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Mora-Rodriguez R, Moreno-Cabañas A, Alvarez-Jimenez L, Mora-Gonzalez D, Ortega JF, Morales-Palomo F. A bout of aerobic exercise in the heat increases carbohydrate use but does not enhance the disposal of an oral glucose load, in healthy active individuals. Am J Physiol Endocrinol Metab 2024; 326:E648-E662. [PMID: 38568152 DOI: 10.1152/ajpendo.00312.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 03/01/2024] [Accepted: 03/24/2024] [Indexed: 05/01/2024]
Abstract
We investigated if a bout of exercise in a hot environment (HEAT) would reduce the postprandial hyperglycemia induced by glucose ingestion. The hypothesis was that HEAT stimulating carbohydrate oxidation and glycogen use would increase the disposal of an ingested glucose load [i.e., oral glucose tolerance test (OGTT); 75 g of glucose]. Separated by at least 1 wk, nine young healthy individuals underwent three trials after an overnight fast in a randomized order. Two trials included 50 min of pedaling at 58 ± 5% V̇o2max either in a thermoneutral (21 ± 1°C; NEUTRAL) or in a hot environment (33 ± 1°C; HEAT) eliciting similar energy expenditure (503 ± 101 kcal). These two trials were compared with a no-exercise trial (NO EXER). Twenty minutes after exercise (or rest), subjects underwent an OGTT, while carbohydrate oxidation (CHOxid, using indirect calorimetry) plasma blood glucose, insulin concentrations (i.e., [glucose], [insulin]), and double tracer glucose kinetics ([U-13C] glucose ingestion and [6,6-2H2] glucose infusion) were monitored for 120 min. At rest, [glucose], [insulin], and rates of appearance/disappearance of glucose in plasma (glucose Ra/Rd) were similar among trials. During exercise, heart rate, tympanic temperature, [glucose], glycogen oxidation, and total CHOxid were higher during HEAT than NEUTRAL (i.e., 149 ± 35 vs. 124 ± 31 µmol·kg-1·min-1, P = 0.010). However, during the following OGTT, glucose Rd was similar in HEAT and NEUTRAL trials (i.e., 25.1 ± 3.6 vs. 25.2 ± 5.3 µmol·kg-1·min-1, P = 0.981). Insulin sensitivity (i.e., ISIndexMATSUDA) only improved in NEUTRAL compared with NO EXER (10.1 ± 4.6 vs. 8.8 ± 3.7 au; P = 0.044). In summary, stimulating carbohydrate use with exercise in a hot environment does not improve postprandial plasma glucose disposal or insulin sensitivity in a subsequent OGTT.NEW & NOTEWORTHY Exercise in the heat increases estimated muscle glycogen use. Reduced muscle glycogen after exercise in the heat could increase insulin-mediated glucose uptake during a subsequent oral glucose tolerance test (OGTT). However, plasma glucose kinetics are not improved during the OGTT in response to a bout of exercise in the heat, and insulin sensitivity worsens. Heat stress activates glucose counterregulatory hormones whose actions may linger during the OGTT, preventing increased glucose uptake.
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Affiliation(s)
| | - Alfonso Moreno-Cabañas
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
- Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, United Kingdom
- Department for Health, University of Bath, Bath, United Kingdom
| | | | - Diego Mora-Gonzalez
- Department of Nursing, Physiotherapy, and Occupational Therapy, University of Castilla-La Mancha, Toledo, Spain
| | - Juan Fernando Ortega
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
| | - Felix Morales-Palomo
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
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Alvarez-Jimenez L, Morales-Palomo F, Moreno-Cabañas A, Ortega JF, Mora-Gonzalez D, Mora-Rodriguez R. Acute Statin Withdrawal Does not Interfere With the Improvements of a Session of Exercise in Postprandial Metabolism. J Clin Endocrinol Metab 2023; 109:80-91. [PMID: 37565392 DOI: 10.1210/clinem/dgad477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND The risk for atherogenic plaque formation is high after ingestion of meals in individuals with high blood lipid levels (ie, dyslipidemia). Statins and exercise reduce the rise of blood triglyceride concentrations after a meal, but the effect of their combination is unclear. METHODS In a randomized crossover design, 11 individuals with dyslipidemia and metabolic syndrome treated with statins underwent a mixed-meal (970 ± 111 kcal, 24% fat, and 34% carbohydrate) tolerance test. Plasma lipid concentrations, fat oxidation, glucose, and glycerol kinetics were monitored immediately prior and during the meal test. Trials were conducted with participants under their habitual statin treatment and 96 hours after blinded statin withdrawal. Trials were duplicated after a prolonged bout of low-intensity exercise (75 minutes at 53 ± 4% maximal oxygen consumption) to study the interactions between exercise and statins. RESULTS Statins reduced postprandial plasma triglycerides from 3.03 ± 0.85 to 2.52 ± 0.86 mmol·L-1 (17%; P = .015) and plasma glycerol concentrations (ie, surrogate of whole-body lipolysis) without reducing plasma free fatty acid concentration or fat oxidation. Prior exercise increased postprandial plasma glycerol levels (P = .029) and fat oxidation rates (P = .024). Exercise decreased postprandial plasma insulin levels (241 ± 116 vs 301 ± 172 ρmol·L-1; P = .026) but not enough to increase insulin sensitivity (P = .614). Neither statins nor exercise affected plasma glucose appearance rates from exogenous or endogenous sources. CONCLUSIONS In dyslipidemic individuals, statins reduce blood triglyceride concentrations after a meal, but without limiting fat oxidation. Statins do not interfere with exercise lowering the postprandial insulin that likely promotes fat oxidation. Last, statins do not restrict the rates of plasma incorporation or oxidation of the ingested glucose.
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Affiliation(s)
- Laura Alvarez-Jimenez
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, 45004 Toledo, Spain
| | - Felix Morales-Palomo
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, 45004 Toledo, Spain
| | - Alfonso Moreno-Cabañas
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, 45004 Toledo, Spain
| | - Juan F Ortega
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, 45004 Toledo, Spain
| | - Diego Mora-Gonzalez
- Department of Nursing, Physiotherapy, and Occupational Therapy, University of Castilla-La Mancha, 45004 Toledo, Spain
| | - Ricardo Mora-Rodriguez
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, 45004 Toledo, Spain
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Moreno-Cabañas A, Morales-Palomo F, Alvarez-Jimenez L, Mora-Gonzalez D, Ortega JF, Mora-Rodriguez R. Metformin and exercise effects on postprandial insulin sensitivity and glucose kinetics in pre-diabetic and diabetic adults. Am J Physiol Endocrinol Metab 2023; 325:E310-E324. [PMID: 37584610 DOI: 10.1152/ajpendo.00118.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/09/2023] [Accepted: 08/09/2023] [Indexed: 08/17/2023]
Abstract
The potential interaction between metformin and exercise on glucose-lowering effects remains controversial. We studied the separated and combined effects of metformin and/or exercise on fasting and postprandial insulin sensitivity in individuals with pre-diabetes and type 2 diabetes (T2D). Eight T2D adults (60 ± 4 yr) with overweight/obesity (32 ± 4 kg·m-2) under chronic metformin treatment (9 ± 6 yr; 1281 ± 524 mg·day-1) underwent four trials; 1) taking their habitual metformin treatment (MET), 2) substituting during 96 h their metformin medication by placebo (PLAC), 3) placebo combined with 50 min bout of high-intensity interval exercise (PLAC + EX), and 4) metformin combined with exercise (MET + EX). Plasma glucose kinetics using stable isotopes (6,6-2H2 and [U-13C] glucose), and glucose oxidation by indirect calorimetry, were assessed at rest, during exercise, and in a subsequent oral glucose tolerance test (OGTT). Postprandial glucose and insulin concentrations were analyzed as mean and incremental area under the curve (iAUC), and insulin sensitivity was calculated (i.e., MATSUDAindex and OGISindex). During OGTT, metformin reduced glucose iAUC (i.e., MET and MET + EX lower than PLAC and PLAC + EX, respectively; P = 0.023). MET + EX increased MATSUDAindex above PLAC (4.8 ± 1.4 vs. 3.3 ± 1.0, respectively; P = 0.018) and OGISindex above PLAC (358 ± 52 vs. 306 ± 46 mL·min-1·m-2, respectively; P = 0.006). Metformin decreased the plasma appearance of the ingested glucose (Ra OGTT; MET vs. PLAC, -3.5; 95% CI -0.1 to -6.8 µmol·kg-1·min-1; P = 0.043). Metformin combined with exercise potentiates insulin sensitivity during an OGTT in individuals with pre-diabetes and type 2 diabetes. Metformin's blood glucose-lowering effect seems mediated by decreased oral glucose entering the circulation (gut-liver effect) an effect partially blunted after exercise.NEW & NOTEWORTHY Metformin is the most prescribed oral antidiabetic medicine in the world but its mechanism of action and its interactions with exercise are not fully understood. Our stable isotope tracer data suggested that metformin reduces the rates of oral glucose entering the circulation (gut-liver effect). Exercise, in turn, tended to reduce postprandial insulin blood levels potentiating metformin improvements in insulin sensitivity. Thus, exercise potentiates metformin improvements in glycemic control and should be advised to metformin users.
