RESUMO
Postprandial regulation of the gastric emptying (GE) rate plays an important role in food intake. Although oral sweetening with glucose may accelerate GE, the effects of different sweetness intensities of glucose (10% and 20%, w/v) and other energy sweeteners (e.g. fructose and sucrose) remain uncertain. The purpose of this study was to determine the effects of different glucose concentrations (Experiment 1) and different sugars with the same sweet taste intensity (Experiment 2) on postprandial GE. In both experiments, after ingesting a 200 kcal carbohydrate solution containing 50 g of maltodextrin, participants repeatedly sipped, but did not swallow, one of three (water, 10% and 20%, w/v glucose) or four (water and equally sweet 20%, w/v glucose, 12%, w/v fructose, and 14%, w/v sucrose) solutions for 1 min every 5 min over a 30 min period. GE was evaluated by measuring the temporal change in the cross-sectional area of the gastric antrum using ultrasound. In Experiment 1, oral stimulation with 20% (w/v) glucose resulted in greater GE than the control stimulus (i.e. water), but the effect of stimulation with 10% (w/v) glucose on GE was not different from that of the control stimulus. In Experiment 2, stimulation with 20% (w/v) glucose or 12% (w/v) fructose resulted in greater GE than the control stimulus. However, the effect of stimulation with 14% (w/v) sucrose on GE did not differ from that of the control stimulus. Consequently, oral stimulation with glucose or fructose solutions of moderate to high sweetness following a meal facilitates postprandial GE.
Assuntos
Frutose , Esvaziamento Gástrico , Glucose , Sacarose , Humanos , Esvaziamento Gástrico/efeitos dos fármacos , Frutose/farmacologia , Glucose/farmacologia , Glucose/administração & dosagem , Masculino , Adulto , Sacarose/farmacologia , Feminino , Adulto Jovem , Período Pós-Prandial/efeitos dos fármacos , Edulcorantes/farmacologia , Administração OralRESUMO
Blood flow to the active muscles and arterial blood pressure (ABP) increase during dynamic exercise, whereas blood flow to inactive organs (e.g., splanchnic organs and inactive limbs) declines. Aging leads to exaggerated ABP responses to exercise in females, but whether this is related to greater splanchnic vasoconstriction is unknown. This study sought to clarify the effect of aging in females on celiac artery blood flow during dynamic light-intensity exercise. Twelve healthy young females (YF: 20 ± 2 yr, mean ± SD) and 12 healthy older females (OF: 71 ± 4 yr) performed dynamic knee-extension and knee-flexion exercises at 30% of heart rate reserve for 4 min. The absolute changes from baseline (Δ) for mean arterial blood pressure (MAP), celiac artery mean blood flow (celMBF), and celiac vascular conductance (celVC) during exercise were calculated. ABP was measured using an automated sphygmomanometer, and celMBF was recorded by Doppler ultrasonography. The increase in MAP during exercise was greater in OF than in YF (YF: +14 ± 7 mmHg, OF: +24 ± 13 mmHg, P = 0.028). The celMBF decreased during exercise in both groups, but there was no significant difference in the response between YF and OF (YF: -93.0 ± 66.1 mL/min, OF: -89.6 ± 64.0 mL/min, P = 0.951). The celVC also decreased during exercise and remained lower than baseline during exercise. However, the response was not different between YF and OF (YF: -1.8 ± 1.0 mL/min/mmHg, OF: -1.5 ± 0.6 mL/min/mmHg, P = 0.517). These results demonstrate that aging in females has minimal influence on splanchnic artery hemodynamic responses during dynamic light-intensity exercise, suggesting that exaggerated ABP responses during exercise in OF are not due to greater splanchnic vasoconstriction.NEW & NOTEWORTHY During exercise, the splanchnic arteries vasoconstrict, contributing to blood flow redistribution and the blood pressure response. Blood pressure responses to exercise are exaggerated with aging in females; however, the physiological mechanism responsible has not been clarified. We show that celiac artery blood flow changes during light-intensity dynamic exercise do not differ with age in females. This indicates the exaggerated blood pressure to exercise with aging is likely not due to a difference in splanchnic vasoconstriction.
