scholarly journals Dietary Observations of Ultra-Endurance Runners in Preparation for and During a Continuous 24-h Event

2021 ◽  
Vol 12 ◽  
Author(s):  
Emma J. Kinrade ◽  
Stuart D. R. Galloway
Keyword(s):  
Heart Rate ◽  
Dietary Intake ◽  
Glucose Concentration ◽  
Research Team ◽  
Absolute Requirement ◽  
Interstitial Glucose ◽  
Endurance Runners ◽  
Positive Correlations ◽  
Ultra Running ◽  
Ultra Endurance

Carbohydrate (CHO) intake recommendations for events lasting longer than 3h indicate that athletes should ingest up to 90g.h.−1 of multiple transportable carbohydrates (MTC). We examined the dietary intake of amateur (males: n=11, females: n=7) ultra-endurance runners (mean age and mass 41.5±5.1years and 75.8±11.7kg) prior to, and during a 24-h ultra-endurance event. Heart rate and interstitial glucose concentration (indwelling sensor) were also tracked throughout the event. Pre-race diet (each 24 over 48h) was recorded via weighed intake and included the pre-race meal (1–4h pre-race). In-race diet (24h event) was recorded continuously, in-field, by the research team. Analysis revealed that runners did not meet the majority of CHO intake recommendations. CHO intake over 24–48h pre-race was lower than recommended (4.0±1.4g·kg−1; 42±9% of total energy), although pre-race meal CHO intake was within recommended levels (1.5±0.7g·kg−1). In-race CHO intake was only in the 30–60g·h−1 range (mean intake 33±12g·h−1) with suboptimal amounts of multiple transportable CHO consumed. Exercise intensity was low to moderate (mean 68%HRmax 45%VO2max) meaning that there would still be an absolute requirement for CHO to perform optimally in this ultra-event. Indeed, strong to moderate positive correlations were observed between distance covered and both CHO and energy intake in each of the three diet periods studied. Independent t-tests showed significantly different distances achieved by runners consuming ≥5 vs. <5g·kg−1 CHO in pre-race diet [98.5±18.7miles (158.5±30.1km) vs. 78.0±13.5miles (125.5±21.7km), p=0.04] and ≥40 vs. <40g·h−1 CHO in-race [92.2±13.9miles (148.4±22.4km) vs. 74.7±13.5miles (120.2±21.7km), p=0.02]. Pre-race CHO intake was positively associated with ultra-running experience, but no association was found between ultra-running experience and race distance. No association was observed between mean interstitial glucose and dietary intake, or with race distance. Further research should explore approaches to meeting pre-race dietary CHO intake as well as investigating strategies to boost in-race intake of multiple transportable CHO sources. In 24-h ultra-runners, studies examining the performance enhancing benefits of getting closer to meeting pre-race and in-race carbohydrate recommendations are required.

scholarly journals Correction to: Analysis of food and fluid intake in elite ultra-endurance runners during a 24-h world championship

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Chloé Lavoué ◽  
Julien Siracusa ◽  
Émeric Chalchat ◽  
Cyprien Bourrilhon ◽  
Keyne Charlot
Keyword(s):  
Fluid Intake ◽  
World Championship ◽  
Endurance Runners ◽  
Ultra Endurance ◽  
Food And Fluid Intake

An amendment to this paper has been published and can be accessed via the original article.

Stability of Heart Rate at Physiological Thresholds Between Temperate and Heat Stress Environments in Endurance-Trained Males

2020 ◽  
pp. 1-4
Author(s):  
Ed Maunder ◽  
Daniel J. Plews ◽  
Fabrice Merien ◽  
Andrew E. Kilding
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Relative Humidity ◽  
Blood Lactate ◽  
Endurance Athletes ◽  
Heart Rates ◽  
Stress Environments ◽  
Positive Correlations ◽  
Hot Environments ◽  
Stress Training

Many endurance athletes perform specific blocks of training in hot environments in “heat stress training camps.” It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exercise assessments in 18°C and 35°C (both 60% relative humidity) to determine heart rates at absolute blood lactate and ventilatory thresholds. Heart rate at fixed blood lactate concentrations of 2, 3, and 4 mmol·L−1 and ventilatory thresholds were not significantly different between environments (P > .05), despite significant heat stress-induced reductions in power output of approximately 10% to 17% (P < .05, effect size = 0.65–1.15). The coefficient of variation for heart rate at these blood lactate concentrations (1.4%−2.9%) and ventilatory thresholds (2.3%−2.7%) between conditions was low, with significant strong positive correlations between measurements in the 2 environments (r = .92–.95, P < .05). These data indicate heart rates measured at physiological thresholds in temperate environments are reflective of measurements taken under moderate environmental heat stress. Therefore, endurance athletes embarking on heat stress training camps can use heart rate–based thresholds ascertained in temperate environments to prescribe training under moderate environmental heat stress.

