Post-exercise Metabolism Research Articles

Low-Load and High-Load Resistance Exercise Completed to Volitional Fatigue Induce Increases in Postexercise Metabolic Responses With More Prolonged Responses With the Low-Load Protocol.

Grisebach, D, Bornath, DPD, McCarthy, SF, Jarosz, C, and Hazell, TJ. Low-load and high-load resistance exercise completed to volitional fatigue induce increases in post-exercise metabolic responses with more prolonged responses with the low-load protocol. J Strength Cond Res 38(8): 1386-1393, 2024-Comparisons of high-load with low-load resistance training (RT) exercise have demonstrated no differences in postexercise metabolism when volume is matched. This important limitation of matching or equating volume diminishes benefits of the low-load RT protocol. Therefore, the purpose of this study was to determine the effects of acute low-load high volume and high-load low volume RT protocols completed to volitional fatigue on postexercise metabolism. Eleven recreationally active resistance-trained male subjects (24 ± 2 years; BMI: 25.3 ± 1.5 kg·m -2 ) completed 3 experimental sessions: (a) no-exercise control (CTRL); (b) RT at 30% 1 repetition maximum (1RM; 30% 1RM); and (c) RT at 90% 1RM (90% 1RM) with oxygen consumption (V̇ o2 ) measurements 2 hours postexercise. The RT sessions consisted of 3 sets of back squats, bench press, straight-leg deadlift, military press, and bent-over rows to volitional fatigue completed sequentially with 90 seconds of rest between sets and exercises. Changes were considered important if p < 0.100 with a ≥medium effect size. V̇ o2 1 hour postexercise was elevated following 30% 1RM (25%; p = 0.003, d = 1.40) and 90% 1RM (14%; p = 0.010, d = 1.15) vs. CTRL and remained elevated 2 hours postexercise following 30% 1RM (16%; p = 0.010, d = 1.15) vs. CTRL. Total O 2 consumed postexercise increased following 30% 1RM and 90% 1RM (∼17%; p < 0.044, d > 0.91) vs. CTRL. Fat oxidation was elevated 1 hour postexercise following 30% 1RM and 90% 1RM (∼155%; p < 0.001, d > 2.97) and remained elevated 2 hours postexercise following 30% 1RM compared with CTRL and 90% 1RM (∼69%; p < 0.030, d > 1.03). These data demonstrate beneficial changes to postexercise metabolism following high- and low-load RT sessions, with more prolonged effects following the low-load RT protocol completed to volitional fatigue.

Metabolic Effects of Reduced Volume Sprint Interval Training During and Postexercise.

Abstract McCarthy, SF, McKie, GL, Howe, GJ, Vanderheyden, LW, and Hazell, TJ. Metabolic effects of reduced volume sprint interval training during and postexercise. J Strength Cond Res 38(5): 891–897, 2024—It is unclear what dose of sprint-interval training exercise (exercise volume) is required to derive beneficial metabolic effects during and postexercise. Therefore, we examined how reducing the volume of sprint interval training (SIT) from 2 minutes of “all-out” efforts (8 bouts) to 1.5 minutes (6 bouts) and 1 minute (4 bouts) affected during and postexercise metabolism. Fourteen recreationally active males (age: 25 ± 3 years; body mass index: 25.1 ± 3.1 kg·m−2) had gas exchange measured during and following (3 h) 4 experimental sessions: (a) no-exercise control (CTRL), (b) 8 × 15 SIT (2 minutes exercise), (c) 6 × 15 minutes SIT (1.5 minutes exercise), and (d) 4 × 15 SIT (1 minute exercise). All SIT protocols were 15 seconds “all-out” running efforts with 2 minutes recovery (4, 6, or 8 bouts). Changes were considered important if p &lt; 0.100 and the effect size was ≥medium. During exercise, oxygen consumption (V̇o 2; L) was different between protocols (p &lt; 0.001, d &gt; 2.98) and greater than CTRL (p &lt; 0.001, d &gt; 2.12); however, the rate of O2 consumption (L·min−1) was similar between protocols (p = 0.479, = 0.055). Total V̇o 2 (L) postexercise was elevated following all conditions compared with CTRL (p &lt; 0.003, d &gt; 1.25). Overall session V̇o 2 was different in each condition (p &lt; 0.001, d &gt; 1.89). Fat oxidation was elevated postexercise following all SIT protocols compared with CTRL (p &lt; 0.017, d &gt; 0.98) with no differences between protocols (p &gt; 0.566, d &lt; 0.48). Our results suggest reducing the number of all-out 15 seconds bouts during a SIT session from 8 to 6 or 4 had no differential effects on postexercise metabolism and differences during exercise were due to the longer duration of exercise.