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Affiliation(s)
- Alfonso Moreno-Cabañas
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
- Center for Nutrition, Exercise and Metabolism, University of Bath, Bath, United Kingdom
- Department for Health, University of Bath, Bath, United Kingdom
| | - Felix Morales-Palomo
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
| | | | - Diego Mora-Gonzalez
- Department of Nursing, Physiotherapy, and Occupational Therapy, University of Castilla-La Mancha, Toledo, Spain
| | - Juan Fernando Ortega
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
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Moreno-Cabañas A, Gonzalez JT. Role of prior feeding status in mediating the effects of exercise on blood glucose kinetics. Am J Physiol Cell Physiol 2023; 325:C823-C832. [PMID: 37642241 PMCID: PMC10635662 DOI: 10.1152/ajpcell.00271.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/08/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
Changes in blood glucose concentrations are underpinned by blood glucose kinetics (endogenous and exogenous glucose appearance rates and glucose disappearance rates). Exercise potently alters blood glucose kinetics and can thereby be used as a tool to control blood glucose concentration. However, most studies of exercise-induced changes in glucose kinetics are conducted in a fasted state, and therefore less is known about the effects of exercise on glucose kinetics when exercise is conducted in a postprandial state. Emerging evidence suggests that food intake prior to exercise can increase postprandial blood glucose flux compared with when meals are consumed after exercise, whereby both glucose appearance rates and disappearance rates are increased. The mechanisms underlying the mediating effect of exercise conducted in the fed versus the fasted state are yet to be fully elucidated. Current evidence demonstrates that exercise in the postprandial state increased glucose appearance rates due to both increased exogenous and endogenous appearance and may be due to changes in splanchnic blood flow, intestinal permeability, and/or hepatic glucose extraction. On the other hand, increased glucose disappearance rates after exercise in the fed state have been shown to be associated with increased intramuscular AMPK signaling via a mismatch between carbohydrate utilization and delivery. Due to differences in blood glucose kinetics and other physiological differences, studies conducted in the fasted state cannot be immediately translated to the fed state. Therefore, conducting studies in the fed state could improve the external validity of data pertaining to glucose kinetics and intramuscular signaling in response to nutrition and exercise.
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Affiliation(s)
- Alfonso Moreno-Cabañas
- Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, United Kingdom
- Department for Health, University of Bath, Bath, United Kingdom
- Exercise Physiology Lab at Toledo, University of Castilla-La Mancha, Toledo, Spain
| | - Javier T Gonzalez
- Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, United Kingdom
- Department for Health, University of Bath, Bath, United Kingdom
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For Flux Sake: Isotopic Tracer Methods of Monitoring Human Carbohydrate Metabolism During Exercise. Int J Sport Nutr Exerc Metab 2023; 33:60-70. [PMID: 36448486 DOI: 10.1123/ijsnem.2022-0170] [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: 08/09/2022] [Revised: 09/19/2022] [Accepted: 09/25/2022] [Indexed: 12/05/2022]
Abstract
Isotopic tracers can reveal insights into the temporal nature of metabolism and track the fate of ingested substrates. A common use of tracers is to assess aspects of human carbohydrate metabolism during exercise under various established models. The dilution model is used alongside intravenous infusion of tracers to assess carbohydrate appearance and disappearance rates in the circulation, which can be further delineated into exogenous and endogenous sources. The incorporation model can be used to estimate exogenous carbohydrate oxidation rates. Combining methods can provide insight into key factors regulating health and performance, such as muscle and liver glycogen utilization, and the underlying regulation of blood glucose homeostasis before, during, and after exercise. Obtaining accurate, quantifiable data from tracers, however, requires careful consideration of key methodological principles. These include appropriate standardization of pretrial diet, specific tracer choice, whether a background trial is necessary to correct expired breath CO2 enrichments, and if so, what the appropriate background trial should consist of. Researchers must also consider the intensity and pattern of exercise, and the type, amount, and frequency of feeding (if any). The rationale for these considerations is discussed, along with an experimental design checklist and equation list which aims to assist researchers in performing high-quality research on carbohydrate metabolism during exercise using isotopic tracer methods.
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Gonzalez JT. Novel dietary approaches to appetite regulation, health and performance. J Physiol 2022; 600:1295-1297. [PMID: 35288934 DOI: 10.1113/jp282727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/11/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Javier T Gonzalez
- Department for Health, University of Bath, Bath, UK.,Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, UK
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Smith HA, Betts JA. Nutrient timing and metabolic regulation symposium review from "Novel dietary approaches to appetite regulation, health and performance (2021)". J Physiol 2022; 600:1299-1312. [PMID: 35038774 PMCID: PMC9305539 DOI: 10.1113/jp280756] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 12/09/2021] [Indexed: 11/19/2022] Open
Abstract
Daily (circadian) rhythms coordinate our physiology and behaviour with regular environmental changes. Molecular clocks in peripheral tissues (e.g. liver, skeletal muscle and adipose) give rise to rhythms in macronutrient metabolism, appetite regulation and the components of energy balance such that our bodies can align the periodic delivery of nutrients with ongoing metabolic requirements. The timing of meals both in absolute terms (i.e. relative to clock time) and in relative terms (i.e. relative to other daily events) is therefore relevant to metabolism and health. Experimental manipulation of feeding–fasting cycles can advance understanding of the effect of absolute and relative timing of meals on metabolism and health. Such studies have extended the overnight fast by regular breakfast omission and revealed that morning fasting can alter the metabolic response to subsequent meals later in the day, whilst also eliciting compensatory behavioural responses (i.e. reduced physical activity). Similarly, restricting energy intake via alternate‐day fasting also has the potential to elicit a compensatory reduction in physical activity, and so can undermine weight‐loss efforts (i.e. to preserve body fat stores). Interrupting the usual overnight fast (and therefore also the usual sleep cycle) by nocturnal feeding has also been examined and further research is needed to understand the importance of this period for either nutritional intervention or nutritional withdrawal. In summary, it is important for dietary guidelines for human health to consider nutrient timing (i.e. when we eat) alongside the conventional focus on nutrient quantity and nutrient quality (i.e. how much we eat and what we eat).
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Affiliation(s)
- Harry A Smith
- Centre for Nutrition Exercise and Metabolism, Department for Health, University of Bath, Bath, BA2 7AY, United Kingdom
| | - James A Betts
- Centre for Nutrition Exercise and Metabolism, Department for Health, University of Bath, Bath, BA2 7AY, United Kingdom
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Ogden HB, Fallowfield JL, Child RB, Davison G, Fleming SC, Delves SK, Millyard A, Westwood CS, Layden JD. No protective benefits of low dose acute L-glutamine supplementation on small intestinal permeability, epithelial injury and bacterial translocation biomarkers in response to subclinical exertional-heat stress: A randomized cross-over trial. Temperature (Austin) 2022; 9:196-210. [PMID: 36106146 PMCID: PMC9467553 DOI: 10.1080/23328940.2021.2015227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Exertional heat stress disrupts gastrointestinal permeability and, through subsequent bacterial translocation, can result in potentially fatal exertional heat stroke. Glutamine supplementation is a potential countermeasure although previously validated doses are not universally well tolerated. Ten males completed two 80-minute subclinical exertional heat stress tests (EHSTs) following either glutamine (0.3 g kg FFM-1) or placebo supplementation. Small intestinal permeability was assessed using the lactulose/rhamnose dual sugar absorption test and small intestinal epithelial injury using Intestinal Fatty-Acid Binding Protein (I-FABP). Bacterial translocation was assessed using the total 16S bacterial DNA and Bacteroides/total 16S DNA ratio. The glutamine bolus was well tolerated, with no participants reporting symptoms of gastrointestinal intolerance. Small intestinal permeability was not influenced by glutamine supplementation (p = 0.06) although a medium effect size favoring the placebo trial was observed (d = 0.73). Both small intestinal epithelial injury (p < 0.01) and Bacteroides/total 16S DNA (p = 0.04) increased following exertional heat stress, but were uninfluenced by glutamine supplementation. Low-dose acute oral glutamine supplementation does not protect gastrointestinal injury, permeability, or bacterial translocation in response to subclinical exertional heat stress.
