Metabolic and Hemodynamic Responses to Exercise in Subcutaneous Adipose Tissue and Skeletal Muscle

Boschmann, Michael; Rosenbaum, Milton; Rl, Leibel; Segal, Karen R.

doi:10.1055/s-2002-35527

Cited by 34 publications

(42 citation statements)

References 28 publications

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“…However, the insertion of the probes resulted in muscular myoclonia suggesting that the probes were definitely intramuscular. Moreover, when examining the changes of LossEth between rest and exercise, we found a similar increase to that previously reported and much higher than that found in subcutaneous tissue (Boschmann et al 2002). Therefore, we feel confident with the positioning of the probe in the muscle.…”

Section: Discussionsupporting

confidence: 89%

Validation of a new calibration method for human muscle microdialysis at rest and during exercise

et al. 2004

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Microdialysis presents the unique possibility to measure metabolite concentrations in human interstitial fluid. During exercise, the recovery of these metabolites should be precisely monitored since it is known to increase greatly with muscle blood flow. The loss of ethanol, perfused at low concentration, can be accurately measured and reflects the changes in dialysis conditions. We evaluated whether using the relationship determined in resting metabolic conditions between the loss of ethanol, as reference substance, and the recovery for lactate or glucose would allow us to calculate precisely the concentration of these substances and their variations during exercise. Using the new catheter calibration method (slope method), the error of estimation of lactate and glucose in vitro was limited to -0.6 (5.8)% and -0.7 (6.2)%, respectively. In resting human muscle, the slope method proved to be as accurate as an established calibration technique ("no net flux method") to evaluate interstitial lactate concentration [1.82 (0.58) vs 1.83 (0.47) mM, respectively]. During dynamic knee-extension exercise or light neuromuscular electrical stimulation, the estimated interstitial lactate and glucose concentrations varied differently, but their time course changes remained consistent with their respective plasma values. We conclude that, after an initial calibration step, the slope method allows accurate measurement of interstitial muscle metabolites and it could be used to monitor rapid metabolic changes during exercise.

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Section: Discussionsupporting

confidence: 89%

Validation of a new calibration method for human muscle microdialysis at rest and during exercise

et al. 2004

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“…Endurance exercise leads to a reduction of adipose subcutaneous tissue in laboratory (Boschmann et al 2002) and field studies (Helge et al 2003;Höchli et al 1995;Raschka et al 1991;Raschka and Plath, 1992). Ultra-endurance races are a good opportunity to study the decrease of adipose subcutaneous tissue in long-lasting endurance performance.…”

Section: Introductionmentioning

confidence: 99%

Body Composition, Energy, and Fluid Turnover in a Five-Day Multistage Ultratriathlon: A Case Study

Knechtle¹,

Knechtle²,

Andonie³

et al. 2009

Research in Sports Medicine

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A multistage ultraendurance triathlon over five times the Ironman distance within five consecutive days leads in one ultraendurance triathlete to minimal changes in body mass (BM; -0.3 kg), fat mass (FM; -1.9 kg), skeletal muscle mass (SM; no change), and total body water (TBW; +1.5 l). This might be explained by the continuously slower race times throughout the race every day and the positive energy balance (8,095 kcal), although he suffered an average energy deficit of -1,848 kcal per Ironman distance. The increase of TBW might be explained by the increase of plasma volume (PV) in the first 3 days. The increase of PV and TBW could be a result of an increase of sodium, which was increased after every stage. We presume that this could be the result of an increased activity of aldosterone.1 Body composition, energy and fluid turnover in a five day multi-stage ultra-triathlon: A case study Running title: Body composition in multi-stage ultra-endurance 2 Abstract A multi-stage ultra-endurance triathlon over five times the Ironman distance within five consecutive days leads in one ultra-endurance triathlete to minimal changes in body mass (-0.3 kg), fat mass (-1.9 kg), skeletal muscle mass (no change) and total body water (+ 1.5 l). This might be explained with the continuously slower race times throughout the race every day and the positive energy balance (8,095 kcal) although he suffered an average energy deficit of -1,848 kcal per Ironman distance. The increase of total body water might be explained by the increase of plasma volume in the first three days. The increase of plasma volume and total body water could be a result of an increase of sodium, which was increased after every stage. We presume that this could be the result of an increased activity of aldosterone.