Metabolic plasticity and obesity-associated changes in diurnal postexercise metabolism in mice

BackgroundCircadian disruption is widespread and increases the risk of obesity. Timing of therapeutic interventions may promote coherent and efficient gating of metabolic processes and restore energy homeostasis. AimTo characterize the diurnal postexercise metabolic state in mice and to identify the influence of diet-induced obesity on identified outcomes. MethodsC57BL6/NTac male mice (6 wks of age) were fed a standard chow or high-fat diet for 5 weeks. At week 5, mice were subjected to a 60-min (16 m/min, 5 % incline) running bout (or sham) during the early rest (day) or early active (night) phase. Tissue and serum samples were collected immediately post-exercise (n = 6/group). In vivo glucose oxidation was measured after oral administration of 13C-glucose via 13CO2 exhalation analysis in metabolic cages. Basal and isoproterenol-stimulated adipose tissue lipolysis was assessed ex vivo for 1 h following exercise. ResultsLean mice displayed exercise-timing-specific plasticity in metabolic outcomes, including phase-specificity in systemic glucose metabolism and adipose-tissue-autonomous lipolytic activity depending on time of day. Conversely, obesity impaired temporal postexercise differences in whole-body glucose oxidation, as well as the phase- and exercise-mediated induction of lipolysis in isolated adipose tissue. This obesity-induced alteration in diurnal metabolism, as well as the indistinct response to exercise, was observed concomitant with disruption of core clock gene expression in peripheral tissues. ConclusionsOverall, high-fat fed obese mice exhibit metabolic inflexibility, which is also evident in the diurnal exercise response. Our study provides physiological insight into exercise timing-dependent aspects in the dynamic regulation of metabolism and the influence of obesity on this biology.

Intense interval exercise induces greater changes in post-exercise metabolism compared to submaximal exercise in middle-aged adults.

High-intensity interval training (HIIT) and sprint interval training (SIT) consistently elevate post-exercise metabolism compared to moderate-intensity continuous training (MICT) in young adults (18-25years), however few studies have investigated this in middle-aged adults. To assess the effect of exercise intensity on post-exercise metabolism following submaximal, near-maximal, and supramaximal exercise protocols in middle-aged adults. 12 participants (8 females; age: 44 ± 10years; O2max: 35.73 ± 9.97mL·kg-1min-1) had their oxygen consumption ( O2) measured during and for 2h following 4 experimental sessions: (1) no-exercise control (CTRL); (2) MICT exercise (30min at 65% O2max); (3) HIIT exercise (10 × 1min at 90% maximum heart rate with 1min rest); and (4) modified-SIT exercise (8 × 15s "all-out" efforts with 2min rest). Between session differences for O2 and fat oxidation were compared. O2 consumed post-exercise was elevated during the 1st h and 2nd h following HIIT (15.9 ± 2.6, 14.7 ± 2.3L; P < 0.036, d > 0.98) and modified-SIT exercise (16.9 ± 3.3, 15.30 ± 3.4L; P < 0.041, d > 0.96) compared to CTRL (13.3 ± 1.9, 12.0 ± 2.5 L) while modified-SIT was also elevated vs HIIT in the 1st h (P < 0.041, d > 0.96). Total post-exercise O2 consumption was elevated following all exercise sessions (MICT: 27.7 ± 4.1, HIIT: 30.6 ± 4.8, SIT: 32.2 ± 6.6L; P < 0.027, d > 1.03) compared to CTRL (24.9 ± 4.1L). Modified-SIT exercise increased fat oxidation (0.103 ± 0.019gmin-1) compared to all sessions post-exercise (CTRL: 0.059 ± 0.025, MICT: 0.075 ± 0.022, HIIT: 0.081 ± 0.021g·min-1; P < 0.007, d > 1.30) and HIIT exercise increased compared to CTRL (P = 0.046, d = 0.87). Exercise intensity has an important effect on post-exercise metabolism in middle-aged adults.

Interval Exercise Induces Greater Changes In Post-exercise Metabolism Compared To Submaximal Exercise In Middle-aged Adults

Interval Exercise Induces Greater Changes In Post-exercise Metabolism Compared To Submaximal Exercise In Middle-aged Adults

Population variability in thermal performance of pre-spawning adult Chinook salmon.