Assuntos
Envelhecimento , Artéria Celíaca , Exercício Físico , Humanos , Feminino , Exercício Físico/fisiologia , Envelhecimento/fisiologia , Adulto Jovem , Idoso , Fluxo Sanguíneo Regional , Circulação Esplâncnica , Velocidade do Fluxo Sanguíneo , Pressão Arterial , Vasoconstrição , Pressão Sanguínea/fisiologia , Adulto , Fatores EtáriosRESUMO
The purpose of this study was to clarify the effect of sex and menstrual cycle phase on celiac artery blood flow during dynamic exercise in healthy young humans. Eleven healthy young females (21 ± 2 yr, means ± SD) and 10 males (23 ± 3 yr) performed dynamic knee-extension and -flexion exercises at 30% of heart rate reserve for 4 min. The percent changes from baseline (Δ) for mean arterial blood pressure (MAP), mean blood flow (celMBF) in the celiac artery, and celiac vascular conductance (celVC) during exercise were calculated. Arterial blood pressure was measured using an automated sphygmomanometer, and celiac artery blood flow was recorded by Doppler ultrasonography. Female subjects performed the exercise test in the early follicular phase (EF) and in the midluteal phase (ML) of their menstrual cycle. The increase in MAP during exercise was not significantly (P > 0.05) different between sexes or between menstrual cycle phases (ΔMAP, EF in females: +16.6 ± 6.4%, ML in females: +20.2 ± 11.7%, and males: +19.9 ± 12.2%). The celMBF decreased during exercise in each group, but the response was not significantly (P > 0.05) different between sexes or between menstrual cycle phases (ΔcelMBF, EF in females: -24.6 ± 15.5%, ML in females: -25.2 ± 18.7%, and males: -29.2 ± 4.0%). The celVC decreased during dynamic exercise in each group, with no significant (P > 0.05) difference in the responses between sexes or between menstrual cycle phases (ΔcelVC, EF in females: -38.3 ± 15.0%, ML in females: -41.5 ± 19.1%, and males: -43.4 ± 7.2%). These results suggest that sex and menstrual cycle phase have minimal influence on hemodynamic responses in the splanchnic artery during dynamic moderate-intensity exercise in young healthy individuals.NEW & NOTEWORTHY During dynamic exercise, splanchnic organ blood flow is reduced from resting values. Whether sex and menstrual cycle phase influence splanchnic blood flow responses during exercise remains unknown. We show that the decrease in celiac artery blood flow during dynamic leg exercise does not differ between young females and males or between menstrual cycle phases. In young individuals, sex and menstrual cycle have minimal influence on splanchnic artery hemodynamic responses during dynamic moderate-intensity leg exercise.
Assuntos
Artéria Celíaca , Perna (Membro) , Masculino , Humanos , Feminino , Ciclo Menstrual/fisiologia , Hemodinâmica , Fase Folicular/fisiologiaRESUMO
Blood glucose levels acutely increase postprandially depending on the type of meal consumed. However, it remains unclear whether postprandial hyperglycemia temporally affects cardiovascular responses to static handgrip exercise (SHG-ex). Thus, this study aimed to examine whether increased blood glucose induced by consumption of a high-glycemic index (HGI) meal affects pressor response to SHG-ex. A total of 14 healthy participants (7 women and 7 men) consumed an HGI meal, a low-glycemic index (LGI) meal, or no meal (control). Participants performed 30% maximal voluntary contraction SHG-ex followed by a postexercise muscle ischemia (PEMI) test before the meal and 60 min after consuming the meal. Blood glucose, plasma insulin, and plasma triglyceride levels were measured, and the area under the curve until 60 min (AUC0-60 min) after meal consumption was calculated. The HGI and LGI groups showed higher blood glucose and insulin AUC0-60 min than the control group (P < 0.001). At 60 min after the meal, the changes in blood pressure during SHG-ex were significantly greater in the HGI group, but not in the LGI group, than in the control group. The changes in blood pressure at the onset and end of SHG-ex 60 min after the meal were positively correlated with blood glucose AUC0-60 min (r = 0.321, P = 0.038; r = 0.402, P = 0.008, respectively) and plasma insulin AUC0-60 min (r = 0.339, P = 0.028; r = 0.302, P = 0.052, respectively). However, no association was observed during PEMI. These data suggest that postprandial hyperglycemia and hyperinsulinemia acutely exaggerate pressor response during SHG-ex in healthy young adults.NEW & NOTEWORTHY Postprandial hyperglycemia following consumption of a high-glycemic index (HGI) meal potentiated blood pressure response to static handgrip exercise (SHG-ex) in healthy young adults. These findings provide important insight into the role of the diet on acute circulatory response to exercise in healthy adults.