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“…Because we did not observe changes in blood triacylglyceride balances in the legs before or after training (16), our release data most likely reflect adipose tissue or skeletal muscle lipolysis. In support of this assertion, thigh subcutaneous adipose tissue lipolysis (inferred from microdialysis measurements) can be increased by exercise (2,31), and, as noted above, skeletal muscle triacylglyceride turnover (which could lead to muscle glycerol release) has been demonstrated during exercise (8). Nonetheless, it is clear that during exercise, the substantial and simultaneous uptake of glycerol into leg muscle and release of glycerol from the leg were balanced, such that net leg glycerol balance did not differ significantly from zero during exercise.…”

Section: Discussionmentioning

confidence: 83%

Substantial working muscle glycerol turnover during two-legged cycle ergometry

Wallis

Friedlander²,

Jacobs³

et al. 2007

American Journal of Physiology-Endocrinology and Metabolism

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Wolfel EE, Lopaschuk GD, Brooks GA. Substantial working muscle glycerol turnover during two-legged cycle ergometry. Am J Physiol Endocrinol Metab 293: E950-E957, 2007. First published July 10, 2007; doi:10.1152/ajpendo.00099.2007.-We combined tracer and arteriovenous (a-v) balance techniques to evaluate the effects of exercise and endurance training on leg triacylglyceride turnover as assessed by glycerol exchange. Measurements on an exercising leg were taken to be a surrogate for working skeletal muscle. Eight men completed 9 wk of endurance training [5 days/wk, 1 h/day, 75% peak oxygen consumption (V O2peak)], with leg glycerol turnover determined during two pretraining trials [45 and 65% V O2peak (45% Pre and 65% Pre, respectively)] and two posttraining trials [65% of pretraining V O2peak (ABT) and 65% of posttraining V O2peak (RLT)] using [ 2 H5]glycerol infusion, femoral a-v sampling, and measurement of leg blood flow. Endurance training increased V O2peak by 15% (45.2 Ϯ 1.2 to 52.0 Ϯ 1.8 ml ⅐ kg Ϫ1 ⅐ min Ϫ1 , P Ͻ 0.05). At rest, there was tracer-measured leg glycerol uptake (41 Ϯ 8 and 52 Ϯ 15 mol/min for pre-and posttraining, respectively) even in the presence of small, but significant, net leg glycerol release (Ϫ68 Ϯ 19 and Ϫ50 Ϯ 13 mol/min, respectively; P Ͻ 0.05 vs. zero). Furthermore, while there was no significant net leg glycerol exchange during any of the exercise bouts, there was substantial tracer-measured leg glycerol turnover during exercise (i.e., simultaneous leg muscle uptake and leg release) (uptake, release: 45% Pre, 194 Ϯ 41, 214 Ϯ 33; 65% Pre, 217 Ϯ 79, 201 Ϯ 84; ABT, 275 Ϯ 76, 312 Ϯ 87; RLT, 282 Ϯ 83, 424 Ϯ 75 mol/min; all P Ͻ 0.05 vs. corresponding rest). Leg glycerol turnover was unaffected by exercise intensity or endurance training. In summary, simultaneous leg glycerol uptake and release (indicative of leg triacylglyceride turnover) occurs despite small or negligible net leg glycerol exchange, and furthermore, leg glycerol turnover can be substantially augmented during exercise. exercise; crossover concept; stable isotopes; lipid metabolism WHOLE BODY LIPOLYTIC RATE is typically assessed using the isotope tracer dilution technique (35), and there has been extensive application of this approach to study the response of systemic glycerol turnover to exercise. Systemic glycerol turnover has been shown to increase several-fold in response to exercise (6,25,28), although the effects of whole body exercise on glycerol metabolism in different body segments and particularly in the working limbs and muscles of those limbs have received limited attention. In fact, our understanding of the response of whole working limb glycerol metabolism to exercise (e.g., the legs during 2-legged cycle ergometry) is largely limited to the interpretation of net limb glycerol balance data (i.e., arteriovenous concentration difference ϫ blood flow) (1, 13). Previously, we reported essentially zero net leg glycerol balance during two-legged cycle ergometry regardless of exercise intensity or endurance trainin...

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Metabolic and Hemodynamic Responses to Exercise in Subcutaneous Adipose Tissue and Skeletal Muscle

Cited by 34 publications

References 28 publications

Validation of a new calibration method for human muscle microdialysis at rest and during exercise

Validation of a new calibration method for human muscle microdialysis at rest and during exercise

Body Composition, Energy, and Fluid Turnover in a Five-Day Multistage Ultratriathlon: A Case Study

Substantial working muscle glycerol turnover during two-legged cycle ergometry

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