Climate change is causing large declines in many Pacific salmon populations. In particular, warm rivers are associated with high levels of premature mortality in migrating adults. The Fraser River watershed in British Columbia, Canada, supports some of the largest Chinook salmon (Oncorhynchus tshawytscha) runs in the world. However, the Fraser River is warming at a rate that threatens these populations at critical freshwater life stages. A growing body of literature suggests salmonids are locally adapted to their thermal migratory experience, and thus, population-specific thermal performance information can aid in management decisions. We compared the thermal performance of pre-spawning adult Chinook salmon from two populations, a coastal fall-run from the Chilliwack River (125km cooler migration) and an interior summer-run from the Shuswap River (565km warmer migration). We acutely exposed fish to temperatures reflecting current (12°C, 18°C) and future projected temperatures (21°C, 24°C) in the Fraser River and assessed survival, aerobic capacity (resting and maximum metabolic rates, absolute aerobic scope (AAS), muscle and ventricle citrate synthase), anaerobic capacity (muscle and ventricle lactate dehydrogenase) and recovery capacity (post-exercise metabolism, blood physiology, tissue lactate). Chilliwack Chinook salmon performed worse at high temperatures, indicated by elevated mortality, reduced breadth in AAS, enhanced plasma lactate and potassium levels and elevated tissue lactate concentrations compared with Shuswap Chinook salmon. At water temperatures exceeding the upper pejus temperatures (Tpejus, defined here as 80% of maximum AAS) of Chilliwack (18.7°C) and Shuswap (20.2°C) Chinook salmon populations, physiological performance will decline and affect migration and survival to spawn. Our results reveal population differences in pre-spawning Chinook salmon performance across scales of biological organization at ecologically relevant temperatures. Given the rapid warming of rivers, we show that it is critical to consider the intra-specific variation in thermal physiology to assist in the conservation and management of Pacific salmon.

A Comparison Of High-intensity Interval Running And Tabata On Post-exercise Metabolism: A Pilot Analysis

PURPOSE: Compare the metabolic rate following: 1) no exercise (rest), 2) completion of high-intensity interval running (HIIR) and 3) completion of Tabata. METHODS: Recreationally active individuals (n = 7; 6F, 1 M; age = 22.2 ± 2.1 yrs; body mass = 64.2 ± 12.0 kg; body fat% = 26.2 ± 3.1) performed each of the 3 bouts on separate days with at least 7 days in between each bout. Rest consisted of sitting for 25 minutes. Tabata was performed for 25 minutes and involved performing repeated cycles of body calisthenics at maximal effort for 20 seconds followed with 10 seconds of rest. HIIR was performed for 25 minutes with repeated cycles of running for 20 seconds followed with 10 seconds of rest. Both Tabata and HIIR were set up to be performed at the same heart rate (HR). Ten minutes following the completion of each bout, the participants’ metabolic rate (MR) was assessed in 10-minute intervals over the next hour. The MR assessment included the participants’ average VO2 (l/min), respiratory exchange ratio (RER), fat oxidation (total grams), and total energy expenditure (TEE). Significant differences (p < .05) between the bouts were determined using a one-way, repeated measures ANOVA and Bonferroni post-hoc test. RESULTS: Average HR (bpm) during Tabata (174.9 ± 5.2) was significantly higher (p = .027, ES = 1.2) compared to HIIR (166.4 ± 9.3). Average VO2 was unchanged between bouts (p = .62). TEE was unchanged between bouts (p = .28). RER was significantly lower following both HIIR (.75 ± .04, p = .002, ES = -1.8) and Tabata (.71 ± .02, p = .001, ES = -2.5) compared to rest (.83 ± .05) and there was no significant difference between exercises (p = .084). Fat oxidation was significantly higher following both HIIR (5.7 ± 1.5, p = .001; ES = 1.4) and Tabata (6.9 ± 1.4, p = .0004; ES = 2.2) compared to rest (3.7 ± 1.5) and Tabata was significantly higher than HIIR (p = .035, ES = .83). CONCLUSION: Despite the significant differences in heart rate between HIIR and Tabata both exercise bouts elicited similar changes in post-exercise metabolism when compared to rest. Both HIIR and Tabata might be lifestyle practices that promote healthy weight management; however, the small sample size and short metabolic assessment period limits the application of our results. A larger sample size and an expanded assessment period could better clarify the effectiveness of these exercises.

