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Mora-Rodriguez R, Ortega JF, Morales-Palomo F, Ramirez-Jimenez M. Weight loss but not gains in cardiorespiratory fitness after exercise-training predicts improved health risk factors in metabolic syndrome. Nutr Metab Cardiovasc Dis 2018; 28:1267-1274. [PMID: 30459053 DOI: 10.1016/j.numecd.2018.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 07/19/2018] [Accepted: 08/16/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS To examine the relationship between changes in cardiorespiratory fitness (CRF; estimated by VO2max) and metabolic syndrome (MetS) after an exercise training intervention to confirm/contradict the high association found in cross-sectional observational studies. METHODS AND RESULTS MetS individuals (54 ± 8 yrs old; BMI of 32 ± 5) were randomly allocated (6:1 ratio) to a group that exercised trained for 16-weeks (EXER; n = 138) or a control sedentary group (CONT; n = 22). At baseline, MetS components, body composition and exercise responses were similar between groups (all P > 0.05). After 16 weeks of intervention, only EXER reduced body weight, waist circumference (-1.21 ± 0.22 kg and -2.7 ± 0.3 cm; P < 0.001), mean arterial blood pressure and hence the composite MetS Z-score (-7.06 ± 0.77 mmHg and -0.21 ± 0.03 SD; P < 0.001). In the EXER group, CRF increased by 16% (0.302 ± 0.026, 95% CI 0.346 to 0.259 LO2·min-1; P < 0.001) but was not a significant predictor of MetS Z-score improvements (r = -0.231; β = -0.024; P = 0.788). Instead, body weight reductions predicted 25% of MetS Z-score changes (r = 0.508; β = 0.360; P = 0.001). CONCLUSIONS In MetS individuals, the exercise-training increases in CRF are not predictive of the improvements in their health risk factors. Instead, body weight loss (<2%) was a significant contributor to the improved MetS Z-score and thus should be emphasized in exercise training programs. ClinicalTrials.gov identifier: NCT03019796.
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Affiliation(s)
- R Mora-Rodriguez
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Spain.
| | - J F Ortega
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Spain
| | - F Morales-Palomo
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Spain
| | - M Ramirez-Jimenez
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Spain
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Ramirez-Jimenez M, Morales-Palomo F, Ortega JF, Mora-Rodriguez R. Effects of intense aerobic exercise and/or antihypertensive medication in individuals with metabolic syndrome. Scand J Med Sci Sports 2018; 28:2042-2051. [PMID: 29771450 DOI: 10.1111/sms.13218] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2018] [Indexed: 11/29/2022]
Abstract
We studied the blood pressure lowering effects of a bout of exercise and/or antihypertensive medicine with the goal of studying if exercise could substitute or enhance pharmacologic hypertension treatment. Twenty-three hypertensive metabolic syndrome patients chronically medicated with angiotensin II receptor 1 blockade antihypertensive medicine underwent 24-hr monitoring in four separated days in a randomized order; (a) after taking their habitual dose of antihypertensive medicine (AHM trial), (b) substituting their medicine by placebo medicine (PLAC trial), (c) placebo medicine with a morning bout of intense aerobic exercise (PLAC+EXER trial) and (d) combining the exercise and antihypertensive medicine (AHM+EXER trial). We found that in trials with AHM subjects had lower plasma aldosterone/renin activity ratio evidencing treatment compliance. Before exercise, the trials with AHM displayed lower systolic (130 ± 16 vs 133 ± 15 mm Hg; P = .018) and mean blood pressures (94 ± 11 vs 96 ± 10 mm Hg; P = .036) than trials with placebo medication. Acutely (ie, 30 min after treatments) combining AHM+EXER lowered systolic blood pressure (SBP) below the effects of PLAC+EXER (-8.1 ± 1.6 vs -4.9 ± 1.5 mm Hg; P = .015). Twenty-four hour monitoring revealed no differences among trials in body motion. However, PLAC+EXER and AHM lowered SBP below PLAC during the first 10 hours, time at which PLAC+EXER effects faded out (ie, at 19 PM). Adding exercise to medication (ie, AHM+EXER) resulted in longer reductions in SBP than with exercise alone (PLAC+EXER). In summary, one bout of intense aerobic exercise in the morning cannot substitute the long-lasting effects of antihypertensive medicine in lowering blood pressure, but their combination is superior to exercise alone.
