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1.
Optom Vis Sci ; 97(2): 104-109, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32011583

RESUMO

SIGNIFICANCE: Peripapillary retinoschisis is associated with primary and secondary glaucoma. It is important that clinicians are familiar with the presentation and management of peripapillary retinoschisis to understand its effects on the patient's glaucoma and to avoid unnecessary referral when the macula is not involved. PURPOSE: We present a case of peripapillary retinoschisis found incidentally on routine optical coherence tomographic (OCT) surveillance of primary open-angle glaucoma. CASE REPORT: A 70-year-old man presented for his annual diabetic eye examination. Surveillance with OCT revealed a splitting of the inner peripapillary retina corresponding to a previously noted notch in the right optic nerve. Further imaging of the right eye using enhanced depth imaging OCT revealed a defect in the lamina cribrosa that may have contributed to the formation and persistence of peripapillary retinoschisis. Retinal nerve fiber layer analysis showed a 5-year history of progressive temporal and inferotemporal thickening in the right eye. The patient was managed conservatively with instruction on regular Amsler grid testing. CONCLUSIONS: As seen in this case, peripapillary retinoschisis typically alters retinal nerve fiber layer thickness on OCT and can be mistakenly attributed to glaucomatous change. Glaucoma-associated peripapillary retinoschisis is usually not vision threatening and can be managed conservatively; in rare cases of progression to macular involvement, patients should be referred to a retina specialist.

2.
J Int Soc Sports Nutr ; 16(1): 50, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31699159

RESUMO

Background In this Position Statement, the International Society of Sports Nutrition (ISSN) provides an objective and critical review of the literature pertinent to nutritional considerations for training and racing in single-stage ultra-marathon. Recommendations for Training. i) Ultra-marathon runners should aim to meet the caloric demands of training by following an individualized and periodized strategy, comprising a varied, food-first approach; ii) Athletes should plan and implement their nutrition strategy with sufficient time to permit adaptations that enhance fat oxidative capacity; iii) The evidence overwhelmingly supports the inclusion of a moderate-to-high carbohydrate diet (i.e., ~ 60% of energy intake, 5-8 g·kg- 1·d- 1) to mitigate the negative effects of chronic, training-induced glycogen depletion; iv) Limiting carbohydrate intake before selected low-intensity sessions, and/or moderating daily carbohydrate intake, may enhance mitochondrial function and fat oxidative capacity. Nevertheless, this approach may compromise performance during high-intensity efforts; v) Protein intakes of ~ 1.6 g·kg- 1·d- 1 are necessary to maintain lean mass and support recovery from training, but amounts up to 2.5 g.kg- 1·d- 1 may be warranted during demanding training when calorie requirements are greater; Recommendations for Racing. vi) To attenuate caloric deficits, runners should aim to consume 150-400 Kcal·h- 1 (carbohydrate, 30-50 g·h- 1; protein, 5-10 g·h- 1) from a variety of calorie-dense foods. Consideration must be given to food palatability, individual tolerance, and the increased preference for savory foods in longer races; vii) Fluid volumes of 450-750 mL·h- 1 (~ 150-250 mL every 20 min) are recommended during racing. To minimize the likelihood of hyponatraemia, electrolytes (mainly sodium) may be needed in concentrations greater than that provided by most commercial products (i.e., > 575 mg·L- 1 sodium). Fluid and electrolyte requirements will be elevated when running in hot and/or humid conditions; viii) Evidence supports progressive gut-training and/or low-FODMAP diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to alleviate symptoms of gastrointestinal distress during racing; ix) The evidence in support of ketogenic diets and/or ketone esters to improve ultra-marathon performance is lacking, with further research warranted; x) Evidence supports the strategic use of caffeine to sustain performance in the latter stages of racing, particularly when sleep deprivation may compromise athlete safety.


