred. The client was now able to ride light for the first time in his career without dehydrating, thereby challenging the cultural practices inherent in the sport.


Assuntos
Tecido Adiposo/metabolismo , Afeto , Desidratação/prevenção & controle , Dieta Redutora , Ingestão de Energia , Esportes , Redução de Peso/fisiologia , Animais , Metabolismo Basal , Dieta Redutora/psicologia , Exercício Físico/fisiologia , Exercício Físico/psicologia , Comportamento Alimentar , Cavalos , Humanos , Masculino , Concentração Osmolar , Esportes/psicologia , Urina/fisiologia , Adulto Jovem
14.
Artigo em Inglês | MEDLINE | ID: mdl-22710736

RESUMO

Professional jockeys are unique amongst weight-making athletes as they are often required to make weight daily and in many cases, all year round. Common methods employed by jockeys include dehydration, severe calorie restriction and sporadic eating, all of which have adverse health effects. In contrast, this paper outlines a structured diet and exercise plan employed by a 22 year old professional National Hunt jockey in an attempt to reduce weight from 70.3 to 62.6 kg that does not rely on any of the aforementioned techniques. Prior to the intervention, the client's typical daily energy intake was 8.2 MJ (42% CHO, 36% fats, 22% protein) consumed in two meals only. During the 9-week intervention, daily energy intake was approximately equivalent to resting metabolic rate and consumed as 6 meals per day (7.6 MJ, 46% CHO, 19% fats, 36% protein). This change in frequency and composition of energy intake combined with structured exercise, resulted in a total body mass loss of 8 kg, corresponding to reductions in percent body fat from 14.5 to 9%. No form of intentional dehydration occurred throughout this period and mean urine osmolality was 285 mOs·kg-1 (SD 115 mOs·kg-1). In addition, positive changes in mood scores (BRUMS scale) also occurred. The client was now able to ride light for the first time in his career thereby challenging the cultural practices inherent to the sport.

15.
Sports Med ; 42(2): 119-34, 2012 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-22229259

RESUMO

Recent reports from needle exchange programmes and other public health initiatives have suggested growing use of anabolic steroids (AS) in the UK and other countries. Data indicate that AS use is not confined to body-builders or high-level sportsmen. Use has spread to professionals working in emergency services, casual fitness enthusiasts and subelite sportsmen and women. Although the precise health consequences of AS use is largely undefined, AS use represents a growing public health concern. Data regarding the consequences of AS use on cardiovascular health are limited to case studies and a modest number of small cohort studies. Numerous case studies have linked AS use with a variety of cardiovascular disease (CVD) events or endpoints, including myocardial infarction, stroke and death. Large-scale epidemiological studies to support these links are absent. Consequently, the impact of AS use upon known CVD risk factors has been studied in relatively small, case-series studies. Data relating AS use to elevated blood pressure, altered lipid profiles and ECG abnormalities have been reported, but are often limited in scope, and other studies have often produced equivocal outcomes. The use of AS has been linked to the appearance of concentric left ventricular hypertrophy as well as endothelial dysfunction but the data again remains controversial. The mechanisms responsible for the negative effect of AS on cardiovascular health are poorly understood, especially in humans. Possibilities include direct effects on myocytes and endothelial cells, reduced intracellular Ca2+ levels, increased release of apoptogenic factors, as well as increased collagen crosslinks between myocytes. New data relating AS use to cardiovascular health risks are emerging, as novel technologies are developed (especially in non-invasive imaging) that can assess physiological structure and function. Continued efforts to fully document the cardiovascular health consequences of AS use is important to provide a clear, accurate, public health message to the many groups now using AS for performance and image enhancement.


Assuntos
Anabolizantes/efeitos adversos , Doenças Cardiovasculares/induzido quimicamente , Miocárdio , Proteína C-Reativa , Doenças Cardiovasculares/epidemiologia , Sistema Cardiovascular/efeitos dos fármacos , Diástole/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Nível de Saúde , Humanos , Inflamação , Medição de Risco , Sístole/efeitos dos fármacos , Estados Unidos/epidemiologia
16.
Med Sci Sports Exerc ; 44(4): 583-90, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21900841

RESUMO

PURPOSE: The purpose of this study was to investigate the effect of anabolic steroid (AS) use on cardiac structure and function and cardiovascular risk factors. METHODS: We recruited 47 strength-trained individuals (male = 46, female = 1), with 28 self-reporting regular AS use and 19 self-reporting never taking AS. Participants underwent assessment of body composition, lipid profiles, blood pressure, 12-lead ECG, and a comprehensive echocardiographic examination incorporating speckle tracking of longitudinal, radial, and circumferential left ventricular (LV) motion. A subgroup of AS users (n = 4) were tested during periods of AS use and abstinence. RESULTS: AS users were heavier (96 ± 15 vs 81 ± 9 kg, P < 0.05), had higher LDL (3.68 ± 0.47 vs 2.41 ± 0.49 mmol·L⁻¹, P < 0.05), and had higher resting HR (79 ± 12 vs 64 ± 13 beats·min⁻¹), although blood pressures did not differ significantly between groups. In AS, LV wall thickness and mass were significantly greater (12 ± 2 vs 11 ± 1 mm and 280 ± 60 vs 231 ± 44 g, respectively, P < 0.05), whereas ejection fractions and peak longitudinal strain ([Latin Small Letter Open E]) were significantly lower (58% ± 8% vs 63% ± 6% and -14.6% ± 2.3% vs -16.9% ± 2.2%, P < 0.05). Indices of global diastolic function were reduced in AS users (E/A, E'/A'). Some diastolic strain rates (ESR and ASR) were altered in AS users. The E/A SR ratio was reduced in the longitudinal plane as well as in the circumferential and radial plane at the basal level (P < 0.05). Basal LV E/A rotation rate was also decreased in AS users (P < 0.05). CONCLUSIONS: AS use is associated with alterations in cardiac structure and function that, allied to poor lipid profiles, represent an increased cardiovascular risk profile.