Assuntos
Índice Glicêmico , Hiperglicemia , Masculino , Adulto Jovem , Humanos , Feminino , Índice Glicêmico/fisiologia , Glicemia , Pressão Sanguínea , Força da Mão , Carboidratos da Dieta , Insulina , Período Pós-Prandial , Estudos Cross-OverRESUMO
NEW FINDINGS: What is the central question of this study? Increased work of breathing and the accumulation of metabolites have neural and cardiovascular consequences through a respiratory muscle-induced metaboreflex. The influence of the respiratory muscle-induced metaboreflex on splanchnic blood flow in humans remains unknown. What is the main finding and its importance? Coeliac artery blood flow decreased gradually during inspiratory resistive breathing, accompanied by a progressive increase in arterial blood pressure. It is possible that the respiratory muscle-induced metaboreflex contributes to splanchnic blood flow regulation. ABSTRACT: The purpose of this study was to clarify the effect of increasing inspiratory muscle work on coeliac artery blood flow. Eleven healthy young males completed the study. The subjects performed voluntary hyperventilation with or without inspiratory resistance (loading or non-loading trial; tidal volume of 40% of vital capacity and breathing frequency of 20 breaths/min). The loading trial was conducted with inspiratory resistance (40% of maximal inspiratory pressure) and was terminated when the subjects could no longer maintain the target tidal volume or breathing frequency. The non-loading trial was conducted without inspiratory resistance and was of the same duration as the loading trial. Arterial blood pressure was recorded using finger photoplethysmography, and coeliac artery blood flow was measured using Doppler ultrasound. Mean arterial blood pressure increased gradually during the loading trial (mean ± SD; from 89.0 ± 10.8 to 103.9 ± 17.3 mmHg) but not in the non-loading trial (from 88.7 ± 5.9 to 90.4 ± 9.9 mmHg). Coeliac artery blood flow and coeliac vascular conductance decreased gradually during the loading trial (from 601.2 ± 155.7 to 482.6 ± 149.5 mL/min and from 6.9 ± 2.2 to 4.8 ± 1.7 mL/min/mmHg, respectively) but were unchanged in the non-loading trial (from 630.7 ± 157.1 to 635.6 ± 195.7 mL/min and from 7.1 ± 1.8 to 7.2 ± 2.9 mL/min/mmHg, respectively). These results show that increasing inspiratory muscle work affects splanchnic blood flow regulation, and we suggest that this might be mediated by the inspiratory muscle-induced metaboreflex.
Assuntos
Inalação , Trabalho Respiratório , Pressão Sanguínea/fisiologia , Artéria Celíaca , Humanos , Inalação/fisiologia , Masculino , Músculos Respiratórios/fisiologiaRESUMO
BACKGROUND: This study aims to compare the effects of soy protein isolate (SPI) and soy peptide (PEP) preload 30 min before a 75-g oral glucose tolerance test (OGTT) on the gastric emptying rate, plasma insulin, and blood glucose responses. METHODS: Nine healthy young subjects were evaluated on four occasions. The participants consumed a 200-ml solution containing either 20 g of SPI or PEP in experiment 1. In experiment 2, 30 min after consuming either 20 g of SPI or PEP solutions, an OGTT was performed to evaluate the individual glycemic response. The gastric emptying rate was measured by the 13C-sodium acetate breath test. Blood glucose and plasma insulin were measured before and after consuming either the SPI or PEP solutions and during the OGTT. RESULTS: In experiment 1, plasma insulin levels were higher 30 min after consuming the PEP solution than after the SPI solution. PEP resulted in a faster gastric emptying rate than SPI. In experiment 2, just before performing the OGTT, the plasma insulin response was higher for PEP than for SPI. Fifteen minutes after starting the OGTT, the blood glucose response was lower after consuming PEP than after SPI. The gastric emptying rate tended to be faster after consuming PEP than after SPI (p = 0.08). CONCLUSION: A PEP preload might be slightly more effective for the suppression of postprandial blood glucose excursion compared with SPI; thus, a PEP preload potentially induces an enhanced insulin response just before the OGTT.
Assuntos
Glicemia , Esvaziamento Gástrico , Controle Glicêmico , Humanos , Insulina/metabolismo , Insulina/farmacologia , Proteínas de Soja/farmacologiaRESUMO
The relative influence of skin vascular conductance in glabrous (G; palm) and non-glabrous (NG; dorsal and forearm) regions to upstream brachial artery-shear stress (BA-SS) profile are unknown. This study aimed to elucidate the effects of G and/or NG skin vascular conductance (VC), which were modulated by warming or cooling manipulation, on BA-shear rate (SR, an estimate of SS) during cycling exercise. Seven healthy subjects performed 60-min exercise. Between 20 and 50 min of the exercise, the NG+G or G skin region were warmed to 42°C or cooled to 15°C using a water bath. Throughout the protocol, diameter and blood velocity in BA and skin VCs in forearm and palm were measured. All measurements showed that a steady-state response was reached after 20 min of exercise. Subsequently, during cooling manipulation, forearm VC was significantly decreased, and the concomitant BA-SR profile was revealed (primarily characterized by decreased antegrade SR and increased retrograde SR) in the NG+G. Such changes were not observed in G alone. During warming manipulation, forearm VC and mean BA-SR significantly increased only in the NG+G. In conclusion, vascular response in NG skin possibly plays a major role in the modulation of BA-SS profile during cycling exercise.
