scholarly journals Physiological, metabolic, and performance implications of a prolonged hill walk: influence of energy intake

2003 ◽  
Vol 94 (3) ◽  
pp. 1075-1083 ◽  
Author(s):  
Philip N. Ainslie ◽  
Iain T. Campbell ◽  
Keith N. Frayn ◽  
Sandy M. Humphreys ◽  
Donald P. M. MacLaren ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Reaction Times ◽  
High Energy ◽  
Nonesterified Fatty Acids ◽  
Impaired Performance ◽  
Middle Range ◽  
And Performance ◽  
Blood Glucose Concentrations ◽  
Mean Blood Glucose ◽  
The Hill

We aimed to examine the effects of different energy intakes on a range of responses that are relevant to the safety of hill walkers. In a balanced design, 16 men completed a strenuous self-paced mountainous hill walk over 21 km, under either a low-energy (2.6 MJ; 616 kcal) intake (LEI) or high-energy (12.7 MJ; 3,019 kcal) intake (HEI) condition. During the hill walk, rectal temperatures were measured continuously, and blood samples for the analysis of metabolites and hormones were drawn before breakfast and immediately after the walk. Subjects also completed a battery of performance tests that included muscular strength, reaction times, flexibility, balance, and kinesthetic differentiation tests. During the LEI, mean blood glucose concentrations leveled off at the low-middle range of normoglycemia, whereas, on the HEI, they were significantly elevated compared with the LEI. The maintained blood glucose concentrations, during the LEI, were probably mediated via the marked fat mobilization, reflected by a two- to fivefold increase in nonesterified fatty acids, 3-hydroxybutyrate, and glycerol concentrations. The LEI group showed significantly slower one- and two-finger reaction time, had an impaired ability to balance, and were compromised in their ability to maintain body temperature, when compared with the HEI group. The modestly impaired performance (particularly with respect to balance) and thermoregulation during the LEI condition may increase susceptibly to both fatigue and injury during the pursuit of recreational activity outdoors.

scholarly journals Efecto del consumo de hidratos de carbono en los deportes de resistencia

2019 ◽  
pp. 1-7
Author(s):  
Ricardo LÓPEZ-SOLÍS ◽  
Brenda Hildeliza CAMACHO-DÍAZ ◽  
Roberto CAMPOS-MENDIOLA ◽  
María Araceli ORTÍZ-RODRÍGUEZ
Keyword(s):  
Blood Glucose ◽  
Endurance Sports ◽  
Carbohydrate Consumption ◽  
Glucose Levels ◽  
Oxidation Rates ◽  
Health Authorities ◽  
Carbohydrate Feeding ◽  
Promotion Of Physical Activity ◽  
And Performance ◽  
Blood Glucose Concentrations

The aim of this review is to summarize the effects of carbohydrate consumption on endurance sports. Due to the promotion of physical activity by health authorities, participation in endurance sports is increasing. Regardless of the level, athletes look for ways to optimize their performance through training and nutrition. In consequence, research in the field of sports nutrition has focused on those strategies that can improve performance. Fatigue during prolonged exercise is associated with depletion of muscle glycogen and reduced blood glucose concentrations. Therefore, carbohydrate feeding during exercise has shown that it can improve capacity and performance, because it helps maintain blood glucose levels, as well as, increase carbohydrate oxidation rates and preserve glycogen, finding better results when are consumed multiple-tranportable carbohydrates for absortion (e.g., fructose and glucose), since in this way is possible to increase absorption rates, gastric emptying and fluid absorption, in addition to decrease gastrointestinal distress.

Effect of glycemia and nonesterified fatty acids on forearm glucose uptake in normal humans

1991 ◽  
Vol 261 (3) ◽  
pp. E304-E311 ◽  
Author(s):  
M. Walker ◽  
G. R. Fulcher ◽  
C. F. Sum ◽  
H. Orskov ◽  
K. G. Alberti
Keyword(s):  
Fatty Acid ◽  
Blood Glucose ◽  
Glucose Uptake ◽  
Whole Body ◽  
Glucose Disposal ◽  
Nonesterified Fatty Acid ◽  
Nonesterified Fatty Acids ◽  
Glucose Levels ◽  
And Control ◽  
Blood Glucose Concentrations

The purpose of this study was to examine the effect of physiological plasma nonesterified fatty acid (NEFA) levels on insulin-stimulated forearm and whole body glucose uptake and substrate oxidation during euglycemia and hyperglycemia. Seven healthy men received Intralipid and heparin for 210 min in two studies, with saline as control in two further studies. Insulin (0.05 U.kg-1.h-1) was infused from 60 min, and euglycemia was maintained during lipid (EL) and control (EC) studies, and hyperglycemia was maintained in the other studies (HL and HC). Forearm NEFA uptake was comparable in the lipid studies (+61 +/- 10 and +52 +/- 8 nmol.100 ml forearm-1.min-1, EL and HL) and was suppressed in the controls. With Intralipid, forearm glucose uptake decreased during euglycemia but not during hyperglycemia (+3.85 +/- 0.34 vs. +3.34 +/- 0.25 mumol.100 ml forearm-1.min-1, EC vs. EL, P less than 0.02), with comparable changes in whole body glucose uptake. Glucose oxidation and forearm alanine release decreased with Intralipid at both blood glucose levels, with no significant change in the rates of nonoxidative glucose disposal. These observations support the operation of the glucose-fatty acid cycle at physiological plasma NEFA levels at both blood glucose concentrations, but this was associated with a decrease in peripheral insulin sensitivity only during euglycemia.