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Affiliation(s)
- Henry B. Ogden
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, UK,CONTACT Henry B. Ogden
| | - Joanne L. Fallowfield
- Environmental Medicine and Science Division, Institute of Naval Medicine, Alverstoke, UK
| | - Robert B. Child
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Glen Davison
- Endurance Research Group, School of Sport and Exercise Sciences, University of Kent, Chatham Maritime, UK
| | - Simon C. Fleming
- Department of Clinical Chemistry, Royal Cornwall NHS Trust, Truro, UK
| | - Simon K. Delves
- Environmental Medicine and Science Division, Institute of Naval Medicine, Alverstoke, UK
| | - Alison Millyard
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, UK
| | | | - Joseph D. Layden
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, UK
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Rothschild JA, Islam H, Bishop DJ, Kilding AE, Stewart T, Plews DJ. Factors Influencing AMPK Activation During Cycling Exercise: A Pooled Analysis and Meta-Regression. Sports Med 2021; 52:1273-1294. [PMID: 34878641 DOI: 10.1007/s40279-021-01610-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 01/14/2023]
Abstract
BACKGROUND The 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a cellular energy sensor that is activated by increases in the cellular AMP/adenosine diphosphate:adenosine triphosphate (ADP:ATP) ratios and plays a key role in metabolic adaptations to endurance training. The degree of AMPK activation during exercise can be influenced by many factors that impact on cellular energetics, including exercise intensity, exercise duration, muscle glycogen, fitness level, and nutrient availability. However, the relative importance of these factors for inducing AMPK activation remains unclear, and robust relationships between exercise-related variables and indices of AMPK activation have not been established. OBJECTIVES The purpose of this analysis was to (1) investigate correlations between factors influencing AMPK activation and the magnitude of change in AMPK activity during cycling exercise, (2) investigate correlations between commonly reported measures of AMPK activation (AMPK-α2 activity, phosphorylated (p)-AMPK, and p-acetyl coenzyme A carboxylase (p-ACC), and (3) formulate linear regression models to determine the most important factors for AMPK activation during exercise. METHODS Data were pooled from 89 studies, including 982 participants (93.8% male, maximal oxygen consumption [[Formula: see text]] 51.9 ± 7.8 mL kg-1 min-1). Pearson's correlation analysis was performed to determine relationships between effect sizes for each of the primary outcome markers (AMPK-α2 activity, p-AMPK, p-ACC) and factors purported to influence AMPK signaling (muscle glycogen, carbohydrate ingestion, exercise duration and intensity, fitness level, and muscle metabolites). General linear mixed-effect models were used to examine which factors influenced AMPK activation. RESULTS Significant correlations (r = 0.19-0.55, p < .05) with AMPK activity were found between end-exercise muscle glycogen, exercise intensity, and muscle metabolites phosphocreatine, creatine, and free ADP. All markers of AMPK activation were significantly correlated, with the strongest relationship between AMPK-α2 activity and p-AMPK (r = 0.56, p < 0.001). The most important predictors of AMPK activation were the muscle metabolites and exercise intensity. CONCLUSION Muscle glycogen, fitness level, exercise intensity, and exercise duration each influence AMPK activity during exercise when all other factors are held constant. However, disrupting cellular energy charge is the most influential factor for AMPK activation during endurance exercise.
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Affiliation(s)
- Jeffrey A Rothschild
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
| | - Hashim Islam
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - David J Bishop
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia.,School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Tom Stewart
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Romeres D, Schiavon M, Basu A, Cobelli C, Basu R, Dalla Man C. Exercise effect on insulin-dependent and insulin-independent glucose utilization in healthy individuals and individuals with type 1 diabetes: a modeling study. Am J Physiol Endocrinol Metab 2021; 321:E122-E129. [PMID: 33998292 PMCID: PMC8321821 DOI: 10.1152/ajpendo.00084.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Exercise effects (EE) on whole body glucose rate of disappearance (Rd) occur through insulin-independent (IIRd) and insulin-dependent (IDRd) mechanisms. Quantifying these processes in vivo would allow a better understanding of the physiology of glucose regulation. This is of particular importance in individuals with type 1 diabetes (T1D) since such a knowledge may help to improve glucose management. However, such a model is still lacking. Here, we analyzed data from six T1D and six nondiabetic (ND) subjects undergoing a labeled glucose clamp study during, before, and after a 60-min exercise session at 65% V̇o2max on three randomized visits: euglycemia-low insulin, euglycemia-high insulin, and hyperglycemia-low insulin. We tested a set of models, all sharing a single-compartment description of glucose kinetics, but differing in how exercise is assumed to modulate glucose disposal. Model selection was based on parsimony criteria. The best model assumed an exercise-induced immediate effect on IIRd and a delayed effect on IDRd. It predicted that exercise increases IIRd, compared with rest, by 66%-82% and 67%-97% in T1D and ND, respectively, not significantly different between the two groups. Conversely, the exercise effect on IDRd ranged between 81% and 155% in T1D and it was significantly higher than ND, which ranged between 10% and 40%. The exaggerated effect observed in IDRd can explain the higher hypoglycemia risk related to individuals with T1D. This novel exercise model could help in informing safe and effective glucose management during and after exercise in individuals with T1D.NEW & NOTEWORTHY Here, we present a new mathematical model describing the effect of moderate physical activity on insulin-mediated and noninsulin-mediated glucose disposal in subjects with and without diabetes. We believe that this represents a step-forward in the knowledge of type 1 diabetes pathophysiology, and an useful tool to design safe and effective insulin-therapies.
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Affiliation(s)
- Davide Romeres
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Michele Schiavon
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Ananda Basu
- Division of Endocrinology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Claudio Cobelli
- Department of Woman and Child's Health, University of Padova, Padova, Italy
| | - Rita Basu
- Division of Endocrinology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
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11
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Gabriel BM, Zierath JR. Zeitgebers of skeletal muscle and implications for metabolic health. J Physiol 2021; 600:1027-1036. [PMID: 33963554 DOI: 10.1113/jp280884] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/04/2021] [Indexed: 12/25/2022] Open
Abstract
Metabolic health is a crucial area of current research, and is an outcome of innate physiology, and interactions with the environment. Environmental cues, such as the Earth's day-night rhythm, partly regulate diurnal hormones and metabolites. Circadian physiology consists of highly conserved biological processes over ∼24-h cycles, which are influenced by external cues (Zeitgebers - 'time-keepers'). Skeletal muscle has diurnal variations of a large magnitude, owing in part to the strong nature of physical activity throughout the day and other external Zeitgebers. The orchestration of whole-body and skeletal muscle metabolism is a complex, finely tuned process, and molecular diurnal variations are regulated by a transcription-translation feedback loop controlled by the molecular clock, as well as non-transcriptional metabolic processes. The mitochondrion may play an important role in regulating diurnal metabolites within skeletal muscle, given its central role in the regulation of NAD+ /NADH, O2 , reactive oxygen species and redox metabolism. These molecular pathways display diurnal variation and illustrate the complex orchestration of circadian metabolism in skeletal muscle. Probably the most robust Zeitgeber of skeletal muscle is exercise, which alters glucose metabolism and flux, in addition to a range of other diurnal metabolic pathways. Indeed, performing exercise at different times of the day may alter metabolism and health outcomes in some cohorts. The objective of this Symposium Review is to briefly cover the current literature, and to speculate regarding future areas of research. Thus, we postulate that metabolic health may be optimized by altering the timing of external cues such as diet and exercise.
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Affiliation(s)
- Brendan M Gabriel
- Aberdeen Cardiovascular & Diabetes Centre, The Rowett Institute, University of Aberdeen, Aberdeen, UK.,Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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King MA, Rollo I, Baker LB. Nutritional considerations to counteract gastrointestinal permeability during exertional heat stress. J Appl Physiol (1985) 2021; 130:1754-1765. [PMID: 33955260 DOI: 10.1152/japplphysiol.00072.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Intestinal barrier integrity and function are compromised during exertional heat stress (EHS) potentially leading to consequences that range from minor gastrointestinal (GI) disturbances to fatal outcomes in exertional heat stroke or septic shock. This mini-review provides a concise discussion of nutritional interventions that may protect against intestinal permeability during EHS and suggests physiological mechanisms responsible for this protection. Although diverse nutritional interventions have been suggested to be protective against EHS-induced GI permeability, the ingestion of certain amino acids, carbohydrates, and fluid per se is potentially effective strategy, whereas evidence for various polyphenols and pre/probiotics is developing. Plausible physiological mechanisms of protection include increased blood flow, epithelial cell proliferation, upregulation of intracellular heat shock proteins, modulation of inflammatory signaling, alteration of the GI microbiota, and increased expression of tight junction (TJ) proteins. Further clinical research is needed to propose specific nutritional candidates and recommendations for their application to prevent intestinal barrier disruption and elucidate mechanisms during EHS.
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Affiliation(s)
- Michelle A King
- Gatorade Sports Science Institute, PepsiCo R&D Life Sciences, Barrington, Illinois
| | - Ian Rollo
- Gatorade Sports Science Institute, PepsiCo R&D Life Sciences, Leicestershire, United Kingdom
| | - Lindsay B Baker
- Gatorade Sports Science Institute, PepsiCo R&D Life Sciences, Barrington, Illinois
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Zhang X, Wongpipit W, Sun F, Sheridan S, Huang WYJ, Sit CHP, Wong SHS. Walking Initiated 20 Minutes before the Time of Individual Postprandial Glucose Peak Reduces the Glucose Response in Young Men with Overweight or Obesity: A Randomized Crossover Study. J Nutr 2021; 151:866-875. [PMID: 33561220 DOI: 10.1093/jn/nxaa420] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/29/2020] [Accepted: 12/02/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Although a single bout of postmeal exercise can lower postprandial glucose (PPG), its optimal timing remains unclear. OBJECTIVE This study aimed to investigate the effect of exercise timing using an individualized approach on PPG in overweight or obese young men. METHODS Twenty men [age: 23.0 ± 4.3 y; BMI (kg/m2): 27.4 ± 2.8] each completed three 240-min trials in a randomized order separated by 6-14 d: 1) sitting (SIT), 2) walking initiated at each participant's PPG-peak time (PPGP) (iP), and 3) walking initiated 20 min before the PPGP (20iP). For each participant, PPGP was predetermined using continuous glucose monitoring. Walking was performed at 50% maximal oxygen consumption for 30 min. Venous blood was collected at 15- and 30-min intervals for 0-120 min and 120-240 min, respectively. The primary outcome was plasma PPG. Generalized estimating equations were used for comparison between trials. RESULTS Compared with SIT, the 4-h incremental AUCs (iAUCs) for plasma PPG (-0.6 mmol · L-1 · h; P = 0.047) and insulin (-28.7%, P < 0.001) were reduced in 20iP only, and C-peptide concentrations were lower after iP (-14.9%, P = 0.001) and 20iP (-28.7%, P < 0.001). Plasma insulin (-11.1%, P = 0.006) and C-peptide (-8.3%, P = 0.012) were lower due to the 20iP compared with iP treatment. Finally, PPG reductions due to iP and 20iP occurred only in men with a BMI > 27.5 kg/m2 (iP, -11.2%; 20iP, -14.7%; P = 0.047) and higher glucose iAUC values during SIT (iP, -25.5%; 20iP, -25.7%; P < 0.001). CONCLUSIONS Walking initiated 20 min before PPGP lowered PPG and plasma insulin and C-peptide concentrations in young men with overweight or obesity, in particular in those with high BMI or glucose iAUC values during SIT; it also lowered plasma insulin and C-peptide concentrations more effectively than did exercise initiated at PPGP. This trial was registered at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/index.aspx) as ChiCTR1900023175.