Impact of slow versus rapid digesting carbohydrates on substrate oxidation in pre-pubertal children: A randomized crossover trial

Consumption of rapid digesting sugars by children are under increased scrutiny because of their contribution to unhealthy weight gain. Previous studies in adults and children have suggested that altering the blend of carbohydrates (CHOs) consumed may cause shifts in substrate utilization. The purpose of this study was to examine the effects of consuming a slow digesting carbohydrate (SDC) and rapid digesting carbohydrate (RDC) on CHO and fat oxidation, glucose, and insulin responses at rest, during exercise, and post-exercise rest in pre-pubescent children. A randomized, double-blind, crossover design was used. Nineteen pre-pubescent children (n=10 boys, n=9 girls, mean±standard error, age=9.84±0.37-yrs) participated. Visits to the laboratory began with a 30-min measurement of resting metabolism followed by consumption of either an RDC or SDC drink. Postprandial resting metabolism was recorded for 60-min, immediately followed by 60-min of submaximal cycling exercise while metabolism was recorded, which was immediately followed by another 60-min recording of post-exercise metabolism. Total CHO and fat oxidation, endogenous and exogenous CHO oxidation, blood glucose, and insulin were assessed. Total CHO oxidation rate (g∙min-1) was greater after the RDC drink at 60min (p=0.032). Endogenous CHO oxidation rate (g∙min-1) was greater after the SDC drink at 15min (p≤0.010). Cumulative endogenous CHO oxidation (g) was greater after the SDC drink at 45min (p=0.009). Endogenous CHO oxidation accounted for a greater proportion of substrate oxidation after the first 60-min rest period (p=0.028), while exogenous CHO oxidation accounted for a greater proportion of substrate oxidation for the RDC at all time points (p≤0.019). The present study provides novel data suggesting that an SDC promotes greater endogenous substrate utilization in pre-pubertal children, which may have beneficial health impacts on energy intake and carbohydrate regulation/metabolism during growth and development. NCT03185884, clinicaltrials.gov.

Exercise and GLUT4.

The glucose transporter GLUT4 is critical for skeletal muscle glucose uptake in response to insulin and muscle contraction/exercise. Exercise increases GLUT4 translocation to the sarcolemma and t-tubule and, over the longer term, total GLUT4 protein content. Here, we review key aspects of GLUT4 biology in relation to exercise, with a focus on exercise-induced GLUT4 translocation, postexercise metabolism and muscle insulin sensitivity, and exercise effects on GLUT4 expression.

Chronic Fatigue in a Mouse Model of Gulf War Illness

The Gulf War, a war fought in the deserts of Saudi Arabia, left a quarter of US troops debilitated with a set of symptoms known as Gulf War Illness (GWI). These include neurological impairments, gastrointestinal disturbances and chronic fatigue suggesting that gut‐brain interactions may be provoking metabolic dysfunction leading to chronic fatigue. This study was focused on establishing a mouse model of GWI to better understand the etiology and pathophysiology of chronic fatigue in GWI. This study tested the hypothesis that GWI mice exposed to GW agents (acetylcholinesterase inhibitor, pyridostigmine bromide (PB), the insecticide permethrin, and the insect repellant, N,N‐Diethyl‐meta‐toluomide (DEET), and restraint stress, would produce exercise intolerance and resting and post‐exercise metabolic dysfunction. To simulate the route/duration in troop exposure, adult male C57B16/N mice were given PB (13 mg/kg, oral gavage), permethrin (0.3 mg/kg, 70% ethanol, top) and DEET (40 mg/kg; 70% ethanol, top) daily for 5d/wk X 4 wk. Mice were also exposed to 5min restraint stress. Sham controls received saline gavage, topical alcohol and restraint stress. Testing was conducted 1wk after exposure (PT) and at 90d PT. Fasted mice were subjected to an insulin tolerance test (0.5U/kg Humulin N i.p.) and blood glucose measured subsequently. One week later, mice were subjected to a 5‐day exercise endurance (EE) test to test for fatigue. Specific criteria were established to confirm the determination of exhaustion. During optimization of the EE test (3d training, 2d testing), we found that motivating mice to run for over 20min was feasible without electric shock. On exercise endurance, GW exposure produced a decreased latency to fatigue relative to sham (p&lt;.05). GW mice showed exercise exhaustion relative to the sham controls immediately following post‐treatment (PT) (15.4 +/− 2.6 min), and at 90PT (8.7 +/− 1.3 min). Corresponding values for sham were (23.5 +/− 2.5 min), and (26.8 +/− 5.1 min), respectively. These mean values show a significantly lesser latency to exhaustion that persisted in for GW relative to sham. Metabolic measures taken immediately after EE showed incremental elevations in post‐exercise lactate levels in GW mice relative to their pre‐treatment control (p&lt;0.001 n=6–7/per group). In contrast, shams showed similar post‐exercise lactate elevations at pre‐treatment, PT and PT90. Mean (+/− sem) values were 6.1 +/− 0.38 mmol/dL pre‐treatment, 6.1 +/− 0.4 mmol/dL at PT and 6.8 +/− 1.8 mmol/dL at PT90. Insulin injection reduced average glycemia to a greater peak in sham than in GW, i.e., 64.1% vs 78% baseline (p&lt;.05, n=3–6/group) but the latter normalized at PT90. In combination, our results show that GW agents reduce time to exercise exhaustion, and produce abnormal post‐exercise metabolism and insulin insensitivity that may explain, in part, chronic fatigue in GWI.Support or Funding InformationAmerican Physiological Society (A.B.) and UC Minigrant (A.B. and J.T.)