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Affiliation(s)
- M Ramirez-Jimenez
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
| | - F Morales-Palomo
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
| | - J F Ortega
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
| | - R Mora-Rodriguez
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
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Guadalupe-Grau A, Fernández-Elías VE, Ortega JF, Dela F, Helge JW, Mora-Rodriguez R. Effects of 6-month aerobic interval training on skeletal muscle metabolism in middle-aged metabolic syndrome patients. Scand J Med Sci Sports 2017; 28:585-595. [DOI: 10.1111/sms.12881] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2017] [Indexed: 12/20/2022]
Affiliation(s)
- A. Guadalupe-Grau
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
- ImFINE Research Group; Department of Health and Human Performance; Technical University of Madrid; Madrid Spain
| | - V. E. Fernández-Elías
- Exercise Physiology Laboratory at Toledo; University of Castilla-La Mancha; Toledo Spain
- Department of Sport Science; European University of Madrid; Madrid Spain
| | - J. F. Ortega
- Exercise Physiology Laboratory at Toledo; University of Castilla-La Mancha; Toledo Spain
| | - F. Dela
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - J. W. Helge
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - R. Mora-Rodriguez
- Exercise Physiology Laboratory at Toledo; University of Castilla-La Mancha; Toledo Spain
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Mora-Rodriguez R, Ortega JF, Guio de Prada V, Fernández-Elías VE, Hamouti N, Morales-Palomo F, Martinez-Vizcaino V, Nelson RK. Effects of Simultaneous or Sequential Weight Loss Diet and Aerobic Interval Training on Metabolic Syndrome. Int J Sports Med 2015; 37:274-81. [PMID: 26667921 DOI: 10.1055/s-0035-1564259] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Our purpose in this study was to investigate efficient and sustainable combinations of exercise and diet-induced weight loss (DIET), in order to combat obesity in metabolic syndrome (MetS) patients. We examined the impact of aerobic interval training (AIT), followed by or concurrent to a DIET on MetS components. 36 MetS patients (54±9 years old; 33±4 BMI; 27 males and 9 females) underwent 16 weeks of AIT followed by another 16 weeks without exercise from the fall of 2013 to the spring of 2014. Participants were randomized to AIT without DIET (E CON, n=12), AIT followed by DIET (E-then-D, n=12) or AIT concurrent with DIET (E+D, n=12) groups. Body weight decreased below E CON similarly in the E-then-D and E+D groups (~5%). Training improved blood pressure and cardiorespiratory fitness (VO2peak) in all groups with no additional effect of concurrent weight loss. However, E+D improved insulin sensitivity (HOMA) and lowered plasma triglycerides and blood cholesterol below E CON and E-then-D (all P<0.05). Weight loss in E-then-D in the 16 weeks without exercise lowered HOMA to the E+D levels and maintained blood pressure at trained levels. Our data suggest that a new lifestyle combination consisting of aerobic interval training followed by weight loss diet is similar, or even more effective on improving metabolic syndrome factors than concurrent exercise plus diet.
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Affiliation(s)
- R Mora-Rodriguez
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - J F Ortega
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | | | - V E Fernández-Elías
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - N Hamouti
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - F Morales-Palomo
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - V Martinez-Vizcaino
- Health and Social Research Center, Universidad de Castilla-La Mancha, Cuenca, Spain
| | - R K Nelson
- College of Health Professions, Central Michigan University, Mt Pleasant, United States
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Ortega JF, Fernández-Elías VE, Hamouti N, Pallares JG, Mora-Rodriguez R. Higher Insulin-sensitizing Response after Sprint Interval Compared to Continuous Exercise. Int J Sports Med 2015; 36:e4. [PMID: 25811624 DOI: 10.1055/s-0035-1548800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- J F Ortega
- Sport Sciences, Universidad de Castilla-La Mancha, Toledo, Spain
| | - V E Fernández-Elías
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - N Hamouti
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - J G Pallares
- Physical Education, Murcia, Univeristy of Murcia, Spain
| | - R Mora-Rodriguez