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Affiliation(s)
- Xiaoyuan Zhang
- Department of Sports Science and Physical Education, Faculty of Education, The Chinese University of Hong Kong, Hong Kong, China
| | - Waris Wongpipit
- Department of Sports Science and Physical Education, Faculty of Education, The Chinese University of Hong Kong, Hong Kong, China.,Division of Health and Physical Education, Faculty of Education, Chulalongkorn University, Bangkok, Thailand
| | - Fenghua Sun
- Department of Health and Physical Education, The Education University of Hong Kong, Hong Kong, China
| | - Sinead Sheridan
- Department of Sports Science and Physical Education, Faculty of Education, The Chinese University of Hong Kong, Hong Kong, China
| | - Wendy Y J Huang
- Department of Sport, Physical Education, and Health, Hong Kong Baptist University, Hong Kong, China
| | - Cindy H P Sit
- Department of Sports Science and Physical Education, Faculty of Education, The Chinese University of Hong Kong, Hong Kong, China
| | - Stephen H S Wong
- Department of Sports Science and Physical Education, Faculty of Education, The Chinese University of Hong Kong, Hong Kong, China
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14
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Rollo I, Gonzalez JT, Fuchs CJ, van Loon LJC, Williams C. Primary, Secondary, and Tertiary Effects of Carbohydrate Ingestion During Exercise. Sports Med 2021; 50:1863-1871. [PMID: 32936440 PMCID: PMC8159838 DOI: 10.1007/s40279-020-01343-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The purpose of this current opinion paper is to describe the journey of ingested carbohydrate from 'mouth to mitochondria' culminating in energy production in skeletal muscles during exercise. This journey is conveniently described as primary, secondary, and tertiary events. The primary stage is detection of ingested carbohydrate by receptors in the oral cavity and on the tongue that activate reward and other centers in the brain leading to insulin secretion. After digestion, the secondary stage is the transport of monosaccharides from the small intestine into the systemic circulation. The passage of these monosaccharides is facilitated by the presence of various transport proteins. The intestinal mucosa has carbohydrate sensors that stimulate the release of two 'incretin' hormones (GIP and GLP-1) whose actions range from the secretion of insulin to appetite regulation. Most of the ingested carbohydrate is taken up by the liver resulting in a transient inhibition of hepatic glucose release in a dose-dependent manner. Nonetheless, the subsequent increased hepatic glucose (and lactate) output can increase exogenous carbohydrate oxidation rates by 40-50%. The recognition and successful distribution of carbohydrate to the brain and skeletal muscles to maintain carbohydrate oxidation as well as prevent hypoglycaemia underpins the mechanisms to improve exercise performance.
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Affiliation(s)
- Ian Rollo
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire, UK. .,School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK.
| | | | - Cas J Fuchs
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Luc J C van Loon
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Clyde Williams
- School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK
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15
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Sacchetti M, Haxhi J, Sgrò P, Scotto di Palumbo A, Nicolò A, Bellini A, Bazzucchi I, di Luigi L. Effects of exercise before and/or after a mixed lunch on postprandial metabolic responses in healthy male individuals. Eur J Nutr 2021; 60:3437-3447. [PMID: 33635408 DOI: 10.1007/s00394-021-02512-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 02/05/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE Exercise plays an important role in preventing and treating postprandial dysmetabolism. We investigated the postprandial metabolic responses to a standard lunch when a session of aerobic exercise is performed in the early postprandial phase or divided between the pre- and postprandial period. METHODS Nine healthy volunteers consumed a standardised mixed lunch and rested for the following 3 h (Con) or performed 40 min of cycling at 65% V̇O2max after lunch (CPPEx), or two 20-min sessions, one before (SplitEx1) and the other after lunch (SplitEx2), at the same intensity. RESULTS At 1-h post-lunch, a significant reduction (P < 0.001) in glycaemia was observed for CPPEx (- 25 ± 10%) and SplitEx (- 34 ± 7%) compared to Con. Yet, a post-exercise rebound lessened the exercise effect on the glycaemic area under the curve (AUC) at 2 and 3 h. At 1 h, a significant reduction (P < 0.009) in plasma insulin (SplitEx - 53 ± 31%; CCPEx - 48 ± 20%) and C-peptide (SplitEx - 57 ± 20%; CCPEx - 47 ± 24%) was observed compared to Con. Glucose-dependent insulinotropic polypeptide (GIP) increased after the meal, without differences between conditions. Compared with SplitEx1, cortisol response was attenuated during SplitEx2 and CPPEx. At 3 hours, triglyceride AUC was significantly higher (P = 0.039) in SplitEx compared to Con (+ 19 ± 8%). CONCLUSION Forty minutes of postprandial exercise or 20 min of pre- and postprandial exercise are both effective at attenuating the glycaemic and insulinaemic response to a mixed lunch, while a higher lipaemia was found in the pre- and postprandrial exercise condition.
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Affiliation(s)
- Massimo Sacchetti
- Unit of Exercise Physiology, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy.
| | - Jonida Haxhi
- Unit of Exercise Physiology, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy
| | - Paolo Sgrò
- Unit of Endocrinology, Department of Movement, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy
| | - Alessandro Scotto di Palumbo
- Unit of Exercise Physiology, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy
| | - Andrea Nicolò
- Unit of Exercise Physiology, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy
| | - Alessio Bellini
- Unit of Exercise Physiology, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy
| | - Ilenia Bazzucchi
- Unit of Exercise Physiology, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy
| | - Luigi di Luigi
- Unit of Endocrinology, Department of Movement, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy
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16
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Ogden HB, Fallowfield JL, Child RB, Davison G, Fleming SC, Edinburgh RM, Delves SK, Millyard A, Westwood CS, Layden JD. Reliability of gastrointestinal barrier integrity and microbial translocation biomarkers at rest and following exertional heat stress. Physiol Rep 2021; 8:e14374. [PMID: 32170836 PMCID: PMC7070100 DOI: 10.14814/phy2.14374] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/14/2020] [Accepted: 01/21/2020] [Indexed: 01/23/2023] Open
Abstract
PURPOSE Exertional heat stress adversely distrupts (GI) barrier integrity and, through subsequent microbial translocation (MT), negativly impacts health. Despite widespread application, the temporal reliability of popular GI barrier integity and MT biomarkers is poorly characterised. METHOD Fourteen males completed two 80-min exertional heat stress tests (EHST) separated by 7-14 days. Venous blood was drawn pre, immediately- and 1-hr post both EHSTs. GI barrier integrity was assessed using the serum Dual-Sugar Absorption Test (DSAT), Intestinal Fatty-Acid-Binding Protein (I-FABP) and Claudin-3 (CLDN-3). MT was assessed using plasma Lipopolysaccharide Binding Protein (LBP), total 16S bacterial DNA and Bacteroides DNA. RESULTS No GI barrier integrity or MT biomarker, except absolute Bacteroides DNA, displayed systematic trial order bias (p ≥ .05). I-FABP (trial 1 = Δ 0.834 ± 0.445 ng ml-1 ; trial 2 = Δ 0.776 ± 0.489 ng ml-1 ) and CLDN-3 (trial 1 = Δ 0.317 ± 0.586 ng ml-1 ; trial 2 = Δ 0.371 ± 0.508 ng ml-1 ) were increased post-EHST (p ≤ .01). All MT biomarkers were unchanged post-EHST. Coefficient of variation and typical error of measurement post-EHST were: 11.5% and 0.004 (ratio) for the DSAT 90-min postprobe ingestion; 12.2% and 0.004 (ratio) at 150-min postprobe ingestion; 12.1% and 0.376 ng ml-1 for I-FABP; 4.9% and 0.342 ng ml-1 for CLDN-3; 9.2% and 0.420 µg ml-1 for LBP; 9.5% and 0.15 pg µl-1 for total 16S DNA; and 54.7% and 0.032 for Bacteroides/total 16S DNA ratio. CONCLUSION Each GI barrier integrity and MT translocation biomarker, except Bacteroides/total 16S ratio, had acceptable reliability at rest and postexertional heat stress.