The Effect of Vitamin D3 Supplementation on Hepcidin, Iron, and IL-6 Responses after a 100 km Ultra-Marathon.

Deficiencies in iron and vitamin D are frequently observed in athletes. Therefore, we examined whether different baseline vitamin D3 levels have any impact on post-exercise serum hepcidin, IL-6 and iron responses in ultra-marathon runners. In this randomized control trial, the subjects (20 male, amateur runners, mean age 40.75 ± 7.15 years) were divided into two groups: experimental (VD) and control (CON). The VD group received vitamin D3 (10,000 UI/day) and the CON group received a placebo for two weeks before the run. Venous blood samples were collected on three occasions—before the run, after the 100 km ultra-marathon and 12 h after the run—to measure iron metabolism indicators, hepcidin, and IL-6 concentration. After two weeks of supplementation, the intervention group demonstrated a higher level of serum 25(OH)D than the CON group (27.82 ± 5.8 ng/mL vs. 20.41 ± 4.67 ng/mL; p < 0.05). There were no differences between the groups before and after the run in the circulating hepcidin and IL-6 levels. The decrease in iron concentration immediately after the 100-km ultra-marathon was smaller in the VD group than CON (p < 0.05). These data show that various vitamin D3 status can affect the post-exercise metabolism of serum iron.

The effects of a pre-exercise meal on postexercise metabolism following a session of sprint interval training.

Sprint interval training (SIT) has demonstrated reductions in fat mass through potential alterations in postexercise metabolism. This study examined whether exercising in the fasted or fed state affects postexercise metabolism following acute SIT. Ten active males performed a bout of modified SIT (8 × 15-s sprints; 120 s recovery) in both a fasted (FAST) and fed (FED) state. Gas exchange was collected through 3 h postexercise, appetite perceptions were measured using a visual analog scale, and energy intake was recorded using dietary food logs. There was no difference in energy expenditure between conditions at any time point (p > 0.329) or in total session energy expenditure (FED: 514.8 ± 54.9 kcal, FAST: 504.0 ± 74.3 kcal; p = 0.982). Fat oxidation at 3 h after exercise was higher in FED (0.110 ± 0.04 g·min-1) versus FAST (0.069 ± 0.02 g·min-1; p = 0.013) though not different between conditions across time (p > 0.340) or in total postexercise fat oxidation (FED: 0.125 ± 0.04 g·min-1, FAST: 0.105 ± 0.02 g·min-1; p = 0.154). Appetite perceptions were lower in FED (-4815.0 ± 4098.7 mm) versus FAST (-707.5 ± 2010.4 mm, p = 0.022); however, energy intake did not differ between conditions (p = 0.429). These results demonstrate the fasted or fed state does not augment postexercise metabolism following acute SIT in a way that would favour fat loss following training. Novelty Energy expenditure was similar between conditions, while fat oxidation was significantly greater in FED at 3 h after exercise. Appetite perceptions were significantly lower in FED; however, energy intake was not different between conditions. Current findings suggest that performing SIT in the fed or fasted state would not affect fat loss following training.

EPOC

EPOC

Abstract P297: The Decline in Excess Post-Exercise Oxygen Consumption in Response to Dietary Nitrate is Eliminated With Concurrent Caffeine Intake