Assuntos
Carboidratos da Dieta/administração & dosagem , Ingestão de Energia , Necessidades Nutricionais , Corrida/fisiologia , Fenômenos Fisiológicos da Nutrição Esportiva , Atletas , Desempenho Atlético , Comportamento Competitivo , Proteínas na Dieta/administração & dosagem , Humanos , Resistência Física , Corrida/classificação , Sociedades
3.
Eur J Sport Sci ; : 1-10, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31282783

RESUMO

Background: Clinical electrocardiographic (ECG) guidelines for athlete's heart are based upon cross-sectional data. We aimed to longitudinally evaluate the influence of endurance training on the ECG and compare the prevalence of ECG abnormalities defined by contemporary criteria. Methods: A group of 66 training-naïve individuals completed a six-month training programme with resting ECGs and cardiopulmonary exercise tests performed at baseline, two and six months. Data were analysed using repeated measures analysis of variance and the prevalence of ECG abnormalities compared between proposed criteria. Results: Maximal oxygen consumption increased from 45.4 ± 7.1 to 50.3 ± 7.1 ml·kg-1·min-1 (p < 0.05) pre-to-post training. ECG changes included, bradycardia (60 ± 12 vs. 53 ± 8 beats·min-1; p < 0.05), shorter P wave duration (106 ± 10 vs. 103 ± 11 ms; p < 0.05), reduced QTc (413 ± 27 vs. 405 ± 22 ms; p < 0.05), and increased left ventricular Sokolow-Lyon index (2.45 ± 0.66 vs. 2.62 ± 0.78 mV; p < 0.05). 85% of individuals showed ≥1 'training-related' ECG finding at six months vs. 68% at baseline. Using the 2013 Seattle Criteria, 4 ECGs were 'abnormal' at baseline and 3 at month six vs. 2 at baseline and 1 at month six, using the 2017 International Consensus. Prevalence of 'borderline' findings did not increase with training (11% at baseline and six months). Conclusion: Six-months endurance training leads to a greater prevalence of 'training-related' but not 'borderline' or 'training-unrelated' ECGs. 'Borderline findings' may not necessarily represent training-related cardiac remodelling in novice athletes following a six-month training intervention. KEY MESSAGES This study aimed to assess the longitudinal ECG changes following six months of endurance training, in training-naïve individuals, and whether these ECG changes support the revisions made to the recent 2017 international consensus criteria. The prevalence of 'training-related' findings were increased with six months of endurance training, however the prevalence of the revised 'borderline' criteria, according to the 2017 international consensus, did not increase and the associated quantitative ECG data (e.g. P-wave amplitude, QRS axis and QRS duration) remained unchanged. Further clinical consideration may be warranted for individuals within the early phase of exercise engagement presenting with 'borderline' ECG abnormalities, defined by the International criteria.

4.
Front Physiol ; 10: 589, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31156464

RESUMO

Background: This case-report characterized the respiratory, cardiovascular, and nutritional/gastrointestinal (GI) responses of a trained individual to a novel ultra-endurance exercise challenge. Case Presentation: A male athlete (age 45 years; V ˙ O2max 54.0 mL⋅kg-1⋅min-1) summited 100 mountains on foot in 25 consecutive days (all elevations >600 m). Measures: Laboratory measures of pulmonary function (spirometry, whole-body plethysmography, and single-breath rebreathe), respiratory muscle function (maximum static mouth-pressures), and cardiovascular structure and function (echocardiography, electrocardiography, large vessel ultrasound, and flow-mediated dilatation) were made at baseline and 48 h post-challenge. Dietary intake (four-day food diary), self-reported GI symptoms and plasma endotoxin concentrations were assessed at baseline, pre/post mid-point, pre/post end-point, and 48 h post-challenge. Results: The challenge was completed in a total exercise time of 142 h (5.3 ± 2.8 h⋅d-1), with a distance of 1141 km (42.3 ± 43.9 km⋅d-1), and energy expenditure of 80460 kcal (2980 ± 1451 kcal⋅d-1). Relative to baseline, there were post-challenge decreases in pulmonary capacities and expiratory flows (≤34%), maximum expiratory mouth-pressure (19%), and maximum voluntary ventilation (29%). Heart rate variability deteriorated, manifesting as a 48% decrease in the root mean square of successive differences and a 70% increase in the low-frequency/high-frequency ratio. Pre- to post-challenge endotoxin concentrations were elevated by 60%, with a maximum increase of 130% after a given stage, congruent with an increased frequency and severity of GI symptoms. Conclusion: The challenge resulted in pulmonary and autonomic dysfunction, endotoxaemia, and GI distress. The findings extend our understanding of the limits of physiological function and may inform medical best-practice for personnel supporting ultra-endurance events.