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Affiliation(s)
- Henry B Ogden
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
| | | | - Robert B Child
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Glen Davison
- Endurance Research Group, School of Sport and Exercise Sciences, University of Kent, Chatham Maritime, United Kingdom
| | | | | | | | - Alison Millyard
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
| | - Caroline S Westwood
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
| | - Joseph D Layden
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
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17
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Edinburgh RM, Koumanov F, Gonzalez JT. Impact of pre‐exercise feeding status on metabolic adaptations to endurance‐type exercise training. J Physiol 2021; 600:1327-1338. [DOI: 10.1113/jp280748] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/29/2020] [Indexed: 12/16/2022] Open
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18
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Augustijns P, Vertzoni M, Reppas C, Langguth P, Lennernäs H, Abrahamsson B, Hasler WL, Baker JR, Vanuytsel T, Tack J, Corsetti M, Bermejo M, Paixão P, Amidon GL, Hens B. Unraveling the behavior of oral drug products inside the human gastrointestinal tract using the aspiration technique: History, methodology and applications. Eur J Pharm Sci 2020; 155:105517. [DOI: 10.1016/j.ejps.2020.105517] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 08/12/2020] [Accepted: 08/16/2020] [Indexed: 02/08/2023]
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19
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Rothschild JA, Kilding AE, Plews DJ. What Should I Eat before Exercise? Pre-Exercise Nutrition and the Response to Endurance Exercise: Current Prospective and Future Directions. Nutrients 2020; 12:nu12113473. [PMID: 33198277 PMCID: PMC7696145 DOI: 10.3390/nu12113473] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/20/2022] Open
Abstract
The primary variables influencing the adaptive response to a bout of endurance training are exercise duration and exercise intensity. However, altering the availability of nutrients before and during exercise can also impact the training response by modulating the exercise stimulus and/or the physiological and molecular responses to the exercise-induced perturbations. The purpose of this review is to highlight the current knowledge of the influence of pre-exercise nutrition ingestion on the metabolic, physiological, and performance responses to endurance training and suggest directions for future research. Acutely, carbohydrate ingestion reduces fat oxidation, but there is little evidence showing enhanced fat burning capacity following long-term fasted-state training. Performance is improved following pre-exercise carbohydrate ingestion for longer but not shorter duration exercise, while training-induced performance improvements following nutrition strategies that modulate carbohydrate availability vary based on the type of nutrition protocol used. Contrasting findings related to the influence of acute carbohydrate ingestion on mitochondrial signaling may be related to the amount of carbohydrate consumed and the intensity of exercise. This review can help to guide athletes, coaches, and nutritionists in personalizing pre-exercise nutrition strategies, and for designing research studies to further elucidate the role of nutrition in endurance training adaptations.
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Abstract
PURPOSE OF REVIEW Prevalence of metabolic-associated fatty liver disease (MAFLD) is increasing, and as pharmacological treatment does not exist, lifestyle interventions (i.e. diet and exercise) represent the cornerstone management and treatment strategy. Although the available data clearly demonstrate that changes in lifestyle influence intrahepatic triglyceride (IHTG) content, the mechanisms through which this is achieved are seldom investigated. Here, we review recent evidence demonstrating the influence of lifestyle interventions on hepatic fatty acid metabolism and IHTG content. RECENT FINDINGS Diet and exercise influence IHTG content through various, and often interrelated factors. These include alterations in whole-body and tissue-specific insulin sensitivity, which may influence the flux of fatty acid and lipogenic substrates to the liver, and changes in intrahepatic fatty acid synthesis and partitioning. Notably, there are only a few studies that have investigated intrahepatic fatty acid metabolism in vivo in humans before and after an intervention. SUMMARY Lifestyle interventions represent an effective means of influencing hepatic fatty acid metabolism. IHTG content is decreased without weight-loss either through exercise or by changing the macronutrient composition of the diet, although what the optimal macronutrient composition is to achieve this has yet to be defined.
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Affiliation(s)
- Sion A Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford
| | - Mark C Turner
- Research Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK
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21
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Influence of aerobic fitness on gastrointestinal barrier integrity and microbial translocation following a fixed-intensity military exertional heat stress test. Eur J Appl Physiol 2020; 120:2325-2337. [PMID: 32794058 DOI: 10.1007/s00421-020-04455-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE Exertional-heat stress adversely disrupts gastrointestinal (GI) barrier integrity, whereby subsequent microbial translocation (MT) can result in potentially serious health consequences. To date, the influence of aerobic fitness on GI barrier integrity and MT following exertional-heat stress is poorly characterised. METHOD Ten untrained (UT; VO2max = 45 ± 3 ml·kg-1·min-1) and ten highly trained (HT; VO2max = 64 ± 4 ml·kg-1·min-1) males completed an ecologically valid (military) 80-min fixed-intensity exertional-heat stress test (EHST). Venous blood was drawn immediately pre- and post-EHST. GI barrier integrity was assessed using the serum dual-sugar absorption test (DSAT) and plasma Intestinal Fatty-Acid Binding Protein (I-FABP). MT was assessed using plasma Bacteroides/total 16S DNA. RESULTS UT experienced greater thermoregulatory, cardiovascular and perceptual strain (p < 0.05) than HT during the EHST. Serum DSAT responses were similar between the two groups (p = 0.59), although Δ I-FABP was greater (p = 0.04) in the UT (1.14 ± 1.36 ng·ml-1) versus HT (0.20 ± 0.29 ng·ml-1) group. Bacteroides/Total 16S DNA ratio was unchanged (Δ; -0.04 ± 0.18) following the EHST in the HT group, but increased (Δ; 0.19 ± 0.25) in the UT group (p = 0.05). Weekly aerobic training hours had a weak, negative correlation with Δ I-FABP and Bacteroides/total 16S DNA responses. CONCLUSION When exercising at the same absolute workload, UT individuals are more susceptible to small intestinal epithelial injury and MT than HT individuals. These responses appear partially attributable to greater thermoregulatory, cardiovascular, and perceptual strain.
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Savikj M, Zierath JR. Train like an athlete: applying exercise interventions to manage type 2 diabetes. Diabetologia 2020; 63:1491-1499. [PMID: 32529411 PMCID: PMC7351814 DOI: 10.1007/s00125-020-05166-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/12/2020] [Indexed: 01/20/2023]
Abstract
Exercise elicits high energy demands, stimulating cardiorespiratory function and substrate mobilisation and oxidation. Repeated bouts of exercise lead to whole-body adaptations, which improve athletic performance. Distinct exercise modalities and intensities and nutritional conditions pose specific physiological challenges, subsequently inducing different adaptations to training. Athletes often modify these variables to achieve individualised training goals and maximise performance. Exercise training improves glycaemic control in individuals with type 2 diabetes; however, the precise training regimen that confers the most beneficial metabolic adaptations in this population is unknown. In this review, we discuss how modifying exercise type, intensity and modality and nutritional status affects the beneficial effects of exercise on glycaemic control in individuals with type 2 diabetes. Evidence indicates that greater improvements in glycaemic control can be achieved through combined aerobic and resistance training regimens compared with either training type alone. However, the increased frequency of training and a greater number of exercise bouts during combined programmes could be responsible for apparent advantages over a single training modality. The beneficial effects of aerobic exercise on glycaemic control seem to rise with training intensity, with superior adaptations achieved by high-intensity interval training (HIT). In addition, training with low carbohydrate availability ('training low') improves cardiorespiratory function and skeletal muscle oxidative capacity more than conventional training in healthy untrained individuals. Examinations of various training regimens are warranted to assess the safety, efficacy, feasibility and beneficial effects in the type 2 diabetes population. Just like competitive athletes, individuals with type 2 diabetes should be encouraged to adopt training regimens that improve fitness and metabolism. Graphical abstract.
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Affiliation(s)
- Mladen Savikj
- Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, 171 77, Stockholm, Sweden.
- Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Edinburgh RM, Bradley HE, Abdullah NF, Robinson SL, Chrzanowski-Smith OJ, Walhin JP, Joanisse S, Manolopoulos KN, Philp A, Hengist A, Chabowski A, Brodsky FM, Koumanov F, Betts JA, Thompson D, Wallis GA, Gonzalez JT. Lipid Metabolism Links Nutrient-Exercise Timing to Insulin Sensitivity in Men Classified as Overweight or Obese. J Clin Endocrinol Metab 2020; 105:5599745. [PMID: 31628477 PMCID: PMC7112968 DOI: 10.1210/clinem/dgz104] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/02/2019] [Indexed: 02/06/2023]
Abstract
CONTEXT Pre-exercise nutrient availability alters acute metabolic responses to exercise, which could modulate training responsiveness. OBJECTIVE To assess acute and chronic effects of exercise performed before versus after nutrient ingestion on whole-body and intramuscular lipid utilization and postprandial glucose metabolism. DESIGN (1) Acute, randomized, crossover design (Acute Study); (2) 6-week, randomized, controlled design (Training Study). SETTING General community. PARTICIPANTS Men with overweight/obesity (mean ± standard deviation, body mass index: 30.2 ± 3.5 kg⋅m-2 for Acute Study, 30.9 ± 4.5 kg⋅m-2 for Training Study). INTERVENTIONS Moderate-intensity cycling performed before versus after mixed-macronutrient breakfast (Acute Study) or carbohydrate (Training Study) ingestion. RESULTS Acute Study-exercise before versus after breakfast consumption increased net intramuscular lipid utilization in type I (net change: -3.44 ± 2.63% versus 1.44 ± 4.18% area lipid staining, P < 0.01) and type II fibers (-1.89 ± 2.48% versus 1.83 ± 1.92% area lipid staining, P < 0.05). Training Study-postprandial glycemia was not differentially affected by 6 weeks of exercise training performed before versus after carbohydrate intake (P > 0.05). However, postprandial insulinemia was reduced with exercise training performed before but not after carbohydrate ingestion (P = 0.03). This resulted in increased oral glucose insulin sensitivity (25 ± 38 vs -21 ± 32 mL⋅min-1⋅m-2; P = 0.01), associated with increased lipid utilization during exercise (r = 0.50, P = 0.02). Regular exercise before nutrient provision also augmented remodeling of skeletal muscle phospholipids and protein content of the glucose transport protein GLUT4 (P < 0.05). CONCLUSIONS Experiments investigating exercise training and metabolic health should consider nutrient-exercise timing, and exercise performed before versus after nutrient intake (ie, in the fasted state) may exert beneficial effects on lipid utilization and reduce postprandial insulinemia.
