Exogenous Ketone Salt Supplementation and Whole-Body Cooling Do Not Improve Short-Term Physical Performance

Exogenous ketone supplementation and whole-body cooling (WBC) have shown to independently influence exercise metabolism. Whether readily available ketone salts, with and without WBC, would provide similar metabolic benefits during steady-state aerobic and time-trial performances was investigated. Nine active males (VO2peak: 56.3 ± 2.2 mL·kg−1·min−1) completed three single-blind exercise sessions preceded by: (1) ingestion of placebo (CON), (2) ketone supplementation (0.3 g·kg−1 β-OHB) (KET), and (3) ketone supplementation with WBC (KETCO). Participants cycled in steady-state (SS, 60% Wmax) condition for 30-min, immediately followed by a 15-min time trial (TT). Skin and core temperature, cardio-metabolic, and respiratory measures were collected continuously, whereas venous blood samples were collected before and after supplementation, after SS and TT. Venous β-OHB was elevated, while blood glucose was lower, with supplementation vs. CON (p < 0.05). TT power output was not different between conditions (p = 0.112, CON: 190 ± 43.5 W, KET: 185 ± 40.4 W, KETCO: 211 ± 50.7 W). RER was higher during KETCO (0.97 ± 0.09) compared to both CON (0.88 ± 0.04, p = 0.012) and KET (0.88 ± 0.05, p = 0.014). Ketone salt supplementation and WBC prior to short-term exercise sufficiently increase blood β-OHB concentrations, but do not benefit metabolic shifts in fuel utilization or improve time trial performance.

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Dietary Composition Influences Short-term Endurance Training–Induced Adaptations of Substrate Partitioning during Exercise

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.14.1.38 ◽

2004 ◽

Vol 14 (1) ◽

pp. 38-61 ◽

Cited By ~ 2

Author(s):

Kevin A. Jacobs ◽

David R. Paul ◽

Ray J. Geor ◽

Kenneth W. Hinchcliff ◽

W. Michael Sherman

Keyword(s):

Endurance Training ◽

Time Trial ◽

Whole Body ◽

High Fat ◽

Short Term ◽

Time Trial Performance ◽

Glucose Flux ◽

Before And After ◽

Substrate Partitioning ◽

Trial Performance

The purpose of the current study was to examine the influence of dietary composition on short-term endurance training–induced adaptations of substrate partitioning and time trial exercise performance. Eight untrained males cycled for 90 min at ~54% aerobic capacity while being infused with [6,62H]glucose before and after two 10-d experimental phases separated by a 2-week washout period. Time trial performance was measured after the 90-min exercise trials before and after the 2nd experimental phase. During the first 10-d phase, subjects were randomly assigned to consume either a high carbohydrate or high fat diet while remaining inactive (CHO or FAT). During the second 10-d phase, subjects consumed the opposite diet, and both groups performed identical daily supervised endurance training (CHO+T or FAT+T). CHO and CHO+T did not affect exercise metabolism. FAT reduced glucose flux at the end of exercise, while FAT+T substantially increased whole body lipid oxidation during exercise and reduced glucose flux at the end of exercise. Despite these differences in adaptation of substrate use, training resulted in similar improvements in time trial performance for both groups. We conclude that (a) 10-d high fat diets result in substantial increases in whole body lipid oxidation during exercise when combined with daily aerobic training, and (b) diet does not affect short-term training-induced improvements in high-intensity time trial performance.

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No Effect of Short-Term Green Tea Extract Supplementation on Metabolism at Rest or During Exercise in the Fed State

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.2013-0202 ◽

2014 ◽

Vol 24 (6) ◽

pp. 656-664 ◽

Cited By ~ 7

Author(s):

Brian J. Martin ◽

Rachel B. Tan ◽

Jenna B. Gillen ◽

Michael E. Percival ◽

Martin J. Gibala

Keyword(s):