Metabolic effects of dobutamine in normal man

1992 ◽  
Vol 82 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Ceri J. Green ◽  
R. S. Frazer ◽  
S. Underhill ◽  
Paula Maycock ◽  
Judith A. Fairhurst ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Glucose ◽  
Glucose Concentration ◽  
Respiratory Exchange Ratio ◽  
Blood Glucose Concentration ◽  
Plasma Potassium ◽  
Metabolic Effects ◽  
Dobutamine Infusion ◽  
Plasma Insulin Concentration ◽  
Placebo Infusion

1. Dobutamine in 5% (w/v) d-glucose was infused at sequential doses of 2, 5 and 10 μg min−1 kg−1, 45 min at each dose, into eight healthy male subjects, and the effects were compared with those produced by infusion of the corresponding volumes of 5% (w/v) d-glucose alone. 2. The energy expenditure increased and was 33% higher than control (P<0.001) at 10 μg of dobutamine min−1 kg−1. The respiratory exchange ratio decreased from 0.85 (sem 0.02) before infusion to 0.80 (sem 0.01) at 10 μg of dobutamine min−1 kg−1, but did not alter during the placebo infusion (P> 0.001). 3. Plasma noradrenaline concentrations were lower during the dobutamine infusion compared with during the infusion of d-glucose alone (P < 0.025). Plasma dopamine concentrations remained below 0.1 nmol/l throughout both infusions. 4. Compared with during the placebo infusion, the blood glucose concentration decreased (P < 0.001), the plasma glycerol and free fatty acid concentrations increased by 150 and 225%, respectively (both P < 0.001), and the plasma potassium concentration decreased from 3.8 (sem 0.07) to 3.6 (sem 0.04) mmol/l (P<0.01) during dobutamine infusion. The plasma insulin concentration increased at 2 and 5 μg of dobutamine min−1 kg−1 (P<0.001) with no further rise at 10 μg of dobutamine min−1 kg−1. 5. Compared with during the placebo infusion, the systolic and diastolic blood pressures and the heart rate increased during dobutamine infusion (P<0.01). At 10 μg of dobutamine min−1 kg−1, the systolic blood pressure was around 160 mmHg (P < 0.001) and the heart rate was around 92 (sem 8) beats/min compared with 59 (sem 4) beats/min during the placebo infusion (P < 0.001). 6. Dobutamine has metabolic effects. It is markedly thermogenic and lipolytic. It depresses the respiratory exchange ratio and endogenous noradrenaline secretion, stimulates insulin secretion and depresses the blood glucose concentration.

Heart rate at 4 s after the onset of exercise in endurance-trained men

2014 ◽  
Vol 92 (6) ◽  
pp. 476-480 ◽  
Author(s):  
Divanei Zaniqueli ◽  
Elis Aguiar Morra ◽  
Eduardo Miranda Dantas ◽  
Marcelo Perim Baldo ◽  
Luciana Carletti ◽  
...  
Keyword(s):  
Heart Rate ◽  
Frequency Spectrum ◽  
High Frequency ◽  
Sinus Node ◽  
Low Frequency ◽  
Spectral Indices ◽  
High Frequency Band ◽  
Band Ratio ◽  
Endurance Runners ◽  
Vagal Influence

It has been suggested that the increase in heart rate (HR) at the onset of exercise is caused by vagal withdrawal. In fact, endurance runners show a lower HR in maximum aerobic tests. However, it is still unknown whether endurance runners have a lower HR at 4 s after the onset of exercise (4th-sec-HR). We sought to measure the HR at the onset of the 4 s exercise test (4-sET), clarifying its relationship to heart rate variability (HRV), spectral indices, and cardiac vagal index (CVI) in endurance runners (ER) and healthy untrained controls (CON). HR at 4th-sec-HR, CVI, and percent HR increase during exercise were analyzed in the 4-sET. High frequency spectrum (HF-nu), low frequency spectrum (LF-nu), and low frequency/high frequency band ratio (LF/HF) were analyzed from the HRV. ER showed a significantly higher HF, and both a lower LF and LF/HF ratio compared with the CON. ER presented a significantly lower 4th-sec-HR, although neither CVI nor HR increases during exercise were statistically different from the CON. In conclusion, ER presented a lower 4th-sec-HR secondary to increased vagal influence over the sinus node. CVI seems to be too weak to use for discriminating individuals with respect to the magnitude of HR vagal control.