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Affiliation(s)
| | - Helen E Bradley
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Nurul-Fadhilah Abdullah
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Health Sciences, Faculty of Sport Sciences and Coaching, Universiti Pendidikan Sultan Idris, Perak, Malaysia
| | - Scott L Robinson
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | | | | | - Sophie Joanisse
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | | | - Andrew Philp
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Aaron Hengist
- Department for Health, University of Bath, Bath, United Kingdom
| | - Adrian Chabowski
- Department of Physiology, Medical University of Bialystok, Bialystok, Poland
| | - Frances M Brodsky
- Division of Biosciences, University College London, London, United Kingdom
| | | | - James A Betts
- Department for Health, University of Bath, Bath, United Kingdom
| | - Dylan Thompson
- Department for Health, University of Bath, Bath, United Kingdom
| | - Gareth A Wallis
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Javier T Gonzalez
- Department for Health, University of Bath, Bath, United Kingdom
- Correspondence and Reprint Requests: Javier T. Gonzalez, MD, Department for Health, University of Bath, Bath, BA2 7AY, United Kingdom. E-mail:
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24
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Ogden HB, Child RB, Fallowfield JL, Delves SK, Westwood CS, Layden JD. The Gastrointestinal Exertional Heat Stroke Paradigm: Pathophysiology, Assessment, Severity, Aetiology and Nutritional Countermeasures. Nutrients 2020; 12:E537. [PMID: 32093001 PMCID: PMC7071449 DOI: 10.3390/nu12020537] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 02/14/2020] [Accepted: 02/15/2020] [Indexed: 12/12/2022] Open
Abstract
Exertional heat stroke (EHS) is a life-threatening medical condition involving thermoregulatory failure and is the most severe condition along a continuum of heat-related illnesses. Current EHS policy guidance principally advocates a thermoregulatory management approach, despite growing recognition that gastrointestinal (GI) microbial translocation contributes to disease pathophysiology. Contemporary research has focused to understand the relevance of GI barrier integrity and strategies to maintain it during periods of exertional-heat stress. GI barrier integrity can be assessed non-invasively using a variety of in vivo techniques, including active inert mixed-weight molecular probe recovery tests and passive biomarkers indicative of GI structural integrity loss or microbial translocation. Strenuous exercise is strongly characterised to disrupt GI barrier integrity, and aspects of this response correlate with the corresponding magnitude of thermal strain. The aetiology of GI barrier integrity loss following exertional-heat stress is poorly understood, though may directly relate to localised hyperthermia, splanchnic hypoperfusion-mediated ischemic injury, and neuroendocrine-immune alterations. Nutritional countermeasures to maintain GI barrier integrity following exertional-heat stress provide a promising approach to mitigate EHS. The focus of this review is to evaluate: (1) the GI paradigm of exertional heat stroke; (2) techniques to assess GI barrier integrity; (3) typical GI barrier integrity responses to exertional-heat stress; (4) the aetiology of GI barrier integrity loss following exertional-heat stress; and (5) nutritional countermeasures to maintain GI barrier integrity in response to exertional-heat stress.
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Affiliation(s)
- Henry B. Ogden
- Faculty of Sport, Health and Wellbeing, Plymouth MARJON University, Derriford Rd, Plymouth PL6 8BH, UK; (C.S.W.); (J.D.L.)
| | - Robert B. Child
- School of Chemical Engineering, University of Birmingham, Birmingham B15 2QU, UK;
| | | | - Simon K. Delves
- Institute of Naval Medicine, Alverstoke PO12 2DW, UK; (J.L.F.); (S.K.D.)
| | - Caroline S. Westwood
- Faculty of Sport, Health and Wellbeing, Plymouth MARJON University, Derriford Rd, Plymouth PL6 8BH, UK; (C.S.W.); (J.D.L.)
| | - Joseph D. Layden
- Faculty of Sport, Health and Wellbeing, Plymouth MARJON University, Derriford Rd, Plymouth PL6 8BH, UK; (C.S.W.); (J.D.L.)
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25
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Parsons IT, Stacey MJ, Woods DR. Heat Adaptation in Military Personnel: Mitigating Risk, Maximizing Performance. Front Physiol 2019; 10:1485. [PMID: 31920694 PMCID: PMC6928107 DOI: 10.3389/fphys.2019.01485] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/21/2019] [Indexed: 12/22/2022] Open
Abstract
The study of heat adaptation in military personnel offers generalizable insights into a variety of sporting, recreational and occupational populations. Conversely, certain characteristics of military employment have few parallels in civilian life, such as the imperative to achieve mission objectives during deployed operations, the opportunity to undergo training and selection for elite units or the requirement to fulfill essential duties under prolonged thermal stress. In such settings, achieving peak individual performance can be critical to organizational success. Short-notice deployment to a hot operational or training environment, exposure to high intensity exercise and undertaking ceremonial duties during extreme weather may challenge the ability to protect personnel from excessive thermal strain, especially where heat adaptation is incomplete. Graded and progressive acclimatization can reduce morbidity substantially and impact on mortality rates, yet individual variation in adaptation has the potential to undermine empirical approaches. Incapacity under heat stress can present the military with medical, occupational and logistic challenges requiring dynamic risk stratification during initial and subsequent heat stress. Using data from large studies of military personnel observing traditional and more contemporary acclimatization practices, this review article (1) characterizes the physical challenges that military training and deployed operations present (2) considers how heat adaptation has been used to augment military performance under thermal stress and (3) identifies potential solutions to optimize the risk-performance paradigm, including those with broader relevance to other populations exposed to heat stress.
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Affiliation(s)
- Iain T. Parsons
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King’s College London, London, United Kingdom
| | - Michael J. Stacey
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Department of Diabetes and Endocrinology, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - David R. Woods
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Department of Sport and Exercise Endocrinology, Carnegie Research Institute, Leeds Beckett University, Leeds, United Kingdom
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26
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Karppinen JE, Rottensteiner M, Wiklund P, Hämäläinen K, Laakkonen EK, Kaprio J, Kainulainen H, Kujala UM. Fat oxidation at rest and during exercise in male monozygotic twins. Eur J Appl Physiol 2019; 119:2711-2722. [PMID: 31673759 PMCID: PMC6858391 DOI: 10.1007/s00421-019-04247-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 10/24/2019] [Indexed: 11/24/2022]
Abstract
PURPOSE We aimed to investigate if hereditary factors, leisure-time physical activity (LTPA) and metabolic health interact with resting fat oxidation (RFO) and peak fat oxidation (PFO) during ergometer cycling. METHODS We recruited 23 male monozygotic twin pairs (aged 32-37 years) and determined their RFO and PFO with indirect calorimetry for 21 and 19 twin pairs and for 43 and 41 twin individuals, respectively. Using physical activity interviews and the Baecke questionnaire, we identified 10 twin pairs as LTPA discordant for the past 3 years. Of the twin pairs, 8 pairs participated in both RFO and PFO measurements, and 2 pairs participated in either of the measurements. We quantified the participants' metabolic health with a 2-h oral glucose tolerance test. RESULTS Fat oxidation within co-twins was correlated at rest [intraclass correlation coefficient (ICC) = 0.54, 95% confidence interval (CI) 0.15-0.78] and during exercise (ICC = 0.67, 95% CI 0.33-0.86). The LTPA-discordant pairs had no pairwise differences in RFO or PFO. In the twin individual-based analysis, PFO was positively correlated with the past 12-month LTPA (r = 0.26, p = 0.034) and the Baecke score (r = 0.40, p = 0.022) and negatively correlated with the area under the curve of insulin (r = - 0.42, p = 0.015) and glucose (r = - 0.31, p = 0.050) during the oral glucose tolerance test. CONCLUSIONS Hereditary factors were more important than LTPA for determining fat oxidation at rest and during exercise. Additionally, PFO, but not RFO, was associated with better metabolic health.