Heart Rate ◽

Steady State ◽

Green Tea ◽

Time Trial ◽

Fat Oxidation ◽

Whole Body ◽

Short Term ◽

Main Effect ◽

Tea Extract ◽

Trial Performance

Supplementation with green tea extract (GTE) in animals has been reported to induce numerous metabolic adaptations including increased fat oxidation during exercise and improved performance. However, data regarding the metabolic and physiological effects of GTE during exercise in humans are limited and equivocal.Purpose:To examine the effects of short-term GTE treatment on resting energy expenditure (REE), wholebody substrate utilization during exercise and time trial performance.Methods:Fifteen active men (24 ± 3 y; VO2peak = 48 ± 7 ml·kg·min−1; BMI = 26 ± 3 kg·m2(–1)) ingested GTE (3x per day = 1,000 mg/d) or placebo (PLA) for 2 day in a double-blind, crossover design (each separated by a 1 week wash-out period). REE was assessed in the fasted state. Subjects then ingested a standardized breakfast (~5.0 kcal·kg-1) and 90 min later performed a 60 min cycling bout at an intensity corresponding to individual maximal fat oxidation (44 ± 11% VO2peak), followed by a 250 kJ TT.Results:REE, whole-body oxygen consumption (VO2) and substrate oxidation rates during steady-state exercise were not different between treatments. However, mean heart rate (HR) was lower in GTE vs. PLA (115 ± 16 vs. 118 ± 17 beats·min−1; main effect, p = .049). Mixed venous blood [glycerol] was higher during rest and exercise after GTE vs. PLA (p = .006, main effect for treatment) but glucose, insulin and free-fatty acids were not different. Subsequent time trial performance was not different between treatments (GTE = 25:38 ± 5:32 vs. PLA = 26:08 ± 8:13 min; p = .75).Conclusion:GTE had minimal effects on whole-body substrate metabolism but significantly increased plasma glycerol and lowered heart rate during steady-state exercise, suggesting a potential increase in lipolysis and a cardiovascular effect that warrants further investigation.

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Therapeutic hypothermia in asphyxiated newborns: selective head cooling vs. whole body cooling — comparison of short term outcomes

Ginekologia Polska ◽

10.5603/gp.2019.0069 ◽

2019 ◽

Vol 90 (7) ◽

pp. 403-410 ◽

Cited By ~ 1

Author(s):

Ewa Matylda Gulczynska ◽

Janusz Gadzinowski ◽

Marcin Kesiak ◽

Barbara Sobolewska ◽

Joanna Caputa ◽

...

Keyword(s):

Therapeutic Hypothermia ◽

Whole Body ◽

Short Term ◽

Head Cooling ◽

Body Cooling ◽

Whole Body Cooling

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Oral sapropterin augments reflex vasoconstriction in aged human skin through noradrenergic mechanisms

Journal of Applied Physiology ◽

10.1152/japplphysiol.00626.2013 ◽

2013 ◽

Vol 115 (7) ◽

pp. 1025-1031 ◽

Cited By ~ 17

Author(s):

Anna E. Stanhewicz ◽

Lacy M. Alexander ◽

W. Larry Kenney

Keyword(s):

Human Skin ◽

Venous Blood ◽

Placebo Treatment ◽

Whole Body ◽

Double Blind ◽

Doppler Flowmetry ◽

Adrenergic Mechanisms ◽

Aged Skin ◽

Body Cooling ◽

Whole Body Cooling

Reflex vasoconstriction is attenuated in aged skin due to a functional loss of adrenergic vasoconstriction. Bioavailability of tetrahydrobiopterin (BH4), an essential cofactor for catecholamine synthesis, is reduced with aging. Locally administered BH4 increases vasoconstriction through adrenergic mechanisms in aged human skin. We hypothesized that oral sapropterin (Kuvan, a pharmaceutical BH4) would augment vasoconstriction elicited by whole-body cooling and tyramine perfusion in aged skin. Ten healthy subjects (age 75 ± 2 yr) ingested sapropterin (10 mg/kg) or placebo in a randomized, double-blind crossover design. Venous blood samples were collected prior to, and 3 h following ingestion. Three intradermal microdialysis fibers were placed in the forearm skin for local delivery of 1) lactated Ringer, 2) 5 mM BH4, and 3) 5 mM yohimbine + 1 mM propranolol (Y+P; to inhibit adrenergic vasoconstriction). Red cell flux was measured at each site by laser-Doppler flowmetry (LDF) as reflex vasoconstriction was induced by lowering and then clamping whole-body skin temperature ( T̄sk) using a water-perfused suit. Following whole-body cooling, subjects were rewarmed and 1 mM tyramine was perfused at each site to elicit endogenous norepinephrine release from the perivascular nerve terminal. Cutaneous vascular conductance was calculated as CVC = LDF/mean arterial pressure and expressed as change from baseline (ΔCVC). Plasma BH4 was elevated 3 h after ingestion of sapropterin (43.8 ± 3 vs. 19.1 ± 2 pmol/ml; P < 0.001). Sapropterin increased reflex vasoconstriction at the Ringer site at T̄sk ≤ 32.5°C ( P < 0.05). Local BH4 perfusion augmented reflex vasoconstriction at T̄sk ≤ 31.5°C with placebo treatment only ( P < 0.05). There was no treatment effect on reflex vasoconstriction at the BH4-perfused or Y+P-perfused sites. Sapropterin increased pharmacologically induced vasoconstriction at the Ringer site (−0.19 ± 0.03 vs. −0.08 ± 0.02 ΔCVC; P = 0.01). There was no difference in pharmacologically induced vasoconstriction between treatments at the BH4-perfused site (−0.16 ± 0.04 vs. −0.14 ± 0.03 ΔCVC; P = 0.60) or the Y+P-perfused site (−0.05 ± 0.02 vs.−0.06 ± 0.02 ΔCVC; P = 0.79). Sapropterin increases both reflex (cold-induced) and pharmacologically induced vasoconstriction through adrenergic mechanisms and may be a viable intervention to improve reflex vasoconstriction in aged humans.