Assuntos
Artéria Braquial , Exercício Físico , Ciclismo/fisiologia , Artéria Braquial/fisiologia , Exercício Físico/fisiologia , Antebraço , Humanos , Estresse MecânicoRESUMO
Consumption of 2,4-decadienal (2,4-DD) delays gastric emptying (GE) rate in animals. Oil heating produces 2,4-DD and other aldehydes. Here we examined whether heated oil affects GE rate and food intake in humans, and whether it is mediated by 2,4-DD. In the first experiment, 10 healthy volunteers consumed 240-g pumpkin soup with 9.2 g of heated (HO) or non-heated corn oil (CO). Subsequently, 17 participants consumed pumpkin soup containing 3.1 g of either heated corn oil (HO), 1 mg 2,4-DD + non-heated corn oil (2,4-DD), or non-heated corn oil (CO). Sixty minutes following pumpkin soup, cod roe spaghetti was provided, and then energy intake was determined. To evaluate GE rate, 13C breath test (Experiment 1) and ultrasonography (Experiments 1 and 2) were used. The results from the Experiment 1 confirmed that consumption of heated corn oil reduced GE rate. Experiment 2 showed a delayed GE rate in HO and 2,4-DD trials compared with CO trial (p < 0.05). Energy intake was approximately 600-650 kJ lower in HO and 2,4-DD trials compared with CO trial (p < 0.05). These findings suggest that 2,4-DD, either formed by oil heating or added to food, contributes to suppressing GE rate and energy intake.
Assuntos
Aldeídos/administração & dosagem , Óleo de Milho/administração & dosagem , Ingestão de Energia/efeitos dos fármacos , Esvaziamento Gástrico/efeitos dos fármacos , Temperatura Alta , Testes Respiratórios , Estudos Cross-Over , Cucurbita , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Aditivos Alimentares , Voluntários Saudáveis , Humanos , Masculino , Ultrassonografia , Adulto JovemRESUMO
AIM: We examined the effect of modulating the shear stress (SS) profile using forearm warming and cooling on subsequent endothelial function in the brachial artery (BA) during exercise. METHODS: Twelve healthy young subjects immersed their right forearm in water (15 â or 42 â) during a leg cycling exercise at 120-130 bpm for 60 min. The same exercise without water immersion served as a control. The BA diameter and blood velocity were simultaneously recorded using Doppler ultrasonography to evaluate the antegrade, retrograde, and mean shear rates (SRs, an estimate of SS) before, during, and after exercise. The endothelial function in the right BA was evaluated using flow-mediated dilation (FMD) (%) using two-dimensional high-resolution ultrasonography before (baseline) and 15 and 60 min after exercise. RESULTS: During exercise, compared with the control trial, higher antegrade and mean SRs and lower retrograde SRs were observed in the warm trial; conversely, lower antegrade and mean SRs and higher retrograde SRs were observed in the cool trial. At 15 min postexercise, no significant change was observed in the FMD from baseline in the warm (Δ%FMD: +1.6%, tendency to increase; p = 0.08) and control trials (Δ%FMD: +1.1%). However, in the cool trial, the postexercise FMD at 60 min decreased from baseline (Δ%FMD: -2.7%) and was lower than that of the warm (Δ%FMD: +1.5%) and control (Δ%FMD: +1.2%) trials. Accumulated changes in each SR during and after exercise were significantly correlated with postexercise FMD changes. CONCLUSION: Modulation of shear profiles in the BA during exercise appears to be associated with subsequent endothelial function.
Assuntos
Artéria Braquial/fisiologia , Crioterapia , Exercício Físico/fisiologia , Antebraço , Hipertermia Induzida , Perna (Membro) , Velocidade do Fluxo Sanguíneo/fisiologia , Endotélio Vascular/fisiologia , Feminino , Humanos , Masculino , Valores de Referência , Fluxo Sanguíneo Regional/fisiologia , Resistência ao Cisalhamento/fisiologia , Estresse Mecânico , Ultrassonografia Doppler , Vasodilatação/fisiologia , Adulto JovemRESUMO
We reported previously that a static handgrip exercise evoked regional differences in the facial blood flow. The present study examined whether regional differences in facial blood flow are also evoked during dynamic exercise. Facial blood flow was measured by laser speckle flowgraphy during 15 min of cycling exercise at heart rates of 120 bpm, 140 bpm and 160 bpm in 12 subjects. The facial vascular conductance index was calculated from the blood flow and mean arterial pressure. The regional blood flow and conductance index values were determined in the forehead, eyelid, nose, cheek, ear and lip. One-way ANOVA and Tukey's post-hoc test were used to examine effects of exercise intensity and target regions. The blood flow and conductance index in skin areas increased significantly with the exercise intensity. The blood flow and conductance index in the lip increased significantly at 120 bpm and 140 bpm compared to the control, while the values in the lip at 160 bpm did not change from the control values. These results suggest that the blood flow in facial skin areas, not in the lip, responds similarly to dynamic exercise, in contrast to the responses to static exercise.
