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Margolis LM, Wilson MA, Drummer DJ, Carrigan CT, Murphy NE, Allen JT, Dawson MA, Mantzoros CS, Young AJ, Pasiakos SM. Pioglitazone does not enhance exogenous glucose oxidation or metabolic clearance rate during aerobic exercise in men under acute high-altitude exposure. Am J Physiol Regul Integr Comp Physiol 2024; 327:R25-R34. [PMID: 38682243 DOI: 10.1152/ajpregu.00064.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/09/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024]
Abstract
Insulin insensitivity decreases exogenous glucose oxidation and metabolic clearance rate (MCR) during aerobic exercise in unacclimatized lowlanders at high altitude (HA). Whether use of an oral insulin sensitizer before acute HA exposure enhances exogenous glucose oxidation is unclear. This study investigated the impact of pioglitazone (PIO) on exogenous glucose oxidation and glucose turnover compared with placebo (PLA) during aerobic exercise at HA. With the use of a randomized crossover design, native lowlanders (n = 7 males, means ± SD, age: 23 ± 6 yr, body mass: 84 ± 11 kg) consumed 145 g (1.8 g/min) of glucose while performing 80 min of steady-state (1.43 ± 0.16 V̇o2 L/min) treadmill exercise at HA (460 mmHg; [Formula: see text] 96.6 mmHg) following short-term (5 days) use of PIO (15 mg oral dose per day) or PLA (microcrystalline cellulose pill). Substrate oxidation and glucose turnover were determined using indirect calorimetry and stable isotopes ([13C]glucose and 6,6-[2H2]glucose). Exogenous glucose oxidation was not different between PIO (0.31 ± 0.03 g/min) and PLA (0.32 ± 0.09 g/min). Total carbohydrate oxidation (PIO: 1.65 ± 0.22 g/min, PLA: 1.68 ± 0.32 g/min) or fat oxidation (PIO: 0.10 ± 0.0.08 g/min, PLA: 0.09 ± 0.07 g/min) was not different between treatments. There was no treatment effect on glucose rate of appearance (PIO: 2.46 ± 0.27, PLA: 2.43 ± 0.27 mg/kg/min), disappearance (PIO: 2.19 ± 0.17, PLA: 2.20 ± 0.22 mg/kg/min), or MCR (PIO: 1.63 ± 0.37, PLA: 1.73 ± 0.40 mL/kg/min). Results from this study indicate that PIO is not an effective intervention to enhance exogenous glucose oxidation or MCR during acute HA exposure. Lack of effect with PIO suggests that the etiology of glucose metabolism dysregulation during acute HA exposure may not result from insulin resistance in peripheral tissues.NEW & NOTEWORTHY Short-term (5 days) use of the oral insulin sensitizer pioglitazone does not alter circulating glucose or insulin responses to enhance exogenous glucose oxidation during steady-state aerobic exercise in young healthy men under simulated acute (8 h) high-altitude (460 mmHg) conditions. These results indicate that dysregulations in glucose metabolism in native lowlanders sojourning at high altitude may not be due to insulin resistance at peripheral tissue.
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Affiliation(s)
- Lee M Margolis
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Marques A Wilson
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Devin J Drummer
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
- Oak Ridge Institute for Science and Education, Belcamp, Maryland, United States
| | - Christopher T Carrigan
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Nancy E Murphy
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Jillian T Allen
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - M Alan Dawson
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Christos S Mantzoros
- Department of Medicine, Beth-Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States
- Department of Medicine, Veterans Affairs Boston Healthcare System, Boston, Massachusetts, United States
| | - Andrew J Young
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
- Oak Ridge Institute for Science and Education, Belcamp, Maryland, United States
| | - Stefan M Pasiakos
- Office of Dietary Supplements, National Institutes of Health, Bethesda, Maryland, United States
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Hillebrandt D, Gurtoo A, Kupper T, Richards P, Schöffl V, Shah P, van der Spek R, Wallis N, Milledge J. UIAA Medical Commission Recommendations for Mountaineers, Hillwalkers, Trekkers, and Rock and Ice Climbers with Diabetes. High Alt Med Biol 2023; 24:110-126. [PMID: 30335516 PMCID: PMC10282971 DOI: 10.1089/ham.2018.0043] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 08/20/2018] [Indexed: 01/01/2023] Open
Abstract
Hillebrandt, David, Anil Gurtoo, Thomas Kupper, Paul Richards, Volker Schöffl, Pankaj Shah, Rianne van der Spek, Nikki Wallis, and Jim Milledge. UIAA Medical Commission recommendations for mountaineers, hillwalkers, trekkers, and rock and ice climbers with diabetes. High Alt Med Biol. 24: 110-126.-The object of this advice article is not only to give the diabetic mountaineer general guidance but also to inform his or her medical team of practical aspects of care that may not be standard for nonmountaineers. The guidelines are produced in seven sections. The first is an introduction to the guidelines, and the second is an introduction to this medical problem and is designed to be read and understood by diabetic patients and their companions. The third section is for use in an emergency in mountains. The fourth is for rock, ice, and competition climbers operating in a less remote environment. These initial sections are deliberately written in simple language. The fifth and sixth sections are written for clinicians and those with skills to read more technical information, and the seventh looks at modern technology and its pros and cons in diabetes management in a remote area. Sections One and Two could be laminated and carried when in the mountains, giving practical advice.