5.
J Sports Sci Med ; 16(3): 311-317, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28912647

RESUMO

The physical demands of fast-medium bowling are increasingly being recognised, yet comparative exploration of the differing demands between competitive formats (i.e. one-day [OD] versus multi-day [MD] matches) remain minimal. The aim of this study was to describe in-match physiological profiles of professional fast-medium bowlers from England across different versions of competitive matches using a multivariable wearable monitoring device. Seven professional cricket fast-medium bowlers wore the BioharnessTM monitoring device during matches, over three seasons (>80 hours in-match). Heart Rate (HR) and Acceleromety (ACC) was compared across match types (OD, MD) and different in-match activity states (Bowling, Between over bowling, Fielding). Peak acceleration during OD bowling was significantly higher in comparison to MD cricket ([OD vs. MD] 234.1 ± 57.9 vs 226.6 ± 32.9 ct·episode-1, p < 0.05, ES = 0.11-0.30). Data for ACC were also higher during OD than MD fielding activities (p < 0.01, ES = 0.11-.30). OD bowling stimulated higher mean HR responses (143 ± 14 vs 137 ± 16 beats·min-1, p < 0.05, ES = 0.21) when compared to MD matches. This increase in OD cricket was evident for both between over (129 ± 9 vs 120 ± 13 beats·min-1,p < 0.01, ES = 0.11-0.50) and during fielding (115 ± 12 vs 106 ± 12 beats·min-1, p < 0.01, ES = 0.36) activity. The increased HR and ACC evident in OD matches suggest greater acute physical loads than MD formats. Therefore, use of wearable technology and the findings provided give a valuable appreciation of the differences in match loads, and thus required physiological preparation and recovery in fast-medium bowlers.

6.
Pulm Circ ; 7(2): 361-371, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28597759

RESUMO

Few studies have examined the utility of serial echocardiography in the evaluation, management, and prognosis of patients with pulmonary arterial hypertension (PAH). Therefore, we sought to evaluate the prognostic significance of follow-up tricuspid annular plane systolic excursion (TAPSE) in PAH. We prospectively studied 70 consecutive patients with PAH who underwent baseline right heart catheterization (RHC) and transthoracic echocardiogram, who survived to follow-up echocardiogram after initiation of PAH therapy. Baseline TAPSE was 1.6 ± 0.5 cm which increased to 2.0 ± 0.4 cm on follow-up ( P < 0.0001). The cohort was dichotomized by TAPSE at one-year follow-up: Group 1 (n = 37): follow-up TAPSE ≥ 2 cm; Group 2 (n = 33): follow-up TAPSE < 2 cm. Group 1 participants were significantly more likely to reach WHO functional class I-II status and achieve a higher six-minute walk distance on follow-up. Of the 68 patients who survived more than one year, 18 died (26.5%) over a median follow-up of 941 days (range, 3-2311 days), with significantly higher mortality in Group 2 versus Group 1 (41.9% vs. 13.5%; P = 0.003). While baseline TAPSE stratified at 2 cm did not predict survival in this cohort, TAPSE ≥ 2 cm at follow-up strongly predicted survival in bivariable models (hazard ratio, 0.21; 95% confidence interval, 0.08-0.60). In conclusion, follow-up TAPSE ≥ 2 cm is a prognostic marker and potential treatment target in a PAH population.