- Sport Sciences, Universidad de Castilla-La Mancha, Toledo, Spain
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Ortega JF, Fernández-Elías VE, Hamouti N, Pallarés JG, Mora-Rodriguez R. Higher insulin-sensitizing response after sprint interval compared to continuous exercise. Int J Sports Med 2014; 36:209-14. [PMID: 25376729 DOI: 10.1055/s-0034-1389942] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
This study investigated which exercise mode (continuous or sprint interval) is more effective for improving insulin sensitivity. Ten young, healthy men underwent a non-exercise trial (CON) and 3 exercise trials in a cross-over, randomized design that included 1 sprint interval exercise trial (SIE; 4 all-out 30-s sprints) and 2 continuous exercise trials at 46% VO2peak (CELOW) and 77% VO2peak (CEHIGH). Insulin sensitivity was assessed using intravenous glucose tolerance test (IVGTT) 30 min, 24 h and 48 h post-exercise. Energy expenditure was measured during exercise. Glycogen in vastus lateralis was measured once in a resting condition (CON) and immediately post-exercise in all trials. Plasma lipids were measured before each IVGTT. Only after CEHIGH did muscle glycogen concentration fall below CON (P<0.01). All exercise treatments improved insulin sensitivity compared with CON, and this effect persisted for 48-h. However, 30-min post-exercise, insulin sensitivity was higher in SIE than in CELOW and CEHIGH (11.5±4.6, 8.6±5.4, and 8.1±2.9 respectively; P<0.05). Insulin sensitivity did not correlate with energy expenditure, glycogen content, or plasma fatty acids concentration (P>0.05). After a single exercise bout, SIE acutely improves insulin sensitivity above continuous exercise. The higher post-exercise hyperinsulinemia and the inhibition of lipolysis could be behind the marked insulin sensitivity improvement after SIE.
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Affiliation(s)
- J F Ortega
- Sport Sciences, Universidad de Castilla-La Mancha, Toledo, Spain
| | - V E Fernández-Elías
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - N Hamouti
- Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain
| | - J G Pallarés
- Physical Education, Murcia, Univeristy of Murcia, Spain
| | - R Mora-Rodriguez
- Sport Sciences, Universidad de Castilla-La Mancha, Toledo, Spain
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Mora-Rodriguez R, Ortega JF, Hamouti N, Fernandez-Elias VE, Cañete Garcia-Prieto J, Guadalupe-Grau A, Saborido A, Martin-Garcia M, Guio de Prada V, Ara I, Martinez-Vizcaino V. Time-course effects of aerobic interval training and detraining in patients with metabolic syndrome. Nutr Metab Cardiovasc Dis 2014; 24:792-798. [PMID: 24656853 DOI: 10.1016/j.numecd.2014.01.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 12/20/2013] [Accepted: 01/07/2014] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND AIMS Exercise training can improve health of patients with metabolic syndrome (MetS). However, which MetS factors are most responsive to exercise training remains unclear. We studied the time-course of changes in MetS factors in response to training and detraining. METHODS AND RESULTS Forty eight MetS patients (52 ± 8.8 yrs old; 33 ± 4 BMI) underwent 4 months (3 days/week) of supervised aerobic interval training (AIT) program. After 1 month of training, there were progressive increases in high density lipoprotein cholesterol (HDL-c) and reductions in waist circumference and blood pressure (12 ± 3, -3.9 ± 0.4, and -12 ± 1%, respectively after 4 months; all P < 0.05). However, fasting plasma concentration of triglycerides and glucose were not reduced by training. Insulin sensitivity (HOMA), cardiorespiratory fitness (VO2peak) and exercise maximal fat oxidation (FOMAx) also progressively improved with training (-17 ± 5; 21 ± 2 and 31 ± 8%, respectively, after 4 months; all P < 0.05). Vastus lateralis samples from seven subjects revealed that mitochondrial O2 flux was markedly increased with training (71 ± 11%) due to increased mitochondrial content. After 1 month of detraining, the training-induced improvements in waist circumference and blood pressure were maintained. HDL-c and VO2peak returned to the values found after 1-2 months of training while HOMA and FOMAx returned to pre-training values. CONCLUSIONS The health related variables most responsive to aerobic interval training in MetS patients are waist circumference, blood pressure and the muscle and systemic adaptations to consume oxygen and fat. However, the latter reverse with detraining while blood pressure and waist circumference are persistent to one month of detraining.