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Affiliation(s)
- David Hillebrandt
- Union Internationale des Associations d'Alpinisme Medical Commission (UIAA MedCom), Bern, Switzerland
- Derriton House, Holsworthy, England
| | - Anil Gurtoo
- Union Internationale des Associations d'Alpinisme Medical Commission (UIAA MedCom), Bern, Switzerland
- Department of Medicine, Lady Hardinge Medical College and Associated SSK Hospital, New Delhi, India
| | - Thomas Kupper
- Union Internationale des Associations d'Alpinisme Medical Commission (UIAA MedCom), Bern, Switzerland
- Institute of Occupational and Social Medicine, RWTH Aachen University, Aachen, Germany
| | - Paul Richards
- Faculty of PreHospital Care, Basildon and Brentwood CCG, Essex, England
| | - Volker Schöffl
- Union Internationale des Associations d'Alpinisme Medical Commission (UIAA MedCom), Bern, Switzerland
- Section Sportsmedicine, Department of Trauma and Orthopedic Surgery, Klinikum Bamberg, Bamberg, Germany
- Department of Trauma Surgery, University of Erlangen-Nuermebrg, Germany
- Section of Wilderness Medicine, Department of Emergency Medicine, University of Colorado School of Medicine, Denver, Colorado
| | - Pankaj Shah
- Division of Endocrinology, Mayo Clinic, Rochester, Minnesota
| | - Rianne van der Spek
- Union Internationale des Associations d'Alpinisme Medical Commission (UIAA MedCom), Bern, Switzerland
- Department of Endocrinology and Metabolism, University of Amsterdam, Academic Medical Center, Amsterdam, The Netherlands
| | - Nikki Wallis
- Emergency Department, Ysbyty Gwynedd, Bangor, Wales
| | - Jim Milledge
- Union Internationale des Associations d'Alpinisme Medical Commission (UIAA MedCom), Bern, Switzerland
- Northwick Park Hospital, Harrow, United Kingdom
- Department of Medicine, Medical Research Council, United Kingdom
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Fullerton ZS, McNair BD, Marcello NA, Schmitt EE, Bruns DR. Exposure to High Altitude Promotes Loss of Muscle Mass That Is Not Rescued by Metformin. High Alt Med Biol 2022; 23:215-222. [PMID: 35653735 PMCID: PMC9526469 DOI: 10.1089/ham.2022.0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/22/2022] [Indexed: 11/12/2022] Open
Abstract
Fullerton, Zackery S., Benjamin D. McNair, Nicholas A. Marcello, Emily E. Schmitt, and Danielle R. Bruns. Exposure to high altitude promotes loss of muscle mass that is not rescued by metformin. High Alt Med Biol. 23:215-222, 2022. Background: Exposure to high altitude (HA) causes muscle atrophy. Few therapeutic interventions attenuate muscle atrophy; however, the diabetic drug, metformin (Met), has been suggested as a potential therapeutic to preserve muscle mass with aging and obesity-related atrophy. The purpose of the present study was to test the hypothesis that HA would induce muscle atrophy that could be attenuated by Met. Methods: C57Bl6 male and female mice were exposed to simulated HA (∼5,200 m) for 4 weeks, while control (Con) mice remained at resident altitude (∼2,180 m). Met was administered in drinking water at 200 mg/(kg·day). We assessed muscle mass, myocyte cell size, muscle and body composition, and expression of molecular mediators of atrophy. Results: Mice exposed to HA were leaner and had a smaller hind limb complex (HLC) mass than Con mice. Loss of HLC mass and myocyte size were not attenuated by Met. Molecular markers for muscle atrophy were activated at HA in a sex-dependent manner. While the atrophic regulator, atrogin, was unchanged at HA or with Met, myostatin expression was upregulated at HA. In female mice, Met further stimulated myostatin expression. Conclusions: Although HA exposure resulted in loss of muscle mass, particularly in male mice, Met did not attenuate muscle atrophy. Identification of other interventions to preserve muscle mass during ascent to HA is warranted.