EFFECTS OF POSTFEEDING INTERVAL ON BLOOD CONSTITUENTS RELATED TO ENERGY METABOLISM IN NONPREGNANT ANGUS AND HEREFORD HEIFERS

1973 ◽  
Vol 53 (4) ◽  
pp. 641-646 ◽  
Author(s):  
D. M. BOWDEN
Keyword(s):  
Blood Glucose ◽  
Plasma Nefa ◽  
Blood Concentrations ◽  
Nonesterified Fatty Acids ◽  
Blood Constituents ◽  
Initial Sampling ◽  
Glucose Plasma ◽  
Blood Glucose Concentrations ◽  
Subcutaneous Adipose ◽  
Angus Heifers

Ten Angus heifers and 10 Hereford heifers were fasted for 48 h to study changes in blood glucose, plasma nonesterified fatty acids (NEFA), and plasma ketone concentrations and their relationships to prefast feeding levels and breed. Prior to fasting, five heifers of each breed were fed for 140 days on one of two rations, which produced significantly different average rates of gain (0.16 vs. 0.47 kg/day) and average depths of subcutaneous adipose tissue (5.0 vs. 10.3 mm). Blood was sampled at 1, 24, and 48 h postfeeding. Blood glucose concentrations were higher (P < 0.01) at 24 h postfeeding but did not change from 24 to 48 h postfeeding. Plasma NEFA concentrations increased during the 48-h fast. Plasma ketones were lower (P < 0.01) at 24 h postfeeding but at 48 h were higher (P < 0.01) than at 1 h postfeeding. Packed cell volume (PCV) increased during 24 and 48 h of fasting. Blood concentrations of glucose, NEFA, and ketones at either 24 or 48 h of fasting were not influenced by prefast feeding level. Angus heifers had higher (P < 0.05) blood glucose and higher (P < 0.05) PCV than Hereford heifers. Correlations between the blood constituents at the three sampling times were generally low. Only the correlations of plasma NEFA with ketone concentrations at 24 h postfeeding (.55) and glucose with PCV at the initial sampling (−.52) reached significance (P < 0.05).

Cerebral carbohydrate and energy metabolism during hypoglycemia in newborn dogs

1981 ◽  
Vol 240 (3) ◽  
pp. R192-R199 ◽  
Author(s):  
R. C. Vannucci ◽  
E. E. Nardis ◽  
S. J. Vannucci ◽  
P. A. Campbell
Keyword(s):  
Blood Glucose ◽  
Glucose Consumption ◽  
Regular Insulin ◽  
High Energy ◽  
Glycolytic Flux ◽  
Glucose Levels ◽  
Glycolytic Intermediates ◽  
Withdrawal Reflexes ◽  
Lactate Levels ◽  
Blood Glucose Concentrations

The metabolic responses of the perinatal brain to hypoglycemia were studied in newborn dogs. Hypoglycemia, induced by the intravenous injection of regular insulin (0.2-0.3 U/g body wt), resulted in final blood glucose concentrations ranging from 0.1 to 1.5 mmol/l; blood lactate levels were little changed from normoglycemic values. Righting, sucking, and nociceptive withdrawal reflexes were progressively lost during the course of hypoglycemia. Slowing of the electroencephalogram was apparent at or below 1.5 mmol/l blood glucose and advanced to paroxysmal discharges and convulsive activity as glucose approached 0.5 mmol/l. In lightly anesthetized, paralyzed, and artificially ventilated puppies, blood glucose concentrations approximating 1.0 mmol/l were associated with a 91% reduction in cerebral glucose; the concentrations of other glycolytic intermediates (glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-diphosphate, pyruvate, lactate) were unchanged from control. Further declines in blood glucose resulted in cerebral glucose levels below 0.1 mmol/kg as well as in partial depletions of all measured glycolytic intermediates including lactate. These changes reflect reduced cerebral glucose consumption and glycolytic flux. Despite the alterations in carbohydrate metabolism, both lactate/pyruvate ratios and high-energy phosphate reserves (phosphocreatine, ATP, ADP) in brain were well preserved even at the extreme of hypoglycemia. The present data, coupled with previous findings of enhanced lactic acid entry into and consumption by newborn dog brain, suggest that this metabolite serves as an important, if not the predominant, substitute fuel for cerebral oxidative metabolism during perinatal hypoglycemia.