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Affiliation(s)
- R Mora-Rodriguez
- Exercise Physiology Laboratory and GENUD Group University of Castilla-La Mancha, Toledo, Spain.
| | - J F Ortega
- Exercise Physiology Laboratory and GENUD Group University of Castilla-La Mancha, Toledo, Spain
| | - N Hamouti
- Exercise Physiology Laboratory and GENUD Group University of Castilla-La Mancha, Toledo, Spain
| | - V E Fernandez-Elias
- Exercise Physiology Laboratory and GENUD Group University of Castilla-La Mancha, Toledo, Spain
| | | | - A Guadalupe-Grau
- Xlab, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - A Saborido
- Departamento de Bioquímica y Biología Molecular I, University Complutense, Madrid, Spain
| | - M Martin-Garcia
- Exercise Physiology Laboratory and GENUD Group University of Castilla-La Mancha, Toledo, Spain
| | | | - I Ara
- Exercise Physiology Laboratory and GENUD Group University of Castilla-La Mancha, Toledo, Spain
| | - V Martinez-Vizcaino
- Social and Health Care Research Center, University of Castilla-La-Mancha, Cuenca, Spain
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Hamouti N, Fernández-Elías VE, Ortega JF, Mora-Rodriguez R. Ingestion of sodium plus water improves cardiovascular function and performance during dehydrating cycling in the heat. Scand J Med Sci Sports 2012; 24:507-18. [PMID: 23253191 DOI: 10.1111/sms.12028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2012] [Indexed: 11/28/2022]
Affiliation(s)
- N. Hamouti
- Exercise Physiology Laboratory; University of Castilla-La Mancha; Toledo Spain
| | | | - J. F. Ortega
- Exercise Physiology Laboratory; University of Castilla-La Mancha; Toledo Spain
| | - R. Mora-Rodriguez
- Exercise Physiology Laboratory; University of Castilla-La Mancha; Toledo Spain
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Mora-Rodriguez R, Hodgkinson BJ, Byerley LO, Coyle EF. Effects of beta-adrenergic receptor stimulation and blockade on substrate metabolism during submaximal exercise. Am J Physiol Endocrinol Metab 2001; 280:E752-60. [PMID: 11287358 DOI: 10.1152/ajpendo.2001.280.5.e752] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We used beta-adrenergic receptor stimulation and blockade as a tool to study substrate metabolism during exercise. Eight moderately trained subjects cycled for 60 min at 45% of VO(2 peak) 1) during a control trial (CON); 2) while epinephrine was intravenously infused at 0.015 microg. kg(-1) x min(-1) (beta-STIM); 3) after ingesting 80 mg of propranolol (beta-BLOCK); and 4) combining beta-BLOCK with intravenous infusion of Intralipid-heparin to restore plasma fatty acid (FFA) levels (beta-BLOCK+LIPID). beta-BLOCK suppressed lipolysis (i.e., glycerol rate of appearance) and fat oxidation while elevating carbohydrate oxidation above CON (135 +/- 11 vs. 113 +/- 10 micromol x kg(-1) x min(-1); P < 0.05) primarily by increasing rate of disappearance (R(d)) of glucose (36 +/- 2 vs. 22 +/- 2 micromol x kg(-1) x min(-1); P < 0.05). Plasma FFA restoration (beta-BLOCK+LIPID) attenuated the increase in R(d) glucose by more than one-half (28 +/- 3 micromol x kg(-1) x min(-1); P < 0.05), suggesting that part of the compensatory increase in muscle glucose uptake is due to reduced energy from fatty acids. On the other hand, beta-STIM markedly increased glycogen oxidation and reduced glucose clearance and fat oxidation despite elevating plasma FFA. Therefore, reduced plasma FFA availability with beta-BLOCK increased R(d) glucose, whereas beta-STIM increased glycogen oxidation, which reduced fat oxidation and glucose clearance. In summary, compared with control exercise at 45% VO(2 peak) (CON), both beta-BLOCK and beta-STIM reduced fat and increased carbohydrate oxidation, albeit through different mechanisms.