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Affiliation(s)
- Jari E Karppinen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
- Gerontology Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
| | - Mirva Rottensteiner
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Department of Medicine, Central Finland Health Care District, Jyväskylä, Finland
| | - Petri Wiklund
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Exercise Translational Medicine Center and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Epidemiology and Biostatistics, Centre for Environment and Health, School of Public Health, Imperial College London, London, UK
| | | | - Eija K Laakkonen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Gerontology Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Jaakko Kaprio
- Department of Public Health, University of Helsinki, Helsinki, Finland
- Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Heikki Kainulainen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Urho M Kujala
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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27
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Edinburgh RM, Hengist A, Smith HA, Travers RL, Betts JA, Thompson D, Walhin JP, Wallis GA, Hamilton DL, Stevenson EJ, Tipton KD, Gonzalez JT. Skipping Breakfast Before Exercise Creates a More Negative 24-hour Energy Balance: A Randomized Controlled Trial in Healthy Physically Active Young Men. J Nutr 2019; 149:1326-1334. [PMID: 31321428 PMCID: PMC6675614 DOI: 10.1093/jn/nxz018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/02/2018] [Accepted: 01/23/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND At rest, omission of breakfast lowers daily energy intake, but also lowers energy expenditure, attenuating any effect on energy balance. The effect of breakfast omission on energy balance when exercise is prescribed is unclear. OBJECTIVES The aim of this study was to assess the effect on 24-h energy balance of omitting compared with consuming breakfast prior to exercise. METHODS Twelve healthy physically active young men (age 23 ± 3 y, body mass index 23.6 ± 2.0 kg/m2) completed 3 trials in a randomized order (separated by >1 week): a breakfast of oats and milk (431 kcal; 65 g carbohydrate, 11 g fat, 19 g protein) followed by rest (BR); breakfast before exercise (BE; 60 min cycling at 50 % peak power output); and overnight fasting before exercise (FE). The 24-h energy intake was calculated based on the food consumed for breakfast, followed by an ad libitum lunch, snacks, and dinner. Indirect calorimetry with heart-rate accelerometry was used to measure substrate utilization and 24-h energy expenditure. A [6,6-2H2]glucose infusion was used to investigate tissue-specific carbohydrate utilization. RESULTS The 24-h energy balance was -400 kcal (normalized 95% CI: -230, -571 kcal) for the FE trial; this was significantly lower than both the BR trial (492 kcal; normalized 95% CI: 332, 652 kcal) and the BE trial (7 kcal; normalized 95% CI: -153, 177 kcal; both P < 0.01 compared with FE). Plasma glucose utilization in FE (mainly representing liver glucose utilization) was positively correlated with energy intake compensation at lunch (r = 0.62, P = 0.03), suggesting liver carbohydrate plays a role in postexercise energy-balance regulation. CONCLUSIONS Neither exercise energy expenditure nor restricted energy intake via breakfast omission were completely compensated for postexercise. In healthy men, pre-exercise breakfast omission creates a more negative daily energy balance and could therefore be a useful strategy to induce a short-term energy deficit. This trial was registered at clinicaltrials.gov as NCT02258399.
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Affiliation(s)
| | | | | | | | | | | | | | - Gareth A Wallis
- School of Sport, Exercise and Rehabilitation, University of Birmingham, Birmingham, UK
| | - D Lee Hamilton
- Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, UK,School of Exercise and Nutrition Sciences, Faculty of Health, Deakin University, Geelong Waurn Ponds, Australia
| | - Emma J Stevenson
- Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
| | - Kevin D Tipton
- Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, UK
| | - Javier T Gonzalez
- Department for Health, University of Bath, Bath, UK,Address correspondence to JTG (e-mail: )
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28
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Griffiths A, Deighton K, Shannon OM, Matu J, King R, O'Hara JP. Substrate oxidation and the influence of breakfast in normobaric hypoxia and normoxia. Eur J Appl Physiol 2019; 119:1909-1920. [PMID: 31270614 PMCID: PMC6694084 DOI: 10.1007/s00421-019-04179-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/17/2019] [Indexed: 11/02/2022]
Abstract
PURPOSE Previous research has reported inconsistent effects of hypoxia on substrate oxidation, which may be due to differences in methodological design, such as pre-exercise nutritional status and exercise intensity. This study investigated the effect of breakfast consumption on substrate oxidation at varying exercise intensities in normobaric hypoxia compared with normoxia. METHODS Twelve participants rested and exercised once after breakfast consumption and once after omission in normobaric hypoxia (4300 m: FiO2 ~ 11.7%) and normoxia. Exercise consisted of walking for 20 min at 40%, 50% and 60% of altitude-specific [Formula: see text]O2max at 10-15% gradient with a 10 kg backpack. Indirect calorimetry was used to calculate carbohydrate and fat oxidation. RESULTS The relative contribution of carbohydrate oxidation to energy expenditure was significantly reduced in hypoxia compared with normoxia during exercise after breakfast omission at 40% (22.4 ± 17.5% vs. 38.5 ± 15.5%, p = 0.03) and 60% [Formula: see text]O2max (35.4 ± 12.4 vs. 50.1 ± 17.6%, p = 0.03), with a trend observed at 50% [Formula: see text]O2max (23.6 ± 17.9% vs. 38.1 ± 17.0%, p = 0.07). The relative contribution of carbohydrate oxidation to energy expenditure was not significantly different in hypoxia compared with normoxia during exercise after breakfast consumption at 40% (42.4 ± 15.7% vs. 48.5 ± 13.3%, p = 0.99), 50% (43.1 ± 11.7% vs. 47.1 ± 14.0%, p = 0.99) and 60% [Formula: see text]O2max (54.6 ± 17.8% vs. 55.1 ± 15.0%, p = 0.99). CONCLUSIONS Relative carbohydrate oxidation was significantly reduced in hypoxia compared with normoxia during exercise after breakfast omission but not during exercise after breakfast consumption. This response remained consistent with increasing exercise intensities. These findings may explain some of the disparity in the literature.
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Affiliation(s)
- Alex Griffiths
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
| | - Kevin Deighton
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Oliver M Shannon
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.,Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Leech Building, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Jamie Matu
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Roderick King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
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29
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Performance Effects of Carbohydrate Ingestion Between Bouts of Intense Aerobic Interval Exercise. Int J Sports Physiol Perform 2019; 15:262-267. [PMID: 31188694 DOI: 10.1123/ijspp.2019-0239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE This study tested whether CHO intake during a 2-h rest between exercise bouts improved performance in the subsequent bout. METHODS In a randomized, single-blinded, crossover design, 10 recreationally-active participants (23 ± 4 yr, 70.8 ± 6.6 kg, VO2peak:47.0 ± 5.4 mL O2·min-1·kg body mass-1) arrived at the lab post-prandial and completed 2 exercise bouts separated by 2-h rest. Bouts included 5 x 4-min intervals at ~80% VO2peak separated by 2-min at ~40% VO2peak and ended with an endurance trial (ET) to voluntary exhaustion at ~90% VO2peak. During intervals 1 and 4 in each bout expired gases were collected and O2 deficit was estimated. Immediately following bout-1, either a CHO (1.2 g CHO·kg body mass-1) or placebo (PL) solution was consumed. RESULTS ET duration decreased in bout-2 vs. 1 in both conditions (P<0.01) but was ~35% longer in bout-2 with CHO vs. PL (Interaction, P=0.03; post-hoc, P=0.03). VO2 increased during interval 4 vs. 1 in both bouts (P<0.01) but was unaffected by CHO (P≥0.58). O2 deficit was unaffected by CHO (P=0.93), bout or interval (P≥0.15). Perceived exertion was higher in bout-2 vs. 1 (P<0.001) and reduced in intervals 2 and 4 in CHO (P≤0.01). CONCLUSIONS When rest between training sessions is 2 hours, athletes may improve subsequent performance by consuming CHO during recovery. Supported by NSERC, Canada.
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30
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Piton G, Le Gouge A, Brulé N, Cypriani B, Lacherade JC, Nseir S, Mira JP, Mercier E, Sirodot M, Rigaud JP, Malaquin S, Soum E, Djibre M, Gaudry S, Thévenin D, Reignier J. Impact of the route of nutrition on gut mucosa in ventilated adults with shock: an ancillary of the NUTRIREA-2 trial. Intensive Care Med 2019; 45:948-956. [PMID: 31143999 DOI: 10.1007/s00134-019-05649-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 05/15/2019] [Indexed: 12/18/2022]
Abstract
PURPOSE The effects of the route of nutrition on the gut mucosa of patients with shock are unclear. Plasma citrulline concentration is a marker of enterocyte mass, and plasma intestinal fatty acid binding protein (I-FABP) concentration is a marker of enterocyte damage. We aimed to study the effect of the route of nutrition on plasma citrulline concentration measured at day 3 of nutrition. MATERIALS AND METHODS Ancillary study of the NUTRIREA-2 trial. Ventilated adults with shock were randomly assigned to receive enteral or parenteral nutrition. Enterocyte biomarkers were measured at baseline, day 3, and day 8 of nutrition. RESULT A total of 165 patients from 13 French ICUs were included in the study: 85 patients in the enteral group and 80 patients in the parenteral group. At baseline, plasma citrulline was low without difference between groups (12.2 µmol L-1 vs 13.3 µmol L-1). At day 3, plasma citrulline concentration was higher in the enteral group than in the parenteral group (18.7 µmol L-1 vs 15.3 µmol L-1, p = 0.01). Plasma I-FABP concentration was increased at baseline, without difference between groups (245 pg mL-1 vs 244 pg mL-1). Plasma I-FABP concentration was higher in the enteral group than in the parenteral group at day 3 and day 8 (158 pg mL-1 vs 50 pg mL-1, p = 0.005 and 225 pg mL-1 vs 50 pg mL-1, p = 0.03). CONCLUSION Plasma citrulline concentration was higher after 3 days of enteral nutrition than after 3 days of parenteral nutrition. This result raises the question of the possibility that enteral nutrition is associated with a more rapid restoration of enterocyte mass than parenteral nutrition.