Effects of Dialysate Glucose Concentration on Heart Rate Variability in Chronic Hemodialysis Patients: Results of a Prospective Randomized Trial

2011 ◽  
Vol 34 (5) ◽  
pp. 334-343 ◽  
Author(s):  
Manuela Ferrario ◽  
Jochen G. Raimann ◽  
Stephan Thijssen ◽  
Maria Gabriella Signorini ◽  
Anja Kruse ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Randomized Trial ◽  
Glucose Concentration ◽  
Hemodialysis Patients ◽  
Chronic Hemodialysis ◽  
Prospective Randomized Trial

scholarly journals Dietary Intake and Plasma Levels of Choline and Betaine in Children with Autism Spectrum Disorders

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Joanna C. Hamlin ◽  
Margaret Pauly ◽  
Stepan Melnyk ◽  
Oleksandra Pavliv ◽  
William Starrett ◽  
...  
Keyword(s):  
Dietary Intake ◽  
Plasma Levels ◽  
Plasma Concentrations ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Research Network ◽  
Control Group ◽  
Lower Plasma ◽  
One Carbon Metabolism ◽  
Positive Correlations

Abnormalities in folate-dependent one-carbon metabolism have been reported in many children with autism. Because inadequate choline and betaine can negatively affect folate metabolism and in turn downstream methylation and antioxidant capacity, we sought to determine whether dietary intake of choline and betaine in children with autism was adequate to meet nutritional needs based on national recommendations. Three-day food records were analyzed for 288 children with autism (ASDs) who participated in the national Autism Intervention Research Network for Physical Health (AIR-P) Study on Diet and Nutrition in children with autism. Plasma concentrations of choline and betaine were measured in a subgroup of 35 children with ASDs and 32 age-matched control children. The results indicated that 60–93% of children with ASDs were consuming less than the recommended Adequate Intake (AI) for choline. Strong positive correlations were found between dietary intake and plasma concentrations of choline and betaine in autistic children as well as lower plasma concentrations compared to the control group. We conclude that choline and betaine intake is inadequate in a significant subgroup of children with ASDs and is reflected in lower plasma levels. Inadequate intake of choline and betaine may contribute to the metabolic abnormalities observed in many children with autism and warrants attention in nutritional counseling.

scholarly journals Effect of moderate physical exercises on the relationship of variability of the heart rhythm with the level of blood pressure and hemodynamic functions in women with essential hypertension

2020 ◽  
pp. 64-73
Author(s):  
Б.И. Кузник ◽  
Ю.Н. Смоляков ◽  
Е.С. Гусева ◽  
С.О. Давыдов ◽  
И.В. Файн
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Heart Rate Variability ◽  
Essential Hypertension ◽  
High Frequency ◽  
Low Frequency ◽  
Mean Square ◽  
Positive Correlations ◽  
The Relationship