Assuntos
Anabolizantes/efeitos adversos , Coração/efeitos dos fármacos , Coração/fisiologia , Adulto , Anabolizantes/administração & dosagem , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Composição Corporal/efeitos dos fármacos , Composição Corporal/fisiologia , Estudos Transversais , Ecocardiografia , Eletrocardiografia , Feminino , Coração/anatomia & histologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Humanos , Lipídeos/sangue , Lipídeos/fisiologia , Lipoproteínas LDL/sangue , Lipoproteínas LDL/fisiologia , Masculino , Treinamento Resistido , Volume Sistólico/efeitos dos fármacos , Volume Sistólico/fisiologia , Adulto Jovem
17.
Muscle Nerve ; 32(6): 767-74, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16007677

RESUMO

We have investigated the dose- and time-dependency of myocyte apoptosis and necrosis induced by the beta2-adrenergic receptor agonist, clenbuterol, with the aim of determining whether myocyte apoptosis and necrosis are two separate processes or a continuum of events. Male Wistar rats were administered subcutaneous injections of clenbuterol, and immunohistochemistry was used to detect myocyte-specific apoptosis and necrosis. Myocyte apoptosis peaked 4 h after, and necrosis 12 h after, clenbuterol administration. In the soleus, peak apoptosis (5.8 +/- 2.0%; P < 0.05) was induced by 10 mug and peak necrosis (7.4 +/- 1.7%; P < 0.05) by 5 mg x kg(-1) clenbuterol. Twelve hours after clenbuterol administration, 73% of damaged myocytes labeled as necrotic, 27% as apoptotic and necrotic, and 0% as purely apoptotic. Administrations of clenbuterol (10 microg x kg(-1)) at 48-h intervals induced cumulative myocyte death over 8 days. These data show that the phenotype of myocyte death is dependent on the magnitude of the insult and the time at which it is investigated. Only very low doses induced apoptosis alone; in most cases apoptotic myocytes lysed and became necrotic and the magnitude of necrosis was greater than that of apoptosis. Thus, it is important to investigate both apoptotic and necrotic myocyte death, contrary to the current trend of only investigating apoptotic cell death.


Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Apoptose/efeitos dos fármacos , Clembuterol/administração & dosagem , Células Musculares/efeitos dos fármacos , Necrose/induzido quimicamente , Animais , Caspase 3 , Caspases/metabolismo , Contagem de Células/métodos , Relação Dose-Resposta a Droga , Imuno-Histoquímica/métodos , Masculino , Células Musculares/patologia , Primidona/metabolismo , Ratos , Ratos Wistar , Fatores de Tempo
18.
Br J Clin Pharmacol ; 57(1): 62-7, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14678341

RESUMO

AIMS: To study the elimination of ephedrines with reference to the International Olympic Committee (IOC) doping control cut-off levels, following multiple dosing of over-the-counter decongestant preparations. METHODS: A double-blind study was performed in which 16 healthy male volunteers were administered either pseudoephedrine or phenylpropanolamine in maximal recommended therapeutic doses over a 36-h period. Urine was collected every two hours between 08:00 and 24:00 h and at 04:00 h throughout the testing period of three days. Urine drug levels were quantified using high performance liquid chromatography. Side-effects were assessed, including heart rate and blood pressure, every four hours between 08:00 and 20:00 h. RESULTS: Mean (95% CI) total phenylpropanolamine and pseudoephedrine eliminated unchanged was 75 (88, 61) and 81 (92, 71)%, respectively. Maximum urine concentrations of phenylpropanolamine and pseudoephedrine were 112.1 (164.2, 59.9) and 148.5 (215.0, 82.1) mg.l(-1), respectively. A peak in drug urine concentration occurred four hours following the final dose. There were no adverse cardiovascular effects and only mild CNS stimulation was evident. CONCLUSIONS: Following therapeutic, multiple dosing, drug levels remain above the IOC cut-off levels for a minimum of 6 h and 16 h following final doses of phenylpropanolamine and pseudoephedrine, respectively. Athletes require informed advice on this from their healthcare professionals.


Assuntos
Dopagem Esportivo/prevenção & controle , Efedrina/urina , Descongestionantes Nasais/urina , Fenilpropanolamina/urina , Detecção do Abuso de Substâncias/métodos , Simpatomiméticos/urina , Adulto , Pressão Sanguínea/efeitos dos fármacos , Método Duplo-Cego , Ensaio de Imunoadsorção Enzimática , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Medicamentos sem Prescrição
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...