Introduction: Dietary nitrate has been shown to reduce submaximal oxygen consumption (VO 2 ), but less is known about the changes to excess post-exercise oxygen consumption (EPOC). In contrast, caffeine intake increases both exercise VO 2 and EPOC. Minimal research has reported on the combined effects of dietary nitrate/caffeine on exercise and post-exercise metabolism. Hypothesis: Caffeine will elevate exercise VO 2 and EPOC while dietary nitrate will attenuate the change in exercise VO 2 and EPOC. Methods: Seven healthy individuals participated in a double-blind, placebo controlled, crossover experiment. The first of five visits consisted of a maximal volume of oxygen consumption (VO 2max ) treadmill test. Prior to visit 2 - 5, participants consumed either a dietary nitrate (~12.4 mmol, NIT) or placebo nitrate supplement (PLN) combined with either a caffeine (3 mg/kg, CAF) or placebo caffeine (PLC) dose. Supplements were consumed on each of 4 days and the final doses of NIT or PLN and CAF or PLC were consumed 2.5 and 1-hr pre-exercise, respectively. Visits 2 - 5 consisted of a 30-min treadmill run at ~65% VO 2max followed by a 60-min seated recovery. During exercise, VO 2 and heart rate (HR) were measured continuously. During recovery, EPOC, HR, and peripheral (SBP/DBP) and aortic (cSBP/cDBP) blood pressure (via pulse wave analysis) were measured every 20 min. A linear mixed effects model analysis was performed to determine how each supplementation influenced each dependent variable. Treatments (NIT+CAF, CAF+PLN, NIT+PLC, PLN+PLC) and exercise timepoints (10, 20, 30 min) and recovery timepoints (20, 40, and 60 min post-exercise) served as fixed factors. If p&lt;0.05, p ost-hoc pairwise comparisons were performed. Results: Exercise VO 2 (p=0.450) and HR (p=0.622) were not different between treatments at any timepoint. However, EPOC was different between treatments (p&lt;0.001); NIT+PLC (4.0±0.6 ml/kg/min) was significantly lower than NIT+CAF (4.7±0.7 ml/kg/min, p&lt;0.001), CAF+PLN (4.6±0.7 ml/kg/min p=0.001), and PLN+PLC (4.7±0.8 ml/kg/min, p=0.001). Recovery PLN+PLC brachial SBP (117±8 mmHg) was significantly lower than NIT+CAF (122+7 mmHg, p=0.041), CAF+PLN (123+9 mmHg, p=0.003), and NIT+PLC (122+6 mmHg, p=0.013). Recovery treatment differences were found for cSBP (p=0.005); PLN+PLC (104+7 mmHg) was significantly lower than CAF+PLN (109+9 mmHg, p=0.001), and NIT+PLC (108+7 mmHg, p=0.013), but not NIT+CAF (107+7 mmHg, p=0.063). Recovery HR was elevated in PLN+PLC (91+14 bpm) compared to CAF+PLN (86+15 bpm, p=0.029) and NIT+PLC (86+12 bpm, p=0.002). Conclusion: A modest dose of caffeine (3 mg/kg) did not elevate exercise VO 2 or EPOC. Dietary nitrate reduced EPOC and elevated peripheral and aortic SBP in recovery. When caffeine was consumed alongside nitrate, the decrease in EPOC was abolished. Dietary nitrate alone may not be advised to those seeking additional workout caloric expenditure.

Effect Of Hypertriglyceridemia, Sugar Ingestion, And Exercise On Substrate Metabolism In Overweight And Obese Individuals

Carbohydrate ingestion may induce oxidative stress, inflammation, impaired insulin action, and altered substrate metabolism in a way that may counteract exercise-induced improvements in insulin sensitivity and metabolic flexibility. Benefits from exercise may differ in individuals with hypertriglyceredemia (hyperTG) compared to individuals with normal TG (normTG). HyperTG and sugar ingestion are linked to metabolic disease. PURPOSE: Compare the triglyceride (TG), glucose (Glu), insulin (Ins), and C-peptide (CPEP) responses between exercise bouts with sugar sweetened beverage consumption (EX+SSB) verses water only (EX+H2O). METHODS: Overweight and obese men (n=9) and women (n=11) (18-55 years) with fasting TG > (hyperTG) or < (normTG) 150 mg·dl-1 completed exercise. Each exercise was a 45-minute 10% grade uphill walk at 65% predicted VO2max. A standard, isocaloric diet to meet energy needs was given post exercise in the EX+H2O condition, but SSB replaced 2 g per kg lean mass of calories from food in the EX+SSB condition. An oral glucose tolerance test (OGTT) was completed the next day. Blood samples were collected pre-, 15, 30, 45, 60, 90, and 120-minutes post-OGTT for analysis of TG, Glu, Ins, and CPEP. Respiratory exchange ratio (RER) was measured collecting expired gas. RESULTS: The release of insulin, as measured by CPEP from 0 to 30 min of the OGTT, was lower (p=0.04) while fasting TG were higher (p=0.03) for the EX+SSB condition (mean±SEM; 178.5±22.5 mg·dl-1) compared to the EX+H2O condition (148.4±14.1 mg·dl-1). Glucose area under the curve was higher (p<0.001) in the normTG group compared to the hyperTG group in the EX+H2O condition. Resting RER was lower (p=0.05) in the normTG group (0.74±0.03 VCO2/VO2) compared to the hyperTG group (0.78±0.04 VCO2/VO2) in the EX+H2O condition. CONCLUSION: Consuming sugar with exercise was followed by higher fasting TG and lower Glu and Ins responses compared to EX+H2O during the OGTT. Fat utilization and metabolic flexibility during the OGTT were lower in the hyperTG group compared to the normTG group. Sugar consumption affected post-exercise metabolism more negatively in individuals with hyperTG. Supported by the Mountain West Clinical Translational Research - Infrastructure Network under a grant from NIGMS of the NIH under Award Number 1U54GM104944.