Цель исследования - выявление взаимосвязи между показателями вариабельности сердечного ритма (ВСР), кровяным давлением и гемодинамическими функциями у женщин, страдающих гипертонической болезнью (ГБ) и находящихся на медикаментозной терапии (ГБ-1), либо в дополнение к этому, проходящих регулярные курсы кинезитерапии (ГБ-2). Методика. Наблюдения проведены на 72 женщинах, страдающих артериальной гипертензией II стадии. В группу ГБ-1 вошли 37 женщин с ГБ, находящихся на медикаментозной терапии, в группу ГБ-2 - 35 женщин с ГБ, которые, помимо медикаментозной терапии, регулярно проходили на протяжении 2-3 лет по 3-4 полуторамесячных курса кинезитерапии (управляемые умеренные физические нагрузки). Для изучения гемодинамики был использован датчик динамического рассеяния света (miniature Dynamic Light Scattering - mDLS) от Elfi-Tech (Rehovot, Israel), измеряющий сигналы, инициированные кожным кровотоком, и использующий методику разложения сигнала на частотные компоненты, связанные с разными гемодинамическими источниками. Из пульсовой компоненты mDLS сигнала извлекалась информация о вариабельности RR-интервалов и рассчитывались индикаторы вариабельности сердечного ритма. Введен показатель «гемодинамический индекс» (Hemodynamic Index - HI). Зависимость HI от скорости сдвига интерпретируется путем сопоставления каждой полосе частот определенной скорости сдвига (HI1 - низкочастотный, HI2 - промежуточный, HI3 - высокочастотный). Использованы следующие относительные (RHI, Relative Hemodynamic Index) и осцилляторные (OHI, Oscillatory Hemodynamic Indexes) гемодинамические индексы: нейрологический (NEUR), Майера (MAYER), дыхательный (RESP) и пульсовой (PULSE). ВСР показатели включали: HR (Heart Rate), PWR (Power) - общую мощность колебаний, LF (Low Frequency), HF (High Frequency), SDNN (Standard Deviation of the Normal-to-Normal), RMSSD (Root Mean Square of the Successive Differences), а также индексы: CVI (Cardiac Vagal Index) и CSI (Cardiac Sympathetic Index). Результаты. У женщин, находящихся исключительно на медикаментозной терапии (ГБ-1), выявляются отрицательные взаимосвязи LF и LF/HF с систолическим, средним и пульсовым давлением. При ГБ-2 проявляются отрицательные связи PWR, LF, HF с пульсовым давлением. При ГБ-1 обнаружены положительные взаимосвязи между HR и гемодинамическими индексами HI1, RHI2 и отрицательная взаимосвязь с RHI3, а также между RMSSD и RHI3 и между HF и HI1/HI3. У пациенток ГБ-2 обнаружена отрицательная корреляция SDNN и RHI1, а также PWR и RHI1; положительные взаимосвязи между PWR и HI2, HI3, RHI2, HF и RHI3 и LF/HF с HI1/HI3; отрицательные связи HF c HI1/HI3 и с RHI1, а также между LF/HF и RHI3, CSI и RHI3. У больных ГБ-1 имеются прямые связи между SDNN, PWR, LF, HF, CVI и NEUR_HI1, что свидетельствует о действии этих факторов на эндотелиальный кровоток (HI1). В группе ГБ-2 установлено наличие лишь положительных связей между LF, HF и NEUR_HI3. У больных ГБ-1 на уровень АД влияют все без исключения осцилляторные ритмы, которые могут оказывать как отрицательное (с MAYER_HI1, PULSE_HI2), так и положительное (MAYER_HI2, RESP_HI3) влияние. У больных ГБ-2 взаимосвязи АД с осцилляторными индексами не обнаружены. Заключение. Уменьшение в группе ГБ-2 по сравнению с больными группы ГБ-1 числа факторов, влияющих на АД и гемодинамику, носит более совершенный и благоприятный характер, что и обеспечивает более быструю и устойчивую нормализацию артериального давления. Aim. To study the relationship between heart rate variability (HRV), blood pressure and hemodynamic functions in women with essential hypertension (EH) receiving a drug therapy alone (EH-1) or in combination with regular courses of kinesitherapy (EH-2). Methods. The study included 72 women with EH. The EH-1 group consisted of 37 women with stage II arterial hypertension. The EH-2 group consisted of 35 women with stage II arterial hypertension who underwent 3-4 1.5-month courses of kinesitherapy (controlled moderate physical activity) on a regular basis for 2-3 years. Hemodynamics was studied with a miniature Dynamic Light Scattering (mDLS) sensor from Elfi-Tech (Rehovot, Israel), which measures signals initiated by the skin blood flow by decomposing the signal into frequency components associated with different hemodynamic sources. Information on the RR interval variability was extracted from the pulse component of mDLS signal, and indicators of heart rate variability were calculated. A Hemodynamic Index (HI) was introduced. The HI dependence on shear rate was interpreted by matching each frequency band with a specific shear rate (HI1, low-frequency; HI2, intermediate; HI3, high-frequency). The following relative (RHI, Relative Hemodynamic Index) and oscillatory (OHI, Oscillatory Hemodynamic Indexes) indexes were used: neurological (NEUR), Mayer (MAYER), respiratory (RESP), and pulse (PULSE) ones. The HRV indexes included HR (Heart Rate), PWR (Power, total oscillation power), LF (Low Frequency), HF (High Frequency), SDNN (Standard Deviation of the Normal-to-Normal), RMSSD (Root Mean Square of the Successive Differences). CVI (Cardiac Vagal Index), and CSI (Cardiac Sympathetic Index). Results. In women who were on drug therapy alone (EH-1), negative relationships were found for LF and LF/HF with systolic, mean and pulse pressure. For EH-2, PWR, LF, and HF negatively correlated with pulse pressure. For EH-1, HR positively correlated with the hemodynamic indices HI1 and RHI2 and negatively correlated with RHI3; RMSSD negatively correlated with RHI3; and HF negatively correlated with HI1/HI3. For patients with EH-2, negative correlations were observed for SDNN and RHI1, PWR and RHI1; positive correlations were found between PWR and HI2; HI3, RHI2, HF and RHI3; and between LF/HF and HI1/HI3. HF negatively correlated with HI1/HI3 and with RHI1. LF/HF negatively correlated with RHI3, and CSI negatively correlated with RHI3. In patients with EH-1, SDNN, PWR, LF, HF, CVI, and NEUR_HI1 were directly related, which indicated an effect of these factors on the endothelial blood flow (HI1). In the EH-2 group, only positive correlations were found between LF, HF, and NEUR_HI3. In EH-1 patients, all oscillatory rhythms influenced BP; this influence could be both negative (for MAYER_HI1, PULSE_HI2) and positive (for MAYER_HI2, RESP_HI3). In EH-2 patients, no relationship was found between blood pressure and oscillatory indices. Conclusion. The smaller number of factors influencing blood pressure and hemodynamics in the EH-2 group compared to the EH-1 group was more beneficial and favorable, which ensured faster and steadier normalization of blood pressure.

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