7.
Appl Physiol Nutr Metab ; 42(8): 876-883, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28460195

RESUMO

Probiotic and glutamine supplementation increases tissue Hsp72, but their influence on extracellular Hsp72 (eHsp72) has not been investigated. The aim of this study was to investigate the effect of chronic probiotic supplementation, with or without glutamine, on eHsp72 concentration before and after an ultramarathon. Thirty-two participants were split into 3 independent groups, where they ingested probiotic capsules (PRO; n = 11), probiotic + glutamine powder (PGLn; n = 10), or no supplementation (CON; n = 11), over a 12-week period prior to commencement of the Marathon des Sables (MDS). eHsp72 concentration in the plasma was measured at baseline, 7 days pre-race, 6-8 h post-race, and 7 days post-race. The MDS increased eHsp72 concentrations by 124% (F[1,3] = 22.716, p < 0.001), but there was no difference in the response between groups. Additionally, PRO or PGLn supplementation did not modify pre- or post-MDS eHsp72 concentrations compared with CON (p > 0.05). In conclusion, the MDS caused a substantial increase in eHsp72 concentration, indicating high levels of systemic stress. However, chronic PRO or PGLn supplementation did not affect eHsp72 compared with control pre- or post-MDS. Given the role of eHsp72 in immune activation, the commercially available supplements used in this study are unlikely to influence this cascade.


Assuntos
Glutamina/administração & dosagem , Proteínas de Choque Térmico HSP72/metabolismo , Resistência Física/efeitos dos fármacos , Probióticos/administração & dosagem , Adolescente , Adulto , Antropometria , Dieta , Feminino , Proteínas de Choque Térmico HSP72/genética , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Corrida , Inquéritos e Questionários , Adulto Jovem
8.
Nutrients ; 8(11)2016 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-27869661

RESUMO

Gastrointestinal (GI) ischemia during exercise is associated with luminal permeability and increased systemic lipopolysaccharides (LPS). This study aimed to assess the impact of a multistrain pro/prebiotic/antioxidant intervention on endotoxin unit levels and GI permeability in recreational athletes. Thirty healthy participants (25 males, 5 females) were randomly assigned either a multistrain pro/prebiotic/antioxidant (LAB4ANTI; 30 billion CFU·day-1 containing 10 billion CFU·day-1Lactobacillus acidophilus CUL-60 (NCIMB 30157), 10 billion CFU·day-1Lactobacillus acidophillus CUL-21 (NCIMB 30156), 9.5 billion CFU·day-1Bifidobacterium bifidum CUL-20 (NCIMB 30172) and 0.5 billion CFU·day-1Bifidobacterium animalis subspecies lactis CUL-34 (NCIMB 30153)/55.8 mg·day-1 fructooligosaccharides/ 400 mg·day-1 α-lipoic acid, 600 mg·day-1N-acetyl-carnitine); matched pro/prebiotic (LAB4) or placebo (PL) for 12 weeks preceding a long-distance triathlon. Plasma endotoxin units (via Limulus amebocyte lysate chromogenic quantification) and GI permeability (via 5 h urinary lactulose (L): mannitol (M) recovery) were assessed at baseline, pre-race and six days post-race. Endotoxin unit levels were not significantly different between groups at baseline (LAB4ANTI: 8.20 ± 1.60 pg·mL-1; LAB4: 8.92 ± 1.20 pg·mL-1; PL: 9.72 ± 2.42 pg·mL-1). The use of a 12-week LAB4ANTI intervention significantly reduced endotoxin units both pre-race (4.37 ± 0.51 pg·mL-1) and six days post-race (5.18 ± 0.57 pg·mL-1; p = 0.03, ηp² = 0.35), but only six days post-race with LAB4 (5.01 ± 0.28 pg·mL-1; p = 0.01, ηp² = 0.43). In contrast, endotoxin units remained unchanged with PL. L:M significantly increased from 0.01 ± 0.01 at baseline to 0.06 ± 0.01 with PL only (p = 0.004, ηp² = 0.51). Mean race times (h:min:s) were not statistically different between groups despite faster times with both pro/prebiotoic groups (LAB4ANTI: 13:17:07 ± 0:34:48; LAB4: 12:47:13 ± 0:25:06; PL: 14:12:51 ± 0:29:54; p > 0.05). Combined multistrain pro/prebiotic use may reduce endotoxin unit levels, with LAB4ANTI potentially conferring an additive effect via combined GI modulation and antioxidant protection.