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Affiliation(s)
- Zackery S. Fullerton
- Division of Kinesiology and Health, University of Wyoming, Laramie, Wyoming, USA
| | - Benjamin D. McNair
- Division of Kinesiology and Health, University of Wyoming, Laramie, Wyoming, USA
| | - Nicholas A. Marcello
- Division of Kinesiology and Health, University of Wyoming, Laramie, Wyoming, USA
| | - Emily E. Schmitt
- Division of Kinesiology and Health, University of Wyoming, Laramie, Wyoming, USA
- Wyoming WWAMI Medical Education, Laramie, Wyoming, USA
| | - Danielle R. Bruns
- Division of Kinesiology and Health, University of Wyoming, Laramie, Wyoming, USA
- Wyoming WWAMI Medical Education, Laramie, Wyoming, USA
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Metformin anticipates peak of lactate during high-intensity interval training but no changes performance or neuromuscular response in amateur swimmers. Clin Nutr ESPEN 2021; 46:305-313. [PMID: 34857212 DOI: 10.1016/j.clnesp.2021.09.739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/14/2021] [Accepted: 09/20/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND & AIMS Metformin demonstrated potential to improve metabolic efficiency in short-intense and prolonged-continuous efforts. The present study investigates the acute effects of metformin intake on performance, rating of perceived exertion (RPE), blood lactate, blood glucose and neuromuscular parameters related to swimming high-intensity interval series. METHODS A double-blind, crossover, randomized and placebo-controlled study was carried out. Seven healthy swimmers ingested metformin (500 mg) or placebo capsules on different days and performed a typical high-intensity training series (10 bouts of 50 m with a 3-min interval). Performance, RPE, neuromuscular parameters (lower and upper limbs), blood lactate and glucose were analyzed by the Wilcoxon Signed-Rank and Friedman's tests between supplementation situations and moments, respectively (p > 0.05), the moment where glucose and blood lactate peak were found were analyzed by a Student t-test (p > 0.05) and a Bayesian repeated-measures ANOVA for effects analysis (BFincl). RESULTS The anticipation of blood glucose and peak lactate was signaling by the interaction effect (metformin increased and placebo decreased) between the eighth and the last bout (BFincl: 4.230 and 5.188 respectively). The second interaction effect of blood glucose and lactate (metformin maintained and placebo increased) during recoveries between 5 min and 7 min (BFincl: 3.825 and 3.806 respectively) also signaling the anticipatory behavior of both physiological parameters. The anticipation of blood lactate peak concentration after metformin intake confirms the anticipatory behavior of blood lactate (p: 0.015). CONCLUSIONS The anticipatory behavior of glucose was not confirmed. Although the anticipatory peak of blood lactate, metformin does not affect neuromuscular responses, RPE and performance. REGISTRATION OF CLINICAL TRIAL RBR-67wxdw8 Effects of metformin during swimmer training performance.