Assuntos
Exercício Físico/fisiologia , Face/irrigação sanguínea , Fluxo Sanguíneo Regional , Pressão Sanguínea , Orelha Externa/fisiologia , Teste de Esforço , Face/diagnóstico por imagem , Frequência Cardíaca , Hemodinâmica , Humanos , Imagem de Contraste de Manchas a Laser , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Temperatura Cutânea , Adulto JovemRESUMO
This study examined the effect of carbohydrate drink ingestion timing on gastrointestinal tract blood flow and motility after mild cycling exercise. Eight healthy participants were randomly assigned to ingest a liquid solution with 75 g glucose at either 5 min (PE-5) or 30 min (PE-30) after a single bout of leg cycling exercise according to target heart rate (approximately 120 beats/min). As the control trial (Con), participants ingested the same liquid solution without exercise. Celiac artery blood flow (BF), superior mesenteric artery BF, and gastric emptying rate were assessed by ultrasonography before and for 60 min after ingesting the glucose solution. Blood lactate, glucose, and plasma insulin were also measured at baseline and for 60 min after ingesting the glucose solution. Celiac artery BF significantly decreased from resting baseline immediately after exercise in both the PE-5 and PE-30 trials, and then returned to resting baseline just before the ingestion of glucose solution in the PE-30 trial. After ingesting the glucose solution, changes in celiac artery BF, superior mesenteric artery BF, % gastric emptying rate, blood lactate, blood glucose, and plasma insulin were not significantly different among the three trials. The timing of nutrient ingestion after mild exercise does not seem to impact the subsequent gastrointestinal motility, blood flow, and glycemic responses.
Assuntos
Ciclismo , Dieta , Exercício Físico , Esvaziamento Gástrico , Fenômenos Fisiológicos da Nutrição Esportiva , Adulto , Glicemia/metabolismo , Estudos Transversais , Carboidratos da Dieta/administração & dosagem , Suplementos Nutricionais , Feminino , Trato Gastrointestinal/metabolismo , Frequência Cardíaca , Humanos , Insulina/sangue , Ácido Láctico/sangue , Estudos Longitudinais , Masculino , Valor Nutritivo , Ultrassonografia , Adulto JovemRESUMO
This study aimed to examine the carotid baroreflex (CBR) control of the central and peripheral hemodynamics after exercise using the neck pressure (NP) and neck suction (NS) technique. Sixteen healthy young male participants (age: 27 ± 1.5 yr) were in a supine position for 30 min preexercise, followed by 60 min of cycling exercise, and then returned to a supine position for an additional 60 min postexercise. Both pre- and postexercise, the CBR-mediated responses of the central and peripheral hemodynamics were evaluated using 5-s periods of NP and NS (-60, -40, or +40 mmHg). As the central hemodynamics measurements, heart rate (HR), mean arterial pressure (MAP), cardiac output, and total vascular conductance were assessed. To determine peripheral circulation, vascular conductance in active and inactive limbs was measured. Eight participants [responder (RE) group] showed substantial postexercise hypotension (PEH) during recovery from exercise (Δ MAP: approximately -5 ± 0.9 mmHg, P < 0.05). The other eight participants did not display a reduction in MAP after exercise (non-RE group). In the non-RE group, the responsiveness of CBR-mediated changes in HR, MAP, and vascular conductance increased, particularly in response to -40 mmHg NS during postexercise compared with preexercise. However, in the RE group, any alterations in responsiveness to NP and NS were unchanged during PEH compared with preexercise. In conclusion, some normotensive individuals do not show PEH because the responsiveness of the CBR in central and peripheral hemodynamics following exercise is augmented, particularly to high blood pressure.NEW & NOTEWORTHY The carotid baroreflex (CBR) control of central and peripheral hemodynamics was investigated after exercise in both the presence and absence of postexercise hypotension (PEH). In individuals with no PEH, the responsiveness of CBR-mediated changes in all hemodynamics was augmented after exercise, particularly to high blood pressure; conversely, the CBR responsiveness remained unchanged in individuals with PEH. These findings provide insight into the mechanism of CBR control after exercise.