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Outcome of Infants with Hypoxic-Ischemic Encephalopathy Treated by Whole Body Cooling and Magnesium Sulfate

Journal of Child Science ◽

10.1055/s-0041-1736562 ◽

2021 ◽

Vol 11 (01) ◽

pp. e280-e286

Author(s):

Safwat M. Abdel-Aziz ◽

Mohamed Sabry M. Abdel Rahman ◽

Asmaa H. Shoreit ◽

Moustafa Ez El Din ◽

Enas A. Hamed ◽

...

Keyword(s):

Magnesium Sulfate ◽

Therapy Group ◽

Whole Body ◽

P Value ◽

Short Term ◽

Group 3 ◽

Group 2 ◽

Body Cooling ◽

Whole Body Cooling ◽

Group 1

AbstractTherapeutic hypothermia (TH) either by selective head cooling or whole-body cooling decreases brain damage and provide neuroprotection and reduced mortality rate in cases of moderate-to-severe hypoxia-ischemia encephalopathy (HIE) of newborns, especially if started at first 6 hours after birth. Also, management with adjuvant therapies like magnesium sulfate (MS) provides more neuroprotection. The interventional randomized controlled research aimed to assess short-term actions of TH as sole therapy and in combination with MS as a neuroprotective agent for the treatment of HIE newborn infants. A total of 36 full-terms and near-term infants delivered at Assiut University Children's Hospital and fulfilled HIE criteria were enrolled. They were divided equally into three groups; Group 1 (n = 12) received whole body cooling during first 6 hours of life as a sole therapy; Group 2 (n = 12) received whole body cooling in addition to MS as adjuvant therapy; Group 3 (n = 12) received supportive intensive care measures as a control. TH plus MS group (group 2) had a significantly good short-term outcomes as short period of respiratory support and mechanical ventilation (p-value =0.001), less in incidence of convulsion (p-value = 0.001) and early in feeding initiation (p-value = 0.009), compared with other groups managed by TH (group 1) or by supportive treatment (group 3). In conclusion, whole body cooling in addition to MS as adjunctive therapy for the treatment of HIE neonates is safe therapy that improves short-term outcome both clinically and radiologically.

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Effects of cold exposure and exercise in a wet, cold antarctic climate

Journal of Applied Physiology ◽

10.1152/jappl.1965.20.3.417 ◽

1965 ◽

Vol 20 (3) ◽

pp. 417-422 ◽

Cited By ~ 13

Author(s):

G. M. Budd

Keyword(s):

Physical Fitness ◽

Cold Exposure ◽

Subcutaneous Fat ◽

Whole Body ◽

Finger Temperature ◽

Arterial Blood ◽

Before And After ◽

Tissue Insulation ◽

Body Cooling ◽

Whole Body Cooling

Six men were studied before and after 6 weeks of strenuous outdoor work and cold exposure—often in wet clothing—on Heard Island in the Antarctic. Physical fitness increased significantly, while subcutaneous fat and arterial blood pressure decreased significantly. The response of rectal temperature and shivering to a 2-hr period of whole-body cooling did not change significantly (although shivering tended to decrease), suggesting that the reduction in insulation caused by loss of fat was balanced by an increase in the insulation of other tissues. Finger temperature fell more rapidly, there was less cold vasodilatation, and the gradient of skin temperature between elbow and finger increased significantly, suggesting that heat was conserved by means of countercurrent heat exchanges and enhanced vasoconstriction. Discomfort from cold did not change. These results support those of a previous study at Mawson, Antarctica. Frostbite of one subject's hands, which grossly impaired touch sensation and caused marked intolerance to cold, produced no obvious changes in the response to cold of finger temperature. vasomotor adaptation to cold; cold vasodilatation; tissue insulation; subcutaneous fat; shivering; subjective responses to cold; frostbite sequelae; finger temperature before and after cold injury; physical fitness; acclimatization to cold Submitted on September 8, 1964

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