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Affiliation(s)
- R Mora-Rodriguez
- The Human Performance Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas 78712, USA
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Abstract
This study determined the effects of elevated plasma epinephrine on fat metabolism during exercise. On four occasions, seven moderately trained subjects cycled at 25% of peak oxygen consumption (VO(2 peak)) for 60 min. After 15 min of exercise, subjects were intravenously infused with low (0.96 +/- 0.10 nM), moderate (1.92 +/- 0.24 nM), or high (3.44 +/- 0.50 nM) levels (all P < 0.05) of epinephrine to increase plasma epinephrine above control (Con; 0.59 +/- 0.10 nM). During the interval between 35 and 55 min of exercise, lipolysis [i.e., rate of appearance of glycerol] increased above Con (4.9 +/- 0.5 micromol. kg(-1). min(-1)) with low, moderate, and high (6.5 +/- 0.5, 7.1 +/- 0.8, and 10.6 +/- 1.2 micromol. kg(-1). min(-1), respectively; all P < 0.05) levels of epinephrine despite simultaneous increases in plasma insulin. The release of fatty acid into plasma also increased progressively with the graded epinephrine infusions. However, fatty acid oxidation was lower than Con (11.1 +/- 0.8 micromol. kg(-1). min(-1)) during moderate and high levels (8.7 +/- 0.7 and 8.1 +/- 0.9 micromol. kg(-1). min(-1), respectively; P < 0.05). In one additional trial, the same subjects exercised at 45% VO(2 peak) without epinephrine infusion, which produced a plasma epinephrine concentration identical to low levels. However, lipolysis was lower (i.e., 5.5 +/- 0.6 vs. 6.5 +/- 0.5 micromol. kg(-1). min(-1); P < 0.05). In conclusion, elevations in plasma epinephrine concentration during exercise at 25% of VO(2 peak) progressively increase whole body lipolysis but decrease fatty acid oxidation. Last, increasing exercise intensity from 25 to 45% VO(2 peak) attenuates the lipolytic actions of epinephrine.
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Horowitz JF, Mora-Rodriguez R, Byerley LO, Coyle EF. Preexercise medium-chain triglyceride ingestion does not alter muscle glycogen use during exercise. J Appl Physiol (1985) 2000; 88:219-25. [PMID: 10642384 DOI: 10.1152/jappl.2000.88.1.219] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This investigation determined whether ingestion of a tolerable amount of medium-chain triglycerides (MCT; approximately 25 g) reduces the rate of muscle glycogen use during high-intensity exercise. On two occasions, seven well-trained men cycled for 30 min at 84% maximal O(2) uptake. Exactly 1 h before exercise, they ingested either 1) carbohydrate (CHO; 0.72 g sucrose/kg) or 2) MCT+CHO [0.36 g tricaprin (C10:0)/kg plus 0.72 g sucrose/kg]. The change in glycogen concentration was measured in biopsies taken from the vastus lateralis before and after exercise. Additionally, glycogen oxidation was calculated as the difference between total carbohydrate oxidation and the rate of glucose disappearance from plasma (R(d) glucose), as measured by stable isotope dilution techniques. The change in muscle glycogen concentration was not different during MCT+CHO and CHO (42.0 +/- 4.6 vs. 38.8 +/- 4.0 micromol glucosyl units/g wet wt). Furthermore, calculated glycogen oxidation was also similar (331 +/- 18 vs. 329 +/- 15 micromol. kg(-1). min(-1)). The coingestion of MCT+CHO did increase (P < 0.05) R(d) glucose at rest compared with CHO (26.9 +/- 1.5 vs. 20.7 +/- 0. 7 micromol.kg(-1). min(-1)), yet during exercise R(d) glucose was not different during the two trials. Therefore, the addition of a small amount of MCT to a preexercise CHO meal did not reduce muscle glycogen oxidation during high-intensity exercise, but it did increase glucose uptake at rest.
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Affiliation(s)
- J F Horowitz
- Department of Kinesiology and Health Education, The Human Performance Laboratory, The University of Texas at Austin, Austin, Texas 78712, USA
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Abstract
This study determined the effect of carbohydrate ingestion during exercise on the lipolytic rate, glucose disappearance from plasma (Rd Glc), and fat oxidation. Six moderately trained men cycled for 2 h on four separate occasions. During two trials, they were fed a high-glycemic carbohydrate meal during exercise at 30 min (0.8 g/kg), 60 min (0.4 g/kg), and 90 min (0.4 g/kg); once during low-intensity exercise [25% peak oxygen consumption (VO2 peak)] and once during moderate-intensity exercise (68% VO2 peak). During two additional trials, the subjects remained fasted (12-14 h) throughout exercise at each intensity. After 55 min of low-intensity exercise in fed subjects, hyperglycemia (30% increase) and a threefold elevation in plasma insulin concentration (P < 0.05) were associated with a 22% suppression of lipolysis compared with when subjects were fasted (5.2 +/- 0.5 vs. 6.7 +/- 1.2 micromol. kg-1. min-1, P < 0.05), but fat oxidation was not different from fasted levels at this time. Fat oxidation when subjects were fed carbohydrate was not reduced below fasting levels until 80-90 min of exercise, and lipolysis was in excess of fat oxidation at this time. The reduction in fat oxidation corresponded in time with the increase in Rd Glc. During moderate-intensity exercise, the very small elevation in plasma insulin concentration (approximately 3 microU/ml; P < 0.05) during the second hour of exercise when subjects were fed vs. when they were fasted slightly attenuated lipolysis (P < 0.05) but did not increase Rd Glc or suppress fat oxidation. These findings indicate that despite a suppression of lipolysis after carbohydrate ingestion during exercise, the lipolytic rate remained in excess and thus did not limit fat oxidation. Under these conditions, a reduction in fat oxidation was associated in time with an increase in glucose uptake.