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Affiliation(s)
- Gaël Piton
- Medical Intensive Care Unit, CHRU Besançon, Besançon, France. .,EA3920, Université de Franche Comté, Besançon, France. .,Service de Réanimation Médicale, CHRU de Besançon, Boulevard Fleming, 25030, Besançon, France.
| | - Amélie Le Gouge
- Inserm CIC 1415, Tours, France.,Université de Tours, Tours, France.,CHU Tours, Tours, France
| | - Noelle Brulé
- Médecine Intensive Réanimation, CHU de Nantes, Nantes, France
| | - Benoit Cypriani
- Biochemistry Unit, Besançon University Hospital, Besançon, France
| | - Jean-Claude Lacherade
- Médecine Intensive Réanimation, Centre Hospitalier Départemental de la Vendée, La Roche sur Yon, France
| | - Saad Nseir
- Medical Intensive Care Unit, CHU Lille, Lille, France.,Medicine School, Université Lille, Lille, France
| | - Jean-Paul Mira
- Medical Intensive Care Unit, Cochin University Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Emmanuelle Mercier
- Médecine Intensive Réanimation, Hôpital Bretonneau, CHU Tours, Tours, France
| | - Michel Sirodot
- Medical-Surgical Intensive Care Unit, Centre Hospitalier Annecy-Genevois, Metz-Tessy, Pringy, France
| | | | | | - Edouard Soum
- Medical Intensive Care Unit, Hôpital Gabriel Montpied, CHU de Clermont-Ferrand, Clermont-Ferrand, France
| | - Michel Djibre
- Medical-Surgical Intensive Care Unit, Tenon University Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Stéphane Gaudry
- Medical-Surgical Intensive Care Unit, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris (AP-HP), Colombes, France.,Université Paris Diderot, ECEVE, UMR 1123, Sorbonne Paris Cité, Paris, France
| | - Didier Thévenin
- Medical-Surgical Intensive Care Unit, Centre Hospitalier Docteur Schaffner, Lens, France
| | - Jean Reignier
- Médecine Intensive Réanimation, CHU de Nantes, Nantes, France.,Université de Nantes, Nantes, France
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Griffiths A, Shannon OM, Matu J, King R, Deighton K, O'Hara JP. The effects of environmental hypoxia on substrate utilisation during exercise: a meta-analysis. J Int Soc Sports Nutr 2019; 16:10. [PMID: 30813949 PMCID: PMC6391781 DOI: 10.1186/s12970-019-0277-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/13/2019] [Indexed: 02/08/2023] Open
Abstract
Background A better understanding of hypoxia-induced changes in substrate utilisation can facilitate the development of nutritional strategies for mountaineers, military personnel and athletes during exposure to altitude. However, reported metabolic responses are currently divergent. As such, this systematic review and meta-analysis aims to determine the changes in substrate utilisation during exercise in hypoxia compared with normoxia and identify study characteristics responsible for the heterogeneity in findings. Methods A total of six databases (PubMed, the Cochrane Library, MEDLINE, SPORTDiscus, PsychINFO, and CINAHL via EBSCOhost) were searched for published original studies, conference proceedings, abstracts, dissertations and theses. Studies were included if they evaluated respiratory exchange ratio (RER) and/or carbohydrate or fat oxidation during steady state exercise matched for relative intensities in normoxia and hypoxia (normobaric or hypobaric). A random-effects meta-analysis was performed on outcome variables. Meta-regression analysis was performed to investigate potential sources of heterogeneity. Results In total, 18 studies were included in the meta-analysis. There was no significant change in RER during exercise matched for relative exercise intensities in hypoxia, compared with normoxia (mean difference: 0.01, 95% CI: -0.02 to 0.05; n = 31, p = 0.45). Meta-regression analysis suggests that consumption of a pre-exercise meal (p < 0.01) and a higher exercise intensity (p = 0.04) when exposed to hypoxia may increase carbohydrate oxidation compared with normoxia. Conclusions Exposure to hypoxia did not induce a consistent change in the relative contribution of carbohydrate or fat to the total energy yield during exercise matched for relative intensities, compared with normoxia. The direction of these responses appears to be mediated by the consumption of a pre-exercise meal and exercise intensity. Electronic supplementary material The online version of this article (10.1186/s12970-019-0277-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alex Griffiths
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
| | - Oliver M Shannon
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.,Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Leech Building, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Jamie Matu
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.,Leeds Institute of Rheumatic and Musculoskeletal Medicine, 2nd floor Chapel Allerton Hospital, Chapeltown Road, Leeds, LS7 4SA, UK
| | - Roderick King
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Kevin Deighton
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - John P O'Hara
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
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32
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Stocks B, Dent JR, Ogden HB, Zemp M, Philp A. Postexercise skeletal muscle signaling responses to moderate- to high-intensity steady-state exercise in the fed or fasted state. Am J Physiol Endocrinol Metab 2019; 316:E230-E238. [PMID: 30512989 DOI: 10.1152/ajpendo.00311.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Exercise performed in the fasted state acutely increases fatty acid availability and utilization. Furthermore, activation of energy-sensing pathways and fatty acid metabolic genes can be augmented by fasting and fasted exercise. However, whether a similar effect occurs at higher exercise intensities remains poorly understood. This study aimed to assess the effect of fed and fasted exercise upon postexercise signaling and mRNA responses during moderate- to high-intensity steady-state exercise. Eight male participants [age: 25 (SD 2) yr, V̇o2peak: 47.9 (SD 3.8) ml·kg-1·min-1] performed 1 h of cycling at 70% Wmax in the fasted (FAST) state or 2 h following ingestion of a carbohydrate-rich mixed-macronutrient breakfast (FED). Muscle biopsies were collected pre-, immediately, and 3 h postexercise from the medial vastus lateralis, while venous blood samples were collected throughout the trial. Plasma, nonesterified fatty acid, and glycerol concentrations were elevated during FAST compared with FED, although substrate utilization during exercise was similar. AMPKThr172 phosphorylation was ~2.5-fold elevated postexercise in both trials and was significantly augmented by ~30% during FAST. CREBSer133 phosphorylation was elevated approximately twofold during FAST, although CREBSer133 phosphorylation acutely decreased by ~50% immediately postexercise. mRNA expression of PDK4 was approximately three- to fourfold augmented by exercise and approximately twofold elevated throughout FAST, while expression of PPARGC1A mRNA was similarly activated (~10-fold) by exercise in both FED and FAST. In summary, performing moderate- to high-intensity steady-state exercise in the fasted state increases systemic lipid availability, elevates phosphorylation of AMPKThr172 and CREBSer133, and augments PDK4 mRNA expression without corresponding increases in whole body fat oxidation and the mRNA expression of PPARGC1A.
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Affiliation(s)
- Ben Stocks
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham , Birmingham , United Kingdom
| | - Jessica R Dent
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham , Birmingham , United Kingdom
| | - Henry B Ogden
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham , Birmingham , United Kingdom
| | - Martina Zemp
- Institute of Human Movement Sciences and Sport, ETH Zurich, Zurich , Switzerland
| | - Andrew Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham , Birmingham , United Kingdom
- Mitochondrial Metabolism and Ageing Laboratory, Diabetes and Metabolism Division, Garvan Institute of Medical Research , Darlinghurst , Australia
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Abstract
The objective of this review paper is to evaluate the impact of undertaking aerobic exercise in the overnight-fasted v. fed-state, in the context of optimising the health benefits of regular physical activity. Conducting a single bout of aerobic exercise in the overnight-fasted v. fed-state can differentially modulate the aspects of metabolism and energy balance behaviours. This includes, but is not limited to, increased utilisation of fat as a fuel source, improved plasma lipid profiles, enhanced activation of molecular signalling pathways related to fuel metabolism in skeletal muscle and adipose tissue, and reductions in energy intake over the course of a day. The impact of a single bout of overnight-fasted v. fed-state exercise on short-term glycaemic control is variable, being affected by the experimental conditions, the time frame of measurement and possibly the subject population studied. The health response to undertaking overnight-fasted v. fed-state exercise for a sustained period of time in the form of exercise training is less clear, due to a limited number of studies. From the extant literature, there is evidence that overnight-fasted exercise in young, healthy men can enhance training-induced adaptations in skeletal muscle metabolic profile, and mitigate against the negative consequences of short-term excess energy intake on glucose tolerance compared with exercising in the fed-state. Nonetheless, further long-term studies are required, particularly in populations at-risk or living with cardio-metabolic disease to elucidate if feeding status prior to exercise modulates metabolism or energy balance behaviours to an extent that could impact upon the health or therapeutic benefits of exercise.
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