Glucose lowering effects of inhaled insulin in healthy cats

2008 ◽  
Vol 10 (5) ◽  
pp. 519-522 ◽  
Author(s):  
Amy E. DeClue ◽  
Elizabeth F. Leverenz ◽  
Charles E. Wiedmeyer ◽  
Margaret E. Bryan ◽  
Carol R. Reinero
Keyword(s):  
Blood Glucose ◽  
Severe Hypoglycemia ◽  
Regular Insulin ◽  
Lower Blood Glucose ◽  
Glucose Lowering ◽  
Inhaled Insulin ◽  
Lower Blood ◽  
Adult Cats ◽  
Blood Glucose Concentrations ◽  
Mean Blood Glucose

Inhaled medications have proven effective and well tolerated in cats, and inhaled insulin has been used successfully for the management of diabetes mellitus in humans. Thus, we hypothesize that delivery of aerosolized regular insulin can lower blood glucose in healthy cats. Five adult cats were administered aerosolized 0.9% saline (IS), regular insulin intravenously (IV) 0.5 U/kg, and aerosolized regular insulin 15 U/kg (I15) and 25 U/kg (I25) and blood glucose was evaluated. Mean blood glucose was significantly lower at 15, 30 and 45 min in the I25 and IV groups compared to baseline. Similarly, the IV and I25 groups had a significantly greater maximal percent change in blood glucose than the IS group. Significantly more cats developed severe hypoglycemia (<50 mg/dl; 2.7 mmol/l) in the IV and I25 groups than in the IS group. Results of this study demonstrate that aerosolized insulin can effectively lower blood glucose concentrations in healthy cats.

Pathways ahead for New Zealand hill country farming

2016 ◽  
Vol 78 ◽  
pp. 73-82 ◽  
Author(s):  
F.G. Scrimgeour
Keyword(s):  
New Zealand ◽  
Rural Communities ◽  
New Technologies ◽  
Service Providers ◽  
Farming Systems ◽  
Hill Country ◽  
The Status ◽  
And Performance ◽  
Hill Farming ◽  
The Hill

This paper provides a stocktake of the status of hill country farming in New Zealand and addresses the challenges which will determine its future state and performance. It arises out of the Hill Country Symposium, held in Rotorua, New Zealand, 12-13 April 2016. This paper surveys people, policy, business and change, farming systems for hill country, soil nutrients and the environment, plants for hill country, animals, animal feeding and productivity, and strategies for achieving sustainable outcomes in the hill country. This paper concludes by identifying approaches to: support current and future hill country farmers and service providers, to effectively and efficiently deal with change; link hill farming businesses to effective value chains and new markets to achieve sufficient and stable profitability; reward farmers for the careful management of natural resources on their farm; ensure that new technologies which improve the efficient use of input resources are developed; and strategies to achieve vibrant rural communities which strengthen hill country farming businesses and their service providers. Keywords: farming systems, hill country, people, policy, productivity, profitability, sustainability

Study of the Correlation between Tear Glucose Concentrations and Blood Glucose Concentrations

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 944-P
Author(s):  
MASAKAZU AIHARA ◽  
NAOTO KUBOTA ◽  
TAKASHI KADOWAKI
Keyword(s):  
Blood Glucose ◽  
Tear Glucose ◽  
Blood Glucose Concentrations

Rapid Crystallization and Kinetic Freezing of Site-Disorder in the Lithium Superionic Argyrodite Li6PS5Br

2019 ◽  
Author(s):  
Ajay Gautam ◽  
Marcel Sadowski ◽  
Nils Prinz ◽  
Henrik Eickhoff ◽  
Nicolo Minafra ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Synthesis Method ◽  
Reaction Times ◽  
Ionic Conductivities ◽  
Ionic Transport ◽  
High Energy ◽  
Superionic Conductors ◽  
Rapid Crystallization ◽  
Site Disorder ◽  
Fast Cooling

<p>Lithium argyrodite superionic conductors are currently being investigated as solid electrolytes for all-solid-state batteries. Recently, in the lithium argyrodite Li<sub>6</sub>PS<sub>5</sub>X (X = Cl, Br, I), a site-disorder between the anionsS<sup>2–</sup>and X<sup>–</sup>has been observed, which strongly affects the ionic transport and appears to be a function of the halide present. In this work, we show how such disorder in Li<sub>6</sub>PS<sub>5</sub>Br can be engineered <i>via</i>the synthesis method. By comparing fast cooling (<i>i.e. </i>quenching) to more slowly cooled samples, we find that anion site-disorder is higher at elevated temperatures, and that fast cooling can be used to kinetically trap the desired disorder, leading to higher ionic conductivities as shown by impedance spectroscopy in combination with <i>ab-initio</i>molecular dynamics. Furthermore, we observe that after milling, a crystalline lithium argyrodite can be obtained within one minute of heat treatment. This rapid crystallization highlights the reactive nature of mechanical milling and shows that long reaction times with high energy consumption are not needed in this class of materials. The fact that site-disorder induced <i>via</i>quenching is beneficial for ionic transport provides an additional approach for the optimization and design of lithium superionic conductors.</p>

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