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Affiliation(s)
- J F Horowitz
- The Human Performance Laboratory, Department of Kinesiology and Health Education and Division of Nutritional Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
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Horowitz JF, Mora-Rodriguez R, Byerley LO, Coyle EF. Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise. Am J Physiol 1997; 273:E768-75. [PMID: 9357807 DOI: 10.1152/ajpendo.1997.273.4.e768] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study determined if the suppression of lipolysis after preexercise carbohydrate ingestion reduces fat oxidation during exercise. Six healthy, active men cycled 60 min at 44 +/- 2% peak oxygen consumption, exactly 1 h after ingesting 0.8 g/kg of glucose (Glc) or fructose (Fru) or after an overnight fast (Fast). The mean plasma insulin concentration during the 50 min before exercise was different among Fast, Fru, and Glc (8 +/- 1, 17 +/- 1, and 38 +/- 5 microU/ml, respectively; P < 0.05). After 25 min of exercise, whole body lipolysis was 6.9 +/- 0.2, 4.3 +/- 0.3, and 3.2 +/- 0.5 micromol x kg(-1) x min(-1) and fat oxidation was 6.1 +/- 0.2, 4.2 +/- 0.5, and 3.1 +/- 0.3 micromol x kg(-1) x min(-1) during Fast, Fru, and Glc, respectively (all P < 0.05). During Fast, fat oxidation was less than lipolysis (P < 0.05), whereas fat oxidation approximately equaled lipolysis during Fru and Glc. In an additional trial, the same subjects ingested glucose (0.8 g/kg) 1 h before exercise and lipolysis was simultaneously increased by infusing Intralipid and heparin throughout the resting and exercise periods (Glc+Lipid). This elevation of lipolysis during Glc+Lipid increased fat oxidation 30% above Glc (4.0 +/- 0.4 vs. 3.1 +/- 0.3 micromol x kg(-1) x min(-1); P < 0.05), confirming that lipolysis limited fat oxidation. In summary, small elevations in plasma insulin before exercise suppressed lipolysis during exercise to the point at which it equaled and appeared to limit fat oxidation.
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Affiliation(s)
- J F Horowitz
- Department of Kinesiology and Health Education, The University of Texas at Austin, 78712, USA
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Horowitz JF, Mora-Rodriguez R, Coyle EF. THE EFFECT OF PRE-EXERCISE MEDIUM-CHAIN TRIGLYCERIDE INGESTION ON MUSCLE GLYCOGEN UTILIZATION DURING HIGH INTENSITY EXERCISE. Med Sci Sports Exerc 1995. [DOI: 10.1249/00005768-199505001-01137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mora-Rodriguez R, Gonz??lez-Alonso J, Below PR, Coyle EF. 19 CORE TEMPERATURE AND SKIN BLOOD FLOW RESPOND TO CHANGES IN PLASMA CATECHOLAMINES DURING PROLONGED EXERCISE. Med Sci Sports Exerc 1994. [DOI: 10.1249/00005768-199405001-00020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Gonz??lez-Alonso J, Mora-Rodriguez R, Below PR, Coyle EF. 917 REDUCTIONS IN CARDIAC OUTPUT, MEAN BLOOD PRESSURE AND SKIN VASCULAR CONDUCTANCE WITH DEHYDRATION ARE REVERSED WHEN VENOUS RETURN IS INCREASED. Med Sci Sports Exerc 1994. [DOI: 10.1249/00005768-199405001-00919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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