Effects of dietary macronutrient distribution on resting and post-exercise metabolism

Background Previous research has demonstrated that habitual dietary macronutrient distribution affects energy substrate utilization at rest and during exercise. The primary purpose of the current study was to examine the relationships between habitual baseline macronutrient intakes, expressed relative to bodyweight and percentage of total energy intake, and metabolism at rest and after exercise in women. Methods Twenty recreationally active women (Mean ± SD; Age 24.6 ± 3.9 yrs; Height 164.4 ± 6.6 cm; Weight 62.7 ± 6.6 kg; BF% 28.2 ± 4.8%) volunteered for the current study. Prior to metabolic testing, participants completed strength testing to determine their 1RM for six resistance exercises and completed a 3-day dietary log. Participants were provided with detailed instructions for accurately logging food intake and portion sizes, and instructed to record their regular food intake on two week days and one weekend day. Logs were analyzed using The Food Processor software (ESHA Research, Salem, OR, USA). Body composition was determined using dual-energy X-ray absorptiometry (DXA). Exercise was prescribed using baseline strength data and heart rate reserve calculations. Respiratory exchange ratio (RER) and resting energy expenditure (REE) were analyzed via indirect calorimetry (Parvomedics TrueOne 2400) before exercise (PRE), and during minutes 0-10 (IP), 25-35 (30min), and 50-60 (60min) post-exercise. Bivariate correlations and independent samples t-tests were completed using SPSS software (Version 19.0; IBM, Somers, NY, USA). Participants were stratified based on fat intake as a percentage of total caloric intake (high fat > 35% of total kcals, n=11; low fat 1.3 g/kg, n=11; low fat 35% of kilocalories from fat had a significantly higher bench press 1RM (p=0.048) and lower RER at 30min (p=0.033) and 60 min (p=0.033). Participants consuming > 1.3 g/kg of fat per day trended toward lower fat mass (p=0.09) and BF% (p=0.07). Conclusions Results indicate that baseline macronutrient distribution impacts post-exercise energy metabolism in women. Higher fat and lower CHO intake was associated with greater post-exercise REE and lower post-exercise RER, indicating greater fat utilization. Higher fat intakes may also influence resistance exercise performance and body composition; participants with higher fat intake had a greater bench press 1RM and trended towards lower indices of adiposity. These results suggest that the relative contributions of CHO and fat to total caloric intake may have significant implications for metabolism and body composition in women. Future research should evaluate the effects of modulating habitual macronutrient distribution to impart favorable effects on energy metabolism, body composition, and resistance exercise performance in women.

Metabonomic Response to Milk Proteins after a Single Bout of Heavy Resistance Exercise Elucidated by 1H Nuclear Magnetic Resonance Spectroscopy.

In the present study, proton NMR-based metabonomics was applied on femoral arterial plasma samples collected from young male subjects (milk protein n = 12 in a crossover design; non-caloric control n = 8) at different time intervals (70, 220, 370 min) after heavy resistance training and intake of either a whey or calcium caseinate protein drink in order to elucidate the impact of the protein source on post-exercise metabolism, which is important for muscle hypertrophy. Dynamic changes in the post-exercise plasma metabolite profile consisted of fluctuations in alanine, beta-hydroxybutyrate, branched amino acids, creatine, glucose, glutamine, glutamate, histidine, lipids and tyrosine. In comparison with the intake of a non-caloric drink, the same pattern of changes in low-molecular weight plasma metabolites was found for both whey and caseinate intake. However, the study indicated that whey and caseinate protein intake had a different impact on low-density and very-low-density lipoproteins present in the blood, which may be ascribed to different effects of the two protein sources on the mobilization of lipid resources during energy deficiency. In conclusion, no difference in the effects on low-molecular weight metabolites as measured by proton NMR-based metabonomics was found between the two protein sources.