Assuntos
Antioxidantes/administração & dosagem , Carnosina/análogos & derivados , Endotoxemia/prevenção & controle , Endotoxinas/sangue , Gastroenteropatias/prevenção & controle , Resistência Física , Prebióticos/administração & dosagem , Probióticos/administração & dosagem , Ácido Tióctico/administração & dosagem , Administração Oral , Adulto , Translocação Bacteriana/efeitos dos fármacos , Ciclismo , Biomarcadores/sangue , Cápsulas , Carnosina/administração & dosagem , Método Duplo-Cego , Combinação de Medicamentos , Endotoxemia/sangue , Endotoxemia/microbiologia , Inglaterra , Feminino , Gastroenteropatias/sangue , Gastroenteropatias/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/microbiologia , Humanos , Masculino , Corrida , Natação , Fatores de Tempo , Resultado do Tratamento
9.
J Int Soc Sports Nutr ; 12(1): 1, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25650043

RESUMO

BACKGROUND: The cardio-metabolic and antioxidant health benefits of caffeinated green tea (GT) relate to its catechin polyphenol content. Less is known about decaffeinated extracts, particularly in combination with exercise. The aim of this study was therefore to determine whether a decaffeinated green tea extract (dGTE) positively influenced fat oxidation, body composition and exercise performance in recreationally active participants. METHODS: Fourteen, recreationally active males participated in a double-blind, placebo-controlled, parallel design intervention (mean ± SE; age = 21.4 ± 0.3 yrs; weight = 76.37 ± 1.73 kg; body fat = 16.84 ± 0.97%, peak oxygen consumption [[Formula: see text]] = 3.00 ± 0.10 L·min(-1)). Participants were randomly assigned capsulated dGTE (571 mg·d(-1); n = 7) or placebo (PL; n = 7) for 4 weeks. Following body composition and resting cardiovascular measures, participants cycled for 1 hour at 50% [Formula: see text], followed by a 40 minute performance trial at week 0, 2 and 4. Fat and carbohydrate oxidation was assessed via indirect calorimetry. Pre-post exercise blood samples were collected for determination of total fatty acids (TFA). Distance covered (km) and average power output (W) were assessed as exercise performance criteria. RESULTS: Total fat oxidation rates increased by 24.9% from 0.241 ± 0.025 to 0.301 ± 0.009 g·min(-1) with dGTE (P = 0.05; ηp(2) = 0.45) by week 4, whereas substrate utilisation was unaltered with PL. Body fat significantly decreased with dGTE by 1.63 ± 0.16% in contrast to PL over the intervention period (P < 0.001; ηp(2) = 0.84). No significant changes for FFA or blood pressure between groups were observed. dGTE resulted in a 10.9% improvement in performance distance covered from 20.23 ± 0.54 km to 22.43 ± 0.40 km by week 4 (P < 0.001; ηp(2) = 0.85). CONCLUSIONS: A 4 week dGTE intervention favourably enhanced substrate utilisation and subsequent performance indices, but did not alter TFA concentrations in comparison to PL. The results support the use of catechin polyphenols from dGTE in combination with exercise training in recreationally active volunteers.