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Bastos-Silva VJ, Marinho AH, Bezerra da Silva JB, de Barros Sousa FA, Learsi S, Balikian P, Gomes de Araujo G. Acute metformin administration increases mean power and the early Power phase during a Wingate test in healthy male subjects. Eur J Sport Sci 2021; 22:1065-1072. [PMID: 34003071 DOI: 10.1080/17461391.2021.1930191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The present study tested the hypothesis that acute metformin would increase peak power measured during a Wingate test. Fourteen men (24 ± 6 years; 75.8 ± 10.2 kg; 177 ± 7 cm) participated in four test sessions, conducted in a crossover, counterbalanced, double-blind model. The first and second sessions consisted of anthropometric measurements and one Wingate test per day to assess test-retest reliability. In the last two sessions, the Wingate tests were performed on metformin (500 mg capsule, 1 hour before) or placebo (cellulose capsule, 1 hour before) condition. No differences were found between the placebo and metformin for peak power (1056.8 ± 215.8 W vs. 1095.2 ± 199.3 W, respectively; p = 0.24). Mean power (630.9 ± 87.8 W vs. 613.1 ± 94.8 W, respectively; p=0.01) and total work (18928 ± 2633 kJ vs. 18393 ± 2845 kJ, respectively; p = 0.01) in the metformin condition were higher than the placebo. The power were greater in metformin when compared to the placebo in moments 3 (p = 0.01), 4 (p = 0.01), 5 (p = 0.04), 6 (p = 0.04), 7 (p = 0.02), 8 (p = 0.03) and 9 (p = 0.01) seconds. There were no differences between conditions for the peak lactate (p = 0.08) and the rating of perceived exertion (p = 0.84). Acute metformin administration increased the early power phase and the mean power of a Wingate test.
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Affiliation(s)
- Victor José Bastos-Silva
- Laboratory of Applied Sports Science, Institute of Physical Education and Sports, PPGCS/PPGNUT, Federal University of Alagoas, Maceió, Brazil.,Maurício de Nassau University Center, Maceió, Brazil
| | - Alisson Henrique Marinho
- Laboratory of Applied Sports Science, Institute of Physical Education and Sports, PPGCS/PPGNUT, Federal University of Alagoas, Maceió, Brazil
| | | | - Filipe Antônio de Barros Sousa
- Laboratory of Applied Sports Science, Institute of Physical Education and Sports, PPGCS/PPGNUT, Federal University of Alagoas, Maceió, Brazil
| | - Sara Learsi
- Laboratory of Applied Sports Science, Institute of Physical Education and Sports, PPGCS/PPGNUT, Federal University of Alagoas, Maceió, Brazil
| | - Pedro Balikian
- Laboratory of Applied Sports Science, Institute of Physical Education and Sports, PPGCS/PPGNUT, Federal University of Alagoas, Maceió, Brazil
| | - Gustavo Gomes de Araujo
- Laboratory of Applied Sports Science, Institute of Physical Education and Sports, PPGCS/PPGNUT, Federal University of Alagoas, Maceió, Brazil
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de Araujo GG, Learsi S, Bastos-Silva VJ, Ataide T, Lima-Silva AE. Chronic metformin intake improves anaerobic but not aerobic capacity in healthy rats. Can J Physiol Pharmacol 2020; 98:23-28. [DOI: 10.1139/cjpp-2019-0459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of chronic metformin intake on aerobic and anaerobic capacity was examined in healthy rats. Twenty rats completed 10 days of metformin (MET) ingestion (250 mg). After this period, the animals performed four high-intensity bouts until exhaustion at 9%, 11%, 13%, and 15% of body mass (BM) in swimming, separated by 24 h, with prior metformin (250 mg) or placebo (PL). The critical load (CL) and anaerobic work capacity (AWC – W′) were calculated and considered aerobic and anaerobic capacity, respectively. There was no difference in CL between the MET and PL groups (p > 0.05). The AWC – W′ was higher in the MET group than in the PL group (p = 0.004). Time until exhaustion (seconds) at all bouts were higher (p < 0.004) in the MET group (9% of BM = 434.5 ± 267.3, 11% of BM = 269.6 ± 214.2, 13% of BM = 174.0 ± 40.9, 15% of BM = 146.6 ± 15.9) compared to the PL group (9% of BM = 96.4 ± 22.3, 11% of BM = 65.5 ± 13.4, 13% of BM = 51.1 ± 5.5, 15% of BM = 40.8 ± 7.5). Glucose concentration was higher at 90 and 120 min than at 0 and 30 min for the MET group (intragroup) during the oral glucose test tolerance; there was no difference between the MET and PL groups for area under curve. MET ingestion enhances AWC – W′ and times to exhaustion but not aerobic capacity.