Effect of Sprint Interval Exercise on Postexercise Metabolism and Blood Pressure in Adolescents

The current study examined the effect of sprint interval exercise on postexercise oxygen consumption, respiratory-exchange ratio (RER), substrate oxidation, and blood pressure in adolescents. Participants were 10 normal-weight healthy youth (7 female), age 15-18 years. After overnight fasts, each participant undertook 2 trials in a random balanced order: (a) two 30-s bouts of sprint interval exercise on a cycle ergometer and (b) rested in the laboratory for an equivalent period. Time-matched measurements of oxygen consumption, RER, and blood pressure were made 90 min into recovery, and substrate oxidation were calculated over the time period. Total postexercise oxygen uptake was significantly higher in the exercise than control trial over the 90 min (mean [SD]: control 20.0 [6.0] L, exercise 24.8 [9.8] L; p=.030). After exercise, RER was elevated above control but then fell rapidly and was lower than control 30-60 min postexercise, and fat oxidation was significantly higher in the exercise than control trial 45-60 min postexercise. However, total fat oxidation did not differ between trials (control 4.5 [2.5] g, exercise 5.4 [2.7] g; p=.247). Post hoc tests revealed that systolic blood pressure was significantly lower than in control at 90 min postexercise (control 104 [10] mm Hg, exercise 99 [10] mm Hg; p<.05). These data indicate that acute sprint interval exercise leads to short-term increases in oxygen uptake and reduced blood pressure in youth. The authors suggest that health outcomes in response to sprint interval training be examined in children.

Excess Postexercise Oxygen Consumption following Repeated Bouts of Anaerobic Exercise

PURPOSE: Repeated anaerobic bouts are often used in training and observed in athletic competition. To our knowledge, the elevation in postexercise metabolism following exercise bouts of this nature has not been observed. The purpose of this study was to investigate excess postexercise oxygen consumption (EPOC) following repeated, exhaustive bouts of anaerobic exercise. METHODS: Four recreationally trained male subjects (age: 24.5 + 2.7 yrs), performed nine bouts of anaerobic exercise using the Wingate 30-second cycle protocol. The bouts were separated into sets of three, with a two minute rest after the first and second bout and a six minute forty-five second rest after the third bout, resulting in total test duration of thirty minutes. Prior to the third bout of the third set, subjects were fitted with an appropriate gas collection mask, and calculation of EPOC began immediately following that bout. Subjects reported to the laboratory rested and following a 12-hour fast. Each test was preceded by a 30-minute baseline test to determine resting metabolic rate. Postexercise VO2 was continuously monitored until baseline was re-established. RESULTS: EPOC magnitude and duration from repeated, exhaustive anaerobic exercise bouts was 10.6 + 4.3 L O2 and 58.5 + 38.8 mins, respectively. Heart rate at the completion of recovery was significantly elevated above rest (66.3 + 8.1 bts*min-1 vs. 84.8 + 13.7 bts*min-1, p=.01). CONCLUSIONS: These data indicate that EPOC, and thus caloric expenditure, during recovery from repeated, exhaustive anaerobic bouts of exercise is a noteworthy contributor to total caloric burn following this type of exercise, and is substantially greater than previously published EPOC values reported from aerobic exercise protocols. Heart rate remained significantly elevated above resting levels even after postexercise oxygen consumption returned to baseline. Further investigation of postexercise biomarkers, such as catecholamines, is warranted.

The Influence of a Sports Drink on the Postexercise Metabolism of Elite Athletes as Investigated by NMR-Based Metabolomics

Objective: The aim of this study is to evaluate the systemic effects of an isotonic sports drink on the metabolic status of athletes of the Italian Olympic rowing team during recovery after strenuous and prolonged physical exercise by means of nuclear magnetic resonance (NMR)-based metabolomics analysis on plasma and urine.Methods: Forty-four male athletes of the Italian Olympic rowing team were enrolled in a double-blind crossover study. All subjects underwent 2 evaluations at 1-week intervals. The evaluation was performed on a rowing ergometer after strenuous physical exercise to produce a state of dehydration. Afterward, the athletes were rehydrated either with a green tea–based carbohydrate-hydroelectrolyte drink or with oligomineral water. Three blood samples were drawn for each subject: at rest, after the exercise, and following rehydratation, while 2 urine samples were collected: at rest and after the rehydratation period. Biofluid samples were analyzed by high-resolution 1H NMR metabolic profiling combined with multilevel simultaneous data-analysis (MSCA) and partial-least squares-discriminant analysis (PLS-DA).Results: The between-subject variations, as evaluated by MSCA, reflected the variations of lactate levels induced by the physical exercise. Analysis of the within-individual variance using multilevel PLS-DA models of plasma and urine metabolic profiles showed an effect of the green tea–based sports drink on glucose, citrate, and lactate levels in plasma and on acetone, 3-OH-butyrate, and lactate levels in urine. The increase of caffeine and hippuric acid levels in urine indicated the absorption of green tea extract components.Conclusions: NMR-based metabolomics allowed the complex effects of a green tea extract–based carbohydrate/hydroelectrolyte beverage on the energy metabolism of athletes during recovery by postexercise rehydration to be evaluated.