Assuntos
Barorreflexo , Perna (Membro) , Adulto , Pressão Sanguínea , Exercício Físico , Frequência Cardíaca , Hemodinâmica , Humanos , MasculinoRESUMO
Suppression of oral sweet sensation (OSS) acutely reduces intake of sweet-tasting food due to lower liking. However, little is known about other physiological responses during both the prandial and postprandial phase. Here, we explored the effects of Gymnema sylvestre (GS)-based suppression of OSS of several types of sweet-tasting food (muffin, sweet yogurt, banana) on gastric emptying, blood glucose (BG), plasma insulin (PI), appetite indices (hunger, fullness and prospective consumption), satisfaction and desire for tastes. Fifteen healthy subjects (22 ± 3 years, 9 women) took part in the study. Subjects rinsed their mouth with either GS solution or distilled water before eating the sweet-tasting food. Subjects felt decreased sweet taste intensity and reduced taste liking associated with GS rinsing after consuming each food, compared with rinsing with distilled water (p < 0.05). Gastric emptying, BG, PI and appetite indices during and after the prandial phase did not significantly change with GS rinsing compared to rinsing with distilled water (p > 0.05). Higher desire for sweet taste as well as lower satisfaction (p < 0.05) in the postprandial phase were observed with GS rinsing. These results suggest that the suppression of OSS does not affect gastric emptying, glycemic response and appetite during and after consumption of sweet-tasting food.
Assuntos
Apetite/efeitos dos fármacos , Glicemia , Ingestão de Alimentos/efeitos dos fármacos , Preferências Alimentares/efeitos dos fármacos , Esvaziamento Gástrico/efeitos dos fármacos , Gymnema sylvestre/química , Satisfação Pessoal , Extratos Vegetais/farmacologia , Período Pós-Prandial/fisiologia , Sensação/efeitos dos fármacos , Edulcorantes , Percepção Gustatória/efeitos dos fármacos , Paladar/efeitos dos fármacos , Adulto , Apetite/fisiologia , Estudos Cross-Over , Ingestão de Alimentos/fisiologia , Feminino , Preferências Alimentares/fisiologia , Esvaziamento Gástrico/fisiologia , Voluntários Saudáveis , Humanos , Masculino , Sensação/fisiologia , Paladar/fisiologia , Percepção Gustatória/fisiologia , Adulto JovemRESUMO
PURPOSE: To quantify the dynamics of blood flow in brachial artery (BF-BA) in response to sinusoidal work rate (WR) leg cycling exercises of 2-, 4-, and 6-min periods and to examine their relationship with the forearm skin blood flow (SBF). METHODS: Seven healthy young male subjects performed upright leg ergometer exercise with a constant WR (mean sinusoidal WR) for 30 min followed by sinusoidal WR exercise of three different periods (number of repetitions): 2 min (7), 4 min (4), and 6 min (3). The WR fluctuated from 20 W to a peak WR corresponding to 60% peak oxygen uptake (VO2). We continuously measured pulmonary gas exchange, heart rate (HR), blood velocity and cross-sectional area of BA, and forearm SBF and sweating rate (SR). RESULTS: All variables were followed by the sinusoidal WR. The phases of the variables for gas exchange and central circulation, such as VO2 and HR with WR forcing were similar (e.g., phase shift (θ) in HR [°]: 2 min, 60 ± 7; 4 min, 45 ± 10; 6 min, 37 ± 8; mean ± SD) to previous study results, that is, a longer period showed a shorter θ and larger amplitude of responses. Contrarily, the BF-BA response showed anti-phase (approximately 180°) regardless of the period, whereas the θ of forearm SBF and SR were similar to gas exchange and central circulation. CONCLUSIONS: Inactive limb BF-BA during sinusoidal leg cycling exercise was out of phase relative to the regulation of O2-delivery to active muscles and thermoregulation. The response of BF-BA seems to not always reflect the response of forearm SBF in the downstream area.
Assuntos
Artéria Braquial/fisiologia , Exercício Físico/fisiologia , Antebraço/irrigação sanguínea , Perna (Membro)/irrigação sanguínea , Pele/irrigação sanguínea , Adulto , Voluntários Saudáveis , Frequência Cardíaca/fisiologia , Hemodinâmica , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Sudorese/fisiologia , Adulto JovemRESUMO
Previously, we reported that oral stimulation with Gymnema sylvestre (GS), a plant that selectively suppresses sweet taste sensation in humans, delayed gastric emptying and glycemic response during and after oral glucose ingestion. It is unclear whether these responses are triggered by sweet taste sensing per se. We tested the hypothesis that the effects of sweet taste sensing involving a low-energy sweetener, aspartame, alters gastric emptying, blood glucose, and plasma insulin responses during and after the prandial phase. Nine participants rinsed their mouths with either 25â¯mL of water (control) or a 2.5% GS solution, and then ingested 200 g (50 gâ¯×â¯four times) of either 0.09% aspartame or 15% glucose solution containing 100 mg of 13C-sodium acetate. Gastric emptying was measured with a 13C breath test. Blood glucose and plasma insulin were measured at baseline as well as during and after ingestion of the sweet solutions. Decreased subjective sweet taste intensity was observed in the GS group for both the aspartame and glucose trials. In the aspartame trial, no measurements showed significant differences between either group. In the glucose trial, gastric emptying was delayed in the GS group compared to controls. In the initial phase, both during and after glucose ingestion in the glucose trial, blood glucose and plasma insulin responses were lower in the GS group than the controls. The presence or absence of sweet taste-sensing involving glucose had a significant effect on gastric emptying and glycemic metabolism, both during and after the prandial phase, as opposed to the effects involving aspartame.