10.
J Int Soc Sports Nutr ; 11(1): 8, 2014 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-24589205

RESUMO

BACKGROUND: Whilst exogenous carbohydrate oxidation (CHOEXO) is influenced by mono- and disaccharide combinations, debate exists whether such beverages enhance fluid delivery and exercise performance. Therefore, this study aimed to ascertain CHOEXO, fluid delivery and performance times of a commercially available maltodextrin/ fructose beverage in comparison to an isocaloric maltodextrin beverage and placebo. METHODS: Fourteen club level cyclists (age: 31.79 ± 10.02 years; height: 1.79 ± 0.06 m; weight: 73.69 ± 9.24 kg; VO2max: 60.38 ± 9.36 mL · kg·-1 min-1) performed three trials involving 2.5 hours continuous exercise at 50% maximum power output (Wmax: 176.71 ± 25.92 W) followed by a 60 km cycling performance test. Throughout each trial, athletes were randomly assigned, in a double-blind manner, either: (1) 1.1 g · min-1 maltodextrin + 0.6 g · min-1 fructose (MD + F), (2) 1.7 g · min-1 of maltodextrin (MD) or (3) flavoured water (P). In addition, the test beverage at 60 minutes contained 5.0 g of deuterium oxide (2H2O) to assess quantification of fluid delivery. Expired air samples were analysed for CHOEXO according to the 13C/12C ratio method using gas chromatography continuous flow isotope ratio mass spectrometry. RESULTS: Peak CHOEXO was significantly greater in the final 30 minutes of submaximal exercise with MD + F and MD compared to P (1.45 ± 0.09 g · min-1, 1.07 ± 0.03 g · min-1and 0.00 ± 0.01 g · min-1 respectively, P < 0.0001), and significantly greater for MD + F compared to MD (P = 0.005). The overall appearance of 2H2O in plasma was significantly greater in both P and MD + F compared to MD (100.27 ± 3.57 ppm, 92.57 ± 2.94 ppm and 78.18 ± 4.07 ppm respectively, P < 0.003). There was no significant difference in fluid delivery between P and MD + F (P = 0.078). Performance times significantly improved with MD + F compared with both MD (by 7 min 22 s ± 1 min 56 s, or 7.2%) and P (by 6 min 35 s ± 2 min 33 s, or 6.5%, P < 0.05) over 60 km. CONCLUSIONS: A commercially available maltodextrin-fructose beverage improves CHOEXO and fluid delivery, which may benefit individuals during sustained moderate intensity exercise. The greater CHOEXO observed when consuming a maltodextrin-fructose beverage may support improved performance times.

11.
Appl Physiol Nutr Metab ; 38(12): 1245-53, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24195625

RESUMO

The study investigated the ingestion of maltodextrin, fructose, and protein on exogenous carbohydrate oxidation (CHOEXO) and exercise performance. Seven trained cyclists and (or) triathletes (maximal oxygen consumption, 59.20 ± 9.00 mL · kg(-1) · min(-1)) performed 3 exercise trials that consisted of 150 min of cycling at 50% maximal power output (160 ± 11 W), followed by a 60-km time trial. One of 3 beverages were randomly assigned during each trial and consumed at 15-min intervals: (i) 0.84 g · min(-1) maltodextrin + 0.52 g · min(-1) fructose + 0.34 g · min(-1) protein (MD+F+P); (ii) 1.10 g · min(-1) maltodextrin + 0.60 g · min(-1) fructose (MD+F); or (iii) 1.70 g · min(-1) maltodextrin (MD). CHO(EXO) and fuel utilisation were assessed via measurement of expired air (13)C content and indirect calorimetry, respectively. Mean total CHO oxidation (CHOTOT) rates were 2.35 ± 0.18, 2.76 ± 0.08, and 2.61 ± 0.17 g · min(-1) with MD, MD+F, and MD+F+P, respectively, although not significantly different. Peak CHO(EXO) rates with MD+F were significantly greater by 41.4% (p = 0.001) and 45.4% (p = 0.0001) compared with MD+F+P and MD, respectively (1.57 ± 0.22 g · min(-1), 1.11 ± 0.08 g · min(-1), and 1.08 ± 0.11 g · min(-1), respectively). Performance times were 2.2% and 5.0% faster with MD+F compared with MD+F+P and MD, respectively; however, they were not statistically significant. Ingestion of an MD-fructose-protein commercial sports beverage significantly reduced peak and mean CHO(EXO) rates compared with MD+F, but did not significantly influence CHOTOT. The addition of protein to an MD+F beverage did not enhance performance times.


