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Abstract
We analyzed data from previously completed trials to determine the effects of supplemental guanidinoacetic acid (GAA) on markers of muscle bioenergetics in healthy men using 1.5 T magnetic resonance spectroscopy. No detectable GAA (<0.1 μmol/L) was found in the vastus medialis muscle at baseline nor at follow-up. This implies deficient GAA availability in the human skeletal muscle, suggesting absent or negligible potential for creatine synthesis from GAA inside this tissue, even after GAA loading.
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Affiliation(s)
- Sergej M Ostojic
- a Applied Bioenergetics Laboratory, Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad 21000, Serbia.,b University of Belgrade School of Medicine, 11000 Belgrade, Serbia
| | - Jelena Ostojic
- c Faculty of Health Sciences, University of Southern Denmark, 5000 Odense, Denmark
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Banks L, Wells GD, Clarizia NA, Jean-St-Michel E, McKillop AL, Redington AN, McCrindle BW. Short-term remote ischemic preconditioning is not associated with improved blood pressure and exercise capacity in young adults. Appl Physiol Nutr Metab 2016; 41:903-6. [PMID: 27439445 DOI: 10.1139/apnm-2016-0024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We sought to determine whether a 9-day remote ischemic preconditioning (IPC) causes improvements in exercise performance, energetics, and blood pressure. Ten participants (mean age 24 ± 4 years) had no changes in aerobic capacity (preintervention: 38 ± 10 mL/(kg·min)(-1) vs. postintervention: 38 ± 10 mL/(kg·min)(-1)), blood pressure (preintervention: 112 ± 7/66 ± 6 mm Hg vs. postintervention: 112 ± 10/62 ± 5 mm Hg), cardiac phosphocreatinine-to-adenosine-triphosphate ratio (preintervention: 2.1 ± 0.5 vs. postintervention: 2.3 ± 0.4), and postexercise skeletal muscle phosphocreatine recovery (preintervention: 34 ± 11 s vs. postintervention: 31 ± 11 s). Short-term remote IPC may be ineffective in improving these outcomes.
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Affiliation(s)
- Laura Banks
- a Labatt Family Heart Centre, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Greg D Wells
- b Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada.,d Physiology and Experimental Medicine, the Hospital for Sick Children, Toronto, ON, Canada
| | - Nadia A Clarizia
- a Labatt Family Heart Centre, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Emilie Jean-St-Michel
- a Labatt Family Heart Centre, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Adam L McKillop
- a Labatt Family Heart Centre, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Andrew N Redington
- a Labatt Family Heart Centre, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada.,c Department of Pediatrics, University of Toronto, Toronto, ON, Canada
| | - Brian W McCrindle
- a Labatt Family Heart Centre, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada.,c Department of Pediatrics, University of Toronto, Toronto, ON, Canada
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Ipavec-Levasseur S, Croci I, Choquette S, Byrne NM, Cowin G, O'Moore-Sullivan TM, Prins JB, Hickman IJ. Effect of 1-h moderate-intensity aerobic exercise on intramyocellular lipids in obese men before and after a lifestyle intervention. Appl Physiol Nutr Metab 2015; 40:1262-8. [PMID: 26575100 DOI: 10.1139/apnm-2015-0258] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intramyocellular lipids (IMCL) are depleted in response to an acute bout of exercise in lean endurance-trained individuals; however, it is unclear whether changes in IMCL content are also seen in response to acute and chronic exercise in obese individuals. We used magnetic resonance spectroscopy in 18 obese men and 5 normal-weight controls to assess IMCL content before and after an hour of cycling at the intensity corresponding with each participant's maximal whole-body rate of fat oxidation (Fatmax). Fatmax was determined via indirect calorimetry during a graded exercise test on a cycle ergometer. The same outcome measures were reassessed in the obese group after a 16-week lifestyle intervention comprising dietary calorie restriction and exercise training. At baseline, IMCL content decreased in response to 1 h of cycling at Fatmax in controls (2.8 ± 0.4 to 2.0 ± 0.3 A.U., -39%, p = 0.02), but not in obese (5.4 ± 2.1 vs. 5.2 ± 2.2 A.U., p = 0.42). The lifestyle intervention lead to weight loss (-10.0 ± 5.4 kg, p < 0.001), improvements in maximal aerobic power (+5.2 ± 3.4 mL/(kg·min)), maximal fat oxidation rate (+0.19 ± 0.22 g/min), and a 29% decrease in homeostasis model assessment score (all p < 0.05). However, when the 1 h of cycling at Fatmax was repeated after the lifestyle intervention, there remained no observable change in IMCL (4.6 ± 1.8 vs. 4.6 ± 1.9 A.U., p = 0.92). In summary, there was no IMCL depletion in response to 1 h of cycling at moderate intensity either before or after the lifestyle intervention in obese men. An effective lifestyle intervention including moderate-intensity exercise training did not impact rate of utilisation of IMCL during acute exercise in obese men.
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Affiliation(s)
| | - Ilaria Croci
- a The University of Queensland Diamantina Institute, Brisbane, Australia.,b School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia.,c Mater Research Institute, University of Queensland, Brisbane, Australia
| | - Stéphane Choquette
- d Faculty of Physical Education and Sports, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Nuala M Byrne
- e Bond Institute of Health and Sport, Bond University, Robina, Australia.,f Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Gary Cowin
- g Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
| | - Trisha M O'Moore-Sullivan
- c Mater Research Institute, University of Queensland, Brisbane, Australia.,h Department of Diabetes and Endocrinology, Princess Alexandra Hospital, Brisbane, Australia
| | - Johannes B Prins
- c Mater Research Institute, University of Queensland, Brisbane, Australia
| | - Ingrid J Hickman
- a The University of Queensland Diamantina Institute, Brisbane, Australia.,c Mater Research Institute, University of Queensland, Brisbane, Australia
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