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Affiliation(s)
- Gustavo Gomes de Araujo
- Applied Sport Science Research Group and Experimental Nutrition Laboratory, Federal University of Alagoas (PPGNUT/PPGCS), Avenue Lourival Melo Mota, s/n, University City, Maceio 57072-900, Brazil
| | - Sara Learsi
- Applied Sport Science Research Group and Experimental Nutrition Laboratory, Federal University of Alagoas (PPGNUT/PPGCS), Avenue Lourival Melo Mota, s/n, University City, Maceio 57072-900, Brazil
| | - Victor José Bastos-Silva
- Applied Sport Science Research Group and Experimental Nutrition Laboratory, Federal University of Alagoas (PPGNUT/PPGCS), Avenue Lourival Melo Mota, s/n, University City, Maceio 57072-900, Brazil
| | - Terezinha Ataide
- Applied Sport Science Research Group and Experimental Nutrition Laboratory, Federal University of Alagoas (PPGNUT/PPGCS), Avenue Lourival Melo Mota, s/n, University City, Maceio 57072-900, Brazil
| | - Adriano Eduardo Lima-Silva
- The Human Performance Research Group, Technological Federal University of Parana, Pedro Gusso Street 2601, Neoville, Parana 81310900, Brazil
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Newman AA, Grimm NC, Wilburn JR, Schoenberg HM, Trikha SRJ, Luckasen GJ, Biela LM, Melby CL, Bell C. Influence of Sodium Glucose Cotransporter 2 Inhibition on Physiological Adaptation to Endurance Exercise Training. J Clin Endocrinol Metab 2019; 104:1953-1966. [PMID: 30597042 DOI: 10.1210/jc.2018-01741] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022]
Abstract
CONTEXT The combination of two beneficial antidiabetes interventions, regular exercise and pharmaceuticals, is intuitively appealing. However, metformin, the most commonly prescribed diabetes medication, attenuates the favorable physiological adaptations to exercise; in turn, exercise may impede the action of metformin. OBJECTIVE We sought to determine the influence of an alternative diabetes treatment, sodium glucose cotransporter 2 (SGLT2) inhibition, on the response to endurance exercise training. DESIGN, PARTICIPANTS, AND INTERVENTION In a randomized, double-blind, repeated measures parallel design, 30 sedentary overweight and obese men and women were assigned to 12 weeks of supervised endurance exercise training, with daily ingestion of either a placebo or SGLT2 inhibitor (dapagliflozin: ≤10 mg/day). OUTCOME MEASUREMENTS AND RESULTS Endurance exercise training favorably modified body mass, body composition (dual-energy x-ray absorptiometry), peak oxygen uptake (graded exercise with indirect calorimetry), responses to standardized submaximal exercise (indirect calorimetry, heart rate, and blood lactate), and skeletal muscle (vastus lateralis) citrate synthase activity (main effects of exercise training, all P < 0.05); SGLT2 inhibition did not influence any of these physiological adaptations (exercise training × treatment interaction, all P > 0.05). However, after endurance exercise training, fasting blood glucose was greater with SGLT2 inhibition, and increased insulin sensitivity (oral glucose tolerance test/Matsuda index) was abrogated with SGLT2 inhibition (exercise training × treatment interaction, P < 0.01). CONCLUSION The efficacy of combining two beneficial antidiabetes interventions, regular endurance exercise and SGLT2 inhibition, was not supported. SGLT2 inhibition blunted endurance exercise training-induced improvements in insulin sensitivity, independent of effects on aerobic fitness or body composition.
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Affiliation(s)
- Alissa A Newman
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Nathan C Grimm
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Jessie R Wilburn
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Hayden M Schoenberg
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - S Raj J Trikha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, Colorado
| | - Laurie M Biela
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Christopher L Melby
- Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, Colorado
| | - Christopher Bell
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
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Burtscher M. Metformin for high-altitude performance? Clin Exp Pharmacol Physiol 2017; 44:903. [PMID: 28500767 DOI: 10.1111/1440-1681.12782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Accepted: 05/04/2017] [Indexed: 11/28/2022]
Abstract
Metformin has been introduced for treatment of type 2 diabetes but may also have ergogenic properties at high altitude by improving muscle glycogen repletion. However, very little information is available on potential risks associated with the (mis)use of metformin by healthy people.
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