Assuntos
Carboidratos da Dieta , Frutose , Bebidas , Glicemia/metabolismo , Carboidratos da Dieta/metabolismo , Exercício , Humanos
12.
J Int Soc Sports Nutr ; 9(1): 5, 2012 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-22400992

RESUMO

BACKGROUND: The purpose of this study was to undertake an independent investigation into the effects of ingesting a carbohydrate-protein-electrolyte (CPE) beverage on repeated submaximal and time-trial cycling performance. METHODS: Sixteen recreationally trained males (height: 1.76 ± 0.07 m; weight: 70.05 ± 7.90 kg; VO2max: 49.69 ± 4.19 ml.kg-1.min-1) performed two exercise trials separated by 7 days. Each trial comprised two bouts of 90 minutes exercise separated by a 2 hour recovery period. Each bout comprised 45 minutes exercise on a cycle-ergometer at 60%VO2max (ST), followed immediately by a 45 minute performance test (PT). Participants were randomly assigned an 8% CPE beverage or colour/taste matched placebo (PL) prior to each trial. Participants consumed 100 ml of the assigned beverage every 10 minutes during each ST, and 500 ml at 0 and 60 minutes into recovery (total caloric delivery per trial: 617.6 kcal for CPE and12.8 kcal for PL). Mean power output (W), speed (km.hr-1) and distance covered (km) were assessed throughout both trials. Expired air was sampled at 10 minute intervals throughout ST. Blood glucose and lactate were assessed during ST and recovery. RESULTS: Distance covered during ST was significantly reduced with PL by 9.12% (20.18 ± 0.28 km in ST1 v 18.34 ± 0.36 km in ST2; P = 0.0001). With CPE, distance covered, power output and average speed were maintained between ST1 and ST2. Oxygen uptake was not significantly different between ST1 and ST2, or conditions. Respiratory exchange ratio (RER) values decreased from 0.98 ± 0.02 in ST1 to 0.91 ± 0.02 in ST2 for PL (P = 0.003), supporting reduced total carbohydrate oxidation rates (P = 0.007). Mean blood glucose was maintained in CPE across ST trials, and was significantly greater than PL in ST2 (4.77 ± 0.09 mmol.L-1 for CPE compared with 4.18 ± 0.06 mmol.L-1 for PL, P < 0.001). Mean distance during PT2 was 2.96 km (or 17.1%) further with CPE than PL (P = 0.003). Mean power significantly decreased across PT with PL (134.21 ± 4.79 W and 106.90 ± 3.25 W, respectively; P < 0.04). CONCLUSIONS: The use of a CPE beverage improves short-term repeated exercise and subsequent performance compared to PL. Higher rates of carbohydrate oxidation, maintenance of plasma glucose, and decreased levels of fatigue may be beneficial for secondary bouts of performance and faster recovery turnover.

13.
Pulm Circ ; 1(2): 160-81, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22034604

RESUMO

Pulmonary hypertension (PH) is a relatively misunderstood disease, partly related to the fact that many perceive PH to be a singular diagnosis. An unintended consequence of this is the misapplication of the role of the Doppler-Echocardiographic (DE) examination, as well as an underappreciation for its ability to help discern PH pathophysiology prior to right heart catheterization. Since DE often serves as the "gatekeeper" to invasive right heart catheterization, misinterpretation of the DE can lead to missed or delayed diagnosis with devastating consequences. Too often, the primary or nearly exclusive focus of the DE examination is placed on the pulmonary artery pressure estimation. Two main issues with this approach are that Doppler pressure estimations can be inaccurate and even when accurate, without integration of additional 2-D and Doppler information, the clinician will often still not appreciate the pathophysiology of the PH nor its clinical significance. This review will focus on the 2-D and Doppler features necessary to assess pulmonary vascular disease (PVD), discern the salient differences between PVD and pulmonary venous hypertension (PVH), and how to integrate these key DE parameters such that PH pathophysiology can be determined noninvasively and early in the patient workup. Overreliance on any single DE metric, and especially PA pressure estimation, detracts from the overall diagnostic potential of the DE examination. Integrating the relative balance of right and left heart findings, along with proper Doppler interpretation provides a wealth of clinical and pathophysiologic insight prior to invasive hemodynamic assessment. The end results are heightened awareness and improved identification of which patients should be referred for further invasive testing, as well the use of the DE information to compliment the findings from invasive testing.

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