Assuntos
Aspartame/farmacologia , Glicemia/análise , Esvaziamento Gástrico/efeitos dos fármacos , Glucose/farmacologia , Paladar/efeitos dos fármacos , Adulto , Estudos Cross-Over , Feminino , Humanos , Insulina/sangue , MasculinoRESUMO
This study examined the effects of post-resistance exercise protein ingestion timing on the rate of gastric emptying (GE) and blood glucose (BG) and plasma branched-chain amino acid (BCAA) responses. In all, eleven healthy participants randomly ingested 400 ml of a nutrient-rich drink containing 12 g carbohydrates and 20 g protein at rest (Con), at 5 min (post-exercise (PE)-5) or at 30 min (PE-30) after a single bout of strenuous resistance exercises. The first and second sets comprised ten repetitions at 50 % of each participant's one-repetition maximum (1RM). The third, fourth and fifth sets comprised ten repetitions at 75 % of 1RM, and the sixth set involved repeated repetitions until exhaustion. Following ingestion of the nutrient-rich drink, we assessed the GE rate using 13C-sodium acetate breath test and evaluated two parameters according to the T max-calc (time when the recovery per hour is maximised), which is a standard analytical method, and T 1/2 (time when the total cumulative dose of [13CO2] reaches one-half). T max-calc and T 1/2 were slower for the PE-5 condition than for either the PE-30 or Con condition (T max-calc; Con: 53 (sd 7) min, PE-5: 83 (sd 16) min, PE-30: 62 (sd 9) min, T 1/2; Con: 91 (sd 7) min, PE-5: 113 (sd 21) min, PE-30: 91 (sd 11) min, P<0·05). BG and BCAA responses were also slower for the PE-5 condition than for either the PE-30 or Con condition. Ingesting nutrients immediately after strenuous resistance exercise acutely delayed GE, which affected BG and plasma BCAA levels in blood circulation.
Assuntos
Aminoácidos/metabolismo , Ingestão de Energia , Esvaziamento Gástrico , Glucose/metabolismo , Nutrientes/administração & dosagem , Treinamento Resistido , Adolescente , Adulto , Apetite , Glicemia/metabolismo , Testes Respiratórios , Carboidratos da Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Suplementos Nutricionais , Feminino , Humanos , Lactatos/sangue , Masculino , Adulto JovemRESUMO
To explore the control of the peripheral circulation of a nonworking upper limb during leg cycling exercise, blood flow (BF) dynamics in the brachial artery (BA) were determined using a sinusoidal work rate (WR) exercise. Ten healthy subjects performed upright leg cycling exercise at a constant WR for 30 min, followed by 16 min of sinusoidal WR consisting of 4-min periods of WR fluctuating between a minimum output of 20 W and a maximum output corresponding to ventilatory threshold (VT). Throughout the protocol, pulmonary gas exchange, heart rate (HR), mean arterial blood pressure (MAP), blood velocity (BV), and cross-sectional area of the BA, forearm skin BF (SBF), and sweating rate (SR) were measured. Each variable was fitted to a sinusoidal model with phase shift (θ) and amplitude (A). Nearly all variables closely fit a sinusoidal model. Variables relating to oxygen transport, such as VO2 and HR, followed the sinusoidal WR pattern with certain delays (θ: VO2; 51.4 ± 4.0°, HR; 41.8 ± 5.4°, mean ± SD). Conversely, BF response in the BA was approximately in antiphase (175.1 ± 28.9°) with a relatively large A, whereas the phase of forearm SBF was dissimilar (65.8 ± 35.9°). Thus, the change of BF through a conduit artery to the nonworking upper limb appears to be the reverse when WR fluctuates during sinusoidal leg exercise, and it appears unlikely that this could be ascribed exclusively to altering the downstream circulation to forearm skin.
Assuntos
Artéria Braquial/fisiologia , Exercício Físico , Perna (Membro)/fisiologia , Fluxo Sanguíneo Regional , Braço/irrigação sanguínea , Humanos , Masculino , Consumo de Oxigênio , Pele/irrigação sanguínea , Sudorese , Adulto JovemRESUMO
It is well known that protein ingestion immediately after exercise greatly stimulates muscle protein synthesis during the postexercise recovery phase. However, immediately after strenuous exercise, the gastrointestinal (GI) mucosa is frequently injured by hypoperfusion in the organ/tissue, possibly resulting in impaired GI function (e.g., gastric emptying; GE). The aim of this study was to examine the effect of GI blood flow on the GE rate. Eight healthy young subjects performed an intermittent supramaximal cycling exercise for 30 min, which consisted of a 120% VÌo2peak for 20 s, followed by 20 W for 40 s. The subjects ingested 300 ml of a nutrient drink containing carbohydrate-protein at either 5 min postexercise in one trial (PE-5) or 30 min postexercise in another trial (PE-30). In the control trial (Con), the subjects ingested the same drink without exercise. The celiac artery blood flow (CABF) and superior mesenteric artery blood flow (SMABF) and GE rate were assessed by ultrasonography. Before drink ingestion in PE-5, CABF significantly decreased from baseline, whereas in PE-30, it returned to baseline. Following drink ingestion in PE-5, CABF did not change from baseline, but it significantly increased in PE-30 and Con. SMABF increased significantly later in PE-5 than in PE-30 and Con. The GE rate was consistently slower in PE-5 than in PE-30 and Con. In conclusion, the CABF response after exercise seems to modulate the subsequent GE rate and SMABF response.NEW & NOTEWORTHY A carbohydrate-protein drink was ingested at either 5 min (i.e., profoundly decreased celiac artery blood flow; CABF) or 30 min (i.e., already recovered CABF) postexercise. In the 5-min postexercise trial, the gastric emptying (GE) rate and superior mesenteric artery blood flow (SMABF) response were slower than those in the 30-min postexercise trial. The GE rate and SMABF response may be altered depending on the postexercise CABF response.
Assuntos
Carboidratos da Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Exercício Físico/fisiologia , Esvaziamento Gástrico/fisiologia , Trato Gastrointestinal/irrigação sanguínea , Trato Gastrointestinal/fisiologia , Adulto , Suplementos Nutricionais , Feminino , Mucosa Gástrica/irrigação sanguínea , Mucosa Gástrica/fisiologia , Humanos , Mucosa Intestinal/irrigação sanguínea , Mucosa Intestinal/fisiologia , Masculino , Distribuição Aleatória , Fluxo Sanguíneo Regional/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
An oral sweet taste sensation (OSTS) exaggerates digestive activation transiently, but whether it has a role after swallowing a meal is not known. Gymnema sylvestre (GS) can inhibit the OSTS in humans. We explored the effect of the OSTS of glucose intake on gastrointestinal blood flow, gastric emptying, blood-glucose, and plasma-insulin responses during the postprandial phase. Eight participants ingested 200 g (50 g × 4 times) of 15% glucose solution containing 100 mg of 13C-sodium acetate after rinsing with 25 mL of 2.5% roasted green tea (control) or 2.5% GS solution. During each protocol, gastrointestinal blood flow and gastric emptying were measured by ultrasonography and 13C-sodium acetate breath test, respectively. Decreased subjective sweet taste intensity was observed in all participants in the GS group. The time to attain a peak value of blood flow in the celiac artery and gastric emptying were delayed in the GS group compared with the control group. At the initial phase after glucose intake, blood-glucose and plasma-insulin responses were lower in the GS group than those for the control group. These results suggest that the OSTS itself has a substantial role in controlling postprandial gastrointestinal activities, which may affect subsequent glycemic metabolism.
Assuntos
Esvaziamento Gástrico , Trato Gastrointestinal/irrigação sanguínea , Período Pós-Prandial , Paladar/fisiologia , Adulto , Feminino , Glucose/farmacologia , Gymnema sylvestre , Humanos , MasculinoRESUMO
OBJECTIVE: Premeal consumption of whey protein improves the postmeal glycemic profile, but little information exists on soy protein. The study aim was to examine the effect of consuming different amounts of a soy protein isolate (SPI) before a 75-g oral glucose tolerance test (OGTT) on subsequent glycemic control. METHODS: After overnight fasting, eight healthy young subjects consumed a 400-mL liquid meal containing 0 g (SP0), 20 g (SP20) or 40 g (SP40) SPI. Thirty minutes after SPI consumption, an OGTT was performed to evaluate the individual glycemic response. Blood glucose and plasma insulin concentrations were measured immediately before the SPI preload (i.e., 30 min before the start of the OGTT) and before (-10 min) and during the OGTT (15, 30, 45, 60, 90, and 120 min). RESULTS: The incremental area under the curve and peak blood glucose response were significantly less for SP40 than those for SP0 and SP20. Insulin secretion was significantly higher for SP20 and SP40 than that for SP0 before and at 15 min after oral glucose consumption. The incremental area under the curve of plasma insulin was significantly higher for SP20 and SP40 than that for SP0. CONCLUSIONS: An SPI preload of 40 g, but not 20 g, improved glycemic control in young healthy subjects. Glycemic control appears to be attributed not only to the exaggerated insulin response to SPI preload, but also to non-insulin dependent mechanism(s), such as delayed gastric emptying.